BERKELEY 

LIBRARY 

UNIVERSITY  OF 
CALIFORNIA 

EARTH 

SCIENCES 

LIBRARY 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 


PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


jsr* 


PRINCIPLES 


OF 


GEOLOGY. 


VIEW    OF    THF,    TEMPLE    OF    SERA.PIS    AT    PUZZUOLI    IN    1836. 


V      V 


PRINCIPLES 


OF 


GEOLOGY; 


OK, 


THE  MODERN  CHANGES  OF  THE  EARTH  AND  ITS 
INHABITANTS 

CONSIDERED    AS    ILLUSTRATIVE    OF    GEOLOGY. 


BY 

SIR  CHARLES  LYELL,  M.A.  F.R.& 

VICE-PRESIDENT   OF   THE    GEOLOGICAL   SOCillETSI    \1V   LONDON;     AUTHOR   OF  "A  MANUAL  Of 

ELEMENTARY    GEOLOGY,"    "TRAVELS   IN    NORTH   AMERICA,"    "A    SECOND 

VISIT   TO    THE   UNITED   STATES,"    ETC.    ETC. 


NEW  AND  ENTIRELY  REVISED  EDITION. 


Sllnatrafei  mitjr  3#np3,  'fykiu,  unit  IBnutats. 


NEW  YOKE: 
D.  APPLETON  &  CO.,  346  &  348  BROADWAY. 

* 
M.DCOO.L1V. 


"  Vere  scire  est  per  causas  scire." — BACON. 

"The  stony  rocks  are  not  primeval,  but  the  daughters  of  Time." — LINNAEUS, 
Syst.  Nat.  ed.  5,  Stockholm,  1748,  p.  219. 

"  Amid  all  the  revolutions  of  the  globe,  the  economy  of  nature  has  been  uniform, 
and  her  laws  are  the  only  things  that  have  resisted  the  general  movement.  The 
rivers  and  the  rocks,  the  seas  and  the  continents  have  been  changed  in  all  their 
parts  ;  but  the  laws  which  direct  those  changes,  and  the  rules  to  which  they  are 
subject,  have  remained  invariably  the  same." — PLAYFAIK,  Illustrations  of  the  Hut- 
tonian  Theory,  §  374. 

"  The  inhabitants  of  the  globe,  like  all  the  other  parts  of  it,  are  subject  to  change. 
It  is  not  only  the  individual  that  perishes,  but  whole  species. 

"  A  change  in  the  animal  kingdom  seems  to  be  a  part  of  the  order  of  Nature,  and 
is  visible  in  instances  to  which  human  power  cannot  have  extended." — PLAYFAIR, 
Illustrations  of  the  Huttonian  Theory,  §  413. 


PEEFACE  TO  THE  NINTH  EDITION. 


THE  Principles  of  Geology  in  the  first  five  editions  embraced 
not  only  a  view  of  the  modern  changes  of  the  earth  and  its 
inhabitants,  as  set  forth  in  the  present  work,  but  also  some 
account  of  those  monuments  of  analogous  changes  of  ancient 
date,  both  in  the  organic  and  inorganic  world,  which  it  is  the 
business  of  the  geologist  to  interpret.  The  subject  last  men- 
tioned, or  "  geology  proper,"  constituted  originally  a  fourth 
book,  now  omitted,  the  same  having  been  enlarged  into  a  sepa- 
rate treatise,  first  published  in  1838,  in  one  volume  12mo.,  and 
called  "  The  Elements  of  Geology,"  afterwards  recast  in  two 
volumes  12mo.  in  1842,  and  again  re-edited  under  the  title  of 
"Manual  of  Elementary  Geology,"  in  one  volume  8vo.  in  1851. 
The  "  Principles"  and  "  Manual"  thus  divided,  occupy,  with  one 
exception,  to  which  I  shall  presently  allude,  very  different 
ground.  The  "  Principles"  treat  of  such  portions  of  the  econ- 
omy of  existing  nature,  animate  and  inanimate,  as  are  illus- 
trative of  Geology,  so  as  to  comprise  an  investigation  of  the 
permanent  effects  of  causes  now  in  action,  which  may  serve  as 
records  to  after  ages  of  the  present  condition  of  the  globe  and 
its  inhabitants.  Such  effects  are  the  enduring  monuments  of 
the  ever-varying  state  of  the  physical  geography  of  the  globe, 
the  lasting  signs  of  its  destruction  and  renovation,  and  the 
memorials  of  the  equally  fluctuating  condition  of  the  organic 
world.  They  may  be  regarded,  in  short,  as  a  symbolical  lan- 
guage, in  which  the  earth's  autobiography  is  written. 

In  the  "  Manual  of  Elementary  Geology,"  on  the  other  hand, 
I  have  treated  briefly  of  the  component  materials  of  the  earth's 
crust,  their  arrangement  and  relative  position,  and  their  organic 
contents,  which,  when  deciphered  by  aid  of  the  key  supplied 


VI  PKEFACE. 

by  the  study  of  the  modern  changes  above  alluded  to,  reveal  to 
us  the  annals  of  a  grand  succession  of  past  events — a  series  of 
revolutions  which  the  solid  exterior  of  the  globe,  and  its  living 
inhabitants,  have  experienced  in  times  antecedent  to  the  creation 
of  man. 

In  thus  separating  the  two  works,  however,  I  have  retained 
in  the  "  Principles"  (book  i.)  the  discussion  of  some  matters 
which  might  fairly  be  regarded  as  common  to  both  treatises  ; 
as  for  example,  an  historical  sketch  of  the  early  progress  of 
geology,  followed  by  a  series  of  preliminary  essays  to  explain 
the  facts  and  arguments  which  lead  me  to  believe  that  the 
forces  now  operating  upon  and  beneath  the  earth's  surface  may 
be  the  same,  both  in  kind  and  degree,  as  those  which  at  remote 
epochs  have  worked  out  geological  changes.  (See  Analysis  of 
Contents  of  this  work,  p.  ix.) 

If  I  am  asked  whether  the  "  Principles"  or  the  "  Manual" 
should  be  studied  first,  I  feel  much  the  same  difficulty  in 
answering  the  question  as  if  a  student  should  inquire  whether 
he  ought  to  take  up  first  a  treatise  on  Chemistry,  or  one  on 
Natural  Philosophy,  subjects  sufficiently  distinct,  yet  insepara- 
bly connected.  On  the  whole,  while  I  have  endeavored  to  make 
each  of  the  two  treatises,  in  their  present  form,  quite  indepen- 
dent of  the  other,  I  would  recommend  the  reader  to  study  first 
the  modern  changes  of  the  earth  and  its  inhabitants  as  they  are 
discussed  in  the  present  volume,  proceeding  afterwards  to  the 
classification  and  interpretation  of  the  monuments  of  more 
remote  ages. 

CHARLES  LYELL. 

11  Harley  Street,  London,  May  24,  1853. 


Dates  of  the  successive  Editions  of  the  "Principles"  and  "Elements'" 
(or  Manual)  of  Geology,  by  the  Author. 


Principles,  1st  vol.  in  octavo,  published  in Jan.  1830. 

,  2d  vol.          do.  do Jan.  1832. 

,  1st  vol.  2d  edition  in  octavo 1832. 

,  2d  vol.  2d  edition     do Jan.  1833. 

,  3d  vol.  1st  edition     do May,  1833. 

,  New  edition  (called  the  3d)  of  the  whole  work  in  4  vols. 

12mo May,  1834. 

,  4th  edition,  4  vols.  12mo June,  1835. 

,  5th     do.         do.         do Mar.  1837. 

Elements,  1st  edition  in  one  vol July,  1838. 

Principles,  6th     do.         3  vols.  12mo June,  1840. 

Elements,  2d  edition  in  2  vols.  12mo , July,  1841. 

Principles,  7th  edition  in  one  vol.  8vo ; Feb.  1847. 

,  8th  edition  in  one  vol.  8vo May,  1850, 

Manual  of  Elementary  Geology  (or  "  Elements,"  3d  edition)  in  one  vol. 

8vo. Jan.  1851, 

Manual,  4th  edition,  one  voL  8vo Jan.  1852 

Principles,  9th  edition,  now  published  in  one  vol.  8vo. June,  1853 


ANALYSIS  OF  THE  CONTENTS 

OF 

THE  PRINCIPLES  OF  GEOLOGY. 


BOOK  I.     (CHAPTERS  I.  to  XIII.) 


HISTOEICAL  SKETCH  OF  THE  PROGRESS  OF  GEOLOGY,  WITH  A  SERIES  OF  ESSAYS  TO  SHOW 
THAT  THE  MONUMENTS  OF  THE  ANCIENT  STATE  OF  THE  EARTH  AND  ITS  INHABITANTS, 
WHICH  THIS  SCIENCE  INTERPRETS,  CAN  ONLY  BE  UNDERSTOOD  BY  A  PREVIOUS  AC- 
QUAINTANCE WITH  TERRESTRIAL  CHANGES  NOW  IN  PROGRESS,  BOTH  IN  THE  ORGANIC) 
AND  INORGANIC  WORLDS. 

CHAPTEE  I. 
Geology  defined — Its  relation  to  other  Sciences Page  i 

CHAPTER  II. 

Oriental  and  Egyptian  Cosmogonies — Doctrines  of  the  Greeks  and  Komans  bearing 
on  Geology I 

CHAPTER  III. 

Historical  progress  of  Geology — Arabian  Writers — Italian.  French,  German,  and 
English  geologists  before  the  19th  century — Physico- theological  school  ....  17 

CHAPTER  IV. 
Werner  and  Hutton — Modern  progress  of  the  science 46 

CHAPTEE  V. 

Prepossessions  in  regard  to  the  duration  of  past  time,  and  other  causes  which  have 
retarded  the  progress  of  Geology 61 

CHAPTEE  VI. 

Agreement  of  the  ancient  and  modern  course  of  nature  considered — Changes  of  cli- 
mate   73 

CHAPTERS  VII.  VIII. 

Causes  of  vicissitudes  in  climate,  and  their  connection  with  changes  in  physical  geog- 
raphy    92,  114 

CHAPTEE  IX. 

Theory  of  the  progressive  development  of  organic  life  at  successive  periods  consid- 
ered—Modern origin  of  Man 130 


X  CONTENTS. 

CHAPTER  X. 

Supposed  intensity  of  aqueous  forces  at  remote  periods — Erratic  blocks — Deluges 

Page  153 

CHAPTER  XI. 

Supposed  former  intensity  of  the  igneous  forces — Upheaval  of  land — Volcanic  action. 

160 

CHAPTER  XII. 

Causes  of  the  difference  in  texture  of  older  and  newer  rocks— Plutonic  and  Meta- 
morphic  action 175 

CHAPTER  XIII. 

Supposed  alternate  periods  of  repose  and  disorder — Opposite  doctrine,  which  refers 
geological  phenomena  to  an  uninterrupted  series  of  changes  in  the  organic  and  in- 
organic world,  unattended  with  general  catastrophes,  or  the  development  of  parox- 
ysmal forces 180 


BOOK  II.     (CHAPTERS  XIV.  to  XXXII.) 

OBSERVED  CHANGES  IN  THE  INORGANIC  WORLD  NOW  IN  PROGRESS:  FIRST,  THE  EFFECTS 
OF  AQUEOUS  CAUSES,  SUCH  AS  RIVERS,  SPRINGS,  GLACIERS,  WAVES,  TIDES,  AND  CUR- 
RENTS ;  SECONDLY,  OF  IGNEOUS  CAUSES,  OR  SUBTERRANEAN  HEAT,  AS  EXHIBITED  IN  THE 
VOLCANO  AND  THE  EARTHQUAKE. 

CHAPTER  XIV. 
Aqueous  causes — Excavating  and  transporting  power  of  rivers 198 

*                                               CHAPTER  XV. 
Carrying  power  of  river-ice — Glaciers  and  Icebergs 219 

CHAPTER  XVI. 
Phenomena  of  springs , 232 

CHAPTER  XVII. 
Reproductive  effects  of  rivers — Deltas  of  lakes  and  inland  seas 251 

CHAPTER  XVIII. 
Deltas  of  the  Mississippi,  Ganges,  and  other  rivers  exposed  to  tidal  action. . .        263 

CHAPTERS  XIX.  XX.  XXI. 

Denuding,  transporting,  and  depositing  agency  of  the  waves,  tides,  and  currents — 
Waste  of  sea-cliffs  on  the  coast  of  England — Delta  of  the  Rhine — Deposition  of 
sediment  under  the  influence  of  marine  currents 290,  821,  837 

CHAPTER  XXII. 
Observed  effects  of  igneous  causes — Regions  of  active  volcanoes 344 

CHAPTERS  XXIII.  XXIV. 

History  of  the  volcanic  eruptions  of  the  district  round  Naples — Structure  of  Vesu- 
vius—Herculaneum  and  Pompeii 860,  375 


CONTENTS.  XI 

CHAPTER  XXV. 
Etna  —  Its  eruptions  —  Structure  and  antiquity  of  the  cone  .............        Page  398 

CHAPTER  XXVI. 

Volcanoes  of  Iceland,  Mexico,  the  Canaries,  and  Grecian  Archipelago  —  Mud  volca- 
noes .................................................................         424 

CHAPTER  XXVII. 
Earthquakes  and  the  permanent  changes  attending  them  ..................        451 

CHAPTER  XXVIII. 
Earthquake  of  1783  in  Calabria  ..........................................        471 


CHAPTER  XXIX. 

land,  and  of  the  be 
—Evidence  of  the  same  afforded  by  the  Temple  of  Serapis  near  Naples  .  .  .        493 


Elevation  and  subsidence  of  dry  land,  and  of  the  bed  of  the  sea  during  earthquakes 

les  .  .  . 


CHAPTER  XXX. 

Elevation  and  subsidence  of  land  in  regions  free  from  volcanoes  and  earthquakes  — 
Rising  of  land  in  Sweden  ..............................................        519 

CHAPTERS  XXXI.  XXXII. 

Causes  of  earthquakes  and  volcanoes  —  Theory  of  central  fluidity  of  the  earth  —  Chem- 
ical theory  of  volcanoes  —  Causes  of  permanent  upheaval  and  depression  of  land. 


BOOK  III.     (CHAPTERS  XXXIII  to  L.) 

OBSERVED  CHANGES  OF  THE  ORGANIC  WORLD  NOW  IN  PROGRESS ;  FIRST,  NATURE  AND 
GEOGRAPHICAL  DISTRIBUTION  OF  SPECIES,  AND  THEORIES  RESPECTING  THEIR  CREATION 
AND  EXTINCTION  ;  SECONDLY,  THE  INFLUENCE  OF  ORGANIC  BEINGS  IN  MODIFYING 
PHYSICAL  GEOGRAPHY  ;  THIRDLY,  THE  LAWS  ACCORDING  TO  WHICH  THEY  ARE  IM- 
BEDDED IN  VOLCANIC,  FRESHWATER,  AND  MARINE  DEPOSITS. 

CHAPTERS  XXXIII.  XXXIV,  XXXV.  XXXVI. 

Whether  species  have  a  real  existence  in  nature — Theory  of  transmutation  of  species 
— Variability  of  species — Phenomena  of  hybrids  in  animals  and  plants 

566,  578,  591,  600 

CHAPTER  XXXVII. 

Laws  which  regulate  the  geographical  distribution  of  species — Distinct  provinces  of 
peculiar  species  of  plants — Their  mode  of  diffusion 612 

CHAPTER  XXXVIII. 

Distinct  provinces  of  peculiar  species  of  animals — Distribution  and  dispersion  of 
quadrupeds,  birds,  and  reptiles 629 

CHAPTER  XXXIX. 

Geographical  distribution  and  migrations  offish — Of  testacea — Of  zoophytes — Of  in- 
sects— Geographical  distribution  and  diffusion  of  the  human  race 646 

CHAPTER  XL. 

Theories  respecting  the  original  introduction  of  species — Reciprocal  influence  of 
species  on  each  other 665 


Xll  CONTENTS. 

CHAPTEKS  XLI.  XLII. 

Extinction  of  species — How  every  extension  of  the  range  of  a  species  alters  the  con- 
dition of  many  others — Effect  of  changes  of  climate Page  677,  689 

CHAPTEK  XLIII. 

Creation  of  species — Whether  the  loss  of  certain  animals  and  plants  is  compensated 
by  the  introduction  of  new  species 701 

CHAPTER  XLIV. 
Modifications  in  physical  geography  caused  by  organic  beings 708 

CHAPTEK  XLV. 
Imbedding  of  organic  remains  in  peat,  blown  sand,  and  volcanic  ejections. . .        718 

CHAPTER  XLVI. 
Imbedding  of  the  same  in  alluvial  deposits  and  in  caves 780 

CHAPTER  XLVII. 

Imbedding  of  organic  remains  in  aqueous  deposits — Terrestrial  plants — Insects,  rep- 
tiles, birds,  quadrupeds 742 

CHAPTER  XL VIII. 
Imbedding  of  the  remains  of  man  and  his  works 758 

CHAPTER  XLIX. 

Imbedding  of  aquatic  animals  and  plants,  both  freshwater  and  marine,  in  aqueous 
deposits 765 

CHAPTER  L. 
Formation  of  coral  reefs 775 


LIST  OF  PLATES. 


DIRECTIONS  TO   THE   BINDER. 


FRONTISPIECE,  View  of  the  Temple  of  Serapis  at  Puzzuoli  in  1886,  to  face  titlepage. 

PLATE  1.  Map  showing  the  Area  in  Europe  which  has  been  covered 

by  "Water  since  the  beginning  of  the  Eocene  Period to  face  p.  121 

2.  Boulders  drifted  by  Ice  on  the  Shores  of  the  St.  Lawrence. .        —        220 

8.  View  looking  up  the  Val  del  Bove,  Etna '    —       408 

4.  View  of  the  Val  del  Bove,  Etna,  as  seen  from  above —       404 


PRINCIPLES  OF  GEOLOGY. 


BOOK  I. 
CHAPTER    I. 

Geology  defined — Compared  to  History — Its  relation  to  other  Physical  Sciences — 
Not  to  V>e  confounded  with  Cosmogony. 

GEOLOGY  is  the  science  which  investigates  the  successive  changes  that 
have  taken  place  in  the  organic  and  inorganic  kingdoms  of  nature  ;  it 
inquires  into  the  causes  of  these  changes,  and  the  influence  which  they 
have  exerted  in  modifying  the  surface  and  external  structure  of  our  planet. 

By  these  researches  into  the  state  of  the  earth  and  its  inhabitants  at 
former  periods,  we  acquire  a  more  perfect  knowledge  of  its  present  con- 
dition, and  more  comprehensive  views  concerning  the  laws  now  govern- 
ing its  animate  and  inanimate  productions.  When  we  study  history,  we 
obtain  a  more  profound  insight  into  human  nature,  by  instituting  a  com- 
parison between  the  present  and  former  states  of  society.  We  trace  the 
long  series  of  events  which  have  gradually  led  to  the  actual  posture  of 
affairs  ;  and  by  connecting  effects  with  their  causes,  we  aro  enabled  to 
classify  and  retain  in  the  memory  a  multitude  of  complicated  relations — 
the  various  peculiarities  of  national  character — the  different  degrees  of 
moral  and  intellectual  refinement,  and  numerous  other  circumstances, 
which,  without  historical  associations,  would  be  uninteresting  or  imper- 
fectly understood.  As  the  present  condition  of  nations  is  the  result  of 
many  antecedent  changes,  some  extremely  remote,  and  others  recent, 
some  gradual,  others  sudden  and  violent ;  so  the  state  of  the  natural 
world  is  the  result  of  a  long  succession  of  events  ;  and  if  we  would  en- 
large our  experience  of  the  present  economy  of  nature,  we  must  investi- 
gate the  effects  of  her  operations  in  former  epochs. 

We  often  discover  with  surprise,  on  looking  back  into  the  chronicles 
of  nations,  how  the  fortune  of  some  battle  has  influenced  the  fate  of 
millions  of  our  contemporaries,  when  it  has  long  been  forgotten  by  the 
mass  of  the  population.  With  this  remote  event  we  may  find  insepar- 
ably connected  the  geographical  boundaries  of  a  great  state,  the  lan- 
guage now  spoken  by  the  inhabitants,  their  peculiar  manners,  laws,  and 
religious  opinions.  But  far  more  astonishing  and  unexpected  are  the 
connections  brought  to  light,  when  we  carry  back  our  researches  into 
the  history  of  nature.  The  form  of  a  coast,  the  configuration  of  the  in- 


2  GEOLOGY   COMPARED   TO   HISTORY.  [On.  1. 

terior  of  a  country,  the  existence  and  extent  of  lakes,  valleys,  and  moun- 
tains, can  often  be  traced  to  the  former  prevalence  of  earthquakes  and 
volcanoes  in  regions  which  have  long  been  undisturbed.  To  these  remote 
convulsions  the  present  fertility  of  some  districts,  the  sterile  character  of 
others,  the  elevation  of  land  above  the  sea,  the  climate,  and  various  pe- 
culiarities, may  be  distinctly  referred.  On  the  other  hand,  many  distin- 
guishing features  of  the  surface  may  often  be  ascribed  to  the  operation, 
at  a  remote  era,  of  slow  and  tranquil  causes — to  the  gradual  deposition 
of  sediment  in  a  lake  or  in  the  ocean,  or  to  the  prolific  increase  of  testa- 
cea  and  corals. 

To  select  another  example,  we  find  in  certain  localities  subterranean 
deposits  of  coal,  consisting  of  vegetable  matter,  formerly  drifted  into 
seas  and  lakes.  These  seas  and  lakes  have  since  been  filled  up,  the  lands 
whereon  the  forests  grew  have  disappeared  or  changed  their  form,  the 
rivers  and  currents  which  floated  the  vegetable  masses  can  no  longer  be 
traced,  and  the  plants  belonged  to  species  which  for  ages  have  passed 
away  from  the  surface  of  our  planet.  Yet  the  commercial  prosperity, 
and  numerical  strength  of  a  nation,  may  now  be  mainly  dependent  on 
the  local  distribution  of  fuel  determined  by  that  ancient  state  of  things. 

Geology  is  intimately  related  to  almost  all  the  physical  sciences,  as 
history  is  to  the  moral.  An  historian  should,  if  possible,  be  at  once  pro- 
foundly acquainted  with  ethics,  politics,  jurisprudence,  the  military  art, 
theology ;  in  a  word,  with  all  branches  of  knowledge  by  which  any  in- 
sight into  human  affairs,  or  into  the  moral  and  intellectual  nature  of  man, 
can  be  obtained.  It  would  be  no  less  desirable  that  a  geologist  should 
be  well  versed  in  chemistry,  natural  philosophy,  mineralogy,  zoology, 
comparative  anatomy,  botany ;  in  short,  in  every  science  relating  to  or- 
ganic and  inorganic  nature.  With  these  accomplishments,  the  historian 
and  geologist  would  rarely  fail  to  draw  correct  and  philosophical  conclu- 
sions from  the  various  monuments  transmitted  to  them  of  former  occur- 
rences. They  would  know  to  what  combination  of  causes  analogous 
effects  were  referable,  and  they  would  often  be  enabled  to  supply,  by 
inference,  information  concerning  many  events  unrecorded  in  the  defect- 
ive archives  of  former  ages.  But  as  such  extensive  acquisitions  are 
scarcely  within  the  reach  of  any  individual,  it  is  necessary  that  men  who 
have  devoted  their  lives  to  different  departments  should  unite  their 
efforts ;  and  as  the  historian  receives  assistance  from  the  antiquary,  and 
from  those  who  have  cultivated  different  branches  of  moral  and  political 
science,  so  the  geologist  should  avail  himself  of  the  aid  of  many  natural- 
ists, and  particularly  of  those  who  have  studied  the  fossil  remains  of  lost 
species  of  animals  and  plants. 

The  analogy,  however,  of  the  monuments  consulted  in  geology,  and 
those  available  in  histoiy,  extends  no  farther  than  to  one  class  of  histor- 
ical monuments — those  which  may  be  said  to  be  undesignedly  commem- 
orative of  former  events.  The  canoes,  for  example,  and  stone  hatchets 
found  in  our  peat  bogs,  afford  an  insight  into  the  rude  arts  and  manners 
of  the  earliest  inhabitants  of  our  island  ;  the  buried  coin  fixes  the  date 


CH.  I.]  GEOLOGY   DISTINCT   FROM   COSMOGONY.  3 

of  the  reign  of  some  Roman  emperor  ;  the  ancient  encampment  indicates 
the  districts  once  occupied  by  invading  armies,  and  the  former  method 
of  constructing  military  defences ;  the  Egyptian  mummies  throw  light 
on  the  art  of  embalming,  the  rites  of  sepulture,  or  the  average  stature 
of  the  human  race  in  ancient  Egypt.  This  class  of  memorials  yields  to 
no  other  in  authenticity,  but  it  constitutes  a  small  part  only  of  the  re- 
sources on  which  the  historian  relies,  whereas  in  geology  it  forms  the 
only  kind  of  evidence  which  is  at  our  command.  For  this  reason  we 
must  not  expect  to  obtain  a  full  and  connected  account  of  any  series  of 
events  beyond  the  reach  of  history.  But  the  testimony  of  geological 
monuments,  if  frequently  imperfect,  possesses  at  least  the  advantage  of 
being  free  from  all  intentional  misrepresentation.  We  may  be  deceived 
in  the  inferences  which  we  draw,  in  the  same  manner  as  we  often  mistake 
the  nature  and  import  of  phenomena  observed  in  the  daily  course  of  na- 
ture ;  but  our  liability  to  err  is  confined  to  the  interpretation,  and,  if  this 
be  correct,  our  information  is  certain.  » 

It  was  long  before  the  distinct  nature  and  legitimate  objects  of  geology 
were  fully  recognized,  and  it  was  at  first  confounded  with  many  other 
branches  of  inquiry,  just  as  the  limits  of  history,  poetry,  and  mythology 
were  ill-defined  in  the  infancy  of  civilization.  Even  in  Werner's  time, 
or  at  the  close  of  the  eighteenth  century,  geology  appears  to  have  been 
regarded  as  little  other  than  a  subordinate  department  of  mineralogy ; 
and  Desmarest  included  it  under  the  head  of  Physical  Geography.  But 
the  most  common  and  serious  source  of  confusion  arose  from  the  notion, 
that  it  was  the  business  of  geology  to  discover  the  mode  in  which  the 
earth  originated,  or,  as  some  imagined,  to  study  the  effects  of  those  cos- 
mological  causes  which  were  employed  by  the  Author  of  Nature  to 
bring  this  planet  out  of  a  nascent  and  chaotic  state  into  a  more  perfect 
and  habitable  condition.  Hutton  was  the  first  who  endeavored  to  draw 
a  strong  line  of  demarcation  between  his  favorite  science  and  cosmogony, 
for  he  declared  that  geology  was  in  nowise  concerned  "  with  questions 
as  to  the  origin  of  things." 

An  attempt  will  be  made  in  the  sequel  of  this  work  to  demonstrate 
that  geology  differs  as  widely  from  cosmogony,  as  speculations  concern- 
ing the  mode  of  the  first  creation  of  man  differ  from  history.  But,  be- 
fore entering  more  at  large  on  this  controverted  question,  it  will  be  de- 
sirable to  trace  the  progress  of  opinion  on  this  topic,  from  the  earliest 
ages  to  the  commencement  of  the  present  century. 


CHAPTER  II. 

HISTORICAL    SKETCH    OF    THE    PROGRESS    OF    GEOLOGY. 

Oriental  Cosmogony — Hymns  of  the  Vedas — Institutes  of  Menu — Doctrine  of  the 
successive  destruction  and  renovation  of  the  world — Origin  of  this  doctrine — 
Common  to  the  Egyptians — Adopted  by  the  Greeks — System  of  Pythagoras — 
Of  Aristotle — Dogmas  concerning  the  extinction  and  reproduction  of  genera 
and  species — Strabo's  theory  of  elevation  by  earthquakes — Pliny — Concluding 
Remarks  on  the  knowledge  of  the  Ancients. 

Oriental  Cosmogony. — THE  earliest  doctrines  of  the  Indian  and  Egyp- 
tian schools  of  philosophy  agreed  in  ascribing  the  first  creation  of  the 
world  to  an  omnipotent  and  infinite  Being.  They  concurred  also  in  rep- 
resenting this  Being,  who  had  existed  from  all  eternity,  as  having  re- 
peatedly destroyed  and  reproduced  the  world  and  all  its  inhabitants. 
In  the  sacred  volume  of  the  Hindoos,  called  the  Ordinances  of  Menu, 
comprising  the  Indian  system  of  duties  religious  and  civil,  we  find  a  pre- 
liminary chapter  treating  of  the  Creation,  in  which  the  cosmogony  is 
known  to  have  been  derived  from  earlier  writings  and  traditions  ;  and 
principally  from  certain  hymns  of  high  antiquity,  called  the  Vedas. 
These  hymns  were  first  put  together,  according  to  Mr.  Colebrooke,*  in 
a  connected  series,  about  thirteen  centuries  before  the  Christian  era,  but 
they  appear  from  internal  evidence  to  have  been  written  at  various  an- 
tecedent periods.  In  them,  as  we  learn  from  the  researches  of  Profes- 
sor Wilson,  the  eminent  Sanscrit  scholar,  two  distinct  philosophical  sys- 
tems are  discoverable.  According  to  one  of  them,  all  things  were  origi- 
nally brought  into  existence  by  the  sole  will  of  a  single  First  Cause, 
which  existed  from  eternity ;  according  to  the  other,  there  have  always 
existed  two  principles,  the  one  material,  but  without  form,  the  other 
spiritual  and  capable  of  compelling  "  inert  matter  to  develop  its  sensible 
properties."  This  development  of  matter  into  "individual  and  visible 
existences"  is  called  creation,  and  is  assigned  to  a  subordinate  agent,  or  the 
creative  faculty  of  the  Supreme  Being  embodied  in  the  person  of  Brahma. 

In  the  first  chapter  of  the  Ordinances  of  Menu  above  alluded  to,  we 
meet  with  the  following  passages  relating  to  former  destructions  and 
renovations  of  the  world  : — 

"  The  Being,  whose  powers  are  incomprehensible,  having  created  me 
(Menu)  and  this  universe,  again"  became  absorbed  in  the  supreme  spirit, 
changing  the  time  of  energy  for  the  hour  of  repose. 

"  When  that  Power  awakes,  then  has  this  world  its  full  expansion  ; 
but  when  he  slumbers  with  a  tranquil  spirit,  then  the  whole  system 
fades  away For  while  he  reposes,  as  it  were,  embodied  spirits 

*  Essays  on  the  Philosophy  of  the  Hindoos. 


CH.  II]  INSTITUTES   OF   MENU. ORIENTAL    COSMOGONY.  5 

endowed  with  principles  of  action  depart  from  their  several  acts,  and 
the  mind  itself  becomes  inert." 

The  absorption  of  all  beings  into  the  Supreme  essence  is  then  de- 
scribed, and  the  Divine  soul  itself  is  said  to  slumber,  and  to  remain  for 
a  time  immersed  in  "  the  first  idea,  or  in  darkness."  After  which  the 
text  thus  proceeds  (verse  fifty-seven),  "  Thus  that  immutable  power 
by  waking  and  reposing  alternately,  revivifies  and  destroys,  in  eternal  suc- 
cession, this  whole  assemblage  of  locomotive  and  immovable  creatures." 

It  is  then  declared  that  there  has  been  a  long  succession  of  manwan- 
taras,  or  periods,  each  of  the  duration  of  many  thousand  ages,  and — 

"  There  are  creations  also,  and  destructions  of  worlds  innumerable : 
the  Being,  supremely  exalted,  performs  all  this  with  as  much  ease  as  if 
in  sport,  again  and  again,  for  the  sake  of  conferring  happiness."* 

No  part  of  the  Eastern  cosmogony,  from  which  these  extracts  are 
made,  is  more  interesting  to  the  geologist  than  the  doctrine,  so  fre- 
quently alluded  to,  of  the  reiterated  submersion  of  the  land  beneath  the 
waters  of  a  universal  ocean.  In  the  beginning  of  things,  we  are  told, 
the  First  Sole  Cause  "  with  a  thought  created  the  waters,"  and  then 
moved  upon  their  surface  in  the  form  of  Brahma  the  creator,  by  whose 
agency  the  emergence  of  the  dry  land  was  effected,  and  the  peopling 
of  the  earth  with  plants,  animals,  celestial  creatures,  and  man.  After- 
wards, as  often  as  a  general  conflagration  at  the  close  of  each  manwan- 
tara  had  annihilated  every  visible  and  existing  thing,  Brahma,  on 
awaking  from  his  sleep,  finds  the  whole  world  a  shapeless  ocean.  Ac- 
cordingly, in  the  legendary  poems  called  the  Puranas,  composed  at  a 
later  date  than  the  Vedas,  the  three  first  Avatars  or  descents  of  the 
Deity  upon  earth  have  for  their  object  to  recover  the  land  from  the 
waters.  For  this  purpose  Vishnu  is  made  successively  to  assume  the 
form  of  a  fish,  a  tortoise,  and  a  boar. 

Extravagant  as  may  be  some  of  the  conceits  and  fictions  which  dis- 
figure these  pretended  revelations,  we  can  by  no  means  look  upon  them 
as  a  pure  effort  of  the  unassisted  imagination,  or  believe  them  to  have 
been  composed  without  regard  to  opinions  and  theories  founded  on  the 
observation  of  Nature.  In  astronomy,  for  instance,  it  is  declared  that, 
at  the  North  Pole,  the  year  was  divided  into  a  long  day  and  night,  and 
that  their  long  day  was  the  northern,  and  their  night  the  southern 
course  of  the  sun  ;  and  to  the  inhabitants  of  the  moon,  it  is  said  one 
day  is  equal  in  length  to  one  month  of  mortals.f  If  such  statements 
cannot  be  resolved  into  mere  conjectures,  we  have  no  right  to  refer  to- 
mere  chance  the  prevailing  notion  that  the  earth  and  its  inhabitants  had 
formerly  undergone  a  succession  of  revolutions  and  aqueous  catastrophes 
interrupted  by  long  intervals  of  tranquillity. 

Now  there  are  two  sources  in  which  such  a  theory  may  have  origi- 
nated. The  marks  of  former  convulsions  on  every  part  of  the  surface  of 

*  Institutes  of  Hindoo  Law,  or   the  Ordinances  of  Menti,  from  the  Sanscrit, 
translated  by  Sir  William  Jones,  1796. 
f  Mend,  Inst.  c.  i.  66,  and  67. 


6  OEIENTAL   COSMOGONY.  [Cn.  II. 

our  planet  are  obvious  and  striking.  The  remains  of  marine  animals 
imbedded  in  the  solid  strata  are  so  abundant,  that  they  may  be  expected 
to  force  themselves  on  the  attention  of  every  people  who  have  made 
some  progress  in  refinement ;  and  especially  where  one  class  of  men 
are  expressly  set  apart  from  the  rest,  like  the  ancient  priesthoods  of 
India  and  Egypt,  for  study  and  contemplation.  If  these  appearances 
are  once  recognized,  it  seems  natural  that  the  mind  should  conclude  in 
favor,  not  only  of  mighty  changes  in  past  ages,  but  of  alternate  periods 
of  repose  and  disorder  ; — of  repose,  when  the  animals  now  fossil  lived, 
grew,  and  multiplied — of  disorder,  when  the  strata  in  which  they  were 
buried  became  transferred  from  the  sea  to  the  interior  of  continents,  and 
were  uplifted  so  as  to  form  part  of  high  mountain-chains.  Those  mod- 
ern writers,  who  are  disposed  to  disparage  the  former  intellectual 
advancement  and  civilization  of  Eastern  nations,  may  concede  some 
foundation  of  observed  facts  for  the  curious  theories  now  under  consid- 
eration, without  indulging  in  exaggerated  opinions  of  the  progress  of 
science ;  especially  as  universal  catastrophes  of  the  world,  and  exter- 
minations of  organic  beings,  in  the  sense  in  which  they  were  understood 
by  the  Brahmins,  are  untenable  doctrines. 

We  know  that  the  Egyptian  priests  were  aware,  not  only  that 
the  soil  beneath  the  plains  of  the  Nile,  but  that  also  the  hills  bounding 
the  great  valley,  contained  marine  shells ;  and  Herodotus  inferred 
from  these  facts,  that  all  lower  Egypt,  and  even  the  high  lands  above 
Memphis,  had  once  been  covered  by  the  sea.*  As  similar  fossil 
remains  occur  in  all  parts  of  Asia  hitherto  explored,  far  in  the 
interior  of  the  continent  as  well  as  near  the  sea,  they  could  hardly 
have  escaped  detection  by  some  Eastern  sages  not  less  capable 
than  the  Greek  historian  of  reasoning  philosophically  on  natural  phe- 
nomena. 

We  also  know  that  the  rulers  of  Asia  were  engaged  in  very  remote 
eras  in  executing  great  national  works,  such  as  tanks  and  canals,  re- 
quiring extensive  excavations.  In  the  fourteenth  century  of  our  era 
(in  the  year  1360),  the  removal  of  soil  necessary  for  such  undertakings 
brought  to  light  geological  facts,  which  attracted  the  attention  of  a  peo- 
ple less  civilized  than  were  many  of  the  older  nations  of  the  East.  The 
historian  Ferishta  relates  that  fifty  thousand  laborers  were  employed 
in  cutting  through  a  mound,  so  as  to  form  a  junction  between  the  rivers 
Selima  and  Sutlej  ;  and  in  this  mound  were  found  the  bones  of  ele- 
phants and  men,  some  of  them  petrified,  and  some  of  them  resembling 
bone.  The  gigantic  dimensions  attributed  to  the  human  bones  show 
them  to  have  belonged  to  sonie  of  the  larger  pachydermata.f 

But,  although  the  Brahmins,  like  the  priests  of  Egypt,  may  have 

*  Herodot.  Euterpe,  12. 

f  A  Persian  MS.  copy  of  the  historian  Ferishta,  in  the  library  of  the  East  India 


ii.part  iii.  p.  389.) 


CH.  II.]  ORIENTAL   COSMOGONY.  7 

been  acquainted  with  the  existence  of  fossil  remains  in  the  strata,  it  is 
possible  that  the  doctrine  of  successive  destructions  and  renovations  of 
the  world,  merely  received  corroboration  from  such  proofs  ;  and  that  it 
may  have  been  originally  handed  down,  like  the  religious  traditions  of 
most  nations,  from  a  ruder  state  of  society.  The  system  may  have  had 
its  source,  in  part  at  least,  in  exaggerated  accounts  of  those  dreadful 
catastrophes  which  are  occasioned  by  particular  combinations  of  natural 
causes.  Floods  and  volcanic  eruptions,  the  agency  of  water  and  fire, 
are  the  chief  instruments  of  devastation  on  our  globe.  We  shall  point 
out  in  the  sequel  the  extent  of  many  of  these  calamities,  recurring  at 
distant  intervals  of  time,  in  the  present  course  of  nature  ;  and  shall  only 
observe  here,  that  they  are  so  peculiarly  calculated  to  inspire  a  lasting 
terror,  and  are  so  often  fatal  in  their  consequences  to  great  multitudes 
of  people,  that  it  scarcely  requires  the  passion  for  the  marvellous,  so 
characteristic  of  rude  and  half- civilized  nations,  still  less  the  exuberant 
imagination  of  Eastern  writers,  to  augment  them  into  general  cataclysms 
and  conflagrations. 

The  great  flood  of  the  Chinese,  which  their  traditions  carry  back  to 
the  period  of  Yaou,  something  more  than  2000  years  before  our  era,  has 
been  identified  by  some  persons  with  the  universal  deluge  described  in 
the  Old  Testament ;  but  according  to  Mr.  Davis,  who  accompanied  two 
of  our  embassies  to  China,  and  who  has  carefully  examined  their  writ- 
ten accounts,  the  Chinese  cataclysm  is  therein  described  as  interrupting 
the  business  of  agriculture,  rather  than  as  involving  a  general  destruc- 
tion of  the  human  race.  The  great  Yu  was  celebrated  for  having 
"  opened  nine  channels  to  draw  off  the  waters,"  which  "  covered  the 
low  hills  and  bathed  the  foot  of  the  highest  mountains."  Mr.  Davis 
suggests  that  a  great  derangement  of  waters  of  the  Yellow  River,  one  of 
the  largest  in  the  world,  might  even  now  cause  the  flood  of  Yaou  to  be 
repeated,  and  lay  the  most  fertile  and  populous  plains  of  China  under 
water.  In  modern  times  the  bursting  of  the  banks  of  an  artificial  canal, 
into  which  a  portion  of  the  Yellow  River  has  been  turned,  has  repeat- 
edly given  rise  to  the  most  dreadful  accidents,  and  is  a  source  of  per- 
petual anxiety  to  the  government.  It  is  easy,  therefore,  to  imagine 
how  much  greater  may  have  been  the  inundation,  if  this  valley  was 
ever  convulsed  by  a  violent  earthquake.* 

Humboldt  relates  the  interesting  fact  that,  after  the  annihilation  of  a 
large  part  of  the  inhabitants  of  Cumana,  by  an  earthquake  in  1766,  a 
season  of  extraordinary  fertility  ensued,  in  consequence  of  the  great 
rains  which  accompanied  the  subterranean  convulsions.  "  The  Indians," 
he  says,  "  celebrated,  after  the  ideas  of  an  antique  superstition,  by  fes- 
tivals and  dancing,  the  destruction  of  the  world  and  the  approaching 
epoch  of  its  regeneration."! 

The  existence  of  such  rites  among  the  rude  nations  of  South  Amer- 

*  See  Davis  on  "  The  Chinese,"  published  by  the  Soc.  for  the  Diffus.  of  Use. 
Know.  vol.  i.  pp.  137,  147. 

f  Humbuldt  et  Bonplaiid,  Voy.  Relat.  Hist.  vol.  i.  p.  30. 


8  EGYPTIAN   COSMOGONY.  [CH.  IL 

ica  is  most  important,  as  showing  what  effects  may  be  produced  by  local 
catastrophes,  recurring  at  distant  intervals  of  time,  on  the  minds  of 
a  barbarous  and  uncultivated  race.  I  shall  point  out  in  the  sequel  how 
the  tradition  of  a  deluge  among  the  Araucanian  Indians  may  be  ex- 
plained, by  reference  to  great  earthquake-waves  which  have  repeatedly 
rolled  over  part  of  Chili  since  the  first  recorded  flood  of  1590.  (See 
chap.  29,  Book  II.)  The  legend  also  of  the  ancient  Peruvians  of  an 
inundation  many  years  before  the  reign  of  the  Incas,  in  which  only  six 
persons  were  saved  on  a  float,  relates  to  a  region  which  has  more  than 
once  been  overwhelmed  by  inroads  of  the  ocean  since  the  days  of  Pizar- 
ro.  (Chap.  29,  Book  II.)  I  might  refer  the  reader  to  my  account  of 
the  submergence  of  a  wide  area  in  Cutch  so  lately  as  the  year  1819, 
when  a  single  tower  only  of  the  fort  of  Sindree  appeared  above  the 
waste  of  waters  (see  Chap.  28,  Book  II.),  if  it  were  necessary,  to  prove 
how  easily  the  catastrophes  of  modern  times  might  give  rise  to  traditionary 
narratives,  among  a  rude  people,  of  floods  of  boundless  extent.  Nations 
without  written  records,  and  who  are  indebted  for  all  their  knowledge  of 
past  events  exclusively  to  oral  tradition,  are  in  the  habit  of  confounding 
in  one  legend  a  series  of  incidents  which  have  happened  at  various 
epochs ;  nor  must  ,we  forget  that  the  superstitions  of  a  savage  tribe  are 
transmitted  through  all  the  progressive  stages  of  society,  till  they  exert 
a  powerful  influence  on  the  mind  of  the  philosopher.  He  may  find,  in 
the  monuments  of  former  changes  on  the  earth's  surface,  an  apparent 
confirmation  of  tenets  handed  down  through  successive  generations, 
from  the  rude  hunter,  whose  terrified  imagination  drew  a  false  picture 
of  those  awful  visitations  of  floods  and  earthquakes,  whereby  the  whole 
earth  as  known  to  him  was  simultaneously  devastated. 

Egyptian  Cosmogony. — Respecting  the  cosmogony  of  the  Egyptian 
priests,  we  gather  much  information  from  writers  of  the  Grecian  sects, 
who  borrowed  almost  all  their  tenets  from  Egypt,  and  amongst  others 
that  of  the  former  successive  destruction  and  renovation  of  the 
world.*  We  learn  from  Plutarch,  that  this  was  the  theme  of  one  of 
the  hymns  of  Orpheus,  so  celebrated  in  the  fabulous  ages  of  Greece. 
It  was  brought  by  him  from  the  banks  of  the  Nile  ;  and  we  even  find 
in  his  verses,  as  in  the  Indian  systems,  a  definite  period  assigned  for 
the  duration  of  each  successive  world. f  The  returns  of  great  catas- 
trophes were  determined  by  the  period  of  the  Annus  Magnus,  or 
great  year,— a  cycle  composed  of  the  revolutions  of  the  sun,  moon, 
and  planets,  and  terminating  when  these  return  together  to  the  same 
sign  whence  they  were  supposed  at  some  remote  epoch  to  have  set  out. 
The  duration  of  this  great  cycle  was  variously  estimated.  According  to 
Orpheus,  it  was  120,000  years;  according  to  others,  300,000;  and  by 
Cassander  it  was  taken  to  be  360,000  years.t 

*  Prichard's  Egypt.  Mythol.  p.  177. 

j-  Plut.  de  Defectu  Oraculorum,  cap.  12.     Censorinus  de  Die  Natali     See  also 
Richard's  Egypt.  Mythol.  p.  182. 
t  Prichard's  Egypt.  Mythol.  p.  182. 


CH.  IT.]  .EGYPTIAN  COSMOGONY.  9 

We  learn  particularly  from  the  Timseus  of  Plato,  that  the  Egyptians 
believed  the  world  to  be  subject  to  occasional  conflagrations  and 
deluges,  whereby  the  gods  arrested  the  career  of  human  wickedness, 
and  purified  the  earth  from  guilt.  After  each  regeneration,  mankind 
were  in  a  state  of  virtue  and  happiness,  from  which  they  gradually 
degenerated  again  into  vice  and  immorality.  From  this  Egyptian 
doctrine,  the  poets  derived  the  fable  of  the  decline  from  the  golden  to 
the  iron  age.  The  sect  of  Stoics  adopted  most  fully  the  system  of  ca- 
tastrophes destined  at  certain  intervals  to  destroy  the  world.  Those 
they  taught  were  of  two  kinds; — the  Cataclysm,  or  destruction  by 
water,  which  sweeps  away  the  whole  human  race,  and  annihilates  all 
the  animal  and  vegetable  productions  of  nature ;  and  the  Ecpyrosis,  or 
destruction  by  fire,  which  dissolves  the  globe  itself.  From  the  Egyp- 
tians also  they  derived  the  doctrine  of  the  gradual  debasement  of  man 
from  a  state  of  innocence.  Towards  the  termination  of  each  era,  the 
gods  could  no  longer  bear  with  the  wickedness  of  men,  and  a  shock  of 
the  elements  or  a  deluge  overwhelmed  them ;  after  which  calamity, 
Astrea  again  descended  on  the  earth  to  renew  the  golden  age.* 

The  connection  between  the  doctrine  of  successive  catastrophes  and 
repeated  deteriorations  in  the  moral  character  of  the  human  race  is  more 
intimate  and  natural  than  might  at  first  be  imagined.  For,  in  a  rude 
state  of  society,  all  great  calamities  are  regarded  by  the  people  as  judg- 
ments of  God  on  the  wickedness  of  man.  Thus,  in  our  own  time,  the 
priests  persuaded  a  large  part  of  the  population  of  Chili,  and  perhaps 
believed  themselves,  that  the  fatal  earthquake  of  1822  was  a  sign  of  the 
wrath  of  Heaven  for  the  great  political  revolution  just  then  consum- 
mated in  South  America.  In  like  manner,  in  the  account  given  to  Solon 
by  the  Egyptian  priests,  of  the  submersion  of  the  island  of  Atlantis 
under  the  waters  of  the  ocean,  after  repeated  shocks  of  an  earthquake, 
we  find  that  the  event  happened  when  Jupiter  had  seen  the  moral  de- 
pravity of  the  inhabitants.f  Now,  when  the  notion  had  once  gained 
ground,  whether  from  causes  before  suggested  or  not,  that  the  earth 
had  been  destroyed  by  several  general  catastrophes,  it  would  next  be  in- 
ferred that  the  human  race  had  been  as  often  destroyed  and  renovated. 
And  since  every  extermination  was  assumed  to  be  penal,  it  could  only 
be  reconciled  with  divine  justice,  by  the  supposition  that  man,  at  each 
successive  creation,  was  regenerated  in  a  state  of  purity  and  innocence. 

A  very  large  portion  of  Asia,  inhabited  by  the  earliest  nations,  whose 
traditions  have  come  down  to  us,  has  been  always  subject  to  tremen- 
dous earthquakes.  Of  the  geographical  boundaries  of  these,  and  their 
effects,  I  shall  speak  in  the  proper  place.  Egypt  has,  for  the  most 
part,  been  exempt  from  this  scourge,  and  the  Egyptian  doctrine  of  great 
catastrophes  was  probably  derived  in  part,  as  before  hinted,  from  early 
geological  observations,  and  in  part  from  Eastern  nations. 

Pythagorean  Doctrines. — Pythagoras,   who  resided  for  more  than 

*  Prichard's  Egypt.  Mythol.  p.  193.  f  Plato's  Timaeus. 


10  PYTHAGOREAN   SYSTEM.  [Cfl.  II. 

twenty  years  in  Egypt,  and,  according  to  Cicero,  had  visited  the  East, 
and  conversed  with  the  Persian  philosophers,  introduced  into  his  own 
country,  on  his  return,  the  doctrine  of  the  gradual  deterioration  of  the 
human  race  from  an  original  state  of  virtue  and  happiness ;  but  if  we 
are  to  judge  of  his  theory  concerning  the  destruction  and  renovation  of 
the  earth  from  the  sketch  given  by  Ovid,  we  must  concede  it  to  have 
been  far  more  philosophical  than  any  known  version  of  the  cosmogonies 
of  Oriental  or  Egyptian  sects. 

Although  Pythagoras  is  introduced  by  the  poet  as  delivering  his  doc- 
trine in  person,  some  of  the  illustrations  are  derived  from  natural  events 
which  happened  after  the  death  of  the  philosopher.  But  notwithstand- 
ing these  anachronisms,  we  may  regard  the  account  as  a  true  picture  of 
the  tenets  of  the  Pythagorean  school  in  the  Augustan  age ;  and  al- 
though perhaps  partially  modified,  it  must  have  contained  the  substance 
of  the  original  scheme.  Thus  considered,  it  is  extremely  curious  and 
instructive ;  for  we  here  find  a  comprehensive  summary  of  almost  all 
the  great  causes  of  change  now  in  activity  on  the  globe,  and  these  ad- 
duced in  confirmation  of  a  principle  of  a  perpetual  and  gradual  revolu- 
tion inherent  in  the  nature  of  our  terrestrial  system.  These  doctrines,  it 
is  true,  are  not  directly  applied  to  the  explanation  of  geological  pheno- 
mena ;  or,  in  other  words,  no  attempt  is  made  to  estimate  what  may 
have  been  in  past  ages,  or  what  may  hereafter  be,  the  aggregate  amount 
of  change  brought  about  by  such  never-ending  fluctuations.  Had  this 
been  the  case,  we  might  have  been  called  upon  to  admire  so  extraordi- 
nary an  anticipation  with  no  less  interest  than  astronomers,  when  they 
endeavor  to  define  by  what  means  the  Samian  philosopher  came  to  the 
knowledge  of  the  Copernican  system. 

Let  us  now  examine  the  celebrated  passages  to  which  we  have  been 
adverting  :* 

"  Nothing  perishes  in  this  world  ;  but  things  merely  vary  and  change 
their  form.  To  be  born,  means  simply  that  a  thing  begins  to  be  some- 
thing different  from  what  it  was  before ;  and  dying,  is  ceasing  to  be 
the  same  thing.  Yet,  although  nothing  retains  long  the  same  image, 
the  sum  of  the  whole  remains  constant."  These  general  propositions 
are  then  confirmed  by  a  series  of  examples,  all  derived  from  natural 
appearances,  except  the  first,  which  refers  to  the  golden  age  giving 
place  to  the  age  of  iron.  The  illustrations  are  thus  consecutively  ad- 
duced. 

1.  Solid  land  has  been  converted  into  sea. 

2.  Sea  has  been  changed  into  land.     Marine  shells  lie  far  distant 
from  the  deep,  and  the  anchor  has  been  found  on  the  summit  of  hills. 

3.  Valleys  have  been  excavated  by  running  water,  and  floods  have 
washed  down  hills  into  the  sea.f 

*  Ovid's  Metamor.  lib.  15. 

f  Eluvie  mons  est  deductus  in  aequor,  v.  267.  The  meaning  of  this  last  verse 
is  somewhat  obscure ;  but,  taken  with  the  context,  may  be  supposed  to  allude  to 
the  abrading  power  of  floods,  torrents,  and  rivers. 


On.  II]  PYTHAGOREAN    SYSTEM.  11 

4.  Marshes  have  become  dry  ground. 

5.  Dry  lands  have  been  changed  into  stagnant  pools. 

6.  During  earthquakes  some  springs  have  been  closed  up,  and  new 
ones  have  broken  out.     Rivers  have  deserted  their  channels,  and  have 
been  re-born  elsewhere,  as  the  Erasinus  in  Greece,  and  Mysus  in  Asia. 

7.  The  waters  of  some  rivers,  formerly  sweet,  have  become  bitter ; 
as  those  of  the  Anigris,  in  Greece,  &c.* 

8.  Islands  have  become  connected  with  the  mainland  by  the  growth 
of  deltas  and  new  deposits ;  as  in  the  case  of  Antissa  joined  to  Lesbos, 
Pharos  to  Egypt,  &c. 

9.  Peninsulas  have  been  divided  from  the  main  land,  and  have  be- 
come islands,  as  Leucadia  ;  and  according  to  tradition,  Sicily,  the  sea 
having  carried  away  the  isthmus. 

10.  Land  has  been  submerged  by  earthquakes ;  the  Grecian  cities  of 
Helice  and  Buris,  for  example,  are  to  be  seen  under  the  sea,  with  their 
walls  inclined. 

11.  Plains  have  been  upheaved  into  hills  by  the  confined  air  seeking 
vent ;  as  at  Trcezene  in  the  Peloponnesus. 

12.  The  temperature  of  some  springs  varies  at  different  periods.     The 
waters  of  others  are  inflammable,  f 

13.  There  are  streams  which  have  a  petrifying  power,  and  convert 
the  substances  which  they  touch  into  marble. 

14.  Extraordinary  medicinal  and  deleterious  effects  are  produced  by 
the  water  of  different  lakes  and  springs. £ 

15.  Some  rocks  and  islands,  after  floating  and  having  been   subject 
to  violent  movements,  have  at  length  become  stationary  and  immovable  ; 
as  Delos  and  the  Cyanean  Isles. § 

16.  Volcanic  vents  shift  their  position  ;  there  was  a  time  when  Etna 
was  not  a  burning  mountain,  and  the  time  will  come  when  it  will  cease 
to  burn.     Whether  it  be  that  some  caverns  become  closed  up  by  the 
movements  of  the  earth,  and  others  opened,  or  whether  the  fuel  is  finally 
exhausted,  &c.,  &c. 

The  various  causes  of  change  in  the  inanimate  world  having  been  thus 
enumerated,  the  doctrine  of  equivocal  generation  is  next  propounded,  as 
illustrating  a  corresponding  perpetual  flux  in  the  animate  creation. || 

*  The  impregnation  from  new  mineral  springs,  caused  by  earthquakes  in  vol- 
canic countries,  is  perhaps  here  alluded  to. 

•j-  That  is  probably  an  allusion  to  the  escape  of  inflammable  gas,  like  that  in 
the  district  of  Baku,  west  of  the  Caspian ;  at  Pietramala,  in  the  Tuscan  Apen- 
nines ;  and  several  other  places. 

\  Many  of  those  described  seem  fanciful  fictions,  like  the  virtue  still  so  com- 
monly attributed  to  mineral  waters. 

§  Raspe,  in  a  learned  and  judicious  essay  (De  Novis  Insulis,  cap.  19),  has  made 
it  appear  extremely  probable  that  all  the  traditions  of  certain  islands  in  the  Med- 
iterranean having  at  some  former  time  frequently  shifted  their  positions,  and  at 
length  become  stationary,  originated  in  the  great  change  produced  in  their  form 
by  earthquakes  and  submarine  eruptions,  of  which  there  have  been  modern  ex- 
amples in  the  new  islands  raised  in  the  time  of  history.  When  the  series  of  con- 
vulsions ended,  the  island  was  said  to  become  fixed. 

||  It  is  not  inconsistent  with  the  Hindoo  mythology  to  suppose  that  Pythagoras 
might  have  found  in  the  East  not  only  the  system  of  universal  ard  violent  catas- 


12  -  AEISTOTELIAN   SYSTEM.  [Cn.  II. 

In  the  Egyptian  and  Eastern  cosmogonies,  and  in  the  Greek  version 
of  them,  no  very  definite  meaning  can,  in  general,  be  attached  to  the 
term  "destruction  of  the  world  ;"  for  sometimes  it  would  seem  almost 
to  imply  the  annihilation  of  our  planetary  system,  and  at  others  a  mere 
revolution  of  the  surface  of  the  earth. 

Opinions  of  Aristotle. — From  the  works  now  extant  of  Aristotle,  and 
from  the  system  of  Pythagoras,  as  above  exposed,  we  might  certainly 
infer  that  these  philosophers  considered  the  agents  of  change  now  oper- 
ating in  nature,  as  capable  of  bringing  about  in  the  lapse  of  ages  a  com- 
plete revolution ;  and  the  Stagyrite  even  considers  occasional  catastro- 
phes, happening  at  distant  intervals  of  time,  as  part  of  the  regular  and 
ordinary  course  of  nature.  The  deluge  of  Deucalion,  he  says,  affected 
Greece  only,  and  principally  the  part  called  Hellas,  and  it  arose  from 
great  inundations  of  rivers,  during  a  rainy  winter.  But  such  extraordi- 
nary winters,  he  says,  though  after  a  certain  period  they  return,  do  not 
always  revisit  the  same  places.* 

Censorinus  quotes  it  as  Aristotle's  opinion  that  there  were  general 
inundations  of  the  globe,  and  that  they  alternated  with  conflagrations ; 
and  that  the  flood  constituted  the  winter  of  the  great  year,  or  astro- 
nomical cycle,  while  the  conflagration,  or  destruction  by  fire,  is  the 
summer,  or  period  of  greatest  heat.f  If  this  passage,  as  Lipsius  sup- 
poses, be  an  amplification,  by  Censorinus,  of  what  is  written  in  "  the 
Meteorics,"  it  is  a  gross  misrepresentation  of  the  doctrine  of  the  Stagy- 
rite,  for  the  general  bearing  of  his  reasoning  in  that  treatise  tends  clearly 
in  an  opposite  direction.  He  refers  to  many  examples  of  changes  now 
constantly  going  on,  and  insists  emphatically  on  the  great  results  which 
they  must  produce  in  the  lapse  of  ages.  He  instances  particular  cases 
of  lakes  that  had  dried  up,  and  deserts  that  had  at  length  become 
watered  by  rivers  and  fertilized.  He  points  to  the  growth  of  the 
Nilotic  Delta  since  the  time  of  Homer,  to  the  shallowing  of  the  Palus 
Mseotis  within  sixty  years  from  his  own  time ;  and  although,  in  the 
same  chapter  he  says  nothing  of  earthquakes,  yet  in  others  of  the  same 
treatise  he  shows  himself  not  unacquainted  with  their  effects.^  He 
alludes,  for  example,  to  the  upheaving  of  one  of  the  Eolian  islands 
previous  to  a  volcanic  eruption.  "  The  changes  of  the  earth,"  he  says, 
"  are  so  slow  in  comparison  to  the  duration  of  our  lives,  that  they  are  over- 
looked (Xavdavsi) :  and  the  migrations  of  people  aftef  great  catastrophes, 
and  their  removal  to  other  regions,  cause  the  event  to  be  forgotten."§ 

trophes  and  periods  of  repose  in  endless  succession,  but  also  that  of  periodical 
revolutions,  effected  by  the  continued  agency  of  ordinary  causes.  For  Brahma, 
Vishnu,  and  Siva,  the  first,  second"  and  third  persons  of  the  Hindoo  triad,  severally 
represented  the  Creative,  the  Preserving,  and  the  Destroying  powers  of  the  De- 
ity. The  coexistence  of  these  three  attributes,  all  in  simultaneous  operation, 
might  well  accord  with  the  notion  of  perpetual  but  partial  alterations  finally  bring- 
ing about  a  complete  change.  But  the  fiction  expressed  in  the  verses  before  quoted 
from  Menu  of  eternal  vicissitudes  in  the  vigils  and  slumbers  of  Brahma  seems  ac- 
commodated to  the  system  of  great  general  catastrophes  followed  by  new  creations 
and  periods  of  repose.  *  Meteor,  lib.  i,  cap.  12.  f  "De  Die  Nat. 

\  Lib.  ii.  cap.  14,  15,  and  16.  §  Lib.  ii.  cap.  14,  15,  and  16. 


On.  II.]  ARISTOTELIAN    SYSTEM.  13 

When  we  consider  the  acquaintance  displayed  by  Aristotle,  in  his 
various  works,  with  the  destroying  and  renovating  powers  of  Nature, 
the  introductory  and  concluding  passages  of  the  twelfth  chapter  of  his 
"  Meteorics"  are  certainly  very  remarkable.  In  the  first  sentence  he 
says,  "  The  distribution  of  land  and  sea  in  particular  regions  does  not 
endure  throughout  all  time,  but  it  becomes  sea  in  those  parts  where 
it  was  land,  and  again  it  becomes  land  where  it  was  sea :  and  there  is 
reason  for  thinking  that  these  changes  take  place  according  to  a  cer- 
tain system,  and  within  a  certain  period."  The  concluding  observation 
is  as  follows  : — "  As  time  never  fails,  and  the  universe  is  eternal,  neither 
the  Tanais,  nor  the  Nile,  can  have  flowed  forever.  The  places  where 
they  rise  were  once  dry,  and  there  is  a  limit  to  their  operations ;  but 
there  is  none  to  time.  So  also  of  all  other  rivers  ;  they  spring  up,  and 
they  perish  ;  and  the  sea  also  continually  deserts  some  lands  and  in- 
vades others.  The  same  tracts,  therefore,  of  the  earth  are  not,  some 
always  sea,  and  others  always  continents,  but  every  thing  changes  in 
the  course  of  time." 

It  seems,  then,  that  the  Greeks  had  not  only  derived  from  preced- 
ing nations,  but  had  also,  in  some  slight  degree,  deduced  from  their 
own  observations,  the  theory  of  periodical  revolutions  in  the  inorganic 
world  :  there  is,  however,  no  ground  for  imagining  that  they  contem- 
plated former  changes  in  the  races  of  animals  and  plants.  Even  the 
fact  that  marine  remains  were  inclosed  in  solid  rocks,  although  ob- 
served by  some,  and  even  made  the  groundwork  of  geological  specu- 
lation, never  stimulated  the  industry  or  guided  the  inquiries  of  natural- 
ists. It  is  not  impossible  that  the  theory  of  equivocal  generation  might 
have  engendered  some  indifference  on  this  subject,  and  that  a  belief  in 
the  spontaneous  production  of  living  beings  from  the  earth  or  corrupt 
matter,  might  have  caused  the  organic  world  to  appear  so  unstable 
and  fluctuating,  that  phenomena  indicative  of  former  changes  would 
not  awaken  intense  curiosity.  The  Egyptians,  it  is  true,  had  taught, 
and  the  Stoics  had  repeated,  that  the  earth  had  once  given  birth  to 
some  monstrous  animals,  which  existed  no  longer ;  but  the  prevailing 
opinion  seems  to  have  been,  that  after  each  great  catastrophe  the  same 
species  of  animals  were  created  over  again.  This  tenet  is  implied  in  a 
passage  of  Seneca,  where,  speaking  of  a  future  deluge,  he  says,  "  Every 
animal  shall  be  generated  anew,  and  man  free  from  guilt  shall  be  given 
to  the  earth."* 

An  old  Arabian  version  of  the  doctrine  of  the  successive  revolutions 
of  the  globe,  translated  by  Abraham  Ecchellensis,f  seems  to  form  a 
singular  exception  to  the  general  rule,  for  here  we  find  the  idea  of  dif- 
ferent genera  and  species  having  been  created.  The  Gerb-mites,  a  sect 

*  Omne  ex  intecro  animal  generabitur,  dubiturque  terrb  homo  inscius  scelo- 
rum. — Qusest.  Nat.  iii.  e.  29. 

f  This  author  was  Rogius  Professor  of  Syriac  and  Arabic  at  Paris,  where,  in 
1685,  he  published  a  Latin  translation  of  many  Arabian  MSS.  on  different  de- 
partments of  philosophy.  This  work  has  always  been  considered  of  high  authority. 


14:  SPECULATIONS    OF   STRABO.  [Cn.  II. 

of  astronomers  who  flourished  some  centuries  before  the  Christian  era, 
taught  as  follows  : — "  That  after  every  period  of  thirty-six  thousand 
four  hundred  and  twenty-five  years,  there  were  produced  a  pair  of 
every  species  of  animal,  both  male  and  female,  from  whom  animals 
might  be  propagated  and  inhabit  this  lower  world.  But  when  a  cir- 
culation of  the  heavenly  orbs  was  completed,  which  is  finished  in  that 
space  of  years,  other  genera  and  species  of  animals  are  propagated,  as 
also  of  plants  and  other  things,  and  the  first  order  is  destroyed,  and  so 
it  goes  on  forever  and  ever."* 

Theory  of  Strabo. — As  we  learn  much  of  the  tenets  of  the  Egyptian 
and  Oriental  schools  in  the  writings  of  the  Greeks,  so,  many  specula- 
tions of  the  early  Greek  authors  are  made  known  to  us  in  the  works  of 
the  Augustan  and  later  ages.  Strabo,  in  particular,  enters  largely,  in 
the  second  book  of  his  Geography,  into  the  opinions  of  Eratosthenes  and 
other  Greeks  on  one  of  the  most  difficult  problems  in  geology,  viz.,  by 
what  causes  marine  shells  came  to  be  plentifully  buried  in  the  earth  at 
such  great  elevations  and  distances  from  the  sea. 

He  notices,  amongst  others,  the  explanation  of  Xanthus  the  Lydian, 
who  said  that  the  seas  had  once  been  more  extensive,  and  that  they  had 
afterwards  been  partially  dried  up,  as  in  his  own  time  many  lakes,  rivers, 
and  wells  in  Asia  had  failed  during  a  season  of  drought.  Treating  this 
conjecture  with  merited  disregard,  Strabo  passes  on  to  the  hypothesis 
of  Strato,  the  natural  philosopher,  who  had  observed  that  the  quantity 
of  mud  brought  down  by  rivers  into  the  Euxine  was  so  great,  that  its 
bed  must  be  gradually  raised,  while  the  rivers  still  continue  to  pour  in 
an  undiminished  quantity  of  water.  He,  therefore,  conceived  that,  ori- 
ginally, when  the  Euxine  was  an  inland  sea,  its  level  had  by  this  means 
become  so  much  elevated  that  it  burst  its  barrier  near  Byzantium,  and 
formed  a  communication  with  the  Propontis  ;  and  this  partial  drainage, 
he  supposed,  had  already  converted  the  left  side  into  marshy  ground, 
and  thus,  at  last,  the  whole  would  be  choked  up  with  soil.  So,  it  was 
argued,  the  Mediterranean  had  once  opened  a  passage  for  itself  by  the 
Columns  of  Hercules  into  the  Atlantic  ;  and  perhaps  the  abundance  of 
sea-shells  in  Africa,  near  the  Temple  of  Jupiter  Ammon,  might  also  be 
the  deposit  of  some  former  inland  sea,  which  had  at  length  forced  a 
passage  and  escaped. 

*  Gerbanitse  docebant  singulos  triginta  sex  mille  annos  quadringentos,  viginti 
quinque  bina  ex  singulis  animalium  speciebus  produci,  marem  scilicet  ac  feminam 
ex  quibus  animalia  propagantnr,  huncque  inferiorem  incolunt  orbem.  Absolute 
autem  coelestium  orbium  circulatione,  quoe  illo  annorum  conficitur  spatio,  iterura 
alia  producuntur  animalium  genera  et  species,  quemadmodum  et  plantarum  alia- 
rumque  rerum,  et  primus  destrui£ur  ordo,  sicque  in  infinitumproducitur. — Histor. 
OrienV  Suppl.  per  Abrahamum  Ecchellensem,  Syrum  Maronitam,  cap.  7.  et  8.  ad 
calcem  Chronic!  Orientali.  Parisiis,  e  Typ.  Regia.  1685,  fol. 

I  have  given  the  punctuation  as  in  the  Paris  edition,  there  being  no  comma 
after  quinque  ;  but,  at  the  suggestion  of  M.  de  Schlegel,  I  have  referred  the  num- 
ber twenty-five  to  the  period  of  years,  and  not  to  the  number  of  pairs  of  each 
species  created  at  one  time,  as  I  had  done  in  the  two  first  editions.  Fortis  in- 
ferred that  twenty-five  new  species  only  were  created  at  a  time  ;  a  construction 
which  the  passage  will  not  admit.  M6m.  sur  1'Hist.  Nat.  de  1'Italie,  vol.  i.  p.  202. 


CH.  II.]  THEORY   OF   STRABO.  15 

But  Strabo  rejects  this  theory,  as  insufficient  to  account  for  all  the 
phenomena,  and  he  proposes  one  of  his  own,  the  profoundness  of  which 
modern  geologists  are  only  beginning  to  appreciate.  "  It  is  not,"  he 
says,  "  because  the  lands  covered  by  seas  were  originally  at  different 
altitudes,  that  the  waters  have  risen,  or  subsided,  or  receded  from  some 
parts  and  inundated  others.  But  the  reason  is,  that  the  same  land  is 
sometimes  raised  up  and  sometimes  depressed,  and  the  sea  also  is  simul- 
taneously raised  and  depressed,  so  that  it  either  overflows  or  returns 
into  its  own  place  again.  We  must,  therefore,  ascribe  the  cause  to  the 
ground,  either  to  that  ground  which  is  under  the  sea,  or  to  that  which 
becomes  flooded  by  it,  but  rather  to  that  which  lies  beneath  the  sea,  for 
this  is  more  movable  and,  on  account  of  its  humidity,  can  be  altered 
with  greater  celerity.*  It  is  proper,"  he  observes  in  continuation,  "  to 
derive  our  explanations  from  things  which  are  obvious,  and  in  some 
measure  of  daily  occurrence,  such  as  deluges,  earthquakes,  and  volcanic 
eruptions^  and  sudden  swellings  of  the  land  beneath  the  sea  ;  for  the 
last  raise  up  the  sea  also ;  and  when  the  same  lands  subside  again,  they 
occasion  the  sea  to  be  let  down.  And  it  is  not  merely  the  small,  but 
the  large  islands  also,  and  not  merely  the  islands,  but  the  continents 
which  can  be  lifted  up  together  with  the  sea ;  and  both  large  and  small 
tracts  may  subside,  for  habitations  and  cities,  like  Bure,  Bizona,  and 
many  others,  have  been  engulphed  by  earthquakes." 

In  another  place,  this  learned  geographer,  in  alluding  to  the  tradition 
that  Sicily  had  been  separated  by  a  convulsion  from  Italy,  remarks,  that 
at  present  the  land  near  the  sea  in  those  parts  was  rarely  shaken  by 
earthquakes,  since  there  were  now  open  orifices  whereby  fire  and  ignited 
maters,  and  waters  escape ;  but  formerly,  when  the  volcanoes  of  Etna, 
the  Lipari  Islands,  Ischia,  and  others,  were  closed  up,  the  imprisoned 
fire  and  wind  might  have  produced  far  more  vehement  movements.]; 
The  doctrine,  therefore,  that  volcanoes  are  safety-valves,  and  that  the 
subterranean  convulsions  are  probably  most  violent  when  first  the  vol- 
canic energy  shifts  itself  to  a  new  quarter,  is  not  modern. 

We  learn  from  a  passage  in  Strabo,§  that  it  was  a  dogma  of  the 
Gaulish  Druids  that  the  universe  was  immortal,  but  destined  to  survive 
catastrophes  both  of  fire  and  water.  That  this  doctrine  was  communi- 
cated to  them  from  the  East,  with  much  of  their  learning,  cannot  be 
doubted.  Csesar,  it  will  be  remembered,  says  that  they  made  use  of 
Greek  letters  in  arithmetical  computations.! 

*  "  Quod  enim  hoc  attollitur  aut  subsidit,  et  vel  inundat  qusedam  loca,  vel  ab 
iis  recedit,  ejus  rei  causa  non  est,  quod  alia  aliis  sola  humiliora  sint  aut  altiora ; 
sed  quod  idem  solutn  modi)  attoliitur  mod6  deprimitur,  simulque  etiam  mod6 
attollitur  modo  deprimitur,  mare :  itaque  vel  exundat  vel  in  suum  redit  locum." 

Postea,  p.  88.  "  Restat,  ut  causam  adscribamus  solo,.sive  quod  mari  subest 
sive  quod  inundatur;  potius  tamen  ei  quod  mari  subest.  Hoc  enim  multo  est 
mobilius,  et  quod  ob  humiditatem  cclerius  multari  possit." — Strabo,  Geog.  Edit. 
Almelov.  Amst.  1707,  lib.  1. 

^.Volcanic  eruptions,  eruptiones  flatuum,  in  the  Latin  translations,  and  in  the 
original  Greek, ava^arj^am,  gaseous  eruptions?  or  inflations  of  land  ? — Ibid.  p.  93. 

\  Strabo,  lib.  vi.  p.  396.  §  Book  iv.  ||  L.  vi.  ch.  xiii. 


16  KNOWLEDGE   OF   THE   ANCIENTS.  [On.  IL 

Pliny. — This  philosopher  had  no  theoretical  opinions  of  his  own  con- 
cerning changes  of  the  earth's  surface  ;  and  in  this  department,  as  in 
others,  he  restricted  himself  to  the  task  of  a  compiler,  without  reasoning 
on  the  facts  stated  by  him,  or  attempting  to  digest  them  into  regular 
order.  But  his  enumeration  of  the  new  islands  which  had  been  formed 
in  the  Mediterranean,  and  of  other  convulsions,  shows  that  the  ancients 
had  not  been  inattentive  observers  of  the  changes  which  had  taken  place 
within  the  memory  of  man. 

Such,  then,  appear  to  have  been  the  opinions  entertained  before  the 
Christian  era,  concerning  the  past  revolutions  of  our  globe.  Although 
no  particular  investigations  had  been  made  for  the  express  purpose  of 
interpreting  the  monuments  of  ancient  changes,  they  were  too  obvious 
to  be  entirely  disregarded  ;  and  the  observation  of  the  present  course  of 
nature  presented  too  many  proofs  of  alterations  continually  in  progress 
on  the  earth  to  allow  philosophers  to  believe  that  nature  was  in  a  state 
of  rest,  or  that  the  surface  had  remained,  and  would  continue  to  remain 
unaltered.  But  they  had  never  compared  attentively  the  results  of  the 
destroying  and  reproductive  operations  of  modern  times  with  those  of 
remote  eras,  nor  had  they  ever  entertained  so  much  as  a  conjecture  con- 
cerning the  comparative  antiquity  of  the  human  race,  or  of  living  species 
of  animals  and  plants,  with  those  belonging  to  former  conditions  of  the 
organic  world.  They  had  studied  the  movements  and  positions  of  the 
heavenly  bodies  with  laborious  industry,  and  made  some  progress  in 
investigating  the  animal,  vegetable,  and  mineral  kingdoms  ;  but  the  an- 
cient history  of  the  globe  was  to  them  a  sealed  book,  and,  although 
written  in  characters  of  the  most  striking  and  imposing  kind,  they  were 
unconscious  even  of  its  existence. 


CHAPTER  III. 

HISTORY    OF    THE    PROGRESS    OF    GEOLOGY Continued. 

Arabian  writers  of  the  tenth  century — Avicenna — Omar — Cosmogony  of  the  Ko- 
ran— Kazwini — Early  Italian  writers — Leonardo  da  Vinci — Fracastoro — Con- 
troversy as  to  the  real  nature  of  fossils — Attributed  to  the  Mosaic  deluge — 
Palissy — Steno — Scilla — Quirini — Boyle — Lister — Leibnitz — Hooke's  Theory 
of  Elevation  by  Earthquakes — Of  lost  species  of  animals — Ray — Physico-theo- 
logical  writers — Woodward's  Diluvial  Theory — Burnet — Whiston— Vallisneri — 
Lazzaro  Moro — Generelli — Buffon — His  theory  condemned  by  the  Sorbonne  as 
unorthodox — His  declaration — Targioni — Arduino — Michell — Catcott  —  Raspe 
Fuchsel — Fortis — Testa — Whitehurst — Pallas — Saussure. 

Arabian  writers. — AFTER  the  decline  of  the  Roman  empire,  the  cul- 
tivation of  physical  science  was  first  revived  with  some  success  by  the 
Saracens,  about  the  middle  of  the  eighth  century  of  our  era.  The 
works  of  the  most  eminent  classic  writers  were  purchased  at  great  ex- 
pense from  the  Christians,  and  translated  into  Arabic  ;  and  Al  Mamun, 
son  of  the  famous  Harun-al-Rashid,  the  contemporary  of  Charlemagne, 
received  with  marks  of  distinction,  at  his  court  at  Bagdad,  astronomers 
and  men  of  learning  from  different  countries.  This  ca\iph,  and  some  of 
his  successors,  encountered  much  opposition  and  jea1-  «sy  from  the  doc- 
tors of  the  Mahometan  law,  who  wished  the  Moslems  to  confine  their 
studies  to  the  Koran,  dreading  the  effects  of  the  diffusion  of  a  taste  for 
the  physical  sciences.* 

Avicenna. — Almost  all  the  works  of  the  early  Arabian  writers  are 
lost.  Amongst  those  of  the  tenth  century,  of  which  fragments  are  now 
extant,  is  a  short  treatise,  "  On  the  Formation  and  Classification  of 
Minerals,"  by  Avicenna,  a  physician,  in  whose  arrangement  there  is  con- 
siderable merit.  The  second  chapter,  "  On  the  Cause  of  Mountains,"  is 
remarkable  ;  for  mountains,  he  says,  are  formed,  some  by  essential, 
others  by  accidental  causes.  In  illustration  of  the  essential,  he  instan- 
ces "  a  violent  earthquake,  by  which  land  is  elevated,  and  becomes  a 
mountain ;"  of  the  accidental,  the  principal,  he  says,  is  excavation  by 
water,  whereby  cavities  are  produced,  and  adjoining  lands  made  to  stand 
out  and  form  eminences.f 

Omar — Cosmogony  of  the  Koran. — In  the  same  century,  also,  Omar, 
surnamed  "  El  Aalem,"  or  "  The  Learned,"  wrote  a  work  on  "  The  Re- 
treat of  the  Sea."  It  appears  that  on  comparing  the  charts  of  his  own 
time  with  those  made  by  the  Indian  and  Persian  astronomers  two  thou- 
sand years  before,  he  had  satisfied  himself  that  important  changes  had 
taken  place  since  the  times  of  history  in  the  form  of  the  coasts  of  Asia, 

*  Mod.  Univ.  Hist.  vol.  ii.  chap.  iv.  section  iii. 

f  Montes  quandoque  fiunt  ex  causa  essentiali,  quandoque  ex  causa  accidentali. 
Ex  essentiali  causa,  ut  ex  vehementi  motu  terrae  elevatur  terra,  et  fit  mons.  Ac- 
cidentali, <fec. — De  Congelatione  Lapidum,  ed.  Gedani,  1682. 

2 


18  OMAK. THE   KORAN.  [On.  III. 

and  that  the  extension  of  the  sea  had  been  greater  at  some  former  pe- 
riods. He  was  confirmed  in  this  opinion  by  the  numerous  salt  springs 
and  marshes  in  the  interior  of  Asia, — a  phenomenon  from  which  Pallas, 
in  more  recent  times,  has  drawn  the  same  inference. 

Von  Hoff  has  suggested,  with  great  probability,  that  the  changes  in 
the  level  of  the  Caspian  (some  of  which  there  is  reason  to  believe  have 
happened  within  the  historical  era),  and  the  geological  appearances  in 
that  district,  indicating  the  desertion  by  that  sea  of  its  ancient  bed,  had 
prpbably  led  Omar  to  his  theory  of  a  general  subsidence.  But  what- 
ever may  have  been  the  proofs  relied  on,  his  system  was  declared  con- 
tradictory to  certain  passages  in  the  Koran,  and  he  was  called  upon 
publicly  to  recant  his  errors  ;  to  avoid  which  persecution  he  went  into 
voluntary  banishment  from  Samarkand.* 

The  cosmological  opinions  expressed  in  the  Koran  are  few,  and 
merely  introduced  incidentally :  so  that  it  is  not  easy  to  understand 
how  they  could  have  interfered  so  seriously  with  free  discussion  on  the 
former  changes  of  the  globe.  The  Prophet  declares  that  the  earth  was 
created  in  two  days,  and  the  mountains  were  then  placed  on  it ;  and 
during  these,  and  two  additional  days,  the  inhabitants  of  the  earth  were 
formed  ;  and  in  two  more  the  seven  heavens.f  There  is  no  more  de- 
tail of  circumstances  ;  and  the  deluge,  which  is  also  mentioned,  is  dis- 
cussed with  equal  brevity.  The  waters  are  represented  to  have  poured 
out  of  an  oven  ;  a  strange  fable,  said  to  be  borrowed  from  the  Persian 
Magi,  who  represented  them  as  issuing  from  the  oven  of  an  old  woman. J 
All  men  were  drowned,  save  Noah  and  his  family ;  and  then  God  said, 
"  0  earth,  swallow  up  thy  waters ;  and  thou,  0  heaven,  withhold  thy 
rain  ;"  and  immediately  the  waters  abated.  § 

We  may  suppose  Omar  to  have  represented  the  desertion  of  the  land 
by  the  sea  to  have  been  gradual,  and  that  his  hypothesis  required  a 
greater  lapse  of  ages  than  was  consistent  with  Moslem  orthodoxy  ;  for 
it  is  to  be  inferred  from  the  Koran,  that  man  and  this  planet  were  cre- 
ated at  the  same  time  ;  and  although  Mahomet  did  not  limit  expressly 
the  antiquity  of  the  human  race,  yet  he  gave  an  implied  sanction  to  the 
Mosaic  chronology,  by  the  veneration  expressed  by  him  for  the  He- 
brew Patriarchs.  || 

*  Von  Hoff,  Geschichte  der  Veranderungen  der  Erdoberflache,  vol.  i.  p.  406, 
who  cites  Delisle,  bey  Hismann  Welt-und  Volkergeschichte.  Alte  Gescbichte 
lter  theil,  s.  234. — The  Arabian  persecutions  for  heretical  dogmas  in  theology  were 
often  very  sanguinary.  In  the  same  ages  wherein  learning  was  most  in  esteem, 
the  Mahometans  were  divided  into  two  sects,  one  of  whom  maintained  that  the 
Koran  was  increate,  and  had  subsisted  in  the  very  essence  of  God  from  all  eter- 
nity ;  and  the  other,  the  Motazalites,  who,  admitting  that  the  Koran  was  institu- 
ted by  God,  conceived  it  to  have'been  first  made  when  revealed  to  the  Prophet 
at  Mecca,  and  accused  their  opponents  of  believing  in  two  eternal  beings.  The 
opinions  of  each  of  these  sects  were  taken  up  by  diffent  caliphs  in  succession,  and 
the  followers  of  each  sometimes  submitted  to  be  beheaded,  or  flogged  till  at  the 
point  of  death,  rather  than  renounce  their  creed. — Mod.  Univ.  Hist.  vol.  ii.  ch.  iv. 

!  Koran,  chap.  xli. 
Sale's  Koran,  chap.  xi.  see  note.  §  Ibid. 

Kossa,  appointed  master  to  the  Caliph  Al  Mamud,  was  author  of  a  book  en 


Oil.  III.]  ARABIAN    WRITERS. KAZWINI.  19 

A  manuscript  work,  entitled  the  "  Wonders  of  Nature,"  is  preserved 
in  the  Royal  Library  at  Paris,  by  an  Arabian  writer,  Mohammed 
Kazwini,  who  flourished  in  the  seventh  century  of  the  Hegira,  or  at 
the  close  of  the  thirteenth  century  of  our  era.*  Besides  several  curious 
remarks  on  aerolites,  earthquakes,  and  the  successive  changes  of  posi- 
tion which  the  land  and  sea  have  undergone,  we  meet  with  the  follow- 
ing beautiful  passage  which  is  given  as  the  narrative  of  Kidhz,  an  alle- 
gorical personage  : — "  I  passed  one  day  by  a  very  ancient  and  wonder- 
fully populous  city,  and  asked  one  of  its  inhabitants  how  long  it  had 
been  founded.  '  It  is  indeed  a  mighty  city,'  replied  he ;  '  we  know 
not  how  long  it  has  existed,  and  our  ancestors  were  on  this  subject 
as  ignorant  as  ourselves.'  Five  centuries  afterwards,  as  I  passed  by 
the  same  place,  I  could  not  perceive  the  slightest  vestige  of  the  city. 
I  demanded  of  a  peasant,  who  was  gathering  herbs  upon  its  former 
site,  how  long  it  had  been  destroyed.  '  In  sooth  a  strange  question  !' 
replied  he.  '  The  ground  here  has  never  been  different  from  what  you 
now  behold  it.' — '  Was  there  not  of  old,'  said  I,  *  a  splendid  city  here  ?' 
— *  Never,'  answered  he,  '  so  far  as  we  have  seen,  and  never  did  our 
fathers  speak  to  us  of  any  such.'  On  my  return  there  500  years  after- 
wards, /  found  the  sea  in  the  same  place,  and  on  its  shores  were  a  party 
of  fishermen,  of  whom  I  inquired  how  long  the  land  had  been  cov- 
ered by  the  waters  ?  '  Is  this  a  question,'  said  they,  '  for  a  man  like 
you  ?  this  spot  has  always  been  what  it  is  now.'  I  again  returned, 
500  years  afterwards,  and  the  sea  had  disappeared ;  I  inquired  of  a 
man  who  stood  alone  upon  the  spot,  how  long  ago  this  change  had 
taken  place,  and  he  gave  me  the  same  answer  as  I  had  received  before. 
Lastly,  on  coming  back  again  after  an  equal  lapse  of  time,  I  found 
there  a  flourishing  city,  more  populous  and  more  rich  in  beautiful  build- 
ings, than  the  city  I  had  seen  the  first  time,  and  when  I  would  fain 
have  informed  myself  concerning  its  origin,  the  inhabitants  answered 
me,  '  Its  rise  is  lost  in  remote  antiquity  :  we  are  ignorant  how  long  it  has 
existed,  and  our  fathers  were  on  this  subject  as  ignorant  as  ourselves.' " 

Early  Italian  writers. — It  was  not  till  the  earlier  part  of  the  six- 
teenth century  that  geological  phenomena  began  to  attract  the  attention 
of  the  Christian  nations.  At  that  period  a  very  animated  controversy 
sprang  up  in  Italy,  concerning  the  true  nature  and  origin  of  marine 
shells,  and  other  organized  fossils,  found  abundantly  in  the  strata  of  the 
peninsula.  The  celebrated  painter  Leonardo  da  Vinci,  who  in  his  youth 
had  planned  and  executed  some  navigable  canals  in  the  north  of  Italy, 
was  one  of  the  first  who  applied  sound  reasoning  to  these  subjects. 
The  mud  of  rivers,  he  said,  had  covered  and  penetrated  into  the  interior 
of  fossil  shells  at  a  time  when  these  were  still  at  the  bottom  of  the  sea 
near  the  coast.  "  They  tell  us  that  these  shells  were  formed  in  the 

titled  "  The  history  of  the  Patriarchs  and  Prophets,  from  the  Creation  of  the 
World."— Mod.  Univ.  Hist.  vol.  ii.  ch.  iv. 

*  Translated  by  MM.  Chezy  and  De  Sacy,  and  cited  by  M.  Elie  de  Beaumont, 
Ann.  des  ScL  Nat.  1832. 


20  FKACASTOEO.  [Cfl.  IIL 

hills  by  the  influence  of  the  stars  ;  but  I  ask  where  in  the  hills  are  the 
stars  now  forming  shells  of  distinct  ages  and  species  ?  and  how  can  the 
stars  explain  the  origin  of  gravel,  occurring  at  different  heights  and 
composed  of  pebbles  rounded  as  if  by  the  motion  of  running  water ;  or 
in  what  manner  can  such  a  cause  account  for  the  petrifaction  in  the 
same  places  of  various  leaves,  sea- weeds,  and  marine-crabs  ?"* 

The  excavations  made  in  1517,  for  repairing  the  city  of  Verona, 
brought  to  light  a  multitude  of  curious  petrifactions,  and  furnished 
matter  for  speculation  to  different  authors,  and  among  the  rest  to 
Fracastoro,t  who  declared  his  opinion,  that  fossil  shells  had  all  belonged 
to  living  animals,  which  had  formerly  lived  and  multiplied  where  there 
exuviae  are  now  found.  He  exposed  the  absurdity  of  having  recourse 
to  a  certain  "  plastic  force,"  which  it  was  said  had  power  to  fashion 
stones  into  organic  forms  ;  and  with  no  less  cogent  arguments,  demon- 
strated the  futility  of  attributing  the  situation  of  the  shells  in  question 
to  the  Mosaic  deluge,  a  theory  obstinately  defended  by  some.  That 
inundation,  he  observed,  was  too  transient ;  it  consisted  principally  of 
fluviatile  waters ;  and  if  it  had  transported  shells  to  great  distances, 
must  have  strewed  them  over  the  surface,  not  buried  them  at  vast 
depths  in  the  interior  of  mountains.  His  clear  exposition  of  the  evi- 
dence would  have  terminated  the  discussion  forever,  if  the  passions  of 
mankind  had  not  been  enlisted  in  the  dispute ;  and  even  though  doubts 
should  for  a  time  have  remained  in  some  minds,  they  would  speedily 
have  been  removed  by  the  fresh  information  obtained  almost  imme- 
diately afterwards,  respecting  the  structure  of  fossil  remains,  and  of 
their  living  analogues. 

But  the  clear  and  philosophical  views  of  Fracastoro  were  disre- 
garded, and  the  talent  and  argumentative  powers  of  the  learned  were 
doomed  for  three  centuries  to  be  wasted  in  the  discussion  of  these  two 
simple  and  preliminary  questions  :  first,  whether  fossil  remains  had 
ever  belonged  to  living  creatures ;  and,  secondly,  whether,  if  this  be 
admitted,  all  the  phenomena  could  not  be  explained  by  the  deluge  of 
Noah.  It  had  been  the  general  belief  of  the  Christian  world  down  to 
the  period  now  under  consideration,  that  the  origin  of  this  planet  was 
not  more  remote  than  a  few  thousand  years ;  and  that  since  the  crea- 
tion the  deluge  was  the  only  great  catastrophe  by  which  considerable 
change  had  been  wrought  on  the  earth's  surface.  On  the  other  hand, 
the  opinion  was  scarcely  less  general,  that  the  final  dissolution  of  our 
system  was  an  event  to  be  looked  for  at  no  distant  period.  The  era,  it 
is  true,  of  the  expected  millennium  had  passed  away ;  and  for  five 
hundred  years  after  the  fatal.hour  when  the  annihilation  of  the  planet 

*  See  Venturi's  extracts  from  Da  Vinci's  MMS.  now  in  Library  of  Institute  of 
France.  They  are  not  mentioned  by  Brocchi,  and  my  attention  was  first  called 
to  them  by  Mr.  Hallam.  L.  da  Vinci  died  A.  D.  1519. 

f  Museum  Calceol. — See  Brocchi's  Discourse  on  the  Progress  of  the  Study  of 
Fossil  Conchology  in  Italy,  where  some  of  the  following  notices  on  Italian  writers 
will  be  found  more  at  large. 


CH.  III.]  EAELY    ITALIAN    WRITERS.  21 

had  been  looked  for,  the  monks  remained  in  undisturbed  enjoyment  of 
rich  grants  of  land  bequeathed  to  them  by  pious  donors,  who,  in  the 

preamble  of  deeds  beginning  "  appropinquante  mundi  termino" 

"  appropinquante  magno  judicii  die,"  left  lasting  monuments  of  the 
popular  delusion.* 

But  although  in  the  sixteenth  century  it  had  become  necessary  to 
interpret  certain  prophecies  respecting  the  millennium  more  liberally, 
and  to  assign  a  more  distant  date  to  the  future  conflagration  of  the 
world,  we  find,  in  the  speculations  of  the  early  geologists,  perpetual 
allusion  to  such  an  approaching  catastrophe ;  while  in  all  that  regarded 
the  antiquity  of  the  earth,  no  modification  whatever  of  the  -opinions  of 
the  dark  ages  had  been  effected.  Considerable  alarm  was  at  first  ex- 
cited when  the  attempt  was  made  to  invalidate,  by  physical  proofs,  an 
article  of  faith  so  generally  received  ;  but  there  was  sufficient  spirit  of 
toleration  and  candor  amongst  the  Italian  ecclesiastics,  to  allow  the  sub- 
ject to  be  canvassed  with  much  freedom.  They  even  entered  warmly 
into  the  controversy  themselves,  often  favoring  different  sides  of  the 
question ;  and  however  much  we  may  deplore  the  loss  of  time  and  labor 
devoted  to  the  defence  of  untenable  positions,  it  must  be  conceded  that 
they  displayed  far  less  polemic  bitterness  than  certain  writers  who  fol- 
lowed them  "  beyond  the  Alps,"  two  centuries  and  a  half  later. 

CONTROVERSY    AS    TO    THE    REAL    NATURE    OF    FOSSIL    ORGANIC    REMAINS. 

Mattioli — Falloppio. — The  system  of  scholastic  disputations,  en- 
couraged in  the  universities  of  the  middle  ages,  had  unfortunately 
trained  men  to  habits  of  indefinite  argumentation ;  and  they  often  pre- 
ferred absurd  and  extravagant  propositions,  because  greater  skill  was 
required  to  maintain  them ;  the  end  and  object  of  these  intellectual 
combats  being  victory,  and  not  truth.  No*  theory  could  be  so  far- 
fetched or  fantastical  as  not  to  attract  some  followers,  provided  it  fell 
in  with  popular  notions  ;  and  as  cosmogonists  were  not  at  all  restricted, 
in  building  their  systems,  to  the  agency  of  known  causes,  the  opponents 
of  Fracastoro  met  his  arguments  by  feigning  imaginary  causes,  which 
differed  from  each  other  rather  in  name  than  in  substance.  Andrea 
Mattioli,  for  instance,  an  eminent  botanist,  the  illustrator  of  Dioscorides, 
embraced  the  notion  of  Agricola,  a  skilful  German  miner,  that  a  certain 
"  materia  pinguis,"  or  "  fatty  matter,"  set  into  fermentation  by  heat, 
gave  birth  to  fossil  organic  shapes.  Yet  Mattioli  had  come  to  the  con- 
clusion, from  his  own  observations,  that  porous  bodies,  such  as  bones 
and  shells,  might  be  converted  into  stone,  as  being  permeable  to  what 
he  termed  the  "lapidifying  juice."  In  like  manner,  Falloppio  of  Padua 
conceived  that  petrified  shells  were  generated  by  fermentation  in  the 
spots  where  they  are  found,  or  that  they  had  in  some  cases  acquired 

*  In  Sicily,  in  particular,  the  title-deeds  of  many  valuable  grants  of  land  to  the 
monasteries  are  headed  by  such  preambles,  composed  by  the  testators  about  the 
period  when  the  good  King  Roger  was  expelling  the  Saracens  from  that  island. 


22  CARDANO. CESALPINO. — MAJOLI.  [On.  IIL 

their  form  from  "  the  tumultuous  movements  of  terrestrial  exhalations." 
Although  celebrated  as  a  professor  of  anatomy,  he  taught  that  certain 
tusks  of  elephants,  dug  up  in  his  time  in  Apulia,  were  mere  earthy  con- 
cretions ;  and,  consistently  with  these  principles,  he  even  went  so  far  as 
to  consider  it  probable,  that  the  vases  of  Monte  Testaceo  at  Rome  were 
natural  impressions  stamped  in  the  soil.*  In  the  same  spirit,  Mercati, 
who  published,  in  1574,  faithful  figures  of  the  fossil  shells  preserved  by 
Pope  Sixtus  V.  in  the  Museum  of  the  Vatican,  expressed  an  opinion  that 
they  were  mere  stones,  which  had  assumed  their  peculiar  configuration 
from  the  influence  of  the  heavenly  bodies ;  and  Olivi  of  Cremona,  who 
described  the  fossil  remains  of  a  rich  museum  at  Verona,  was  satisfied 
with  considering  them  as  mere  "  sports  of  nature." 

Some  of  the  fanciful  notions  of  those  times  were  deemed  less  un- 
reasonable, as  being  somewhat  in  harmony  with  the  Aristotelian  theory 
of  spontaneous  generation,  then  taught  in  all  the  schools. f  For  men 
who  had  been  taught  in  early  youth,  that  a  large  proportion  of  living 
animals  and  plants  was  formed  from  the  fortuitous  concourse  of  atoms, 
or  had  sprung  from  the  corruption  of  organic  matter,  might  easily  per- 
suade themselves  that  organic  shapes,  often  imperfectly  preserved  in 
the  interior  of  solid  rocks,  owed  their  existence  to  causes  equally  ob- 
scure and  mysterious. 

Cardano,  1552. — But  there  were  not  wanting  some  who,  during  the 
progress  of  this  century,  expressed  more  sound  and  sober  opinions.  The 
title  of  a  work  of  Cardano's,  published  in  1552,  "De  Subtilitate"  (cor- 
responding to  what  would  now  be  called  Transcendental  Philosophy), 
would  lead  us  to  expect,  in  the  chapter  on  minerals,  many  far-fetched 
theories  characteristic  of  that  age ;  but  when  treating  of  petrified  shells, 
he  decided  that  they  clearly  indicated  the  former  sojourn  of  the  sea 
upon  the  mountains.}; 

Cesalpino — Majoli,  1597. — Cesalpino,  a  celebrated  botanist,  con- 
ceived that  fossil  shells  had  been  left  on  the  land  by  the  retiring  sea, 
and  had  concreted  into  stone  during  the  consolidation  of  the  soil  ;§  and 
in  the  following  year  (1597),  Simeone  Majoli||  went  still  farther  ;  and, 
coinciding  for  the  most  part  with  the  views  of  Cesalpino,  suggested  that 
the  shells  and  submarine  matter  of  the  Veronese,  and  other  districts, 
might  have  been  cast  up  upon  the  land  by  volcanic  explosions,  like 
those  which  gave  rise,  in  1538,  to  Monte  Nuovo,  near  Puzzuoli.  This 
hint  seems  to  have  been  the  first  imperfect  attempt  to  connect  the  posi- 
tion of  fossil  shells  with  the  agency  of  volcanoes,  a  system  afterwards  more 
fully  developed  by  Hooke,  Lazzaro  Moro,  Hutton,  and  other  writers. 

Two  years  afterwards,  Imperati  advocated  the  animal  origin  of  fossil- 
ized shells,  yet  admitted  that  stones  could  vegetate  by  force  of  "  an 
internal  principle ;"  and,  as  evidence  of  this,  he  referred  to  the  teeth  ol 
fish  and  spines  of  echini  found  petrified.1!" 

*  De  Fossilib.  pp.  109,  176.  f  Aristotle,  On  Animals,  chaps.  1,  15. 

\  Brocchi,  Con.  Fos.  Subap.  Disc,  sui  ProgressL  voL  i.  p.  57. 

§  De  Metallicis.  f  Dies  Caniculares.  ^f'Storia  Naturale. 


CH.   III.]  PALISSY. COLONNA. STENO.  23 

Palissy,  1580. — Palissy,  a  French  writer  on  "The  Origin  of  Springs 
from  Rain- water, "and  of  other  scientific  works,  undertook,  in  1580,  to 
combat  the  notions  of  many  of  his  contemporaries  in  Italy,  that  petrified 
shells  had  all  been  deposited  by  the  universal  deluge.  "  He  was  the 
first,"  said  Fontenelle,  when,  in  the  French  Academy,  he  pronounced 
his  eulogy,  nearly  a  century  and  a  half  later,  "  who  dared  assert,"  in 
Paris,  that  fossil  remains  of  testacea  and  fish  had  once  belonged  to  ma- 
rine animals. 

Fabio  Colonna. — To  enumerate  the  multitude  of  Italian  writers,  who 
advanced  various  hypotheses,  all  equally  fantastical,  in  the  early  part  of 
the  seventeenth  century,  would  be  unprofitably  tedious  ;  but  Fabio  Co- 
lonna deserves  to  be  distinguished ;  for,  although  he  gave  way  to  the 
dogma,  that  all  fossil  remains  were  to  be  referred  to  the  deluge  of  Noah, 
he  resisted  the  absurd  theory  of  Stelluti,  who  taught  that  fossil  wood 
and  ammonites  were  mere  clay,  altered  into  such  forms  by  sulphureous 
waters  and  subterranean  heat ;  and  he  pointed  out  the  different  states 
of  shells  buried  in  the  strata,  distinguishing  between,  first,  the  mere 
mould  or  impression ;  second,  the  cast  or  nucleus ;  and,  thirdly,  the 
remains  of  the  shell  itself.  He  had  also  the  merit  of  being  the  first  to 
point  out  that  some  of  the  fossils  had  belonged  to  marine  and  some  to 
terrestrial  testacea.* 

Steno,  1669. — But  the  most  remarkable  work  of  that  period  was 
published  by  Steno,  a  Dane,  once  professor  of  anatomy  at  Padua,  and 
who  afterwards  resided  many  years  at  the  court  of  the  Grand  Duke  of 
Tuscany.  His  treatise  bears  the  quaint  title  of  "  De  Solido  intra  Soli- 
dum  naturaltier  contento  (1669),"  by  which  the  author  intended  to 
express,  "  On  Gems,  Crystals,  and  organic  Petrifactions  inclosed  within 
solid  Rocks."  This  work  attests  the  priority  of  the  Italian  school  in 
geological  research ;  exemplifying  at  the  same  time  the  powerful  obsta- 
cles opposed,  in  that  age,  to  the  general  reception  of  enlarged  views  in 
the  science.  It  was  still  a  favorite  dogma,  that  the  fossil  remains  of 
shells  and  marine  creatures  were  not  of  animal  origin ;  an  opinion  ad- 
hered to  by  many  from  their  extreme  reluctance  to  believe,  that  the 
earth  could  have  been  inhabited  by  living  beings  before  a  great  part  of 
the  existing  mountains  were  formed.  In  reference  to  this  controversy, 
Steno  had  dissected  a  shark  recently  taken  from  the  Mediterranean,  and 
had  demonstrated  that  its  teeth  and  bones  were  identical  with  many 
fossils  found  in  Tuscany.  He  had  also  compared  the  shells  discovered 
in  the  Italian  strata  with  living  species,  pointed  out  their  resemblance, 
and  traced  the  various  gradations  from  shells  merely  calcined,  or  which 
had  only  lost  their  animal  gluten,  to  those  petrifactions  in  which  there 
was  a  perfect  substitution  of  stony  matter.  In  his  division  of  mineral 
masses,  he  insisted  on  the  secondary  origin  of  those  deposits  in  which 
the  spoils  of  animals  or  fragments  of  older  rocks  were  inclosed.  He 
distinguished  between  marine  formations  and  those  of  a  fluviatile  char- 

*  Osserv.  sugli  Animali  aquat.  e  terrest.  162fi. 


24  STENO. SCILLA.  [Cn.  ITI 

acter,  the  last  containing  reeds,  grasses,  or  the  trunks  and  branches  of 
trees.  He  argued  in  favor  of  the  original  horizontality  of  sedimentary 
deposits,  attributing  their  present  inclined  and  vertical  position  some- 
times  to  the  escape  of  subterranean  vapors  heaving  the  crust  of  the 
earth  from  below  upwards,  and  sometimes  to  the  falling  in  of  masses 
overlying  subterranean  cavities. 

He  declared  that  he  had  obtained  proof  that  Tuscany  must  succes- 
sively have  acquired  six  distinct  configurations,  having  been  twice  cov- 
ered by  water,  twice  laid  dry  with  a  level,  and  twice  with  an  irregular 
and  uneven  surface.*  He  displayed  great  anxiety  to  reconcile  his  new 
views  with  Scripture,  for  which  purpose  he  pointed  to  certain  rocks  as 
having  been  formed  before  the  existence  of  animals  and  plants  :  select- 
ing unfortunately  as  examples  certain  formations  of  limestone  and  sand- 
stone in  his  own  country,  now  known  to  contain,  though  sparingly,  the 
remains  of  animals  and  plants, — strata  which  do  not  even  rank  as  the 
oldest  part  of  our  secondary  series.  Steno  suggested  that  Moses,  when 
speaking  of  the  loftiest  mountains  as  having  been  covered  by  the  deluge, 
meant  merely  the  loftiest  of  the  hills  then  existing,  which  may  not  have 
been  very  high.  The  diluvian  waters,  he  supposed,  may  have  issued 
from  the  interior  of  the  earth  into  which  they  had  retired,  when  in  the 
beginning  the  land  was  separated  from  the  sea.  These,  and  other 
hypotheses  on  the  same  subject,  are  not  calculated  to  enhance  the  value 
of  the  treatise,  and  could  scarcely  fail  to  detract  from  the  authority  of 
those  opinions  which  were  sound  and  legitimate  deductions  from  fact 
and  observation.  They  have  served,  nevertheless,  as  the  germs  of  many 
popular  theories  of  later  times,  and  in  an  expanded  form  have  been  put 
forth  as  original  inventions  by  some  of  our  contemporaries . 

Scilla,  1670. — Scilla,  a  Sicilian  painter,  published,  in  1670,  a  treatise, 
in  Latin,  on  the  fossils  of  Calabria,  illustrated  by  good  engravings. 
This  work  proves  the  continued  ascendancy  of  dogmas  often  refuted  ; 
for  we  find  the  wit  and  eloquence  of  the  author  chiefly  directed  against 
the  obstinate  incredulity  of  naturalists  as  to  the  organic  nature  of  fossil 
shells.f  Like  many  eminent  naturalists  of  his  day,  Scilla  gave  way  to  the 
popular  persuasion,  that  all  fossil  shells  were  the  effects  and  proofs  of  the 
Mosaic  deluge.  It  may  be  doubted  whether  he  was  perfectly  sincere, 
and  some  of  his  contemporaries  who  took  the  same  course  were  certainly 
not  so.  But  so  eager  were  they  to  root  out  what  they  justly  considered 
an  absurd  prejudice  respecting  the  nature  of  organized  fossils,  that  they 
seem  to  have  been  ready  to  make  any  concessions,  in  order  to  establish 
this  preliminary  point.  Such  a  compromising  policy  was  short-sighted, 
since  it  was  to  little  purpose- that  the  nature  of  the  documents  should  at 

*  Sex  itaque  distinctas  Etruriae  fades  agnoscimus,  dum  bis  fluida,  bis  plana,  et 
eicca,  bis  aspera  fuerit,  <fec. 

f  Scilla  quotes  the  remark  of  Cicero  on  the  story  that  a  stone  in  Chios  had  been 
cleft  open,  and  presented  the  head  of  Paniscus  in  relief : — "  I  believe,"  said  the 
orator,  "that  the  figure  bore  some  resemblance  to  Paniscus,  but  not  such  that 
you  would  have  deemed  it  sculptured  by  Scopas ;  for  chance  never  perfectly 
imitates  the  truth." 


CH.    III.]  DILUVIAL    THEORY. QUIRINI.  25 

length  be  correctly  understood,  if  men  were  to  be  prevented  from  dedu- 
cin<>-  fair  conclusions  from  them. 

O 

Diluvial  Theory. — The  theologians  who  now  entered  the  field  in 
Italy,  Germany,  France,  and  England,  were  innumerable  ;  and  hence- 
forward, they  who  refused  to  subscribe  to  the  position,  that  all  marine 
organic  remains  were  proofs  of  the  Mosaic  deluge,  were  exposed  to  tho 
imputation  of  disbelieving  the  whole  of  the  sacred  writings.  Scarcely 
any  step  had  been  made  in  approximating  to  sound  theories  since  the 
time  of  Fracastoro,  more  than  a  hundred  years  having  been  lost,  in 
writing  down  the  dogma  that  organized  fossils  were  mere  sports  of 
nature.  An  additional  period  of  a  century  and  a  half  was  now  destined 
to  be  consumed  in  exploding  the  hypothesis,  that  organized  fossils  had 
all  been  buried  in  the  solid  strata  by  Noah's  flood.  Never  did  a  theo- 
retical fallacy,  in  any  branch  of  science,  interfere  more  seriously  with 
accurate  observation  and  the  systematic  classification  of  facts.  In  re- 
cent times,  we  may  attribute  our  rapid  progress  chiefly  to  the  careful 
determination  of  the  order  of  succession  in  mineral  masses,  by  means  of 
their  different  organic  contents,  and  their  regular  superposition.  But 
the  old  diluvialists  were  induced  by  their  system  to  confound  all  the 
groups  of  strata  together  instead  of  discriminating, — to  refer  all  appear- 
ances to  one  cause  and  to  one  brief  period,  not  to  a  variety  of  causes 
acting  throughout  a  long  succession  of  epochs.  They  saw  the  phenom- 
ena only  as  they  desired  to  see  them,  sometimes  misrepresenting  facts, 
and  at  other  times  deducing  false  conclusions  from  correct  data.  Under 
the  influence  of  such  prejudices,  three  centuries  were  of  as  little  avail  as 
a  few  years  in  our  own  times,  when  we  are  no  longer  required  to  propel 
the  vessel  against  the  force  of  an  adverse  current. 

It  may  be  well,  therefore,  to  forewarn  the  reader,  that  in  tracing  the 
history  of  geology  from  the  close  of  the  seventeenth  to  the  end  of  the 
eighteenth  century,  he  must  expect  to  be  occupied  with  accounts  of  the 
retardation,  as  well  as  of  the  advance,  of  the  science.  It  will  be  neces- 
sary to  point  out  the  frequent  revival  of  exploded  errors,  and  the  re- 
lapse from  sound  to  the  most  absurd  opinions ;  and  to  dwell  on  futile 
reasoning  and  visionary  hypothesis,  because  some  of  the  most  extrava- 
gant systems  were  invented  or  controverted  by  men  of  acknowledged 
talent.  In  short,  a  sketch  of  the  progress  of  geology  is  the  history  of 
a  constant  and  violent  struggle  of  new  opinions  against  doctrines  sanc- 
tioned by  the  implicit  faith  of  many  generations,  and  supposed  to  rest 
on  scriptural  authority.  The  inquiry,  therefore,  although  highly  in- 
teresting to  one  who  studies  the  philosophy  of  the  human  mind,  is  too 
often  barren  of  instruction  to  him  who  searches  for  truths  in  physical 
science. 

Quirini,  1676. — Quirini,  in  1676,*  contended,  in  opposition  to  Scilla, 
that  the  diluvian  waters  could  not  have  conveyed  heavy  bodies  to  the 
summit  of  mountains,  since  the  agitation  of  the  sea  never  (as  Boyle  had 

*  De  Testaceis  fossilibus  Mus.  Septaliani. 


26  PLOT. LISTEE. LEIBNITZ.  [On.  IIL 

demonstrated)  extended  to  great  depths  ;*  and  still  less  could  the  tes- 
tacea,  as  some  pretended,  have  lived  in  these  diluvian  waters ;  for  "  the 
duration  of  the  flood  was  brief,  and  the  heavy  rains  must  have  destroyed 
the  saltness  of  the  sea  /"  He  was  the  first  writer  who  ventured  to  main- 
tain that  the  universality  of  the  Mosaic  cataclysm  ought  not  to  be  in- 
sisted upon.  As  to  the  nature  of  petrified  shells,  he  conceived  that  as 
earthy  particles  united  in  the  sea  to  form  the  shells  of  mollusca,  the 
same  crystallizing  process  might  be  effected  on  the  land ;  and  that,  in 
the  latter  case,  the  germs  of  the  animals  might  have  been  disseminated 
through  the  substance  of  the  rocks,  and  afterwards  developed  by  virtue 
of  humidity.  Visionary  as  was  this  doctrine,  it  gained  many  proselytes 
even  amongst  the  more  sober  reasoners  of  Italy  and  Germany ;  for  it 
conceded  that  the  position  of  fossil  bodies  could  not  be  accounted  for  by 
the  diluvial  theory. 

Plot — Lister,  1678. — In  the  mean  time,  the  doctrine  that  fossil  shells 
had  never  belonged  to  real  animals  maintained  its  ground  in  England, 
where  the  agitation  of  the  question  began  at  a  much  later  period.  Dr. 
Plot,  in  his  "  Natural  History  of  Oxfordshire"  (1677),  attributed  to  a 
"  plastic  virtue  latent  in  the  earth"  the  origin  of  fossil  shells  and  fishes  ; 
and  Lister,  to  his  accurate  account  of  British  shells,  in  1678,  added  the 
fossil  species,  under  the  appellation  of  turbinated  and  bivalve  stones. 
"  Either,"  said  he,  "  these  were  terriginous,  or,  if  otherwise,  the  animals 
they  so  exactly  represent  have  become  extinct."  This  writer  appears  to 
have  been  the  first  who  was  aware  of  the  continuity  over  large  districts 
of  the  principal  groups  of  strata  in  the  British  series,  and  who  proposed 
the  construction  of  regular  geological  maps.f 

Leibnitz,  1680. — The  great  mathematician  Leibnitz  published  his 
"Protogoea"  in  1680.  He  imagined  this  planet  to  have  been  originally 
a  burning  luminous  mass,  which  ever  since  its  creation  has  been  under- 
going refrigeration.  When  the  outer  crust  had  cooled  down  sufficiently 
to  allow  the  vapors  to  be  condensed,  they  fell,  and  formed  a  universal 
ocean,  covering  the  loftiest  mountains,  and  investing  the  whole  globe. 
The  crust,  as  it  consolidated  from  a  state  of  fusion,  assumed  a  vesicular 
and  cavernous  structure ;  and  being  rent  in  some  places,  allowed  the 
water  to  rush  into  the  subterranean  hollows,  whereby  the  level  of  the 
primeval  ocean  was  lowered.  The  breaking  in  of  these  vast  caverns  is 
supposed  to  have  given  rise  to  the  dislocated  and  deranged  position  of 
the  strata  "  which  Steno  had  described,"  and  the  same  disruptions  com- 

*  The  opinions  of  Boyle,  alluded  to  by  Quirini,  were  published  a  few  years 
before,  in  a  short  article  entitled  "  On  the  Bottom  of  the  Sea."  From  observations 
collected  from  the  divers  of  the  pearl  fishery,  Boyle  inferred  that,  when  the  waves 
were  six  or  seven  feet  high  above  the  surface  of  the  water,  there  were  no  signs  of 
agitation  at  the  depth  of  fifteen  fathoms ;  and  tha.t  even  during  heavy  gales  of 
wind,  the  motion  of  the  water  was  exceedingly  diminished  at  the  depth  of  twelve 
or  fifteen  feet.  He  had  also  learnt  from  some  of  his  informants,  that  there  were 
currents  running  in  opposite  directions  at  different  depths. — Boyle's  Works,  vol. 
iii.  p.  110.  London,  1744. 

f  See  Conybeare  and  Phillips,  "  Outlines  of  the  Geology  of  England  and  Wales," 
p.  12. 


CH.  Ill]  HOOKE.  27 

municated  violent  movements  to  the  incumbent  waters,  whence  great 
inundations  ensued.  The  waters,  after  they  had  been  thus  agitated, 
deposited  their  sedimentary  matter  during  intervals  of  quiescence,  and 
hence  the  various  stony  and  earthy  strata.  "  We  may  recognize,  there- 
fore," says  Leibnitz,  "a  double  origin  of  primitive  masses,  the  one  by 
refrigeration  from  igneous  fusion,  the  other  by  concretion  from  aqueous 
solution."*  By  the  repetition  of  similar  causes  (the  disruption  of  the 
crust  and  consequent  floods),  alternations  of  new  strata  were  produced, 
until  at  length  these  causes  were  reduced  to  a  condition  of  quiescent 
equilibrium,  and  a  more  permanent  state  of  things  was  established. f 

Hooke,  1688.— The  "Posthumous  Works  of  Robert  Hooke,  M.  D.," 
well  known  as  a  great  mathematician  and  natural  philosopher,  appeared 
in  1705,  containing  "A  Discourse  of  Earthquakes,"  which,  we  are  in- 
formed by  his  editor,  was  written  in  1668,  but  revised  at  subsequent 
periods.;);  Hooke  frequently  refers  to  the  best  Italian  and  English 
authors  who  wrote  before  his  time  on  geological  subjects ;  but  there 
are  no  passages  in  his  works  implying  that  he  participated  in  the  en- 
larged views  of  Steno  and  Lister,  or  of  his  contemporary,  Woodward, 
in  regard  to  the  geographical  extent  of  certain  groups  of  strata.  His 
treatise,  however,  is  the  most  philosophical  production  of  that  age,  in 
regard  to  the  causes  of  former  changes  in  the  organic  and  inorganic 
kingdoms  of  nature. 

"  However  trivial  a  thing,"  he  says,  "  a  rotten  shell  may  appear  to 
some,  yet  these  monuments  of  nature  are  more  certain  tokens  of  an- 
tiquity than  coins  or  medals,  since  the  best  of  those  may  be  counter- 
feited or  made  by  art  and  design,  as  may  also  books,  manuscripts,  and 
inscriptions,  as  all  the  learned  are  now  sufficiently  satisfied  has  often 
been  actually  practised,"  &c. ;  "  and  though  it  must  be  granted  that  it 
is  very  difficult  to  read  them  (the  records  of  nature)  and  to  raise  a 
chronology  out  of  them,  and  to  state  the  intervals  of  the  time  wherein 
such  or  such  catastrophes  and  mutations  have  happened,  yet  it  is  not 
impossible. "§ 

Respecting  the  extinction  of  species,  Hooke  was  aware  that  the 
fossil  ammonites,  nautili,  and  many  other  shells  and  fossil  skeletons 
found  in  England,  were  of  different  species  from  any  then  known ;  but 
he  doubted  whether  the  species  had  become  extinct,  observing  that  the 
knowledge  of  naturalists  of  all  the  marine  species,  especially  those  in- 
habiting the  deep  sea,  was  very  deficient.  In  some  parts  of  his  wri- 

*  Unde  jam  duplex  origo  intelligitur  primorum  corporum,  una,  cum  ab  ignis 
fusione  refrigescerent,  altera,  cum  reconcrescerent  ex  solutione  aquarum. 

f  Redeunte  mox  simili  causa  strata  subinde  alia  aliis  imponerentur,  et  facies 
teneri  adhuc  orbis  stepius  novata  est.  Donee  quiescentibus  causis,  atque  aequili- 
brati?,  consistentior  emergeret  rerum  status. — For  an  able  analysis  of  the  views  of 
Leibnitz,  in  his  Protogosa,  see  Mr.  Conybeare's  Report  to  the  Brit.  Assoc.  on  the 
Progress  of  Geological  Science,  1832. 

\  Between  the  year  1688  and  his  death,  in  1703,  he  read  several  memoirs  to 
the  Royal  Society,  and  delivered  lectures  on  various  subjects,  relating  to  fossil 
remains  and  the  effects  of  earthquakes. 

§  Posth.  Works,  Lecture,  Feb.  29,  1688. 


HOOKE   ON   EXTINCT  SPECIES.  [Cfl.  III. 

tings,  however,  he  leans  to  the  opinion  that  species  had  been  lost ;  and  in 
speculating  on  this  subject,  he  even  suggests  that  there  might  be  some 
connection  between  the  disappearance  of  certain  kinds  of  animals  and 
plants,  and  the  changes  wrought  by  earthquakes  in  former  ages.  Some 
species,  he  observes,  with  great  sagacity,  are  "peculiar  to  certain  places, 
and  not  to  be  found  elsewhere.  If,  then,  such  a  place  had  been  swal- 
lowed up,  it  is  not  improbable  but  that  those  animate  beings  may  have 
been  destroyed  with  it ;  and  this  may  be  true  both  of  aerial  and  aquatic 
animals  ;  for  those  animated  bodies,  whether  vegetables  or  animals, 
which  were  naturally  nourished  or  refreshed  by  the  air,  would  be  de- 
stroyed by  the  water,"  &c.*  Turtles,  he  adds,  and  such  large  ammo- 
nites as  are  found  in  Portland,  seem  to  have  been  the  productions  of 
hotter  countries  ;  and  it  is  necessary  to  suppose  that  England  once  lay 
under  the  sea  within  the  torrid  zone  !  To  explain  this  and  similar  phe- 
nomena, he  indulges  in  a  variety  of  speculations  concerning  changes  in 
the  position  of  the  axis  of  the  earth's  rotation,  "  a  shifting  of  the  earth's 
centre  of  gravity,  analogous  to  the  revolutions  of  the  magnetic  pole," 
&c.  None  of  these  conjectures,  however,  are  proposed  dogmatically, 
but  rather  in  the  hope  of  promoting  fresh  inquiries  and  experiments. 

In  opposition  to  the  prejudices  of  his  age,  we  find  him  arguing 
against  the  idea  that  nature  had  formed  fossil  bodies  "  for  no  other  end 
than  to  play  the  mimic  in  the  mineral  kingdom ;" — maintaining  that 
figured  stones  were  "  really  the  several  bodies  they  represent,  or  the 
mouldings  of  them  petrified,"  and  not,  as  some  have  imagined,  '  a  lusus 
naturae,'  sporting  herself  in  the  needless  formation  of  useless  beings,  "f 

It  was  objected  to  Hooke,  that  his  doctrine  of  the  extinction  of 
species  derogated  from  the  wisdom  and  power  of  the  omnipotent  Crea- 
tor ;  but  he  answered,  that,  as  individuals  die,  there  may  be  some  ter- 
mination to  the  duration  of  a  species ;  and  his  opinions,  he  declared, 
were  not  repugnant  to  Holy  Writ :  for  the  Scriptures  taught  that  our 
system  was  degenerating,  and  tending  to  its  final  dissolution ;  "  and  as, 
when  that  shall  happen,  all  the  species  will  be  lost,  why  not  some  at 
one  time  and  some  at  another  ?"£ 

But  his  principal  object  was  to  account  for  the  manner  in  which  shells 

*  Posth.  Works,  p.  327. 

f  Posth.  Works,  Lecture,  Feb.  15,  1688.  Hooke  explained  with  considerable 
clearness  the  different  modes  wherein  organic  substances  may  become  lapidified ; 
and,  among  other  illustrations,  he  mentions  some  silicified  palm-wood  brought 
from  Africa,  on  which  M.  de  la  Hire  had  read  a  memoir  to  the  Royal  Academy 
of  France  (June,  1692),  wherein  he  had  pointed  out,  not  only  the  tubes  running 
the  length  of  the  trunk,  but  the  roots  at  one  extremity.  De  la  Hire,  says  Hooke, 
also  treated  of  certain  trees  founll  petrified  in  the  "river  that  passes  by  Bakan, 
in  the  kingdom  of  Ava,  and  which  has  for  the  space  of  ten  leagues  the  virtue  of 
petrifying  wood."  It  is  an  interesting  fact  that  the  silicified  wood  of  the  Irawadi 
should  have  attracted  attention  more  than  one  hundred  years  ago.  Remarkable 
discoveries  have  been  made  there  in  later  times  of  fossil  animals  and  vegetables, 
by  Mr.  Crawfurd  and  Dr.  Wallich.— See  Geol.  Trans,  vol.  ii.  part  iii.  p.  377,  second 
series.  De  la  Hire  cites  Father  Duchatz,  in  the  second  volume  of  "  Observations 
made  in  the  Indies  by  the  Jesuits." 

J  Posth.  Works,  Lecture,  May  29,  1689. 


Cu.  III.]  HOOKE    ON   EARTHQUAKES.  29 

had  been  conveyed  into  the  higher  parts  of  "  the  Alps,  Apennines,  and 
Pyrenean  hills,  and  the  interior  of  continents  in  general."  These  and 
other  appearances,  he  said,  might  have  been  brought  about  by  earth- 
quakes, "  which  have  turned  plains  into  mountains,  and  mountains  into 
plains,  seas  into  land,  and  land  into  seas,  made  rivers  where  there  were 
none  before,  and  swallowed  up  others  that  formerly  were,  &c.,  &c.  ;  and 
which,  since  the  creation  of  the  world,  have  wrought  many  great  changes 
on  the  superficial  parts  of  the  earth,  and  have  been  the  instruments  of 
placing  shells,  bones,  plants,  fishes,  and  the  like,  in  those  places  where, 
with  much  astonishment,  we  find  them."*  This  doctrine,  it  is  true,  had 
been  laid  down  in  terms  almost  equally  explicit  by  Strabo,  to  explain 
the  occurrence  of  fossil  shells  in  the  interior  of  continents,  and  to  that 
geographer,  and  other  writers  of  antiquity,  Hooke  frequently  refers ;  but 
the  revival  and  development  of  the  system  was  an  important  step  in  the 
progress  of  modern  science. 

Hooke  enumerated  all  the  examples  known  to  him  of  subterranean 
disturbance,  from  "  the  sad  catastrophe  of  Sodom  and  Gomorrah,"  down 
to  the  Chilian  earthquake  of  1646.  The  elevating  of  the  bottom  of  the 
sea,  the  sinking  and  submersion  of  the  land,  and  most  of  the  inequalities 
of  the  earth's  surface,  might,  he  said,  be  accounted  for  by  the  agency 
of  these  subterranean  causes.  He  mentions  that  the  coast  near  Naples 
was  raised  during  the  eruption  of  Monte  Nuovo  ;  and  that,  in  1591,  land 
rose  in  the  island  of  St.  Michael,  during  an  eruption :  and  although  it 
would  be  more  difficult,  he  says,  to  prove,  he  does  not  doubt  but  that 
there  had  been  as  many  earthquakes  in  the  parts  of  the  earth  under  the 
ocean,  as  in  the  parts  of  the  dry  land ;  in  confirmation  of  which,  he 
mentions  the  immeasurable  depth  of  the  sea  near  some  volcanoes.  To 
attest  the  extent  of  simultaneous  subterranean  movements,  he  refers  to 
an  earthquake  in  the  West  Indies,  in  the  year  1690,  where  the  space  of 
earth  raised,  or  "  struck  upwards,"  by  the  shock,  exceeded,  he  affirms, 
the  length  of  the  Alps  and  Pyrenees. 

Hooke 's  diluvial  Theory. — As  Hooke  declared  the  favorite  hypothesis 
of  the  day,  "  that  marine  fossil  bodies  were  to  be  referred  to  Noah's 
flood,"  to  be  wholly  untenable,  he  appears  to  have  felt  himself  called 
upon  to  substitute  a  diluvial  theory  of  his  own,  and  thus  he  became  in- 
volved in  countless  difficulties  and  contradictions.  "  During  the  great 
catastrophe,"  he  said,  "  there  might  have  been  a  changing  of  that  part 
which  was  before  dry  land  into  sea  by  sinking,  and  of  that  which  was 
sea  into  dry  land  by  raising,  and  marine  bodies  might  have  been  buried 
in  sediment  beneath  the  ocean,  in  the  interval  between  the  creation  and 
the  deluge."f  Then  follows  a  disquisition  on  the  separation  of  the  land 
from  the  waters,  mentioned  in  Genesis ;  during  which  operation  some 
places  of  the  shell  of  the  earth  were  forced  outwards,  and  others  pressed 
downwards  or  inwards,  &c.  His  diluvial  hypothesis  very  much  re- 
sembled that  of  Steno,  and  was  entirely  opposed  to  the  fundamental 

*  Posth.  Works,  p.  812.  f  Posth.  Works,  p.  410. 


30  KAY.  [Cn.  IIL 

principles  professed  by  him,  that  he  would  explain  the  former  changes 
of  the  earth  in  a  more  natural  manner  than  others  had  done.  When, 
in  despite  of  this  declaration,  he  required  a  former  "  crisis  of  nature," 
and  taught  that  earthquakes  had  become  debilitated,  and  that  the  Alps, 
Andes,  and  other  chains,  had  been  lifted  up  in  a  few  months,  he  was 
compelled  to  assume  so  rapid  a  rate  of  change,  that  his  machinery  ap- 
peared scarcely  less  extravagant  than  that  of  his  most  fanciful  prede- 
cessors. For  this  reason,  perhaps,  his  whole  theory  of  earthquakes  met 
with  undeserved  neglect. 

Ray,  1692. — One  of  his  contemporaries,  the  celebrated  naturalist, 
Ray,  participated  in  the  same  desire  to  explain  geological  phenomena 
by  reference  to  causes  less  hypothetical  than  those  usually  resorted  to.* 
In  his  essay  on  "  Chaos  and  Creation,"  he  proposed  a  system,  agreeing 
in  it§  outline,  and  in  many  of  its  details,  with  that  of  Hooke ;  but  his 
knowledge  of  natural  history  enabled  him  to  elucidate  the  subject  with 
various  original  observations.  Earthquakes,  he  suggested,  might  have 
been  the  second  causes  employed  at  the  creation,  in  separating  the  land 
from  the  waters,  and  in  gathering  the  waters  together  into  one  place. 
He  mentions,  like  Hooke,  the  earthquake  of  1646,  which  had  violently 
shaken  the  Andes  for  some  hundreds  of  leagues,  and  made  many  alter- 
ations therein.  In  assigning  a  cause  for  the  general  deluge,  he  preferred 
a  change  in  the  earth's  centre  of  gravity  to  the  introduction  of  earth- 
quakes. Some  unknown  cause,  he  said,  might  have  forced  the  sub- 
terranean waters  outwards,  as  was,  perhaps,  indicated  by  "the  break- 
ing up  of  the  fountains  of  the  great  deep." 

Ray  was  one  of  the  first  of  our  writers  who  enlarged  upon  the  effects 
of  running  water  upon  the  land,  and  of  the  encroachment  of  the  sea 
upon  the  shores.  So  important  did  he  consider  the  agency  of  these 
causes,  that  he  saw  in  them  an  indication  of  the  tendency  of  our  system 
to  its  final  dissolution  ;  and  he  wondered  why  the  earth  did  not  proceed 
more  rapidly  towards  a  general  submersion  beneath  the  sea,  when  so 
much  matter  was  carried  down  by  rivers,  or  undermined  in  the  sea- cliffs. 
We  perceive  clearly  from  his  writings,  that  the  gradual  decline  of  our 
system,  and  its  future  consummation  by  fire,  was  held  to  be  as  necessary 
an  article  of  faith  by  the  orthodox,  as  was  the  recent  origin  of  our  planet. 
His  discourses,  like  those  of  Hooke,  are  highly  interesting,  as  attesting 
the  familiar  association  in  the  minds  of  philosophers,  in  the  age  of  New- 
ton, of  questions  in  physics  and  divinity.  Ray  gave  an  unequivocal  proof 
of  the  sincerity  of  his  mind,  by  sacrificing  his  preferment  in  the  church, 
rather  than  take  an  oath  against  the  Covenanters,  which  he  could  not 
reconcile  with  his  conscience:  His  reputation,  moreover,  in  the  scientific 
world  placed  him  high  above  the  temptation  of  courting  popularity,  by 
pandering  to  the  physico-theological  taste  of  his  age.  It  is,  therefore, 

*  Ray's  Physico-theological  Discourses  were  of  somewhat  later  date  than 
Hooke's  great  work  on  earthquakea  He  speaks  of  Hooke  as  one  "  whom  for  his 
learning  and  deep  insight  into  the  mysteries  of  nature  he  deservedly  honored." 
— On  the  Deluge,  chap.  iv. 


CH.  III.]  WOODWAKD. BURNET.  31 

curious  to  meet  with  so  many  citations  from  the  Christian  fathers  and 
prophets  in  his  essays  on  physical  science — to  find  him  in  one  page  pro- 
ceeding, by  the  strict  rules  of  induction,  to  explain  the  former  changes 
of  the  globe,  and  in  the  next  gravely  entertaining  the  question,  whether 
the  sun  and  stars,  and  the  whole  heavens,  shall  be  annihilated,  together 
with  the  earth,  at  the  era  of  the  grand  conflagration. 

Woodward,  1695. — Among  the  contemporaries  of  Hooke  and  Ray, 
Woodward,  a  professor  of  medicine,  had  acquired  the  most  extensive 
information  respecting  the  geological  structure  of  the  crust  of  the  earth. 
He  had  examined  many  parts  of  the  British  strata  with  minute  atten- 
tion ;  and  his  systematic  collection  of  specimens,  bequeathed  to  the 
University  of  Cambridge,  and  still  preserved  there  as  arranged  by  him, 
shows  how  far  he  had  advanced  in  ascertaining  the  order  of  superposi- 
tion. From  the  great  number  of  facts  collected  by  him,  we  might  have 
expected  his  theoretical  views  to  be  more  sound  and  enlarged  than 
those  of  his  contemporaries  ;  but  in  his  anxiety  to  accommodate  all  ob- 
served phenomena  to  the  scriptural  account  of  the  Creation  and  Deluge, 
he  arrived  at  most  erroneous  results.  He  conceived  "  the  whole  terres- 
trial globe  to  have  been  taken  to  pieces  and  dissolved  at  the  flood,  and 
the  strata  to  have  settled  down  from  this  promiscuous  mass  as  any  earthy 
sediment  from  a  fluid."*  In  corroboration  of  these  views  he  insisted 
upon  the  fact,  that  "  marine  bodies  are  lodged  in  the  strata  according 
to  the  order  of  their  gravity,  the  heavier  shells  in  stone,  the  lighter  in 
chalk,  and  so  of  the  rest."f  Ray  immediately  exposed  the  unfounded 
nature  of  this  assertion,  remarking  truly  that  fossil  bodies  "  are  often 
mingled,  heavy  with  light,  in  the  same  stratum  ;"  and  he  even  went  so 
far  as  to  say,  that  Woodward  "  must  have  invented  the  phenomena  for 
the  sake  of  confirming  his  bold  and  strange  hypothesis"! — a  strong  ex- 
pression from  the  pen  of  a  contemporary. 

Burnet,  1690. — At  the  same  time  Burnet  published  his  "Theory  of 
the  Earth. "§  The  title  is  most  characteristic  of  the  age, — "  The  Sacred 
Theory  of  the  Earth  ;  containing  an  Account  of  the  Original  of  the 
Earth,  and  of  all  the  general  Changes  which  it  hath  already  undergone, 
or  is  to  undergo,  till  the  Consummation  of  all  Things."  Even  Milton 
had  scarcely  ventured  in  his  poem  to  indulge  his  imagination  so  freely 
in  painting  scenes  of  the  Creation  and  Deluge,  Paradise  and  Chaos. 
He  explained  why  the  primeval  earth  enjoyed  a  perpetual  spring  before 
the  flood !  showed  how  the  crust  of  the  globe  was  fissured  by  "  the 
sun's  rays,"  so  that  it  burst,  and  thus  the  diluvial  waters  were  let  loose 
from  a  supposed  central  abyss.  Not  satisfied  with  these  themes,  he 
derived  from  the  books  of  the  inspired  writers,  and  even  from  heathen 
authorities,  prophetic  views  of  the  future  revolutions  of  the  globe,  gave 
a  most  terrific  description  of  the  general  conflagration,  and  proved  that, 

*  Essay  towards  a  Natural  History  of  the  Earth,  1695.     Preface.         f  Ibid. 

±  Consequences  of  the  Deluge,  p.  165. 

§  First  published  in  Latin  between  the  years  1680  and  1690. 


32  BURNET. WHISTON.  [Cn.  III. 

a  new  heaven  and  a  new  earth  will  rise  out  of  a  second  chaos — after 
which  will  follow  the  blessed  millennium. 

The  reader  should  be  informed,  that,  according  to  the  opinion  of  many 
respectable  writers  of  that  age,  there  was  good  scriptural  ground  for 
presuming  that  the  garden  bestowed  upon  our  first  parents  was  not  on 
the  earth  itself,  but  above  the  clouds,  in  the  middle  region  between  our 
planet  and  the  moon.  Burnet  approaches  with  becoming  gravity  the 
discussion  of  so  important  a  topic.  He  was  willing  to  concede  that  the 
geographical  position  of  Paradise  was  not  in  Mesopotamia,  yet  he  main- 
tained that  it  was  upon  the  earth,  and  in  the  southern  hemisphere,  near  the 
equinoctial  line.  Butler  selected  this  conceit  as  a  fair  mark  for  his  satire, 
when,  amongst  the  numerous  accomplishments  of  Hudibras,  he  says, — 

"  He  knew  the  seat  of  Paradise, 
Could  tell  in  what  degree  it  lies; 
And,  as  he  was  disposed,  could  prove  it 
Below  the  moon,  or  else  above  it." 

Yet  the  same  monarch,  who  is  said  never  to  have  slept  without  Butler's 
poem  under  his  pillow,  was  so  great  an  admirer  and  patron  of  Burnet's 
book,  that  he  ordered  it  to  be  translated  from  the  Latin  into  English. 
The  style  of  the  "  Sacred  Theory"  was  eloquent,  and  the  book  dis- 
played powers  of  invention  of  no  ordinary  stamp.  It  was,  in  fact,  a 
fine  historical  romance,  as  Buffon  afterwards  declared ;  but  it  was 
treated  as  a  work  of  profound  science  in  the  time  of  its  author,  and  was 
panegyrized  by  Addison  in  a  Latin  ode,  while  Steele  praised  it  in  the 
"  Spectator." 

Whiston,  1696. — Another  production  of  the  same  school,  and  equally 
characteristic  of  the  time,  was  that  of  Whiston,  entitled,  "A  New 
Theory  of  the  Earth ;  wherein  the  Creation  of  the  world  in  Six  Days, 
the  Universal  Deluge,  and  the  General  Conflagration,  as  laid  down  in 
the  Holy  Scriptures,  are  shown  to  be  perfectly  agreeable  to  Reason  and 
Philosophy."  He  was  at  first  a  follower  of  Burnet ;  but  his  faith  in 
the  infallibility  of  that  writer  was  shaken  by  the  declared  opinion  of 
Newton,  that  there  was  every  presumption  in  astronomy  against  any 
former  change  in  the  inclination  of  the  earth's  axis.  This  was  a  leading 
dogma  in  Burnet's  system,  though  not  original,  for  it  was  borrowed 
from  an  Italian,  Alessandro  degli  Alessandri,  who  had  suggested  it  in 
the  beginning  of  the  fifteenth  century,  to  account  for  the  former  occu- 
pation of  the  present  continents  by  the  sea.  La  Place  has  since  strength- 
ened the  arguments  of  Newton,  against  the  probability  of  any  former 
revolution  of  this  kind. 

The  remarkable  comet  of  1680  was  fresh  in  the  memoiy  of  every 
one  when  Whiston  first  began  his  cosmological  studies  ;  and  the  princi- 
pal novelty  of  his  speculations  consisted  in  attributing  the  deluge  to  the 
near  approach  to  the  earth  of  one  of  these  erratic  bodies.  Having 
ascribed  an  increase  of  the  waters  to  this  source,  he  adopted  Wood- 


CH.  III.]  IIUTCIIINSON. CELSIUS. SCHEUCIIZER.  33 

ward's  theory,  supposing  all  stratified  deposits  to  have  resulted  from 
the  "  chaotic  sediment  of  the  flood."  Whiston  was  one  of  the  first  who 
ventured  to  propose  that  the  text  of  Genesis  should  be  interpreted  dif- 
ferently from  its  ordinary  acceptation,  so  that  the  doctrine  of  the  earth 
having  existed  long  previous  to  the  creation  of  man  might  no  longer  be 
regarded  as  unorthodox.  He  had  the  art  to  throw  an  air  of  plausibility 
over  the  most  improbable  parts  of  his  theory,  and  seemed  to  be  pro- 
ceeding in  the  most  sober  manner,  and,  by  the  aid  of  mathematical  de- 
monstration, to  the  establishment  of  his  various  propositions.  Locke 
pronounced  a  panegyric  on  his  theory,  commending  him  for  having  ex- 
plained so  many  wonderful  and  before  inexplicable  things.  His  book, 
as  well  as  Burnet's,  was  attacked  and  refuted  by  Keifl.  *  Like  all  who 
introduced  purely  hypothetical  causes  to  account  for  natural  phenom- 
ena, Whiston  retarded  the  progress  of  truth,  diverting  men  from  the 
investigation  of  the  laws  of  sublunary  nature,  and  inducing  them  to 
waste  time  in  speculations  on  the  power  of  comets  to  drag  the  waters 
of  the  ocean  over  the  land — on  the  condensation  of  the  vapors  of  their 
tails  into  water,  and  other  matters  equally  edifying. 

Hutchinson,  1724. — John  Hutchinson,  who  had  been  employed  by 
Woodward  in  making  his  collection  of  fossils,  published  afterwards,  in 
1724,  the  first  part  of  his  "Moses's  Principia,"  wherein  he  ridiculed 
Woodward's  hypothesis.  He  and  his  numerous  followers  were  accus- 
tomed to  declaim  loudly  against  human  learning  ;  and  they  maintained 
that  the  Hebrew  Scriptures,  when  rightly  translated,  comprised  a  per- 
fect system  of  natural  philosophy,  for  which  reason  they  objected  to  the 
Newtonian  theory  of  gravitation. 

Celsius. — Andrea  Celsius,  the  Swedish  astronomer,  published  about 
this  time  his  remarks  on  the  gradual  diminution  and  sinking  of  the 
waters  in  the  Baltic,  to  which  I  shall  have  occasion  to  advert  more  par- 
ticularly in  the  sequel  (ch.  29). 

Scheuchzer,  1708. — In  Germany,  in  the  mean  time,  Scheuchzer  pub- 
lished his  "  Complaint  and  Vindication  of  the  Fishes  "  (1708),  "  Piscium 
Querelse  et  Vindicise,"  a  work  of  zoological  merit,  in  which  he  gave 
some  good  plates  and  descriptions  of  fossil  fish.  Among  other  conclu- 
sions he  labored  to  prove  that  the  earth  had  been  remodelled  at  the 
deluge.  Pluche,  also,  in  1732,  wrote  to  the  same  effect;  while  Hoi- 
bach,  in  1753,  after  considering  the  various  attempts  to  refer  all  the  an- 
cient formations  to  the  flood  of  Noah,  exposed  the  inadequacy  of  this 
cause. 

Italian  Geologists  —  Vallisneri. — I  return  with  pleasure  to  the  geol- 
ogists of  Italy,  who  preceded,  as  has  been  already  shown,  the  natural- 
ists of  other  countries  in  their  investigations  into  the  ancient  history  of 
the  earth,  and  who  still  maintained  a  decided  pre-eminence.  They  re- 
futed and  ridiculed  the  physico-theological  systems  of  Burnet,  Whiston, 

*  An  Examination  of  Dr.  Burnet's  Theory,  <fec.,  2d  ed.  1734. 
3 


34  ITALIAN    GEOLOGISTS. VALLISNEKI.  [Cn.  III. 

and  Woodward  ;*  while  Vallisneri3f  in  his  comments  on  the  Woodward- 
ian  theory,  remarked  how  much  the  interests  of  religion,  as  well  as  those 
of  sound  philosophy,  had  suffered  by  perpetually  mixing  up  the  sacred 
writings  with  questions  in  physical  science.  The  works  of  this  author 
were  rich  in  original  observations.  He  attempted  the  first  general 
sketch  of  the  marine  deposits  of  Italy,  their  geographical  extent,  and 
most  characteristic  organic  remains.  In  his  treatise  "  On  the  Origin  of 
Springs,"  he  explained  their  dependence  on  the  order,  and  often  on  the 
dislocations,  of  the  strata,  and  reasoned  philosophically  against  the 
opinions  of  those  who  regarded  the  disordered  state  of  the  earth's  crust 
as  exhibiting  signs  of  the  wrath  of  God  for  the  sins  of  man.  He  found 
himself  under  the  necessity  of  contending,  in  his  preliminary  chapter, 
against  St.  Jerome,  and  four  other  principal  interpreters  of  Scripture, 
besides  several  professors  of  divinity,  "  that  springs  did  not  flow  by  sub- 
terranean siphons  and  cavities  from  the  sea  upwards,  losing  their  salt- 
ness  in  the  passage,"  for  this  theory  had  been  made  to  rest  on  the  in- 
fallible testimony  of  Holy  Writ. 

Although  reluctant  to  generalize  on  the  rich  materials  accumulated 
in  his  travels,  Vallisneri  had  been  so  much  struck  with  the  remarkable 
continuity  of  the  more  recent  marine  strata,  from  one  end  of  Italy  to  the 
other,  that  he  came  to  the  conclusion  that  the  ocean  formerly  extended 
over  the  whole  earth,  and  after  abiding  there  for  a  long  time,  had  grad- 
ually subsided.  This  opinion,  however  untenable,  was  a  great  step  be- 
yond Woodward's  diluvian  hypothesis,  against  which  Vallisneri,  and 
after  him  all  the  Tuscan  geologists,  uniformly  contended,  while  it  was 
warmly  supported  by  the  members  of  the  Institute  of  Bologna.J 

Among  others  of  that  day,  Spada,  a  priest  of  Grezzana,  in  1737, 
wrote  to  prove  that  the  petrified  marine  bodies  near  Verona  were  not 
diluvian. §  Mattani  drew  a  similar  inference  from  the  shells  of  Volterra 
and  other  places ;  while  Costantini,  on  the  other  hand,  whose  observa- 
tions on  the  valley  of  the  Brenta  and  other  districts  were  not  without 
value,  undertook  to  vindicate  the  truth  of  the  deluge,  as  also  to  prove 
that  Italy  had  been  peopled  by  the  descendants  of  Japhet.|| 

Moro,  1740. — Lazzaro  Moro,  in  his  work  (published  in  1740)  "  On  the 
Marine  Bodies  which  are  found  in  the  Mountains,  "^[  attempted  to  ap- 
ply the  theory  of  earthquakes,  as  expounded  by  Strabo,  Pliny,  and 
other  ancient  authors,  with  whom  he  was  familiar,  to  the  geological 
phenomena  described  by  Vallisneri.**  His  attention  was  awakened  to 

*  Ramazzini  even  asserted,  that  the  ideas  of  Burnet  were  mainly  borrowed 
from  a  dialogue  of  one  Patrizio ;  but  Brocchi,  after  reading  that  dialogue,  assures 
us  that  there  was  scarcely  any  other  correspondence  between  these  systems,  ex- 
cept that  both  were  equally  whimsical. 

|  Dei  Corpi  Marini,  Lettere  critiche,  <fec.  1721. 

j  Brocchi,  p.  28.  §  Ibid.  p.  33.  |  Ibid. 

Tf  Sui  Crostacei  ed  altri  Corpi  Marini  che  si  trovano  sui  Monti. 

*  Moro  does  not  cite  the  works  of  Hooke  and  Ray ;  and  although  so  many  of 
his  views  were  in  accordance  with  theirs,  he  was  probably  ignorant  of  their  wri- 


CH.  III.]  LAZZARO    MORO.  35 

the  elevating  power  of  subterranean  forces  by  a  remarkable  phenomenon 
which  happened  in  his  own  time,  and  which  had  also  been  noticed  by 
Vallisneri  in  his  letters.  A  new  island  rose  in  1707  from  deep  water  in 
the  Gulf  of  Santorin,  in  the  Mediterranean,  during  continued  shocks  of 
an  earthquake,  and,  increasing  rapidly  in  size,  grew  in  less  than  a  month 
to  be  half  a  mile  in  circumference,  and  about  twenty-five  feet  above 
high-water  mark.  It  was  soon  afterwards  covered  by  volcanic  ejections, 
but,  when  first  examined,  it  was  found  to  be  a  white  rock,  bearing  on 
its  surface  living  oysters  and  Crustacea.  In  order  to  ridicule  the  vari- 
ous theories  then  in  vogue,  Moro  ingeniously  supposes  the  arrival  on 
this  new  island  of  a  party  of  naturalists  ignorant  of  its  recent  origin. 
One  immediately  points  to  the  marine  shells,  as  proofs  of  the  universal 
deluge ;  another  argues  that  they  demonstrate  the  former  residence  of 
the  sea  upon  the  mountains ;  a  third  dismisses  them  as  mere  sports  of 
nature;  while  a  fourth  affirms  that  they  were  born  and  nourished 
within  the  rock  in  ancient  caverns,  into  which  salt  water  had  been  raised 
in  the  shape  of  vapor  by  the  action  of  subterranean  heat. 

Moro  pointed  with  great  judgment  to  the  faults  and  dislocations  of 
the  strata  described  by  Vallisneri,  in  the  Alps  and  other  chains,  in  con- 
firmation of  his  doctrine,  that  the  continents  had  been  heaved  up  by 
subterranean  movements.  He  objected,  on  solid  grounds,  to  the  hy- 
pothesis of  Burnet  and  of  Woodward ;  yet  he  ventured  so  far  to  disregard 
the  protest  of  Vallisneri,  as  to  undertake  the  adaptation  of  every  part  of 
his  own  system  to  the  Mosaic  account  of  the  creation.  On  the  third 
day,  he  said,  the  globe  was  everywhere  covered  to  the  same  depth  by 
fresh  water ;  and  when  it  pleased  the  Supreme  Being  that  the  dry  land 
should  appear,  volcanic  explosions  broke  up  the  smooth  and  regular 
surface  of  the  earth  composed  of  primary  rocks.  These  rose  in  moun- 
tain masses  above  the  waves,  and  allowed  melted  metals  and  salts  to 
ascend  through  fissures.  The  sea  gradually  acquired  its  saltness  from 
volcanic  exhalations,  and,  while  it  became  more  circumscribed  in  area, 
increased  in  depth.  Sand  and  ashes  ejected  by  volcanoes  were  regu- 
larly disposed  along  the  bottom  of  the  ocean,  and  formed  the  secondary 
strata,  which  in  their  turn  were  lifted  up  by  earthquakes.  We  need 
not  follow  this  author  in  tracing  the  progress  of  the  creation  of  vegeta- 
bles and  animals  on  the  other  days  of  creation ;  but,  upon  the  whole,  it 
may  be  remarked,  that  few  of  the  old  cosmological  theories  had  been 
conceived  with  so  little  violation  of  known  analogies. 

Generellis  illustrations  of  Moro,  1749. — The  style  of  Moro  was  ex- 
tremely prolix,  and,  like  Hutton,  who,  at  a  later  period,  advanced  many 
of  the  same  views,  he  stood  in  need  of  an  illustrator.  The  Scotch  geol- 
ogist was  hardly  more  fortunate  in  the  advocacy  of  Playfair,  than  was 
Moro  in  numbering  amongst  his  admirers  Cirillo  Generelli,  who,  nine 

tings,  for  they  had  not  been  translated.  As  he  always  refers  to  the  Latin  edition 
of  Burnet,  and  a  French  translation  of  Woodward,  we  may  presume  that  he  did 
not  read  English. 


[On.  Ill 

years  afterwards,  delivered  at  a  sitting  of  Academicians  at  Cremona  a 
spirited  exposition  of  his  theory.  This  learned  Carmelitan  friar  does  not 
pretend  to  have  been  an  original  observer,  but  he  had  studied  sufficiently 
to  enable  him  to  confirm  the  opinions  of  Moro  by  arguments  from  other 
writers ;  and  his  selection  of  the  doctrines  then  best  established  is  so 
judicious,  that  a  brief  abstract  of  them  cannot  fail  to  be  acceptable,  as 
illustrating  the  state  of  geology  in  Europe,  and  in  Italy  in  particular, 
before  the  middle  of  the  last  century. 

The  bowels  of  the  earth,  says  he,  have  carefully  preserved  the  memo- 
rials of  past  events,  and  this  truth  the  marine  productions  so  frequent 
in  the  hills  attest.  From  the  reflections  of  Lazzaro  Moro,  we  may  as- 
sure ourselves  that  these  are  the  effects  of  earthquakes  in  past  times, 
which  have  changed  vast  spaces  of  sea  into  terra  firma,  and  inhabited 
lands  into  seas.  In  this,  more  than  in  any  other  department  of  physics, 
are  observations  and  experiments  indispensable,  and  we  must  diligently 
consider  facts.  The  land  is  known,  wherever  we  make  excavations,  to 
be  composed  of  different  strata  or  soils  placed  one  above  the  other,  some 
of  sand,  some  of  rock,  some  of  chalk,  others  of  marl,  coal,  pummice, 
gypsum,  lime,  and  the  rest.  These  ingredients  are  sometimes  pure,  and 
sometimes  confusedly  intermixed.  Within  are  often  imprisoned  differ- 
ent marine  fishes,  like  dried  mummies,  and  more  frequently  shells,  crus- 
tacea,  corals,  plants,  &c.,  not  only  in  Italy,  but  in  France,  Germany, 
England,  Africa,  Asia,  and  America ; — sometimes  in  the  lowest,  some- 
times in  the  loftiest  beds  of  the  earth,  some  upon  the  mountains,  some 
in  deep  mines,  others  near  the  sea,  and  others  hundreds  of  miles  distant 
from  it.  Woodward  conjectured  that  these  marine  bodies  might  be 
found  everywhere ;  but  there  are  rocks  in  which  none  of  them  occur, 
as  is  sufficiently  attested  by  Vallisneri  and  Marsilli.  The  remains  of 
fossil  animals  consist  chiefly  of  their  more  solid  parts,  and  the  most 
rocky  strata  must  have  been  soft  when  such  exuviae  were  inclosed  in 
them.  Vegetable  productions  are  found  in  different  states  of  maturity, 
indicating  that  they  were  imbedded  in  different  seasons.  Elephants, 
elks,  and  other  terrestrial  quadrupeds,  have  been  found  in  England  and 
elsewhere,  in  superficial  strata,  never  covered  by  the  sea.  Alternations 
are  rare,  yet  not  without  example,  of  marine  strata,  with  those  which 
contain  marshy  and  terrestrial  productions.  Marine  animals  are  ar- 
ranged in  the  subterraneous  beds  with  admirable  order,  in  distinct 
groups,  oysters  here,  dentalia  or  corals  there,  &c.,  as  now,  according  to 
Marsilli,*  on  the  shores  of  the  Adriatic.  We  must  abandon  the  doc- 
trine, once  so  popular,  which  denies  that  organized  fossils  were  derived 
from  living  beings,  and  we  cannot  account  for  their  present  position  by 
the  ancient  theory  of  Strabo,  nor  by  that  of  Leibnitz,  nor  by  the  uni- 
versal deluge,  as  explained  by  Woodward  and  others ;  "  nor  is  it  rea- 
sonable to  call  the  Deity  capriciously  upon  the  stage,  and  to  make  him 
work  miracles  for  the  sake  of  confirming  our  preconceived  hypothesis." 

*  Saggio  fisico  intorno  alia  Storia  del  Mare,  part  i.  p.  24. 


CH.  III.]  LAZZARO   MOEO'S   THEORY.  37 

— "  I  hold  in  utter  abomination,  most  learned  Academicians  !  those 
systems  which  are  built  with  their  foundations  in  the  air,  and  cannot  be 
propped  up  without  a  miracle ;  and  I  undertake,  with  the  assistance  of 
Moro,  to  explain  to  you  how  these  marine  animals  were  transported 
into  the  mountains  by  natural  causes."* 

A  brief  abstract  then  follows  of  Moro's  theory,  by  which,  says  Gene- 
relli,  we  may  explain  all  the  phenomena,  as  Valiisneri  so  ardently  de- 
sired, "without  violence,  without  fictions,  without  hypothesis,  without 
miracles."\  The  Carmelitan  then  proceeds  to  struggle  against  an  obvi- 
ous objection  to  Moro's  system,  considered  as  a  method  of  explaining 
the  revolutions  of  the  earth,  naturally.  If  earthquakes  have  been  the 
agents  of  such  mighty  changes,  how  does  it  happen  that  their  effects 
since  the  times  of  history  have  been  so  inconsiderable  ?  This  same  dif- 
culty  had,  as  we  have  seen,  presented  itself  to  Hooke,  half  a  century 
before,  and  forced  him  to  resort  to  a  former  "  crisis  of  nature :"  but 
Generelli  defended  his  position  by  showing  how  numerous  were  the 
accounts  of  eruptions  and  earthquakes,  of  new  islands,  and  of  eleva- 
tions and  subsidences  of  land,  and  yet  how  much  greater  a  number  of 
like  events  must  have  been  unattested  and  unrecorded  during  the  last 
six  thousand  years.  He  also  appealed  to  Valiisneri  as  an  authority  to 
prove  that  the  mineral  masses  containing  shells,  bore,  upon  the  whole, 
but  a  small  proportion  to  those  rocks  which  were  destitute  of  organic 
remains  ;  and  the  latter,  says  the  learned  monk,  might  have  been  created 
as  they  now  exist,  in  the  beginning. 

Generelli  then  describes  the  continual  waste  of  mountains  and  conti- 
nents, by  the  action  of  rivers  and  torrents,  and  concludes  with  these 
eloquent  and  original  observations : — "  Is  it  possible  that  this  waste 
should  have  continued  for  six  thousand,  and  perhaps  a  greater  number 
of  years,  and  that  the  mountains  should  remain  so  great,  unless  their 
ruins  have  been  repaired  ?  Is  it  credible  that  the  Author  of  Nature 
should  have  founded  the  world  upon  such  laws,  as  that  the  dry  land 
should  forever  be  growing  smaller,  and  at  last  become  wholly  sub- 
merged beneath  the  waters  ?  Is  it  credible  that,  amid  so  many  created 
things,  the  mountains  alone  should  daily  diminish  in  number  and  bulk, 
without  there  being  any  repair  of  their  losses  ?  This  would  be  contrary 
to  that  order  of  Providence  which  is  seen  to  reign  in  all  other  things  in 
the  universe.  Wherefore  I  deem  it  just  to  conclude,  that  the  same 
cause  which,  in  the  beginning  of  time,  raised  mountains  from  the  abyss, 
has  down  to  the  present  day  continued  to  produce  others,  in  order  to 
restore  from  time  to  time  the  losses  of  all  such  as  sink  down  in  different 
places,  or  are  rent  asunder,  or  in  other  way  suffer  disintegration.  If 
this  be  admitted,  we  can  easily  understand  why  there  should  now  be 

*  "  Abbomino  al  sommo  qualsivoglia  sistema,  che  sia  di  pianta  fabbricato  in 
aria ;  massime  quando  e  tale,  che  non  possa  sostenersi  senza  un  miracolo,"  &c. — 
De'  Crostaceie  di  altre  Produz.  del  Mare,  &c.  1749. 

f  "  Senza  violenze,  senza  finzioni,  senza  supposti,  senza  miracoli."  De'  Crostacei 
e  di  altre  Produz.  del  Mare,  <fec.  1749. 


38  MAESILLI. DONATI.  [Cn.  Ill 

found  upon  many  mountains  so  great  a  number  of  Crustacea  and  other 
marine  animals." 

In  the  above  extract,  I  have  not  merely  enumerated  the  opinions  and 
facts  which  are  confirmed  by  recent  observation,  suppressing  all  that 
has  since  proved  to  be  erroneous,  but  have  given  a  faithful  abridgment 
of  the  entire  treatise,  with  the  omission  only  of  Moro's  hypothesis,  which 
Generelli  adopted,  with  all  its  faults  and  excellences.  The  reader  will 
therefore  remark,  that  although  this  admirable  essay  embraces  so  large 
a  portion  of  the  principal  objects  of  geological  research,  it  makes  no 
allusion  to  the  extinction  of  certain  classes  of  animals  ;  and  it  is  evident 
that  no  opinions  on  this  head  had,  at  that  time,  gained  a  firm  footing  in 
Italy.  That  Lister  and  other  English  naturalists  should  long  before 
have  declared  in  favor  of  the  loss  of  species,  while  Scilla  and  most  of 
his  countrymen  hesitated,  was  perhaps  natural,  since  the  Italian  muse- 
ums were  filled  with  fossil  shells  belonging  to  species  of  which  a  great 
portion  did  actually  exist  in  the  Mediterranean  ;  whereas  the  English 
collectors  could  obtain  no  recent  species  from  such  of  their  own  strata 
as  were  then  explored. 

The  weakest  point  in  Moro's  system  consisted  in  deriving  all  the  strat- 
ified rocks  from  volcanic  ejections  ;  an  absurdity  which  his  opponents 
took  care  to  expose,  especially  Vito  Amici.*  Moro  seems  to  have  been 
misled  by  his  anxious  desire  to  represent  the  formation  of  secondary 
rocks  as  having  occupied  an  extremely  short  period,  while  at  the  same 
time  he  wished  to  employ  known  agents  in  nature.  To  imagine  tor- 
rents, rivers,  currents,  partial  floods,  and  all  the  operations  of  moving 
water,  to  have  gone  on  exerting  an  energy  many  thousand  times  greater 
than  at  present,  would  have  appeared  preposterous  and  incredible,  and 
would  have  required  a  hundred  violent  hypotheses ;  but  we  are  so  unac- 
quainted with  the  true  sources  of  subterranean  disturbances,  that  their 
former  violence  may  in  theory  be  multiplied  indefinitely,  without  its 
being  possible  to  prove  the  same  manifest  contradiction  or  absurdity  in 
the  conjecture.  For  this  reason,  perhaps,  Moro  preferred  to  derive  the 
materials  of  the  strata  from  volcanic  ejections,  rather  than  from  trans- 
portation by  running  water. 

Marsilli. — Marsilli,  whose  work  is  alluded  to  by  Generelli,  had  been 
prompted  to  institute  inquiries  into  the  bed  of  the  Adriatic,  by  discov- 
ering, in  the  territory  of  Parma  (what  Spada  had  observed  near  Verona, 
and  Schiavo  in  Sicily),  that  fossil  shells  were  not  scattered  through  the 
rocks  at  random,  but  disposed  in  regular  order,  according  to  certain 
genera  and  species. 

Vitaliano  Donati,  1750. — But  with  a  view  of  throwing  further  light 
upon  these  questions,  Donati,  in  1750,  undertook  a  more  extensive  inves- 
tigation of  the  Adriatic,  and  discovered,  by  numerous  soundings,  that  de- 
posits of  sand,  marl,  and  tufaceous  incrustations,  most  strictly  analogous 
to  those  of  the  Subapennine  hills,  were  in  the  act  of  accumulating  there. 

*  Sui  Testacei  della  Sicilia. 


CH.  III.]  BALDASSART. BUFFON.  39 

He  ascertained  that  there  were  no  shells  in  some  of  the  submarine 
tracts,  while  in  other  places  they  lived  together  in  families,  particularly 
the  genera  Area,  Pecten,  Venus,  Murex,  and  some  others.  He  also 
states  that  in  divers  localities  he  found  a  mass  composed  of  corals, 
shells,  and  crustaceous  bodies  of  different  species,  confusedly  blended 
with  earth,  sand,  and  gravel.  At  the  depth  of  a  foot  or  more,  the 
organic  substances  were  entirely  petrified  and  reduced  to  marble  ;  at 
less  than  a  foot  from  the  surface,  they  approached  nearer  to  their  natu- 
ral state ;  while  at  the  surface  they  were  alive,  or,  if  dead,  in  a  good 
state  of  preservation. 

Baldassari. — A  contemporary  naturalist,  Baldassari,  had  shown  that 
the  organic  remains  in  the  tertiary  marls  of  the  Siennese  territory  were 
grouped  in  families,  in  a  manner  precisely  similar  to  that  above  alluded 
to  by  Donati. 

Buffon,  1749. — Buffon  first  made  known  his  theoretical  views  con- 
cerning the  former  changes  of  the  earth,  in  his  Natural  History,  pub- 
lished in  1749.  He  adopted  the  theory  of  an  original  volcanic  nucleus, 
together  with  the  universal  ocean  of  Leibnitz.  By  this  aqueous  envel- 
ope the  highest  mountains  were  once  covered.  Marine  currents  then 
acted  violently,  and  formed  horizontal  strata,  by  washing  away  solid 
matter  in  some  parts,  and  depositing  it  in  others ;  they  also  excavated 
deep  submarine  valleys.  The  level  of  the  ocean  was  then  depressed  by 
the  entrance  of  a  part  of  its  waters  into  subterranean  caverns,  and  thus 
some  land  was  left  dry.  Buffon  seems  not  to  have  profited,  like  Leib- 
nitz and  Moro,  by  the  observations  of  Steno,  or  he  could  not  have  ima- 
gined that  the  strata  were  generally  horizontal,  and  that  those  which 
contain  organic  remains  had  never  been  disturbed  since  the  era  of  their 
formation.  He  was  conscious  of  the  great  power  annually  exerted  by 
rivers  and  marine  currents  in  transporting  earthy  materials  to  lower 
levels,  and  he  even  contemplated  the  period  when  they  would  destroy 
all  the  present  continents.  Although  in  geology  he  was  not  an  original 
observer,  his  genius  enabled  him  to  render  his  hypothesis  attractive  ; 
and  by  the  eloquence  of  his  style,  and  the  boldness  of  his  speculations, 
he  awakened  curiosity,  and  provoked  a  spirit  of  inquiry  amongst  his 
countrymen. 

Soon  after  the  publication  of  his  "  Natural  History,"  in  which  was 
included  his  "  Theory  of  the  Earth,"  he  received  an  official  letter  (dated 
January,  1751)  from  the  Sorbonne,  or  Faculty  of  Theology  in  Paris, 
informing  him  that  fourteen  propositions  in  his  works  "  were  reprehen- 
sible, and  contrary  to  the  creed  of  the  church."  The  first  of  these  ob- 
noxious passages,  and  the  only  one  relating  to  geology,  was  as  follows : — t 
"  The  waters  of  the  sea  have  produced  the  mountains  and  valleys  of  the 
land — the  waters  of  the  heavens,  reducing  all  to  a  level,  will  at  last  de- 
liver the  whole  land  over  to  the  sea,  and  the  sea  successively  prevailing 
over  the  land,  will  leave  dry  new  continents  like  those  which  we  in- 
habit." Buffon  was  invited  by  the  College,  in  very  courteous  terms,  to 
send  in  an  explanation,  or  rather  a  recantation  of  his  unorthodox  opin- 


40  TARGIONI. LEHMAN.  [Cn.  III. 

ions.  To  this  he  submitted  ;  and  a  general  assembly  of  the  Faculty 
having  approved  of  his  "  Declaration,"  he  was  required  to  publish  it  in 
his  next  work.  The  document  begins  with  these  words  : — "  I  declare 
that  I  had  no  intention  to  contradict  the  text  of  Scripture  ;  that  I  be- 
lieve most  firmly  all  therein  related  about  the  creation,  both  as  to  order 
of  time  and  matter  of  fact ;  and  /  abandon  every  thing  in  my  look  re- 
specting the  foundation  of  the  earth,  and,  generally,  all  which  may  be 
contraiy  to  the  narration  of  Moses."* 

The  grand  principle  which  Buffon  was  called  upon  to  renounce  was 
simply  this, — that  the  present  mountains  and  valleys  of  the  earth  are 
due  to  secondary  causes,  and  that  the  same  causes  will  in  time  destroy 
all  the  continents,  hills,  and  valleys,  and  reproduce  others  like  them." 
Now,  whatever  may  be  the  defects  of  many  of  his  views,  it  is  no  longer 
controverted  that  the  present  continents  are  of  secondary  origin.  The 
doctrine  is  as  firmly  established  as  the  earth's  rotation  on  its  axis  ;  and 
that  the  land  now  elevated  above  the  level  of  the  sea  will  not  endure 
forever,  is  an  opinion  which  gains  ground  daily,  in  proportion  as  we 
enlarge  our  experience  of  the  changes  now  in  progress. 

Targioni,  1751. — Targioni,  in  his  voluminous  "Travels  in  Tuscany, 
1751  and  1754,"  labored  to  fill  up  the  sketch  of  the  geology  of  that 
region  left  by  Steno  sixty  years  before.  Notwithstanding  a  want  of 
arrangement  and  condensation  in  his  memoirs,  they  contained  a  rich 
store  of  faithful  observations.  He  has  not  indulged  in  many  general 
views,  but  in  regard  to  the  origin  of  valleys,  he  was  opposed  to  the 
theory  of  Buffon,  who  attributed  them  principally  to  submarine  currents. 
The  Tuscan  naturalist  labored  to  show  that  both  the  larger  and  smaller 
valleys  of  the  Apennines  were  excavated  by  rivers  and  floods,  caused 
by  the  bursting  of  the  barriers  of  lakes,  after  the  retreat  of  the  ocean. 
He  also  maintained  that  the  elephants  and  other  quadrupeds,  so  fre- 
quent in  the  lacustrine  and  alluvial  deposits  of  Italy,  had  inhabited  that 
peninsula  ;  and  had  not  been  transported  thither,  as  some  had  conceived, 
by  Hannibal  or  the  Romans,  nor  by  what  they  were  pleased  to  term 
"  a  catastrophe  of  nature." 

Lehman,  1756. — In  the  year  1756  the  treatise  of  Lehman,  a  German 
mineralogist,  and  director  of  the  Prussian  mines,  appeared,  who  also 
divided  mountains  into  three  classes  :  the  first,  those  formed  with  the 
world,  and  prior  to  the  creation  of  animals,  and  which  contained  no 
fragments  of  other  rocks  ;  the  second  class,  those  which  resulted  from 
the  partial  destruction  of  the  primary  rocks  by  a  general  revolution  ; 
and  a  third  class,  resulting  from  local  revolutions,  and  in  part  from  the 
deluge  of  Noah. 

A  French  translation  of  this  work  appeared  in  1759,  in  the  preface 
of  which,  the  translator  displays  very  enlightened  views  respecting  the 
operations  of  earthquakes,  as  well  as  of  the  aqueous  causes.f 

*  Hist.  Nat.  torn.  v.  ed.  de  1'Imp.  Royale,  Paris,  1769. 
f  Eseai  d'une  Hist.  Nat.  des  Couches  de  la  Terre,  1759. 


CH.  III.]  GESNER. ARDUINO. — MICHELL.  41 

Gesner,  1758. — In  this  year  Gesner,  the  botanist,  of  Zurich,  pub- 
lished an  excellent  treatise  on  petrifactions,  and  the  changes  of  the 
earth  which  they  testify.*  After  a  detailed  enumeration  of  the  various 
classes  of  fossils  of  the  animal  and  vegetable  kingdoms,  and  remarks  on 
the  different  states  in  which  they  are  found  petrified,  he  considers  the 
geological  phenomena  connected  with  them  ;  observing,  that  some,  like 
those  of  (Eningen,  resembled  the  testacea,  fish,  and  plants  indigenous 
in  the  neighboring  region  ;f  while  some,  such  as  ammonites,  gryphites, 
belenmites,  and  other  shells,  are  either  of  unknown  species,  or  found 
only  in  the  Indian  and  other  distant  seas.  In  order  to  elucidate  the 
structure  of  the  earth,  he  gives  sections,  from  Verenius,  Buffon,  and 
others,  obtained  in  digging  wells  ;  distinguishes  between  horizontal  and 
inclined  strata ;  and,  in  speculating  on  the  causes  of  these  appearances, 
mentions  Donati's  examination  of  the  bed  of  the  Adriatic  :  the  fillino- 

o 

up  of  lakes  and  seas  by  sediment ;  the  imbedding  of  shells  now  in  pro- 
gress ;  and  many  known  effects  of  earthquakes,  such  as  the  sinking 
down  of  districts,  or  the  heaving  up  of  the  bed  of  the  sea,  so  as  to  form 
new  islands,  and  lay  dry  strata  containing  petrifactions.  The  ocean,  he 
says,  deserts  its  shores  in  many  countries,  as  on  the  borders  of  the 
Baltic;  but  the  rate  of  recession  has  been  so  slow  in  the  last  2000 
years,  that  to  allow  the  Apennines,  whose  summits  are  filled  with  marine 
shells,  to  emerge  to  their  present .  height,  would  have  required  about 
80,000  years, — a  lapse  of  time  ten  times  greater,  or  more,  than  the  age 
of  the  universe.  We  must  therefore  refer  the  phenomenon  to  the  com- 
mand of  the  Deity,  related  by  Moses,  that  "  the  waters  should  be 
gathered  together  in  one  place,  and  the  dry  land  appear."  Gesner 
adopted  the  views  of  Leibnitz,  to  account  for  the  retreat  of  the  primeval 
ocean  :  his  essay  displays  much  erudition  ;  and  the  opinions  of  preced- 
ing writers  of  Italy,  Germany,  and  England,  are  commented  upon  with 
fairness  and  discrimination. 

Arduino,  1759. — In  the  year  following,  Arduino,J  in  his  memoirs  on 
the  mountains  of  Padua,  Vicenza,  and  Verona,  deduced,  from  original 
observations,  the  distinction  of  rocks  into  primary,  secondary,  and  ter- 
tiary, and  showed  that  in  those  districts  there  had  been  a  succession  of 
submarine  volcanic  eruptions. 

Michell,  1760. — In  the  following  year  (1760)  the  Rev.  John  Michell, 
Woodwardian  Professor  of  Mineralogy  at  Cambridge,  published  in  the 
Philosophical  Transactions,  an  Essay  on  the  Cause  and  Phenomena  of 
Earthquakes. §  His  attention  had  been  drawn  to  this  subject  by  the 

*  John  Gesner  published  at  Leyden,  in  Latin.  f  Part  ii.  chap.  9. 

\  Giornale  del  Criselini,  1759. 

§  See  a  sketch  of  the  History  of  English  Geology,  by  Dr.  Fitton,  in  Ediab.  Rev. 
Feb.  1818,  re-edited  Lond.  and  Edinb.  Phil.  Mag.  vols.  i.  and  ii.  1832-3.  Some  of 
Michell's  observations  anticipate  in  so  remarkable  a  manner  the  theories  established 
forty  years  afterwards,  that  his  writings  would  probably  have  formed  an  era  in 
the  science,  if  his  researches  had  been  uninterrupted.  He  held,  however,  his  pro- 
fessorship only  eight  years,  when  his  career  was  suddenly  cut  short  by  preferment 
to  a  benefice.  From  that  time  he  appears  to  have  been  engaged  in  his  clerical 


42  CATCOTT. FOETIS. ODOARDI.  [On.  III. 

great  earthquake  of  Lisbon  in  1755.  He  advanced  many  original  and 
philosophical  views  respecting  the  propagation  of  subterranean  move- 
ments, and  the  caverns  and  fissures  wherein  steam  might  be  generated. 
In  order  to  point  out  the  application  of  his  theory  to  the  structure  of 
the  globe,  he  was  led  to  describe  the  arrangement  and  disturbance  of 
the  strata,  their  usual  horizontality  in  low  countries,  and  their  contortions 
and  fractured  state  in  the  neighborhood  of  mountain  chains.  He  also  ex- 
plained, with  surprising  accuracy,  the  relations  of  the  central  ridges  of 
older  rocks  to  the  "  long  narrow  slips  of  similar  earth,  stones,  and  miner- 
als," which  are  parallel  to  these  ridges.  In  his  generalizations,  derived 
in  great  part  from  his  own  observations  on  the  geological  structure  of 
Yorkshire,  he  anticipated  many  of  the  views  more  fully  developed  by 
later  naturalists. 

Catcott,  1761. — Michell's  papers  were  entirely  free  from  all  physico- 
theological  disquisitions,  but  some  of  his  contemporaries  were  still  ear- 
nestly engaged  in  defending  or  impugning  the  Woodwardian  hypothesis. 
We  find  many  of  these  writings  referred  to  by  Catcott,  a  Hutchinsonian, 
who  published  a  "  Treatise  on  the  Deluge"  in  1761.  He  labored  par- 
ticularly to  refute  an  explanation  offered  by  his  contemporary,  Bishop 
Clayton,  of  the  Mosaic  writings.  That  prelate  had  declared  that  the 
deluge  "  could  not  be  literally  true,  save  in  respect  to  that  part  where 
Noah  lived  before  the  flood."  Catcott  insisted  on  the  universality  of 
the  deluge,  and  referred  to  traditions  of  inundations  mentioned  by  an- 
cient writers,  or  by  travellers,  in  the  East  Indies,  China,  South  America, 
and  other  countries.  This  part  of  his  book  is  valuable,  although  it  is 
not  easy  to  see  what  bearing  the  traditions  have,  if  admitted  to  be  au- 
thentic, on  the  Bishop's  argument,  since  no  evidence  is  adduced  to  prove 
that  the  catastrophes  were  contemporaneous  events,  while  some  of  them 
are  expressly  represented  by  ancient  authors  to  have  occurred  in  suc- 
cession. 

Fortis — Odoardi,  1761. — The  doctrines  of  Arduino,  above  adverted 
to,  were  afterwards  confirmed  by  Fortis  and  Desmarest,  in  their  travels 
in  the  same  country ;  and  they,  as  well  as  Baldassari,  labored  to  com- 
plete the  history  of  the  Subapennine  strata.  In  the  work  of  Odoardi,* 
there  was  also  a  clear  argument  in  favor  of  the  distinct  ages  of  the  older 
Apennine  strata,  and  the  Subapennine  formations  of  more  recent  ori- 
gin. He  pointed  out  that  the  strata  of  these  two  groups  were  uncon- 
formable,  and  must  have  been  the  deposits  of  different  seas  at  distant 
periods  of  time. 

Raspe,  1763. — A  history  of  the  new  islands,  by  Raspe,  a  Hanove- 

duties,  and  to  have  entirely  discontinued  his  scientific  pursuits,  exemplifying  the 
working  of  a  system  still  in  force  at  Oxford  and  Cambridge,  where  the  chairs  of 
mathematics,  natural  philosophy,  chemistry,  botany,  astronomy,  geology,  mineral- 
ogy, and  others,  being  frequently  filled  by  clergymen,  the  reward  of  success  dis- 
qualifies them,  if  they  conscientiously  discharge  their  new  duties,  from  farther 
advancing  the  cause  of  science,  and  that,  too,  at  the  moment  when  their  labors 
would  naturally  bear  the  richest  fruits. 
*  Sui  Corpi  Marini  del  Feltrino,  1761. 


UH.  III.]  EASPE. FUCHSEL.  4:3 

rian,  appeared  in  1763,  in  Latin.*  In  this  work,  all  the  authentic  ac- 
counts of  earthquakes  which  had  produced  permanent  changes  on  the 
solid  parts  of  the  earth  were  collected  together  and  examined  with  judi- 
cious criticism.  The  best  systems  which  had  been  proposed  concerning 
the  ancient  history  of  the  globe,  both  by  ancient  and  modern  writers, 
are  reviewed ;  and  the  merits  and  defects  of  the  doctrines  of  Hooke, 
Ray,  Moro,  Buffon,  and  others,  fairly  estimated.  Great  admiration  is 
expressed  for  the  hypothesis  of  Hooke,  and  his  explanation  of  the  origin 
of  the  strata  is  shown  to  have  been  more  correct  than  Moro's,  while  their 
theory  of  the  effects  of  earthquakes  was  the  same.  Raspe  had  not  seen 
Michell's  memoirs,  and  his  views  concerning  the  geological  structure  of 
the  earth  were  perhaps  less  enlarged ;  yet  he  was  able  to  add  many 
additional  arguments  in  favor  of  Hook's  theory,  and  to  render  it,  as  he 
said,  a  nearer  approach  to  what  Hooke  would  have  written  had  he  lived 
in  later  times.  As  to  the  periods  wherein  all  the  earthquakes  happened, 
to  which  we  owe  the  elevation  of  various  parts  of  our  continents  and 
islands,  Raspe  says  he  pretends  not  to  assign  their  duration,  still  less  to 
defend  Hooke's  suggestion,  that  the  convulsions  almost  all  took  place 
during  the  deluge  of  Noah.  He  adverts  to  the  apparent  indications  of 
the  former  tropical  heat  of  the  climate  of  Europe,  and  the  changes  in 
the  species  of  animals  and  plants,  as  among  the  most  obscure  and  diffi- 
cult problems  in  geology.  In  regard  to  the  islands  raised  from  the  sea, 
within  the  times  of  history  or  tradition,  he  declares  that  some  of  them 
were  composed  of  strata  containing  organic  remains,  and  that  they  were 
not,  as  Buffon  had  asserted,  made  of  mere  volcanic  matter.  His  work 
concludes  with  an  eloquent  exhortation  to  naturalists  to  examine  the  isles 
which  rose,  in  1 70 7,  in  the  Grecian  Archipelago,  and,  in  1 720,  in  the  Azores, 
and  not  to  neglect  such  splendid  opportunities  of  studying  nature  "  in 
the  act  of  parturition."  That  Hooke's  writings  should  have  been  neg- 
lected for  more  than  half  a  century,  was  matter  of  astonishment  to 
Raspe  ;  but  it  is  still  more  wonderful  that  his  own  luminous  exposition 
of  that  theory  should,  for  more  than  another  half  century,  have  excited 
so  little  interest. 

Fuchsel,  1762  and  1773. — Fuchsel,  a  German  physician,  published, 
in  1762,  a  geological  description  of  the  country  between  the  Thuringer- 
wald  and  the  Hartz,  and  a  memoir  on  the  environs  of  Rudelstadt  ;f  and 
afterwards,  in  1773,  a  theoretical  work  on  the  ancient  history  of  the 
earth  and  of  man.J  He  had  evidently  advanced  considerably  beyond 
his  predecessor  Lehman,  and  was  aware  of  the  distinctness,  both  as  to 
position  and  fossil  contents,  of  several  groups  of  strata  of  different  ages, 
corresponding  to  the  secondary  formations  now  recognized  by  geologists 

*  De  Novis  e  Mari  Natis  Insulis.  Raspe  was  also  the  editor  of  the  "  Philosoph- 
ical Works  of  Leibnitz.  Amst.  et  Leipzig,  1765  ;"  also  author  of  "  Tassie'a  Gems," 
and  "  Baron  Munchausen's  Travels." 

f  Acta  Academise  Electoralis  Maguntinse,  vol.  ii.     Erfurt. 

\  This  account  of  Fuchsel  is  derived  from  an  excellent  analysis  of  his  memoirs 
by  M.  Keferstein.  Journ.  de  Geologic,  torn.  ii.  Oct.  1830. 


44:  BEANDER. SOLDANI. FORTTS. TESTA.  [Cn.  III. 

in  various  parts  of  Germany.  He  supposed  the  European  continents  to 
have  remained  covered  by  the  sea  until  the  formation  of  the  marine  strata, 
called  in  Germany  "  muschelkalk,"  at  the  same  time  that  the  terrestrial 
plants  of  many  European  deposits,  attested  the  existence  of  dry  land 
which  bordered  the  ancient  sea  ;  land  which,  therefore,  must  have  occu- 
pied the  place  of  the  present  ocean.  The  pre-existing  continent  had 
been  gradually  swallowed  up  by  the  sea,  different  parts  having  subsided 
in  succession  into  subterranean  caverns.  All  the  sedimentary  strata 
were  originally  horizontal,  and  their  present  state  of  derangement  must 
be  referred  to  subsequent  oscillations  of  the  ground. 

As  there  were  plants  and  animals  in  the  ancient  periods,  so  also  there 
must  have  been  men,  but  they  did  not  all  descend  from  one  pair,  but 
were  created  at  various  points  on  the  earth's  surface  :  and  the  number 
of  these  distinct  birth-places  was  as  great  as  are  the  original  languages 
of  nations. 

In  the  writings  of  Fuchsel  we  see  a  strong  desire  manifested  to  ex- 
plain geological  phenomena  as  far  as  possible  by  reference  to  the  agency 
of  known  causes  ;  and  although  some  of  his  speculations  were  fanciful, 
his  views  coincide  much  more  nearly  with  those  now  generally  adopted, 
than  the  theories  afterwards  promulgated  by  Werner  and  his  followers. 

Brander,  1766. — Gustavus  Brander  published,  in  1766,  his  "Fossilia 
Hantoniensia,"  containing  excellent  figures  of  fossil  shells  from  the  more 
modern  (or  Eocene)  marine  strata  of  Hampshire.  "  Various  opinions," 
he  says  in  the  preface,  "  had  been  entertained  concerning  the  time  when 
and  how  these  bodies  became  deposited.  Some  there  are  who  conceive 
that  it  might  have  been  effected  in  a  wonderful  length  of  time  by  a 
gradual  changing  and  shifting  of  the  sea,"  &c.  But  the  most  common 
cause  assigned  is  that  of  "  the  deluge."  This  conjecture,  he  says,  even 
if  the  universality  of  the  flood  be  not  called  in  question,  is  purely  hypo- 
thetical. In  his  opinion,  fossil  animals  and  testacea  were,  for  the  most 
part,  of  unknown  species ;  and  of  such  as  were  known,  the  living  ana- 
logues now  belonged  to  southern  latitudes. 

Soldani,  1780. — Soldani  applied  successfully  his  knowledge  of  zoology 
to  illustrate  the  history  of  stratified  masses.  He  explained  that  micro- 
scopic testacea  and  zoophytes  inhabited  the  depths  of  the  Mediterranean  ; 
and  that  the  fossil  species  were,  in  like  manner,  found  in  those  deposits 
wherein  the  fineness  of  their  particles,  and  the  absence  of  pebbles,  im- 
plied that  they  were  accumulated  in  a  deep  sea,  or  far  from  shore.  This 
author  first  remarked  the  alternation  of  marine  and  freshwater  strata  in 
the  Paris  basin.* 

Fortis — Testa,  1793. — A  lively  controversy  arose  between  Fortis  and 
another  Italian  naturalist,  Testa,  concerning  the  fish  of  Monte  Bolca,  in 
1793.  Their  letters,f  written  with  great  spirit  and  elegance,  show  that 
they  were  aware  that  a  large  proportion  of  the  Subapennine  shells  were 

*  Saggio  orittografico,  <fec.  1780,  and  other  Works. 
\  Lett,  sui  Pesci  Fossili  di  Bolca.     Milan,  1793. 


CH.  Ill]  WHITEHURST. PALLAS. SAUSSUKE.  45 

identical  with  living  species,  and  some  of  them  with  species  now  living 
in  the  torrid  zone.  Fortis  proposed  a  somewhat  fanciful  conjecture,  that 
when  the  volcanoes  of  the  Vicentin  were  burning,  the  waters  of  the  Adri- 
atic had  a  higher  temperature ;  and  in  this  manner,  he  said,  the  shells 
of  warmer  regions  may  once  have  peopled  their  own  seas.  But  Testa 
was  disposed  to  think  that  these  species  of  testacea  were  still  common 
to  their  own  and  to  equinoctial  seas  ;  for  many,  he  said,  once  supposed 
to  be  confined  to  hotter  regions,  had  been  afterwards  discovered  in  the 
Mediterranean.* 

Cortesi — Spallanzani —  Wallerius —  Whitehurst. — While  these  Ital- 
ian naturalists,  together  with  Cortesi  and  Spallanzani,  were  busily  en- 
gaged in  pointing  out  the  analogy  between  the  deposits  of  modern  and 
ancient  seas,  and  the  habits  and  arrangement  of  their  organic  inhabit- 
ants, and  while  some  progress  was  making,  in  the  same  country,  in 
investigating  the  ancient  and  modern  volcanic  rocks,  some  of  the  most 
original  observers  among  the  English  and  German  writers,  Whitehurstf 
and  Wallerius,  were  wasting  their  strength  in  contending,  according  to 
the  old  Woodwardian  hypothesis,  that  all  the  strata  were  formed  by 
Noah's  deluge.  But  Whitehurst's  description  of  the  rocks  of  Derby- 
shire was  most  faithful ;  and  he  atoned  for  false  theoretical  views,  by 
providing  data  for  their  refutation. 

Pallas — Saussure. — Towards  the  close  of  the  eighteenth  century,  the 
idea  of  distinguishing  the  mineral  masses  on  our  globe  into  separate 
groups,  and  studying  their  relations,  began  to  be  generally  diffused. 
Pallas  and  Saussure  were  among  the  most  celebrated  whose  labors  con- 
tributed to  this  end.  After  an  attentive  examination  of  the  two  great 
mountain  chains  of  Siberia,  Pallas  announced  the  result,  that  the  gra- 
nitic rocks  were  in  the  middle,  the  schistose  at  their  sides,  and  the  lime- 
stones again  on  the  outside  of  these ;  and  this  he  conceived  would 
prove  a  general  law  in  the  formation  of  all  chains  composed  chiefly  of 
primary  rocks.]; 

In  his  "  Travels  in  Russia,"  in  1793  and  1794,  he  made  many  geo- 
logical observations  on  the  recent  strata  near  the  Wolga  and  the  Cas- 
pian, and  adduced  proofs  of  the  greater  extent  of  the  latter  sea  at  no 
distant  era  in  the  earth's  history.  His  memoir  on  the  fossil  bones  of 
Siberia  attracted  attention  to  some  of  the  most  remarkable  phenomena 
in  geology.  He  stated  that  he  had  found  a  rhinoceros  entire  in  the  fro- 
zen soil,  with  its  skin  and  flesh  :  an  elephant,  found  afterwards  in  amass 

*  This  argument  of  Testa  has  been  strengthened  of  late  years  by  the  discovery 
that  dealers  in  shells  had  long  been  in  the  habit  of  selling  Mediterranean  species 
as  shells  of  more  southern  and  distant  latitudes,  for  the  sake  of  enhancing  their 
price.  It  appears,  moreover,  from  several  hundred  experiments  made  by  that 
distinguished  hydrographer,  Capt.  Smith,  on  the  water  within  eight  fathoms  of 
the  surface,  that  the  temperature  of  the  Mediterranean  is  on  an  average  3£°  of 
Fahrenheit  higher  than  the  western  part  of  the  Atlantic  ocean ;  an  important  fact, 
which  in  some  degree  may  help  to  explain  why  many  species  are  common  to 
tropical  latitudes  and  to  the  Mediterranean. 

f  Inquiry  into  the  Original  State  and  Formation  of  the  Earth,  1778. 

\  Observ.  on  the  Formation  of  Mountains.     Act  Petrop.  ann.  1778,  part  i. 


46  WEKNEK.  [Cn.   IV. 

of  ice  on  the  shore  of  the  North  Sea,  removed  all  doubt  as  to  the  ac- 
curacy of  so  wonderful  a  discovery.* 

The  subjects  relating  to  natural  history  which  engaged  the  attention 
of  Pallas,  were  too  multifarious  to  admit  of  his  devoting  a  large  share 
of  his  labors  exclusively  to  geology.  Saussure,  on  the  other  hand,  em- 
ployed the  chief  portion  of  his  time  in  studying  the  structure  of  the 
Alps  and  Jura,  and  he  provided  valuable  data  for  those  who  followed 
him.  He  did  not  pretend  to  deduce  any  general  system  from  his  numer- 
ous and  interesting  observations  ;  and  the  few  theoretical  opinions  which 
escaped  from  him,  seem,  like  those  of  Pallas,  to  have  been  chiefly  de- 
rived from  the  cosmological  speculations  of  preceding  writers. 


CHAPTER  IV. 

HISTORY    OF    THE    PROGRESS    OF    GEOLOGY Continued. 

Werner's  application  of  geology  to  the  art  of  mining — Excursive  character  of  his 
lectures — Enthusiasm  of  his  pupils — His  authority — His  theoretical  errors — 
Desmarest's  Map  and  Description  of  Auvergne — Controversy  between  the  Vul- 
canists  and  Neptunists — Intemperance  of  the  rival  sects — Button's  Theory  of  the 
earth — His  discovery  of  granite  veins — Originality  of  his  views — Why  opposed 
— Playfair's  illustrations — Influence  of  Voltaire's  writings  on  geology — Imputa- 
tions cast  on  the  Huttonians  by  Williams,  Kirwan,  and  De  Luc — Smith's  Map 
of  England — Geological  Society  of  London — Progress  of  the  science  in  France 
— Growing  importance  of  the  study  of  organic  remains. 

Werner. — THE  art  of  mining  has  long  been  taught  in  France,  Ger- 
many, and  Hungary,  in  scientific  institutions  established  for  that  pur- 
pose, where  mineralogy  has  always  been  a  principal  branch  of  instruction. 

Werner  was  named,  in  1775,  professor  of  that  science  in  the  "  School 
of  Mines,"  at  Freyberg,  in  Saxony.  He  directed  his  attention  not 
merely  to  the  composition  and  external  characters  of  minerals,  but  also 
to  what  he  termed  "  geognosy,"  or  the  natural  position  of  minerals  in 
particular  rocks,  together  with  the  grouping  of  those  rocks,  their  geo- 
graphical distribution,  and  various  relations.  The  phenomena  observed 
in  the  structure  of  the  globe  had  hitherto  served  for  little  else  than  to 
furnish  interesting  topics  for  philosophical  discussion  ;  but  when  Werner 
pointed  out  their  application  to  the  practical  purposes  of  mining,  they 
were  instantly  regarded  bya  large  class  of  men  as  an  essential  part  of 
their  professional  education,  and  from  that  time  the  science  was  cultiva- 
ted in  Europe  more  ardently  and  systematically.  Werner's  mind  was 
at  once  imaginative  and  richly  stored  with  miscellaneous  knowledge. 
He  associated  every  thing  with  his  favorite  science,  and  in  his  excursive 

*  Nov.  comm.  Petr.  XVII.  Cuvier,  Eloge  de  Pallas. 


CH.  IV.]  WERNER.  47 

lectures,  he  pointed  out  all  the  economical  uses  of  minerals,  and  their 
application  to  medicine  ;  the  influence  of  the  mineral  composition  of 
rocks  upon  the  soil,  and  of  the  soil  upon  the  resources,  wealth,  and  civ- 
ilization of  man.  The  vast  sandy  plains  of  Tartary  and  Africa,  he 
would  say,  retained  their  inhabitants  in  the  shape  of  wandering  shep- 
herds ;  the  granitic  mountains  and  the  low  calcareous  and  alluvial  plains 
gave  rise  to  different  manners,  degrees  of  wealth,  and  intelligence.  The 
history  even  of  languages,  and  the  migration  of  tribes,  had  been  deter- 
mined by  the  direction  of  particular  strata.  The  qualities  of  certain  stones 
used  in  building  would  lead  him  to  descant  on  the  architecture  of  dif- 
ferent ages  and  nations ;  and  the  physical  geography  of  a  country  fre- 
quently invited  him  to  treat  of  military  tactics.  The  charm  of  his  manners 
and  his  eloquence  kindled  enthusiasm  in  the  minds  of  his  pupils ;  and 
many,  who  had  intended  at  first  only  to  acquire  a  slight  knowledge  of 
mineralogy,  when  they  had  once  heard  him,  devoted  themselves  to  it  as 
the  business  of  their  lives.  In  a  few  years,  a  small  school  of  mines, 
before  unheard  of  in  Europe,  was  raised  to  the  rank  of  a  great  univer- 
sity; and  men  already  distinguished  in  science  studied  the  German 
language,  and  came  from  the  most  distant  countries  to  hear  the  great 
oracle  of  geology.* 

Werner  had  a  great  antipathy  to  the  mechanical  labor  of  writing,  and, 
with  the  exception  of  a  valuable  treatise  on  metalliferous  veins,  he  could 
never  be  persuaded  to  pen  more  than  a  few  brief  memoirs,  and  those 
containing  no  development  of  his  general  views.  Although  the  natural 
modesty  of  his  disposition  was  excessive,  approaching  even  to  timidity, 
he  indulged  in  the  most  bold  and  sweeping  generalizations,  and  he  in- 
spired all  his  scholars  with  a  most  implicit  faith  in  his  doctrines.  Their 
admiration  of  his  genius,  and  the  feelings  of  gratitude  and  friendship 
which  they  all  felt  for  him,  were  not  undeserved  ;  but  the  supreme  au- 
thority usurped  by  him  over  the  opinions  of  his  contemporaries,  was 
eventually  prejudicial  to  the  progress  of  the  science ;  so  much  so,  as 
greatly  to  counterbalance  the  advantages  which  it  derived  from  his  ex- 
ertions. If  it  be  true  that  delivery  be  the  first,  second,  and  third  re- 
quisite in  a  popular  orator,  it  is  no  less  certain,  that  to  travel  is  of  first, 
second,  and  third  importance  to  those  who  desire  to  originate  just  and 
comprehensive  views  concerning  the  structure  of  our  globe.  Now  Wer- 
ner had  not  travelled  to  distant  countries ;  he  had  merely  explored  a 
small  portion  of  Germany,  and  conceived,  and  persuaded  others  to  be- 
lieve, that  the  whole  surface  of  our  planet,  and  all  the  mountain  chains 
in  the  world,  were  made  after  the  model  of  his  own  province.  It  be- 
came a  ruling  object  of  ambition  in  the  minds  of  his  pupils  to  confirm 
the  generalizations  of  their  great  master,  and  to  discover  in  the  most 
distant  parts  of  the  globe  his  "  universal  formations,"  which  he  supposed 
had  been  each  in  succession  simultaneously  precipitated  over  the  whole 
earth  from  a  common  menstruum,  or  "  chaotic  fluid."  It  now  appears 

*  Cuvier,  Eloge  de  Werner. 


48  VULCANISTS    AND    NEPTLTNISTS.  [Cn.  IV. 

that  the  Saxon  professor  had  misinterpreted  many  of  the  most  important 
appearances  even  in  the  immediate  neighborhood  of  Freyberg.  Thus, 
for  example,  within  a  day's  journey  of  his  school,  the  porphyry,  called 
by  him  primitive,  has  been  found  not  only  to  send  forth  veins  or  dikes 
through  strata  of  the  coal  formation,  but  to  overlie  them  in  mass.  The 
granite  of  the  Hartz  mountains,  on  the  other  hand,  which  he  supposed 
to  be  the  nucleus  of  the  chain,  is  now  well  known  to  traverse  the  other 
beds,  as  near  Goslar ;  and  still  nearer  Freyberg,  in  the  Erzgebirge,  the 
mica  slate  does  not  mantle  round  the  granite  as  was  supposed,  but  abuts 
abruptly  against  it.  Fragments,  also,  of  the  grey  wacke  slate,  containing 
organic  remains,  have  recently  been  found  entangled  in  the  granite  of 
the  Hartz,  by  M.  de  Seckendorf.* 

The  principal  merit  of  Werner's  system  of  instruction  consisted  in 
steadily  directing  the  attention  of  his  scholars  to  the  constant  relations 
of  superposition  of  certain  mineral  groups  ;  but  he  had  been  anticipated, 
as  has  been  shown  in  the  last  chapter,  in  the  discovery  of  this  general 
law,  by  several  geologists  in  Italy  and  elsewhere  ;  and  his  leading  di- 
visions of  the  secondary  strata  were  at  the  same  time,  and  independently, 
made  the  basis  of  an  arrangement  of  the  British  strata  by  our  country- 
man, William  Smith,  to  whose  work  I  shall  refer  in  the  sequel. 

Controversy  betiveen  the  Vulcanists  and  Neptunists. — In  regard  to 
basalt  and  other  igneous  rocks,  Werner's  theory  was  original,  but  it  was 
also  extremely  erroneous.  The  basalts  of  Saxony  and  Hesse,  to  v/hich 
his  observations  were  chiefly  confined,  consisted  of  tabular  masses  capping 
the  hills,  and  not  connected  with  the  levels  of  existing  valleys,  like  many 
in  Auvergne  and  the  Vivarais.  These  basalts,  and  all  other  rocks  of 
the  same  family  in  other  countries,  were,  according  to  him,  chemical 
precipitates  from  water.  He  denied  that  they  were  the  products  of 
submarine  volcanoes  ;  and  even  taught  that,  in  the  primeval  ages  of  the 
world,  there  were  no  volcanoes.  His  theory  was  opposed,  in  a  twofold 
sense,  to  the  doctrine  of  the  permanent  agency  of  the  same  causes  in 
nature ;  for  not  only  did  he  introduce,  without  scruple,  many  imaginary 
causes  supposed  to  have  once  effected  great  revolutions  in  the  earth,  and 
then  to  have  become  extinct,  but  new  ones  also  were  feigned  to  have 
come  into  play  in  modern  times  ;  and,  above  all,  that  most  violent  in- 
strument of  change,  the  agency  of  subterranean  heat. 

So  early  as  1768,  before  Werner  had  commenced  his  mineralogical 
studies,  Raspe  had  truly  characterized  the  basalts  of  Hesse  as  of  igneous 
origin.  Arduino,  we  have  seen,  had  pointed  out  numerous  varieties  of 
trap-rock  in  the  Vicentin  as  analogous  to  volcanic  products,  and  as  dis- 
tinctly referable  to  ancient  submarine  eruptions.  Desmarest,  as  before 
stated,  had,  in  company  with  Fortis,  examined  the  Vicentin  in  17G6,  and 
confirmed  Arduino's  views.  In  1772,  Banks,  Solander,  and  Troil  com- 
pared the  columnar  basalt  of  Hecla  with  that  of  the  Hebrides.  Collini, 

*  I  am  indebted  for  this  information  partly  to  Messrs.  Sedgwick  and  Murchison, 
who  have  investigated  ilio  country,  and  partly  to  Dr.  Charles  Hartmann,  the 
translator  of  this  work  into  German. 


CfJ.  IV.]  DESMAREST. DOLOMIEU. MONTLOSIER.  49 

in  1774,  recognized  the  true  nature  of  the  igneous  rocks  on  the  Rhine, 
between  Andernach  and  Bonn.  In  1775,  Guettard  visited  the  Vivarais, 
and  established  the  relation  of  basaltic  currents  to  lavas.  Lastly,  in 
1779,  Faujas  published  his  description  of  the  volcanoes  of  the  Vivarais 
and  Velay,  and  showed  how  the  streams  of  basalt  had  poured  out  from 
craters  which  still  remain  in  a  perfect  state.* 

Desmarest. — When  sound  opinions  had  thus  for  twenty  years  pre- 
vailed in  Europe  concerning  the  true  nature  of  the  ancient  trap-rocks, 
Werner  by  his  simple  dictum  caused  a  retrograde  movement,  and  not 
only  overturned  the  true  theory,  but  substituted  for  it  one  of  the  most 
unphilosophical  that  can  well  be  imagined.  The  continued  ascendancy 
of  his  dogmas  on  this  subject  was  the  more  astonishing,  because  a  va- 
riety of  new  and  striking  facts  were  daily  accumulated  in  favor  of  the 
correct  opinions  previously  entertained.  Desmarest,  after  a  careful 
examination  of  Auvergne,  pointed  out,  first,  the  most  recent  volcanoes 
which  had  their  craters  still  entire,  and  their  streams  of  lava  conforming 
to  the  level  of  the  present  river-courses.  He  then  showed  that  there 
were  others  of  an  intermediate  epoch,  whose  craters  were  nearly  effaced, 
and  whose  lavas  were  less  intimately  connected  with  the  present  valleys  ; 
and,  lastly,  that  there  were  volcanic  rocks,  still  more  ancient,  without 
any  discernible  craters  or  scoriae,  and  bearing  the  closest  analogy  to 
rocks  in  other  parts  of  Europe,  the  igneous  origin  of  which  was  denied 
by  the  school  of  Freyberg.f 

Desmarest's  map  of  Auvergne  was  a  work  of  uncommon  merit.  He 
first  made  a  trigonometrical  survey  of  the  district,  and  delineated  its 
physical  geography  with  minute  accuracy  and  admirable  graphic  power. 
He  contrived,  at  the  same  time,  to  express  without  the  aid  of  colors, 
many  geological  details,  including  the  different  ages  and  sometimes  even 
the  structure,  of  the  volcanic  rocks,  and  distinguishing  them  from  the 
fresh- water  and  the  granitic.  They  alone  who  have  carefully  studied 
Auvergne,  and  traced  the  different  lava  streams  from  their  craters  to 
their  termination, — the  various  isolated  basaltic  cappings, — the  rela- 
tion of  some  lavas  to  the  present  valleys, — the  absence  of  such  relations 
in  others, — can  appreciate  the  extraordinary  fidelity  of  this  elaborate 
work.  No  other  district  of  equal  dimensions  in  Europe  exhibits,  per- 
haps, so  beautiful  and  varied  a  series  of  phenomena ;  and,  fortunately, 
Desmarest  possessed  at  once  the  mathematical  knowledge  required  for 
the  construction  of  a  map,  skill  in  mineralogy,  and  a  power  of  original 
generalization. 

Dolomieu — Montlosier. — Dolomieu,  another  of  Werner's  contempo- 
raries, had  found  prismatic  basalt  among  the  ancient  lavas  of  Etna  ;  and, 
in  1784,  had  observed  the  alternations  of  submarine  lavas  and  calcareous 
strata  in  the  Val  di  Noto,  in  Sicily. J  In  1790,  also,  he  described  simi- 
lar phenomena  in  the  Vicentin  and  in  the  Tyrol.§  Montlosier  published, 

*  Cuvier,  Eloge  de  Desmarest. 

f  Journ.  de  Phys.  vol.  xiii.  p.  115  ;  and  Mem.  de  1'Inst.,  Sciences  Hathe'mat.  et. 
Phys.  vol.  vi.  p.  219. 

J  Journ.  de  Phys.  torn.  xxxv.  p.  191.  §  Ib.  torn,  xxxvii.  part  ii.  p.  200. 

4 


50  BUTTON.  [On.  IV. 

in  1788,  an  essay  on  the  theories  of  volcanoes  of  Auvergne,  combining 
accurate  local  observations  with  comprehensive  views.  Notwithstand- 
ing this  mass  of  evidence  the  scholars  of  Werner  were  prepared  to 
support  his  opinions  to  their  utmost  extent ;  maintaining,  in  the  fulness 
of  their  faith,  that  even  obsidian  was  an  aqueous  precipitate.  As  they 
were  blinded  by  their  veneration  for  the  great  teacher,  they  were  impa- 
tient of  opposition,  and  soon  imbibed  the  spirit  of  a  faction  ;  and  their 
opponents,  the  Vulcanists,  were  not  long  in  becoming  contaminated  with 
the  same  intemperate  zeal.  Ridicule  and  irony  were  weapons  more 
frequently  employed  than  argument  by  the  rival  sects,  till  at  last  the 
controversy  was  carried  on  with  a  degree  of  bitterness  almost  unprece- 
dented in  questions  of  physical  science.  Desmarest  alone,  who  had 
long  before  provided  ample  materials  for  refuting  such  a  theory,  kept 
aloof  from  the  strife  ;  and  whenever  a  zealous  Neptunist  wished  to  draw 
the  old  man  into  an  argument,  he  was  satisfied  with  replying,  "  Go  and 
see."* 

Hutton,  1788. — It  would  be  contrary  to  all  analogy,  in  matters  of 
graver  import,  that  a  war  should  rage  with  such  fury  on  the  Continent, 
and  that  the  inhabitants  of  our  island  should  not  mingle  in  the  affray. 
Although  in  England  the  personal  influence  of  Werner  was  wanting  to 
stimulate  men  to  the  defence  of  the  weaker  side  of  the  question,  they 
contrived  to  find  good  reason  for  espousing  the  Wernerian  errors  with 
great  enthusiasm.  In  order  to  explain  the  peculiar  motives  which  led 
many  to  enter,  even  with  party  feeling,  into  this  contest,  it  will  be  ne- 
cessary to  present  the  reader  with  a  sketch  of  the  views  unfolded  by 
Hutton,  a  contemporary  of  the  Saxon  geologist.  The  former  naturalist 
had  been  educated  as  a  physician,  but  declining  the  practice  of  medi- 
cine, he  resolved,  when  young,  to  remain  content  with  the  small  indi- 
pendence  inherited  from  his  father,  and  thenceforth  to  give  his  undi- 
vided attention  to  scientific  pursuits.  He  resided  at  Edinburgh,  where 
he  enjoyed  the  society  of  many  men  of  high  attainments,  who  loved 
him  for  the  simplicity  of  his  manners,  and  the  sincerity  of  his  character. 
His  application  was  unwearied  ;  and  he  made  frequent  tours  through 
different  parts  of  England  and  Scotland,  acquiring  considerable  skill  as 
a  mineralogist,  and  consequently  arriving  at  grand  and  comprehensive 
views  in  geology.  He  communicated  the  results  of  his  observations 
unreservedly,  and  with  the  fearless  spirit  of  one  who  was  conscious 
that  love  of  truth  was  the  sole  stimulus  of  his  exertions.  When  at 
length  he  had  matured  his  views,  he  published,  in  1788,  his  "Theory 
of  the  Earth, "f  and  the  same,  afterwards  more  fully  developed  in  a 
separate  work,  in  1795.  This  treatise  was  the  first  in  which  geology 
was  declared  to  be  in  no  way  concerned  about  "  questions  as  to  the  ori- 
gin of  things  ;"  the  first  in  which  an  attempt  was  made  to  dispense  en- 
tirely with  all  hypothetical  causes,  and  to  explain  the  former  changes 
of  the  earth's  crust  by  reference  exclusively  to  natural  agents.  Hutton 

*  Cuvier,  Eloge  de  Desmarest.  f  Ed.  Phil.  Trans.  1788. 


CH.  17.]  HUTTONIAN    THEORY.  51 

labored  to  give  fixed  principles  to  geology,' as  Newton  had  succeeded 
in  doing  to  astronomy ;  but,  in  the  former  science,  too  little  progress 
had  been  made  towards  furnishing  the  necessary  data,  to  enable  any 
philosopher,  however  great  his  genius,  to  realize  so  noble  a  project. 

Huttonian  theory. — "The  ruins  of  an  older  world,"  said  Hutton, 
"  are  visible  in  the  present  structure  of  our  planet ;  and  the  strata 
which  now  compose  our  continents  have  been  once  beneath  the  sea,  and 
were  formed  out  of  the  waste  of  pre-existing  continents.  The  same 
forces  are  still  destroying,  by  chemical  decomposition  or  mechanical 
violence,  even  the  hardest  rocks,  and  transporting  the  materials  to  the 
sea,  where  they  are  spread  out,  and  form  strata  analogous  to  those  of 
more  ancient  date.  Although  loosely  deposited  along  the  bottom  of  the 
ocean,  they  become  afterwards  altered  and  consolidated  by  volcanic 
heat,  and  then  heaved  up,  fractured,  and  contorted." 

Although  Hutton  had  never  explored  any  region  of  active  volcanoes, 
he  had  convinced  himself  that  basalt  and  many  other  trap-rocks  were  of 
igneous  origin,  and  that  many  of  them  had  been  injected  in  a  melted  state 
through  fissures  in  the  older  strata.  The  compactness  of  these  rocks, 
and  their  different  aspect  from  that  of  ordinary  lava,  he  attributed  to 
their  having  cooled  down  under  the  pressure  of  the  sea  ;  and  in  order  to 
remove  the  objections  started  against  this  theory,  his  friend,  Sir  James 
Hall,  instituted  a  most  curious  and  instructive  series  of  chemical  exper- 
iments, illustrating  the  crystalline  arrangement  and  texture  assumed  by 
melted  matter  cooled  under  high  pressure. 

The  absence  of  stratification  in  granite,  and  its  analogy,  in  mineral 
character,  to  rocks  which  he  deemed  of  igneous  origin,  led  Hutton  to  con- 
clude that  granite  also  must  have  been  formed  from  matter  in  fusion  ; 
and  this  inference  he  felt  could  not  be  fully  confirmed,  unless  he  dis- 
covered at  the  contact  of  granite  and  other  strata  a  repetition  of  the 
phenomena  exhibited  so  constantly  by  the  trap-rocks.  Resolved  to  try 
his  theory  by  this  test,  he  went  to  the  Grampians,  and  surveyed  the  line 
of  junction  of  the  granite  and  superincumbent  stratified  masses,  until  he 
found  in  Glen  Tilt,  in  1785,  the  most  clear  and  unequivocal  proofs  in 
support  of  his  views.  Veins  of  red  granite  are  there  seen  branching  out 
from  the  principal  mass,  and  traversing  the  black  micaceous  schist  and 
primary  limestone.  The  intersected  stratified  rocks  are  so  distinct  in 
color  and  appearance  as  to  render  the  example  in  that  locality  most 
striking,  and  the  alteration  of  the  limestone  in  contact  was  very  analogous 
to  that  produced  by  trap  veins  on  calcareous  strata.  This  verification  of 
his  system  filled  him  with  delight,  and  called  forth  such  marks  of  joy 
and  exultation,  that  the  guides  who  accompanied  him,  says  his  biogra- 
pher, were  convinced  that  he  must  have  discovered  a  vein  of  silver  or 
gold.*  He  was  aware  that  the  same  theory  would  not  explain  the  origin 
of  the  primary  schists,  but  these  he  called  primary,  rejecting  the  term 
primitive,  and  was  disposed  to  consider  them  as  sedimentary  rocks  al- 

*  Playfair's  Works,  vol.  iv.  p.  75. 


52  IJUTTONIAN    THEORY.  [Cn.  IV. 

tered  by  heat,  and  that  they  originated  in  some  other  form  from  the  waste 
of  previously  existing  rocks. 

By  this  important  discovery  of  granite  veins,  to  which  he  had  been 
led  by  fair  induction  from  an  independent  class  of  facts,  Hutton  prepared 
the  way  for  the  greatest  innovation  of  the  systems  of  his  predecessors. 
Vallisneri  had  pointed  out  the  general  fact  that  there  were  certain  funda- 
mental rocks  which  contained  no  organic  remains,  and  which  he  supposed 
to  have  been  formed  before  the  creation  of  living  beings.  Moro,  Generelli, 
and  other  Italian  writers,  embraced  the  same  doctrine ;  and  Lehman  re- 
garded the  mountains  called  by  him  primitive,  as  parts  of  the  original 
nucleus  of  the  globe.  The  same  tenet  was  an  article  of  faith  in  the 
school  of  Freyberg ;  and  if  any  one  ventured  to  doubt  the  possibility  of 
our  being  enabled  to  carry  back  our  researches  to  the  creation  of  the 
present  order  of  things,  the  granitic  rocks  were  triumphantly  appealed 
to.  On  them  seemed  written,  in  legible  characters,  the  memorable  in- 
scription— 

"  Dinanzi  a  me  non  fur  cose  create 
Se  non  eterne  ;"* 

and  no  small  sensation  was  excited  when  Hutton  seemed,  with  unhal- 
lowed hand,  desirous  to  erase  characters  already  regarded  by  many  as 
sacred.  "  In  the  economy  of  the  world,"  said  the  Scotch  geologist,  "  I 
can  find  no  traces  of  a  beginning,  no  prospect  of  an  end  ;"  a  declara- 
tion the  more  startling  when  coupled  with  the  doctrine,  that  all  past  ages 
on  the  globe  had  been  brought  about  by  the  slow  agency  of  existing 
causes.  The  imagination  was  first  fatigued  and  overpowered  by  en- 
deavoring to  conceive  the  immensity  of  time  required  for  the  annihilation 
of  whole  continents  by  so  insensible  a  process  ;  and  when  the  thoughts 
had  wandered  through  these  interminable  periods,  no  resting-place  was 
assigned  in  the  remotest  distance.  The  oldest  rocks  were  represented 
to  be  of  a  derivative  nature,  the  last  of  an  antecedent  series,  and  that, 
perhaps,  one  of  many  pre-existing  worlds.  Such  views  of  the  immen- 
sity of  past  time,  like  those  unfolded  by  the  Newtonian  philosophy  in  re- 
gard to  space,  were  too  vast  to  awaken  ideas  of  sublimity  unmixed  with 
a  painful  sense  of  our  incapacity  to  conceive  a  plan  of  such  infinite  ex- 
tent. Worlds  are  seen  beyond  worlds  immeasurably  distant  from  each 
other,  and,  beyond  them  all,  innumerable  other  systems  are  faintly  traced 
on  the  confines  of  the  visible  universe. 

The  characteristic  feature  of  the  Huttonian  theory  was,  as  before 
hinted,  the  exclusion  of  all  causes  not  supposed  to  belong  to  the  present 
order  of  nature.  But  Hutton  had  made  no  step  beyond  Hooke,  Moro, 
and  Raspe,  in  pointing  out  in  what  manner  the  laws  now  governing  sub- 
terranean movements  might  bring  about  geological  changes,  if  sufficient 
time  be  allowed.  On  the  contrary,  he  seems  to  have  fallen  far  short  of 
some  of  their  views,  especially  when  he  refused  to  attribute  any  part 

*  "  Before  me  things  create  were  none,  save  things 

Eternal." Dante's  Inferno,  canto  iii.  Gary's  Translation. 


CH.  IV.]  PLAYFAIR'S  ILLUSTRATION  OF  HUTTON.  53 

of  the  external  configuration  of  the  earth's  crust  to  subsidence.  He 
imagined  that  the  continents  were  first  gradually  destroyed  by  aqueous 
degradation  ;  and  when  their  ruins  had  furnished  materials  for  new 
continents,  they  were  upheaved  by  violent  convulsions.  He  therefore 
required  alternate  periods  of  general  disturbance  and  repose  ;  and  such 
he  believed  had  been,  and  would  forever  be,  the  course  of  nature. 

Generelli,  in  his  exposition  of  Moro's  system,  had  made  a  far  nearer 
approximation  towards  reconciling  geological  appearances  with  the  state 
of  nature  as  known  to  us ;  for  while  he  agreed  with  Hutton,  that  the 
decay  and  reproduction  of  rocks  were  always  in  progress,  proceeding 
with  the  utmost  uniformity,  the  learned  Carmelite  represented  the  re- 
pairs of  mountains  by  elevation  from  below  to  be  effected  by  an  equally 
constant  and  synchronous  operation.  Neither  of  these  theories,  con- 
sidered singly,  satisfies  all  the  conditions  of  the  great  problem,  which  a 
geologist,  who  rejects  cosmological  causes,  is  called  upon  to  solve ;  but 
they  probably  contain  together  the  germs  of  a  perfect  system.  There 
can  be  no  doubt,  that  periods  of  disturbance  and  repose  have  followed 
each  other  in  succession  in  every  region  of  the  globe  ;  but  it  may  be 
equally  true,  that  the  energy  of  the  subterranean  movements  has  been 
always  uniform  as  regards  the  whole  earth.  The  force  of  earthquakes 
may  for  a  cycle  of  years  have  been  invariably  confined,  as.  it  is  now,  to 
large  but  determinate  spaces,  and  may  then  have  gradually  shifted  its 
position,  so  that  another  region,  which  had  for  ages  been  at  rest,  became 
in  its  turn  the  grand  theatre  of  action. 

Play  fair's  illustrations  of  Hutton. — The  explanation  proposed  by 
Hutton,  and  by  Playfair,  the  illustrator  of  his  theory,  respecting  the 
origin  of  valleys  and  of  alluvial  accumulations,  was  also  very  imperfect. 
They  ascribed  none  of  the  inequalities  of  the  earth's  surface  to  move- 
ments which  accompanied  the  upheaving  of  the  land,  imagining  that 
valleys  in  general  were  formed  in  the  course  of  ages  by  the  rivers  now 
flowing  in  them  ;  while  they  seem  not  to  have  reflected  on  the  exca- 
vating and  transporting  power  which  the  waves  of  the  ocean  might  exert 
on  land  during  its  emergence. 

Although  Hutton's  knowledge  of  mineralogy  and  chemistry  was  con- 
siderable, he  possessed  but  little  information  concerning  organic  remains ; 
they  merely  served  him,  as  they  did  Werner,  to  characterize  certain 
strata,  and  to  prove  their  marine  origin.  The  theory  of  former  revolu- 
tions in  organic  life  was  not  yet  fully  recognized ;  and  without  this  class 
of  proofs  in  support  of  the  antiquity  of  the  globe,  the  indefinite  periods 
demanded  by  the  Huttonian  hypothesis  appeared  visionary  to  many  ; 
and  some,  who  deemed  the  doctrine  inconsistent  with  revealed  truths, 
indulged  very  uncharitable  suspicions  of  the  motives  of  its  author. 
They  accused  him  of  a  deliberate  design  of  reviving  the  heathen  dogma 
of  an  "  eternal  succession,"  and  of  denying  that  this  world  ever  had  a 
beginning.  Playfair,  in  the  biography  of  his  friend,  has  the  following 
comment  on  this  part  of  their  theory : — "  In  the  planetary  motions, 
where  geometry  has  carried  the  eye  so  far,  both  into  the  future  and  the 


54:  VOLTAIKE.  [On.  IV. 

past,  we  discover  no  mark  either  of  the  commencement  or  termination 
of  the  present  order.  It  is  unreasonable,  indeed,  to  suppose  that  such 
marks  should  anywhere  exist.  The  Author  of  Nature  has  not  given 
laws  to  the  universe,  which,  like  the  institutions  of  men,  carry  in  them- 
selves the  elements  of  their  own  destruction.  He  has  not  permitted  in 
His  works  any  symptom  of  infancy  or  of  old  age,  or  any  sign  by  which 
we  may  estimate  either  their  future  or  their  past  duration.  He  may 
put  an  end,  as  he  no  doubt  gave  a  beginning,  to  the  present  system,  at 
some  determinate  period  of  time ;  but  we  may  rest  assured  that  this 
great  catastrophe  will  not  be  brought  about  by  the  laws  now  existing, 
and  that  it  is  not  indicated,  by  any  thing  which  we  perceive."* 

The  party  feeling  excited  against  the  Huttonian  doctrines,  and  the 
open  disregard  of  candor  and  temper  in  the  controversy,  will  hardly  be 
credited  by  the  reader,  unless  he  recalls  to  his  recollection  that  the  mind  of 
the  English  public  was  at  that  time  in  a  state  of  feverish  excitement. 
A  class  of  writers  in  France  had  been  laboring  industriously  for  many 
years,  to  diminish  the  influence  of  the  clergy,  by  sapping  the  founda- 
tions of  the  Christian  faith  ;  and  their  success,  and  the  consequences  of 
the  Revolution,  had  alarmed  the  most  resolute  minds,  while  the  imagin- 
ation of  the  more  timid  was  continually  haunted  by  dread  of  innovation, 
as  by  the  phantom  of  some  fearful  dream. 

Voltaire. — Voltaire  had  used  the  modern  discoveries  in  physics  as 
one  of  the  numerous  weapons  of  attack  and  ridicule  directed  by  him 
against  the  Scriptures.  He  found  that  the  most  popular  systems  of 
geology  were  accommodated  to  the  sacred  writings,  and  that  much  in- 
genuity had  been  employed  to  make  every  fact  coincide  exactly  with 
the  Mosaic  account  of  the  creation  and  deluge.  It  was,  therefore,  with  no 
friendly  feelings  that  he  contemplated  the  cultivators  of  geology  in  gen- 
eral, regarding  the  science  as  one  which  had  been  successfully  enlisted 
by  theologians  as  an  ally  in  their  cause.f  He  knew  that  the  majority 
of  those  who  were  aware  of  the  abundance  of  fossil  shells  in  the  interior 
of  continents,  were  still  persuaded  that  they  were  proofs  of  the  univer- 
sal deluge  ;  and  as  the  readiest  way  of  shaking  this  article  of  faith,  he 
endeavored  to  inculcate  skepticism  aS  to  the  real  nature  of  such  shells, 
and  to  recall  from  contempt  the  exploded  dogma  of  the  sixteenth  cen- 
tury, that  they  were  sports  of  nature.  He  also  pretended  that  vegeta- 
ble impressions  were  not  those  of  real  plants.|  Yet  he  was  perfectly 
convinced  that  the  shells  had  really  belonged  to  living  testacea,  as  may 

*  Playfair's  "Works,  vol.  iv.  p.  55. 

f  In  allusion  to  the  theories  of  'Bui-net,  Woodward,  and  other  physico-theologi 
cal  writers,  he  declared  that  they  were  as  fond  of  changes  of  scene  on  the  face  of 
the  globe,  as  were  the  populace  at  a  play.  "  Every  one  of  them  destroys  and 
renovates  the  earth  after  his  own  fashion,  as  Descartes  framed  it :  for  philosophers 
put  themselves  without  ceremony  in  the  place  of  God,  and  think  to  create  a  uni- 
verse with  a  word." — Dissertation  envoy ee  a  1' Academic  de  Boulogne,  sur  les 
Changemens  arrives  dans  notre  Globe.  Unfortunately,  this  and  similar  ridicule 
directed  against  the  cosmogonists  was  too  well  deserved. 

\  See  the  chapter  on  "  Des  Pierres  figure's." 


CH.  IV.]  SPIRIT    OF    INTOLERANCE.  55 

be  seen  in  his  essay  "  On  the  formation  of  Mountains."*  He  would 
sometimes,  in  defiance  of  all  consistency,  shift  his  ground  when  address- 
ing the  vulgar  ;  and,  admitting  the  true  nature  of  the  shells  collected  in 
the  Alps  and  other  places,  pretend  that  they  were  Eastern  species, 
which  had  fallen  from  the  hats  of  pilgrims  coming  from  Syria.  The 
numerous  essays  written  by  him  on  geological  subjects  were  all  calcu- 
lated to  strengthen  prejudices,  partly  because  he  was  ignorant  of  the 
real  state  of  the  science,  and  partly  from  his  bad  faith. f  On  the  other 
hand,  they  who  knew  that  his  attacks  were  directed  by  a  desire  to  in- 
validate Scripture,  and  who  were  unacquainted  with  the  true  merits  of 
the  question,  might  well  deem  the  old  diluvian  hypothesis  incontroverti- 
ble, if  Voltaire  could  adduce  no  better  argument  against  it  than  to  deny 
the  true  nature  of  organic  remains. 

It  is  only  by  careful  attention  to  impediments  originating  in  extrinsic 
causes,  that  we  can  explain  the  slow  and  reluctant  adoption  of  the  sim- 
plest truths  in  geology.  First,  we  find  many  able  naturalists  adducing 
the  fossil  remains  of  marine  animals  as  proofs  of  an  event  related  in 
Scripture.  The  evidence  is  deemed  conclusive  by  the  multitude  for  a 
century  or  more ;  for  it  favors  opinions  which  they  entertained  before, 
and  they  are  gratified  by  supposing  them  confirmed  by  fresh  and  unex- 
pected proofs.  Many  who  see  through  the  fallacy  have  no  wish  to  un- 
deceive those  who  are  influenced  by  it,  approving  the  effect  of  the  delu- 
sion, and  conniving  at  it  as  a  pious  fraud ;  until,  finally,  an  opposite  par- 
ty, who  are  hostile  to  the  sacred  writings,  labor  to  explode  the  erroneous 
opinion,  by  substituting  for  it  another  dogma,  which  they  know  to  be 
equally  unsound. 

The  heretical  Vulcanists  were  soon  after  openly  assailed  in  England, 
by  imputations  of  the  most  illiberal  kind.  We  cannot  estimate  the  ma- 
levolence of  such  a  persecution,  by  the  pain  which  similar  insinuations 
might  now  inflict ;  for  although  charges  of  infidelity  and  atheism  must 
always  be  odious,  they  were  injurious  in  the  extreme  at  that  moment  of 
political  excitement ;  and  it  was  better,  perhaps,  for  a  man's  good  recep- 
tion in  society,  that  his  moral  character  should  have  been  traduced,  than 
that  he  should  become  a  mark  for  these  poisoned  weapons. 

I  shall  pass  over  the  works  of  numerous  divines,  who  may  be  excused 
for  sensitiveness  on  points  which  then  excited  so  much  uneasiness  in  the 
public  mind ;  and  shall  say  nothing  of  the  amiable  poet  Cowper,J  who 

*  In  that  essay  he  lays  it  down,  "  that  all  naturalists  are  now  agreed  that  de- 
posits of  shells  in  the  midst  of  the  continents  are  monuments  of  the  continued  occu- 
pation of  these  districts  by  the  ocean."  In  another  place  also,  when  speaking  of 
the  fossil  shells  of  Touraine,  he  admits  their  true  origin. 

f  As  an  instance  of  his  desire  to  throw  doubt  indiscriminately  on  all  geological 
data,  we  may  recall  the  passage  where  he  says,  that  "  the  bones  of  a  reindeer 
and  hippopotamus  discovered  near  Etempes  did  not  prove,  as  some  would  have 
it,  that  Lapland  and  the  Nile  were  once  on  a  tour  from  Paris  to  Orleans,  but 
merely  that  a  lover  of  curiosities  once  preserved  them  in  his  cabinet." 

\  "  Some  drill  and  bore 

The  solid  earth,  and  from  the  strata  there 
Extract  a  register,  by  which  we  learn 


56  KIRWAN. DE    LUC.  [On.  IV. 

could  hardly  be  expected  to  have  inquired  into  the  merit  of  doctrines  in 
physics.  But  in  the  foremost  ranks  of  the  intolerant  are  found  several 
laymen  who  had  high  claims  to  scientific  reputation.  Among  these  ap- 
pears Williams,  a  mineral  surveyor  of  Edinburgh,  who  published  a 
"  Natural  History  of  the  Mineral  Kingdom,"  in  1789  ;  a  work  of  great 
merit,  for  that  day,  and  of  practical  utility,  as  containing  the  best  ac- 
count of  the  coal  strata.  In  his  preface  he  misrepresents  Button's  the- 
ory altogether,  and  charges  him  with  considering  all  rocks  to  be  lavas 
of  different  colors  and  structure  ;  and  also  with  "  warping  every  thing  to 
support  the  eternity  of  the  world."*  He  descants  on  the  pernicious 
influence  of  such  skeptical  notions,  as  leading  to  downright  infidelity 
and  atheism,  "  and  as  being  nothing  less  than  to  depose  the  Almighty 
Creator  of  the  universe  from  his  office. "f 

Kirwan — De  Luc. — Kirwan,  president  of  the  Royal  Academy  of 
Dublin,  a  chemist  and  mineralogist  of  some  merit,  but  who  possessed 
much  greater  authority  in  the  scientific  world  than  he  was  entitled  by 
his  talents  to  enjoy,  said,  in  the  introduction  to  his  "  Geological  Essays, 
1799,"  "that  sound  geology  graduated  into  religion,  and  was  required 
to  dispel  certain  systems  of  atheism  or  infidelity,  of  which  they  had  had 
recent  experience.''^  He  was  an  uncompromising  defender  of  the  aque- 
ous theory  of  all  rocks,  and  was  scarcely  surpassed  by  Burnet  and 
Whiston,  in  his  desire  to  adduce  the  Mosaic  writings  in  confirmation  of 
his  opinions. 

De  Luc,  in  the  preliminary  discourse  to  his  Treatise  on  Geology,§ 
says,  "  The  weapons  have  been  changed  by  which  revealed  religion  is 
attacked ;  it  is  now  assailed  by  geology,  and  the  knowledge  of  this 
science  has  become  essential  to  theologians."  He  imputes  the  failure 
of  former  geological  systems  to  their  having  been  anti-Mosaical,  and 
directed  against  a  "  sublime  tradition."  These  and  similar  imputations, 
reiterated  in  the  works  of  De  Luc,  seem  to  have  been  taken  for  granted 
by  some  modern  writers :  it  is  therefore  necessary  to  state,  in  justice  to 
the  numerous  geologists  of  different  nations,  whose  works  have  been 
considered,  that  none  of  them  were  guilty  of  endeavoring,  by  arguments 
drawn  from  physics,  to  invalidate  scriptural  tenets.  On  the  contrary, 
the  majority  of  those  who  were  fortunate  enough  "  to  discover  the  true 
causes  of  things,"  rarely  deserved  another  part  of  the  poet's  panegyric, 
"Atque  metus  omnes  subjecit  pedibus."  The  caution  and  even  timid  re- 
serve, of  many  eminent  Italian  authors  of  the  earlier  period  is  very  ap- 
parent ;  and  there  can  hardly  be  a  doubt,  that  they  subscribed  to  cer- 
tain dogmas,  and  particularly  to  the  first  diluvian  theory,  out  of  defer- 
ence to  popular  prejudices,  rather  than  from  conviction.  If  they  were 
guilty  of  dissimulation,  we  may  feel  regret,  but  must  not  blame  their 
want  of  moral  courage,  reserving  rather  our  condemnation  for  the  intol- 

That  he  who  made  it,  and  revealed  its  date 
To  Moses,  was  mistaken  in  its  age." 

The  Task,  book  iii.     "  The  Garden." 
*  P.  577.  f  P.  59.  J  Introd.  p.  2.  §  London,  1809. 


CH.  IV.]  PLAYFAIR'S  DEFENCE  OF  IIUTTON,  57 

erance  of  the  times,  and  that  inquisitorial  power  which  forced  Galileo  to 
abjure,  and  the  two  Jesuits  to  disclaim  the  theory  of  Newton.* 

Hutton  answered  Kirwan's  attacks  with  great  warmth,  and  with  the 
indignation  justly  excited  by  unmerited  reproach.  "He  had  always 
displayed,"  says  Playfair,  "  the  utmost  disposition  to  admire  the  benef- 
icent design  manifested  in  the  structure  of  the  world  ;  and  he  contem- 
plated with  delight  those  parts  of  his  theory  which  made  the  greatest 
additions  to  our  knowledge  of  final  causes."  We  may  say  with  equal 
truth,  that  in  no  scientific  works  in  our  language  can  more  eloquent 
passages  .be  found,  concerning  the  fitness,  harmony,  and  grandeur  of  all 
parts  of  the  creation,  than  in  those  of  Playfair.  They  are  evidently  the 
unaffected  expressions  of  a  mind,  which  contemplated  the  study  of 
nature,  as  best  calculated  to  elevate  our  conceptions  of  the  attributes  of 
the  First  Cause.  At  any  other  time  the  force  and  elegance  of  Play- 
fair's  style  must  have  insured  popularity  to  the  Huttonian  doctrines  ; 
but  by  a  singular  coincidence,  Neptunianism  and  orthodoxy  were  now 
associated  in  the  same  creed;  and  the  tide  of  prejudice  ran  so  strong, 
that  the  majority  were  carried  far  away  into  the  chaotic  fluid,  and  other 
cosmological  inventions  of  Werner.  These  fictions  the  Saxon  professor 
had  borrowed  with  little  modification,  and  without  any  improvement, 
from  his  predecessors.  They  had  not  the  smallest  foundation  either  in 
Scripture  or  in  common  sense,  and  were  probably  approved  of  by  many 
as  being  so  ideal  and  unsubstantial,  that  they  could  never  come  into 
violent  collision  with  any  preconceived  opinions. 

According  to  De  Luc,  the  first  essential  distinction  to  be  made  be- 
tween the  various  phenomena  exhibited  on  the  surface  of  the  earth  was, 
to  determine  which  were  the  results  of  causes  still  in  action,  and  which 
had  been  produced  by  causes  that  had  ceased  to  act.  The  form  and 
composition  of  the  mass  of  our  continents,  he  said,  and  their  existence 
above  the  level  of  the  sea,  must  be  ascribed  to  causes  no  longer  in 
action.  These  continents  emerged,  at  no  very  remote  period,  on  the 
sudden  retreat  of  the  ocean,  the  waters  of  which  made  their  way  into 
subterranean  caverns.  The  formation  of  the  rocks  which  enter  into  the 
crust  of  the  earth  began  with  the  precipitation  of  granite  from  a  pri- 
mordial liquid,  after  which  other  strata  containing  the  remains  of  or- 

*  In  a  most  able  article,  by  Mr.  Drinkwater,  on  the  "  Life  of  Galileo,"  published 
in  the  "  Library  of  Useful  Knowledge,"  it  is  stated  that  both  Galileo's  work,  and 
the  book  of  Copernicus,  "  Nisi  corrigatur"  (for,  with  the  omission  of  certain  pas- 
sages, it  was  sanctioned),  were  still  to  be  seen  on  the  forbidden  list  of  the  Index 
at  Rome,  in  1828.  I  was,  however,  assured  in  the  same  year,  by  Professor  Scar- 
pellini,  at  Rome,  that  Pius  VIL,  a  pontiff  distinguished  for  his  love  of  science,  had 
procured  a  repeal  of  the  edicts  against  Galileo  and  the  Copernican  system.  He 
had  assembled  the  Congregation ;  and  the  late  Cardinal  Toriozzi,  assessor  of  the 
Sacred  Office,  proposed  that  they  should  wipe  off  this  scandal  from  the  church." 
The  repeal  was  carried,  with  the  dissentient  voice  of  one  Dominican  only.  Long 
before  that  time  the  Newtonian  theory  had  been  taught  in  the  Sapienza,  and  all 
Catholic  universities  in  Europe  (with  the  exception,  I  am  told,  of  Salamanca);  but 
it  was  always  required  of  professors,  in  deference  to  the  decrees  of  the  church,  to 
use  the  term  hypothesis,  instead  of  theory.  They  now  speak  of  the  Copernican 
theory. 


58  SMITH'S  MAP  OF  ENGLAND.  [Cn.  IV. 

ganized  bodies  were  deposited,  till  at  last  the  present  sea  remained  as 
the  residuum  of  the  primordial  liquid,  and  no  longer  continued  to  pro- 
duce mineral  strata.* 

William  Smith,  1790. — While  the  tenets  of  the  rival  schools  of 
Freyberg  and  Edinburgh  were  warmly  espoused  by  devoted  partisans, 
the  labors  of  an  individual,  unassisted  by  the  advantages  of  wealth  or 
station  in  society,  were  almost  unheeded.  Mr.  William  Smith,  an  Eng- 
lish surveyor,  published  his  "  Tabular  View  of  the  British  Strata"  in 
1790,  wherein  he  proposed  a  classification  of  the  secondary  formations 
in  the  West  of  England.  Although  he  had  not  communicated  with 
Werner,  it  appeared  by  this  work  that  he  had  arrived  at  the  same  views 
respecting  the  laws  of  superposition  of  stratified  rocks ;  that  he  was 
aware  that  the  order  of  succession  of  different  groups  was  never  in- 
verted ;  and  that  they  might  be  identified  at  very  distant  points  by  their 
peculiar  organized  fossils. 

From  the  time  of  the  appearance  of  the  "  Tabular  View,"  the  author 
labored  to  construct  a  geological  map  of  the  whole  of  England ;  and 
with  the  greatest  disinterestedness  of  mind,  communicated  the  results  of 
his  investigations  to  all  who  desired  information,  giving  such  publicity 
to  his  original  views,  as  to  enable  his  contemporaries  almost  to  compete 
with  him  in  the  race.  The  execution  of  his  map  was  completed  in 
1815,  and  remains  a  lasting  monument  of  original  talent  and  extraordi- 
nary perseverance ;  for  he  had  explored  the  whole  country  on  foot, 
without  the  guidance  of  previous  observers,  or  the  aid  of  fellow-laborers, 
and  had  succeeded  in  throwing  into  natural  divisions  the  whole  compli- 
cated series  of  British  rocks.  D'Aubuisson,  a  distinguished  pupil  of 
Werner,  paid  a  just  tribute  of  praise  to  this  remarkable  performance, 
observing,  that  "  what  many  celebrated  mineralogists  had  only  accom- 
plished for  a  small  part  of  Germany  in  the  course  of  half  a  century,  had 
been  effected  by  a  single  individual  for  the  whole  of  England. "f 

Werner  invented  a  new  language  to  express  his  divisions  of  rocks, 
and  some  of  his  technical  terms,  such  as  grauwacke,  gneiss,  and  others, 
passed  current  in  every  country  in  Europe.  Smith  adopted  for  the  most 
part  English  provincial  terms,  often  of  barbarous  sound,  such  as  gault, 
cornbrash,  clunch  clay ;  and  affixed  them  to  subdivisions  of  the  British 
series.  Many  of  these  still  retain  their  place  in  our  scientific  classifica- 
tions, and  attest  his  priority  of  arrangement. 

MODERN    PROGRESS    OF    GEOLOGY. 

The  contention  of  the  rival  factions  of  the  Vulcanists  and  Neptunists 
had  been  carried  to  such  a  height,  that  these  names  had  become  terms 
of  reproach ;  and  the  two  parties  had  been  less  occupied  in  searching 
for  truth,  than  for  such  arguments  as  might  strengthen  their  own  cause 
or  serve  to  annoy  their  antagonists.  A  new  school  at  last  arose,  whc 

*  Elementary  Treatise  on  Geology.     London,  1809.     Translated  by  De  la  Fite 
f  See  Dr.  Fitton's  Memoir,  before  cited,  p.  57. 


CH.  IV.]  GEOLOGICAL   SOCIETY   OF   LONDON.  59 

professed  the  strictest  neutrality,  and  the  utmost  indifference  to  the 
systems  of  Werner  and  Hutton,  and  who  resolved  diligently  to  devote 
their  labors  to  observation.  The  reaction,  provoked  by  the  intemper- 
ance of  the  conflicting  parties,  now  produced  a  tendency  to  extreme 
caution.  Speculative  views  were  discountenanced,  and,  through  fear  of 
exposing  themselves  to  the  suspicion  of  a  bias  towards  the  dogmas  of  a 
party,  some  geologists  became  anxious  to  entertain  no  opinion  whatever 
on  the  causes  of  phenomena,  and  were  inclined  to  skepticism  even  where 
the  conclusions  deducible  from  observed  facts  scarcely  admitted  of  rea- 
sonable doubt. 

Geological  Society  of  London. — But  although  the  reluctance  to  theo- 
rize was  carried  somewhat  to  excess,  no  measure  could  be  more  salutary 
at  such  a  moment  than  a  suspension  of  all  attempts  to  form  what  were 
termed  "  theories  of  the  earth."  A  great  body  of  new  data  were  re- 
quired ;  and  the  Geological  Society  of  London,  founded  in  1807,  con- 
duced greatly  to  the  attainment  of  this  desirable  end.  To  multiply  and 
record  observations,  and  patiently  to  await  the  result  at  some  future 
period,  was  the  object  proposed  by  them ;  and  it  was  their  favorite 
maxim  that  the  time  was  not  yet  come  for  a  general  system  of  geology, 
but  that  all  must  be  content  for  many  years  to  be  exclusively  engaged 
in  furnishing  materials  for  future  generalizations.  By  acting  up  to  these 
principles  with  consistency,  they  in  a  few  years  disarmed  all  prejudice, 
and  rescued  the  science  from  the  imputation  of  being  a  dangerous,  or  at 
best  but  a  visionary  pursuit. 

A  distinguished  modern  writer  has  with  truth  remarked,  that  the  ad- 
vancement of  three  of  the  main  divisions  of  geological  inquiry  have  during 
the  last  half  century  been  promoted  successively  by  three  different  nations 
of  Europe, — the  Germans,  the  English,  and  the  French.*  We  have  seen 
that  the  systematic  study  of  what  may  be  called  mineralogical  geology 
had  its  origin  and  chief  point  of  activity  in  Germany,  where  Werner  first 
described  with  precision  the  mineral  characters  of  rocks.  The  classifica- 
tion of  the  secondary  formations,  each  marked  by  their  peculiar  fossils, 
belongs,  in  a  great  measure,  to  England,  where  the  labors  before  alluded 
to  of  Smith,  and  those  of  the  most  active  members  of  the  Geological 
Society  of  London,  were  steadily  directed  to  these  objects.  The  founda- 
tion of  the  third  branch,  that  relating  to  the  tertiaiy  formations,  was  laid 
in  France  by  the  splendid  work  of  Cuvier  and  Brongniart,  published  in 
1808,  "  On  the  Mineral  Geography  and  Organic  Remains  of  the  Neigh- 
borhood of  Paris." 

We  may  still  trace,  in  the  language  of  the  science  and  our  present 
method's  of  arrangement,  the  various  countries  where  the  growth  of  these 
several  departments  of  geology  was  at  different  times  promoted.  Many 
names  of  simple  minerals  and  rocks  remain  to  this  day  German ;  while 
the  European  divisions  of  the  secondary  strata  are  in  great  part  English, 
and  are,  indeed,  often  founded  too  exclusively  on  English  types.  Lastly, 
the  subdivisions  first  established  of  the  succession  of  strata  in  the  Paris 
*  Whewell,  British  Critic,  No.  xvii.  p.  187,  1831. 


60  STUDY   OF    ORGANIC   REMAINS.  [Cn.  IV. 

basin  have  served  as  normal  groups  to  which  other  tertiary  deposits 
throughout  Europe  have  been  compared,  even  in  cases  where  this 
standard  was  wholly  inapplicable. 

No  period  could  have  been  more  fortunate  for  the  discovery,  in  the 
immediate  neighborhood  of  Paris,  of  a  rich  store  of  well-preserved  fos- 
sils, than  the  commencement  of  the  present  century  ;  for  at  no  former 
era  had  Natural  history  been  cultivated  with  such  enthusiasm  in  the 
French  metropolis.  The  labors  of  Cuvier  in  comparative  osteology,  and 
of  Lamarck  in  recent  and  fossil  shells,  had  raised  these  departments  of 
study  to  a  rank  of  which  they  had  never  previously  been  deemed  sus- 
ceptible. Their  investigations  had  eventually  a  powerful  effect  in  dis- 
pelling the  illusion  which  had  long  prevailed  concerning  the  absence  of 
analogy  between  the  ancient  and  modern  state  of  our  planet.  A  close 
comparison  of  the  recent  and  fossil  species  and  the  inferences  drawn  in 
regard  to  their  habits,  accustomed  the  geologist  to  contemplate  the 
earth  as  having  been  at  successive  periods  the  dwelling-place  of  animals 
and  plants  of  different  races,  some  terrestrial,  and  others  aquatic — some 
fitted  to  live  in  seas,  others  in  the  waters  of  lakes  and  rivers.  By  the 
consideration  of  these  topics,  the  mind  was  slowly  and  insensibly  with- 
drawn from  imaginary  pictures  of  catastrophes  and  chaotic  confusion, 
such  as  haunted  the  imagination  of  the  early  cosmogonists.  Numerous 
proofs  were  discovered  of  the  tranquil  deposition  of  sedimentary  matter, 
and  the  slow  development  of  organic  life.  If  many  writers,  and  Cuvier 
himself  in  the  number,  still  continued  to  maintain,  that  "  the  thread  of 
induction  was  broken,"*  yet,  in  reasoning  by  the  strict  rules  of  induc- 
tion from  recent  to  fossil  species,  they  in  a  great  measure  disclaimed 
the  dogma  which  in  theory  they  professed.  The  adoption  of  the  same 
generic,  and,  in  some  cases,  even  of  the  same  specific,  names  for  the 
exuvise  of  fossil  animals  and  their  living  analogues,  was  an  important  step 
towards  familiarizing  the  mind  with  the  idea  of  the  identity  and  unity  of 
the  system  in  distant  eras.  It  was  an  acknowledgment,  as  it  were,  that 
part  at  least  of  the  ancient  memorials  of  nature  were  written  in  a  living 
language.  The  growing  importance,  then,  of  the  natural  history  of  or- 
ganic remains  may  be  pointed  out  as  the  characteristic  feature  of  the 
progress  of  the  science  during  the  present  century.  This  branch  of 
knowledge  has  already  become  an  instrument  of  great  utility  in  geological 
classification,  and  is  continuing  daily  to  unfold  new  data  for  grand  and 
enlarged  views  respecting  the  former  changes  of  the  earth. 

When  we  compare  the  result  of  observations  in  the  last  fifty  years 
with  those  of  the  three  preceding  centuries,  we  cannot  but  look  forward 
with  the  most  sanguine  expectations  to  the  degree  of  excellence  to  which 
geology  may  be  carried,  even  by  the  labors  of  the  present  generation. 
Never,  perhaps,  did  any  science,  with  the  exception  of  astronomy,  un- 
fold, in  an  equally  brief  period,  so  many  novel  and  unexpected  truths, 
and  overturn  so  many  preconceived  opinions.  The  senses  had  for  ages 
declared  the  earth  to  be  at  rest,  until  the  astronomer  taught  that  it  was 
*  Discours  sur  les  Revol.  <fec. 


CH.  V.]  MODERN   PROGRESS   OF   GEOLOGY.  61 

carried  through  space  with  inconceivable  rapidity.  In  like  manner  was 
the  surface  of  this  planet  regarded  as  having  remained  unaltered  since 
its  creation,  until  the  geologist  proved  that  it  had  been  the  theatre  of 
reiterated  change,  and  was  still  the  subject  of  slow  but  never-ending 
fluctuations.  The  discovery  of  other  systems  in  the  boundless  regions 
of  space  was  the  triumph  of  astronomy  ;  to  trace  the  same  system 
through  various  transformations — to  behold  it  at  successive  eras  adorned 
.with  different  hills  and  valleys,  lakes  and  seas,  and  peopled  with  new  in- 
habitants, was  the  delightful  meed  of  geological  research.  By  the 
geometer  were  measured  the  regions  of  space,  and  the  relative  distances 
of  the  heavenly  bodies ; — by  the  geologist  myriads  of  ages  were 
reckoned,  not  by  arithmetical  computation,  but  by  a  train  of  physical 
events — a  succession  of  phenomena  in  the  animate  and  inanimate  worlds 
— signs  which  convey  to  our  minds  more  definite  ideas  than  figures  can 
do  of  the  immensity  of  time. 

Whether  our  investigation  of  the  earth's  history  and  structure  will 
eventually  be  productive  of  as  great  practical  benefits  to  mankind  as  a 
knowledge  of  the  distant  heavens,  must  remain  for  the  decision  of  pos- 
terity. It  was  not  till  astronomy  had  been  enriched  by  the  observations 
of  many  centuries,  and  had  made  its  way  against  popular  prejudices  to 
the  establishment  of  a  sound  theory,  that  its  application  to  the  useful 
arts  was  most  conspicuous.  The  cultivation  of  geology  began  at  a  later 
period ;  and  in  every  step  which  it  has  hitherto  made  towards  sound 
theoretical  principles,  it  had  to  contend  against  more  violent  preposses- 
sions. The  practical  advantages  already  derived  from  it  have  not  been 
inconsiderable ;  but  our  generalizations  are  yet  imperfect,  and  they 
who  come  after  us  may  be  expected  to  reap  the  most  valuable  fruits  of 
our  labor.  Meanwhile,  the  charm  of  first  discovery  is  our  own  ;  and,  as 
we  explore  this  magnificent  field  of  inquiry,  the  sentiment  of  a  great 
historian  of  our  times  may  continually  be  present  to  our  minds,  that  "  he 
who  calls  what  has  vanished  back  again  into  being,  enjoys  a  bliss  like 
that  of  creating."* 


CHAPTER  V. 

PREJUDICES    WHICH    HAVE    RETARDED    THE    PROGRESS    OF    GEOLOGY 

Prepossessions  in  regard  to  the  duration  of  past  time — Prejudices  arising  from  our 
peculiar  position  as  inhabitants  of  the  land — Of  those  occasioned  by  our  not 
seeing  subterranean  changes  now  in  progress — All  these  causes  combine  to  make 
the  former  course  of  Nature  appear  different  from  the  present — Objections  to 
the  doctrine,  that  causes  similar  in  kind  and  energy  to  those  now  acting,  have 
produced  the  former  changes  of  the  earth's  surface,  considered. 

IF  we  reflect  on  the  history  of  the  progress  of  geology,  as  explained 
in  the  preceding  chapters,  we  perceive  that  there  have  been  great  fluc- 

*  Niebuhr's  Hist,  of  Rome,  vol.  i.  p.  5.     Hare  and  Thirlwall's  translation. 


62  PREJUDICES    WHICH   EETAKD  [On.  V. 

tuations  of  opinion  respecting  the  nature  of  the  causes  to  which  all 
former  changes  of  the  earth's  surface  are  referable.  The  first  observ- 
ers conceived  the  monuments  which  the  geologist  endeavors  to  decipher 
to  relate  to  an  original  state  of  the  earth,  or  to  a  period  when  there 
were  causes  in  activity,  distinct,  in  kind  and  degree,  from  those  now 
constituting  the  economy  of  nature.  These  views  were  gradually  mod- 
ified, and  some  of  them  entirely  abandoned,  in  proportion  as  observa- 
tions were  multiplied,  and  the  signs  of  former  mutations  more  skilfully 
interpreted.  Many  appearances,  which  had  for  a  long  time  been  re- 
garded as  indicating  mysterious  and  extraordinary  agency,  were  finally 
recognized  as  the  necessary  result  of  the  laws  now  governing  the  mate- 
rial world ;  and  the  discovery  of  this  unlooked-for  conformity  has  at 
length  induced  some  philosophers  to  infer,  that,  during  the  ages  contem- 
plated in  geology,  there  has  never  been  any  interruption  to  the  agency 
of  the  same  uniform  laws  of  change.  The  same  assemblage  of  general 
causes,  they  conceive,  may  have  been  sufficient  to  produce,  by  their 
various  combinations,  the  endless  diversity  of  effects,  of  which  the  shell 
of  the  earth  has  preserved  the  memorials  ;  and,  consistently  with  these 
principles,  the  recurrence  of  analogous  changes  is  expected  by  them  in 
time  to  come. 

Whether  we  coincide  or  not  in  this  doctrine,  we  must  admit  that  the 
gradual  progress  of  opinion  concerning  the  succession  of  phenomena  in 
very  remote  eras,  resembles,  in  a  singular  manner,  that  which  has  ac- 
companied the  growing  intelligence  of  every  people,  in  regard  to  the 
economy  of  nature  in  their  own  times.  In  an  early  state  of  advance- 
ment, when  a  great  number  of  natural  appearances  are  unintelligible, 
an  eclipse,  an  earthquake,  a  flood,  or  the  approach  of  a  comet,  with 
many  other  occurrences  afterwards  found  to  belong  to  the  regular 
course  of  events,  are  regarded  as  prodigies.  The  same  delusion  pre- 
vails as  to  moral  phenomena,  and  many  of  these  are  ascribed  to  the 
intervention  of  demons,  ghosts,  witches,  and  other  immaterial  and 
supernatural  agents.  By  degrees,  many  of  the  enigmas  of  the  moral 
and  physical  world  are  explained,  and,  instead  of  being  due  to  extrinsic 
and  irregular  causes,  they  are  found  to  depend  on  fixed  and  invariable 
laws.  The  philosopher  at  last  becomes  convinced  of  the  undeviating 
uniformity  of  secondary  causes ;  and,  guided  by  his  faith  in  this  princi- 
ple, he  determines  the  probability  of  accounts  transmitted  to  him  or 
former  occurrences,  and  often  rejects  the  fabulous  tales  of  former  times, 
on  the  ground  of  their  being  irreconcilable  with  the  experience  of  more 
enlightened  ages. 

Prepossessions  in  regard  to'  the  duration  of  past  time. — As  a  belief  in 
the  want  of  conformity  in  the  causes  by  which  the  earth's  crust  has 
been  modified  in  ancient  and  modern  periods  was,  for  a  long  time,  uni- 
versally prevalent,  and  that,  too,  amongst  men  who  were  convinced  that 
tlie  order  of  nature  had  been  uniform  for  the  last  several  thousand 
years,  every  circumstance  which  could  have  influenced  their  minds  and 
given  an  undue  bias  to  their  opinions  deserves  particular  attention. 


CH.  V.]  THE  PROGRESS  OF  GEOLOGY.  63 

Now  the  reader  may  easily  satisfy  himself,  that,  however  undeviating 
the  course  of  nature  may  have  been  from  the  earliest  epochs,  it  was 
impossible  for  the  first  cultivators  of  geology  to  come  to  such  a  conclu- 
sion, so  long  as  they  were  under  a  delusion  as  to  the  age  of  the  world, 
and  the  date  of  the  first  creation  of  animate  beings.  However  fantas- 
tical some  theories  of  the  sixteenth  century  may  now  appear  to  us, — 
however  unworthy  of  men  of  great  talent  and  sound  judgment, — we 
may  rest  assured  that,  if  the  same  misconception  now  prevailed  in  re- 
gard to  the  memorials  of  human  transactions,  it  would  give  rise  to  a 
similar  train  of  absurdities.  Let  us  imagine,  for  example,  that  Champol- 
lion,  and  the  French  and  Tuscan  literati  lately  engaged  in  exploring  the 
antiquities  of  Egypt,  had  visited  that  country  with  a  firm  belief  that  the 
banks  of  the  Nile  were  never  peopled  by  the  human  race  before  the  be- 
ginning of  the  nineteenth  century,  and  that  their  faith  in  this  dogma  was 
as  difficult  to  shake  as  the  opinion  of  our  ancestors  that  the  earth  was 
never  the  abode  of  living  beings  until  the  creation  of  the  present  conti- 
nents, and  of  the  species  now  existing, — it  is  easy  to  perceive  what 
extravagant  systems  they  would  frame,  while  under  the  influence  of  this 
delusion,  to  account  for  the  monuments  discovered  in  Egypt.  The 
sight  of  the  pyramids,  obelisks,  colossal  statues,  and  ruined  temples, 
would  fill  them  with  such  astonishment,  that  for  a  time  they  would  be 
as  men  spell-bound — wholly  incapable  of  reasoning  with  sobriety.  They 
might  incline  at  first  to  refer  the  construction  of  such  stupendous 
works  to  some  superhuman  powers  of  a  primeval  world.  A  system 
might  be  invented  resembling  that  so  gravely  advanced  by  Manetho, 
who  relates  that  a  dynasty  of  gods  originally  ruled  in  Egypt,  of  whom 
Vulcan,  the  first  monarch,  reigned  nine  thousand  years ;  after  whom 
came  Hercules  and  other  demigods,  who  were  at  last  succeeded  by 
human  kings. 

When  some  fanciful  speculations  of  this  kind  had  amused  their  ima- 
ginations for  a  time,  some  vast  repository  of  mummies  would  be  dis- 
covered, and  would  immediately  undeceive  those  antiquaries  who  en- 
joyed an  opportunity  of  personally  examining  them ;  but  the  prejudices 
of  others  at  a  distance,  who  were  not  eye-witnesses  of  the  whole  phe- 
nomena, would  not  be  so  easily  overcome.  The  concurrent  report  of 
many  travellers  would,  indeed,  render  it  necessary  for  them  to  accom- 
modate ancient  theories  to  some  of  the  new  facts,  and  much  wit  and 
ingenuity  would  be  required  to  modify  and  defend  their  old  positions. 
Each  new  invention  would  violate  a  greater  number  of  known  analogies  ; 
for  if  a  theory  be  required  to  embrace  some  false  principle,  it  becomes 
more  visionary  in  proportion  as  facts  are  multiplied,  as  would  be  the 
case  if  geometers  were  now  required  to  form  an  astronomical  system  on 
the  assumption  of  the  immobility  of  the  earth. 

Amongst  other  fanciful  conjectures  concerning  the  history  of  Egypt, 
we  may  suppose  some  of  the  following  to  be  started.  "As  the  banks 
of  the  Nile  have  been  so  recently  colonized  for  the  first  time,  the  curi- 
ous substances  called  mummies  could  never  in  reality  have  belonged  to 


64  PREJUDICES    WHICH   HAVE   RETARDED  [On.  V. 

men.  They  may  have  been  generated  by  some  plastic  virtue  residing 
in  the  interior  of  the  earth,  or  they  may  be  abortions  of  Nature  pro- 
duced by  her  incipient  efforts  in  the  work  of  creation.  For  if  deformed 
beings  are  sometimes  born  even  now,  when  the  scheme  of  the  universe 
is  fully  developed,  many  more  may  have  been  '  sent  before  their  time, 
scarce  half  made  up,'  when  the  planet  itself  was  in  the  embryo  state. 
But  if  these  notions  appear  to  derogate  from  the  perfection  of  the 
Divine  attributes,  and  if  these  mummies  be  in  all  their  parts  true  repre- 
sentations of  the  human  form,  may  we  not  refer  them  to  the  future 
rather  than  the  past  ? — May  we  not  be  looking  into  the  womb  of  Nature, 
and  not  her  grave  ?  May  not  these  images  be  like  the  shades  of  the 
unborn  in  Virgil's  Elysium — the  archetypes  of  men  not  yet  called  into 
existence  ?" 

These  speculations,  if  advocated  by  eloquent  writers,  would  not  fail 
to  attract  many  zealous  votaries,  for  they  would  relieve  men  from  the 
painful  necessity  of  renouncing  preconceived  opinions.  Incredible  as 
such  skepticism  may  appear,  it  has  been  rivalled  by  many  systems  of 
the  sixteenth  and  seventeenth  centuries,  and  among  others  by  that  of 
the  learned  Falloppio,  who  regarded  the  tusks  of  fossil  elephants  as 
earthy  concretions,  and  the  pottery  or  fragments  of  vases  in  the  Monte 
Testaceo,  near  Rome,  as  works  of  nature,  and  not  of  art.  But  when 
one  generation  had  passed  away,  and  another,  not  compromised  to  the 
support  of  antiquated  dogmas,  had  succeeded,  they  would  review  the 
evidence  afforded  by  mummies  more  impartially,  and  would  no  longer 
controvert  the  preliminary  question,  that  human  beings  had  lived  in 
Egypt  before  the  nineteenth  century  :  so  that  when  a  hundred  years  per- 
haps had  been  lost,  the  industry  and  talents  of  the  philosopher  would 
be  at  last  directed  to  the  elucidation  of  points  of  real  historical  importance. 

But  the  above  arguments  are  aimed  against  one  only  of  many  pre- 
judices with  which  the  earlier  geologists  had  to  contend.  Even  when 
they  conceded  that  the  earth  had  been  peopled  with  animate  beings  at 
an  earlier  period  than  was  at  first  supposed,  they  had  no  conception  that 
the  quantity  of  time  bore  so  great  a  proportion  to  the  historical  era  as 
is  now  generally  conceded.  How  fatal  every  error  as  to  the  quantity  of 
time  must  prove  to  the  introduction  of  rational  views  concerning  the 
state  of  things  in  former  ages,  may  be  conceived  by  supposing  the  an- 
nals of  the  civil  and  military  transactions  of  a  great  nation  to  be  perused 
under  the  impression  that  they  occurred  in  a  period  of  one  hundred  in- 
stead of  two  thousand  years.  Such  a  portion  of  history  would  imme- 
diately assume  the  air  of  a  romance ;  the  events  would  seem  devoid  of 
credibility,  and  inconsistent  with  the  present  course  of  human  affairs. 
A  crowd  of  incidents  would  follow  each  other  in  thick  succession.  Ar- 
mies and  fleets  would  appear  to  be  assembled  only  to  be  destroyed,  and 
cities  built  merely  to  fall  in  ruins.  There  would  be  the  most  violent 
transitions  from  fofoicrn  or  intestine  war  to  periods  of  profound  peace, 
and  the  works  effected  during  the  years  of  disorder  or  tranquillity  would 
appear  alike  superhuman  in  magnitude. 


CH.  V.]  THE  PROGRESS  OF  GEOLOGY.  65 

He  who  should  study  the  monuments  of  the  natural  world  under  the 
influence  of  a  similar  infatuation,  must  draw  a  no  less  exaggerated  pic- 
ture of  the  energy  and  violence  of  causes,  and  must  experience  the 
same  insurmountable  difficulty  in  reconciling  the  former  and  present 
state  of  nature.  If  we  could  behold  in  one  view  all  the  volcanic  cones 
thrown  up  in  Iceland,  Italy,  Sicily,  and  other  parts  of  Europe,  during 
the  last  five  thousand  years,  and  could  see  the  lavas  which  have  flowed 
during  the  same  period  ;  the  dislocations,  subsidences,  and  elevations 
caused  during  earthquakes;  the  lands  added  to  various  deltas,  or  de- 
voured by  the  sea,  together  with  the  effects  of  devastation  by  floods, 
and  imagine  that  all  these  events  had  happened  in  one  year,  we  must 
form  most  exalted  ideas  of  the  activity  of  the  agents,  and  the  sudden- 
ness of  the  revolutions.  Were  an  equal  amount  of  change  to  pass  be- 
fore our  eyes  in  the  next  year,  could  we  avoid  the  conclusion  that  some 
great  crisis  of  nature  was  at  hand  ?  If  geologists,  therefore,  have  mis- 
interpreted the  signs  of  a  succession  of  events,  so  as  to  conclude  that 
centuries  were  implied  where  the  characters  imported  thousands  of 
years,  and  thousands  of  years  where  the  language  of  Nature  signified 
millions,  they  could  not,  if  they  reasoned  logically  from  such  false  prem- 
ises, come  to  any  other  conclusion  than  that  the  system  of  the  natural 
world  had  undergone  a  complete  revolution. 

We  should  be  warranted  in  ascribing  the  erection  of  the  great  pyra- 
mid to  superhuman  power,  if  we  were  convinced  that  it  was  raised  in 
one  day  ;  and  if  we  imagine,  in  the  same  manner,  a  continent  or  moun- 
tain-chain to  have  been  elevated  during  an  equally  small  fraction  of  the 
time  which  was  really  occupied  in  upheaving  it,  we  might  then  be 
justified  in  inferring,  that  the  subterranean  movements  were  once  far 
more  energetic  than  in  our  own  times.  We  know  that  during  one 
earthquake  the  coast  of  Chili  may  be  raised  for  a  hundred  miles  to  the 
average  height  of  about  three  feet.  A  repetition  of  two  thousand 
shocks,  of  equal  violence,  might  produce  a  mountain-chain  one  hun- 
dred miles  long,  and  six  thousand  feet  high.  Now,  should  one  or  two 
only  of  these  convulsions  happen  in  a  century,  it  would  be  consistent 
with  the  order  of  events  experienced  by  the  Chilians  from  the  earliest 
times ;  but  if  the  whole  of  them  were  to  occur  in  the  next  hundred 
years,  the  entire  district  must  be  depopulated,  scarcely  any  animals  or 
plants  could  survive,  and  the  surface  would  be  one  confused  heap  of 
ruin  and  desolation. 

One  consequence  of  undervaluing  greatly  the  quantity  of  past  time, 
is  the  apparent  coincidence  which  it  occasions  of  events  necessarily  dis- 
connected, or  which  are  so  unusual,  that  it  would  be  inconsistent  with 
all  calculation  of  chances  to  suppose  them  to  happen  at  one  and  the 
same  time.  When  the  unlooked-for  association  of  such  rare  phenomena 
is  witnessed  in  the  present  course  of  nature,  it  scarcely  ever  fails  to 
excite  a  suspicion  of  the  preternatural  in  those  minds  which  are  not 
firmly  convinced  of  the  uniform  agency  of  secondary  causes ; — as  if  the 
death  of  some  individual  in  whose  fate  they  are  interested  happens  to 

5 


66  PEEJUDICES    WHICH   HAVE   RETARDED  [CH.  V. 

be  accompanied  by  the  appearance  of  a  luminous  meteor,  or  a  comet,  or 
the  shock  of  an  earthquake.  It  would  be  only  necessary  to  multiply 
such  coincidences  indefinitely,  and  the  mind  of  every  philosopher  would 
be  disturbed.  Now  it  would  be  difficult  to  exaggerate  the  number  of 
physical  events,  many  of  them  most  rare  and  unconnected  in  their  na- 
ture, which  were  imagined  by  the  Woodwardian  hypothesis  to  have 
happened  in  the  course  of  a  few  months ;  and  numerous  other  examples 
might  be  found  of  popular  geological  theories,  which  require  us  to  im- 
agine that  a  long  succession  of  events  happened  in  a  brief  and  almost 
momentary  period. 

Another  liability  to  error,  very  nearly  allied  to  the  former,  arises  from 
the  frequent  contact  of  geological  monuments  referring  to  very  distant 
periods  of  time.  We  often  behold,  at  one  glance,  the  effects  of  causes 
which  have  acted  at  times  incalculably  remote,  and  yet  there  may  be  no 
striking  circumstances  to  mark  the  occurrence  of  a  great  chasm  in  the 
chronological  series  of  Nature's  archives.  In  the  vast  interval  of  time 
which  may  really  have  elapsed  between  the  results  of  operations  thus 
compared,  the  physical  condition  of  the  earth  may,  by  slow  and  insen- 
sible modifications,  have  become  entirely  altered  ;  one  or  more  races  of 
organic  beings  may  have  passed  away,  and  yet  have  left  behind,  in  the 
particular  region  under  contemplation,  no  trace  of  their  existence. 

To  a  mind  unconscious  of  these  intermediate  events,  the  passage  from 
one  state  of  things  to  another  must  appear  so  violent,  that  the  idea  of 
revolutions  in  the  system  inevitably  suggests  itself.  The  imagination  is 
as  much  perplexed  by  the  deception,  as  it  might  be  if  two  distant  points 
in  space  were  suddenly  brought  into  immediate  proximity.  Let  us 
suppose,  for  a  moment,  that  a  philosopher  should  lie  down  to  sleep  in 
some  arctic  wilderness,  and  then  be  transferred  by  a  power,  such  as  we 
read  of  in  tales  of  enchantment,  to  a  valley  in  a  tropical  country,  where, 
on  awaking,  he  might  find  himself  surrounded  by  birds  of  brilliant  plu- 
mage, and  all  the  luxuriance  of  animal  and  vegetable  forms  of  which 
Nature  is  so  prodigal  in  those  regions.  The  most  reasonable  supposi- 
tion, perhaps,  which  he  could  make,  if  by  the  necromancer's  art  he  were 
placed  in  such  a  situation,  would  be,  that  he  was  dreaming ;  and  if  a 
geologist  form  theories  under  a  similar  delusion,  we  cannot  expect  him 
to  preserve  more  consistency  in  his  speculations  than  in  the  train  of  ideas 
in  an  ordinary  dream. 

It  may  afford,  perhaps,  a  lively  illustration  of  the  principle  here  insist- 
ed upon,  if  I  recall  to  the  reader's  recollection  the  legend  of  the  Seven 
Sleepers.  The  scene  of  that  popular  fable  was  placed  in  the  two  centu- 
ries which  elapsed  between  the  reign  of  the  emperor  Decius  and  the 
death  of  Theodosius  the  younger.  In  that  interval  of  time  (between 
the  years  249  and  450  of  our  era)  the  union  of  the  Roman  Empire  had 
been  dissolved,  and  some  of  its  fairest  provinces  overrun  by  the  barba- 
rians of  the  north.  The  seat  of  government  had  passed  from  Rome  to 
Constantinople,  and  the  throne  from  a  pagan  persecutor  to  a  succession 
of  Christian  and  orthodox  princes.  The  genius  of  the  empire  had  been 


CH.  V.]  THE  PROGRESS  OF  GEOLOGY.  67 

humbled  in  the  dust,  and  the  altars  of  Diana  and  Hercules  were  on  the 
point  of  being  transferred  to  Catholic  saints  and  martyrs.  The  legend 
relates,  "that  when  Decius  was  still  persecuting  the  Christians,  seven 
noble  youths  of  Ephesus  concealed  themselves  in  a  spacious  cavern  in 
the  side  of  an  adjacent  mountain,  where  they  were  doomed  to  perish 
by  the  tyrant,  who  gave  orders  that  the  entrance  should  be  firmly  se- 
cured with  a  pile  of  huge  stones.  They  immediately  fell  into  a  deep 
slumber,  which  was  miraculously  prolonged,  without  injuring  the  powers 
of  life,  during  a  period  of  187  years.  At  the  end  of  that  time  the 
slaves  of  Adolius,  to  whom  the  inheritance  of  the  mountain  had  descend- 
ed, removed  the  stones  to  supply  materials  for  some  rustic  edifice  :  the 
light  of  the  sun  darted  into  the  cavern,  and  the  Seven  Sleepers  were 
permitted  to  awake.  After  a  slumber,  as  they  thought,  of  a  few  hours, 
they  were  pressed  by  the  calls  of  hunger,  and  resolved  that  Jambli- 
chus,  one  of  their  number,  should  secretly  return  to  the  city  to  pur- 
chase bread  for  the  use  of  his  companions.  The  youth  could  no  longer 
recognize  the  once  familiar  aspect  of  his  native  country,  and  his  surprise 
was  increased  by  the  appearance  of  a  large  cross  triumphantly  erected 
over  the  principal  gate  of  Ephesus.  His  singular  dress  and  obsolete 
language  confounded  the  baker,  to  whom  he  offered  an  ancient  medal 
of  Decius  as  the  current  coin  of  the  empire ;  and  Jamblichus,  on  the 
suspicion  of  a  secret  treasure,  was  dragged  before  the  judge.  Their 
mutual  inquiries  produced  the  amazing  discovery,  that  two  centuries 
were  almost  elapsed  since  Jamblichus  and  his  friends  had  escaped  from 
the  rage  of  a  pagan  tyrant."* 

This  legend  was  received  as  authentic  throughout  the  Christian  world 
before  the  end  of  the  sixth  century,  and  was  afterwards  introduced  by 
Mahomet  as  a  divine  revelation  into  the  Koran,  and  from  hence  was 
adopted  and  adorned  by  all  the  nations  from  Bengal  to  Africa  who  pro- 
fessed the  Mahometan  faith.  Some  vestiges  even  of  a  similar  tradition 
have  been  discovered  in  Scandinavia.  "  This  easy  and  universal  belief," 
observes  the  philosophical  historian  of  the  Decline  and  Fall,  "  so  expres- 
sive of  the  sense  of  mankind,  may  be  ascribed  to  the  genuine  merit  of 
the  fable  itself.  We  imperceptibly  advance  from  youth  to  age,  without 
observing  the  gradual,  but  incessant,  change  of  human  affairs ;  and  even, 
in  our  larger  experience  of  history,  the  imagination  is  accustomed,  by  a 
perpetual  series  of  causes  and  effects,  to  unite  the  most  distant  revolu- 
tions. But  if  the  interval  between  two  memorable  eras  could  be  in- 
stantly annihilated  ;  if  it  were  possible,  after  a  momentary  slumber  of 
two  hundred  years,  to  display  the  new  world  to  the  eyes  of  a  spectator 
who  still  retained  a  lively  and  recent  impression  of  the  old,  his  surprise 
and  his  reflections  would  furnish  the  pleasing  subject  of  a  philosophical 
romance."! 

Prejudices  arising  from  our  peculiar  position  as  inhabitants  of  the 
land. — The  sources  of  prejudice  hitherto  considered  may  be  deemed 

*  Gibbon,  Decline  and  Fall,  chap,  xxxiii.  f  Id.  Ibid. 


68  PREJUDICES    WHICH    HAVE   KETAKDED  [Cfl.  V. 

peculiar  for  the  most  part  to  the  infancy  of  the  science,  but  others  are 
common  to  the  first  cultivators  of  geology  and  to  ourselves,  and  are  all 
singularly  calculated  to  produce  the  same  deception,  and  to  strengthen 
our  belief  that  the  course  of  nature  in  the  earlier  ages  differed  widely 
from  that  now  established.  Although  these  circumstances  cannot  be 
fully  explained  without  assuming  some  things  as  proved,  which  it  will 
be  the  object  of  another  part  of  this  work  to  demonstrate,  it  may  be 
well  to  allude  to  them  briefly  in  this  place. 

The  first  and  greatest  difficulty,  then,  consists  in  an  habitual  uncon- 
sciousness that  our  position  as  observers  is  essentially  unfavorable,  when 
we  endeavor  to  estimate  the  nature  and  magnitude  of  the  changes  now 
in  progress.  In  consequence  of  our  inattention  to  this  subject,  we 
are  liable  to  serious  mistakes  in  contrasting  the  present  with  former 
states  of  the  globe.  As  dwellers  on  the  land,  we  inhabit  about  a  fourth 
part  of  the  surface  ;  and  that  portion  is  almost  exclusively  a  theatre  of 
decay,  and  not  of  reproduction.  We  know,  indeed,  that  new  deposits 
are  annually  formed  in  seas  and  lakes,  and  that  every  year  some  new 
igneous  rocks  are  produced  in  the  bowels  of  the  earth,  but  we  cannot 
watch  the  progress  of  their  formation ;  and  as  they  are  only  present  to 
our  minds  by  the  aid  of  reflection,  it  requires  an  effort  both  of  the  reason 
and  the  imagination  to  appreciate  duly  their  importance.  It  is,  there- 
fore, not  surprising  that  we  estimate  very  imperfectly  the  result  of  opera- 
tions thus  invisible  to  us ;  and  that,  when  analogous  results  of  former 
epochs  are  presented  to  our  inspection,  we  cannot  immediately  recog- 
nize the  analogy.  He  who  has  observed  the  quarrying  of  stone  from  a 
rock,  and  has  seen  it  shipped  for  some  distant  port,  and  then  endeavors 
to  conceive  what  kind  of  edifice  will  be  raised  by  the  materials,  is  in  the 
same  predicament  as  a  geologist,  who,  while  he  is  confined  to  the  land, 
sees  the  decomposition  of  rocks,  and  the  transportation  of  matter  by 
rivers  to  the  sea,  and  then  endeavors  to  picture  to  himself  the  new  strata 
which  Nature  is  building  beneath  the  waters. 

Prejudices  arising  from  our  not  seeing  subterranean  changes. — Nor  is 
his  position  less  unfavorable  when,  beholding  a  volcanic  eruption,  he 
tries  to  conceive  what  changes  the  column  of  lava  has  produced,  in  its 
passage  upwards,  on  the  intersected  strata ;  or  what  form  the  melted 
matter  may  assume  at  great  depths  on  cooling ;  or  what  may  be  the  ex- 
tent of  the  subterranean  rivers  and  reservoirs  of  liquid  matter  far  be- 
neath the  surface.  It  should,  therefore,  be  remembered,  that  the  task 
imposed  on  those  who  study  the  earth's  history  requires  no  ordinary 
share  of  discretion  ;  for  we  are  precluded  from  collating  the  correspond- 
ing parts  of  the  system  of  things  as  it  exists  now,  and  as  it  existed  at 
former  periods.  If  we  were  inhabitants  of  another  element — if  the  great 
ocean  were  our  domain,  instead  of  the  narrow  limits  of  the  land,  our 
difficulties  would  be  considerably  lessened  ;  while,  on  the  other  hand, 
there  can  be  little  doubt,  although  the  reader  may,  perhaps,  smile  at  the 
bare  suggestion  of  such  an  idea,  that  an  amphibious  being,  who  should 
possess  our  faculties,  would  still  more  easily  arrive  at  sound  theoretical 


CH.  V.]  THE    PROGRESS   OF   GEOLOGY.  69 

opinions  in  geology,  since  he  might  behold,  on  the  one  hand,  the  decom- 
position of  rocks  in  the  atmosphere,  or  the  transportation  of  matter  by 
running  water ;  and,  on  the  other,  examine  the  deposition  of  sediment 
in  the  sea,  and  the  imbedding  of  animal  and  vegetable  remains  in  new 
fctrata.  He  might  ascertain,  by  direct  observation,  the  action  of  a  moun- 
Jain  torrent,  as  well  as  of  a  marine  current ;  might  compare  the  products 
pf  volcanoes  poured  out  upon  the  land  with  those  ejected  beneath  the 
waters  ;  and  might  mark,  on  the  one  hand,  the  growth  of  the  forest, 
and,  on  the  other,  that  of  the  coral  reef.  Yet,  even  with  these  advan- 
tages, he  would  be  liable  to  fall  into  the  greatest  errors,  when  endeavor- 
ing to  reason  on  rocks  of  subterranean  origin.  He  would  seek  in  vain, 
within  the  sphere  of  his  observation,  for  any  direct  analogy  to  the  pro- 
cess of  their  formation,  and  would  therefore  be  in  danger  of  attributing 
them,  wherever  they  are  upraised  to  view,  to  some  "  primeval  state  of 
nature." 

But  if  we  may  be  allowed  so  far  to  indulge  the  imagination,  as  to 
suppose  a  being  entirely  confined  to  the  nether  world — some  "  dusky 
melancholy  sprite,"  like  Umbriel,  who  could  "  flit  on  sooty  pinions  to 
the  central  earth,"  but  who  was  never  permitted  to  "  sully  the  fair  face 
of  light,"  and  emerge  into  the  regions  of  water  and  of  air;  and  if  this 
being  should  busy  himself  in  investigating  the  structure  of  the  globe,  he 
might  frame  theories  the  exact  converse  of  those  usually  adopted  by 
human  philosophers.  He  might  infer  that  the  stratified  rocks,  contain- 
ing shells  and  other  organic  remains,  were  the  oldest  of  created  things, 
belonging  to  some  original  and  nascent  state  of  the  planet.  "  Of  these 
masses,"  he  might  say,  "  whether  they  consist  of  loose  incoherent  sand, 
soft  clay,  or  solid  stone,  none  have  been  formed  in  modern  times.  Every 
year  some  part  of  them  are  broken  and  shattered  by  earthquakes,  or 
melted  by  volcanic  fire ;  and  when  they  cool  down  slowly  from  a  state 
of  fusion,  they  assume  a  new  and  more  crystalline  form,  no  longer  exhib- 
iting that  stratified  disposition  and  those  curious  impressions  and  fan- 
tastic markings,  by  which  they  were  previously  characterized.  This 
process  cannot  have  been  carried  on  for  an  indefinite  time,  for  in  that 
case  all  the  stratified  rocks  would  long  ere  this  have  been  fused  and 
crystallized.  It  is  therefore  probable  that  the  whole  planet  once  con- 
sisted of  these  mysterious  and  curiously  bedded  formations  at  a  time 
when  the  volcanic  fire  had  not  yet  been  brought  into  activity.  Since 
that  period  there  seems  to  have  been  a  gradual  development  of  heat ; 
and  this  augmentation  we  may  expect  to  continue  till  the  whole  globe 
shall  be  in  a  state  of  fluidity  and  incandescence." 

Such  might  be  the  system  of  the  Gnome  at  the  very  time  that  the 
followers  of  Leibnitz,  reasoning  on  what  they  saw  on  the  outer  surface, 
might  be  teaching  the  opposite  doctrine  of  gradual  refrigeration,  and 
averring  that  the  earth  had  begun  its  career  as  a  fiery  comet,  and  might 
be  destined  hereafter  to  become  a  frozen  mass.  The  tenets  of  the 
schools  of  the  nether  and  of  the  upper  world  would  be  directly  opposed 
to  each  other,  for  both  would  partake  of  the  prejudices  inevitably  re- 


70  ASSUMED   DISCOKDANCE   OF  [Cfl.  V. 

suiting  from  the  continual  contemplation  of  one  class  of  phenomena  to 
the  exclusion  of  another.  Man  observes  the  annual  decomposition  of 
crystalline  and  igneous  rocks,  and  may  sometimes  see  their  conversion 
into  stratified  deposits ;  but  he  cannot  witness  the  reconversion  of  the 
sedimentary  into  the  crystalline  by  subterranean  fire.  He  is  in  the  habit 
of  regarding  all  the  sedimentary  rocks  as  more  recent  than  the  unstrati- 
fied,  for  the  same  reason  that  we  may  suppose  him  to  fall  into  the  op- 
posite error  if  he  saw  the  origin  of  the  igneous  class  only. 

It  was  not  an  impossible  contingency,  that  astronomers  might  have 
been  placed  at  some  period  in  a  situation  much  resembling  that  in  which 
the  geologist  seems  to  stand  at  present.  If  the  Italians,  for  example,  in 
the  early  part  of  the  twelfth  century,  had  discovered  at  Amalfi,  instead 
of  the  pandects  of  Justinian,  some  ancient  manuscripts  filled  with  as- 
tronomical observations  relating  to  a  period  of  three  thousand  years, 
and  made  by  some  ancient  geometers  who  possessed  optical  instruments 
as  perfect  as  any  in  modern  Europe,  they  would  probably,  on  consult- 
ing these  memorials,  have  come  to  a  conclusion  that  there  had  been  a 
great  revolution  in  the  solar  and  sidereal  systems.  "  Many  primary  and 
secondary  planets,"  they  might  say,  "  are  enumerated  in  these  tables, 
which  exist  no  longer.  Their  positions  are  assigned  with  such  precision 
that  we  may  assure  ourselves  that  there  is  nothing  in  their  place  at  pres- 
ent but  the  blue  ether.  -*  Where  one  star  is  visible  to  us,  these  docu- 
ments represent  several  thousands.  Some  of  those  which  are  now 
single  consisted  then  of  two  separate  bodies,  often  distinguished  by  dif- 
ferent colors,  and  revolving  periodically  round  a  common  centre  of  grav- 
ity. There  is  nothing  analogous  to  them  in  the  universe  at  present ; 
for  they  were  neither  fixed  stars  nor  planets,  but  seem  to  have  stood  in 
the  mutual  relation  of  sun  and  planet  to  each  other.  We  must  con- 
clude, therefore,  that  there  has  occurred,  at  no  distant  period,  a  tre- 
mendous catastrophe,  whereby  thousands  of  worlds  have  been  annihi- 
lated at  once,  and  some  heavenly  bodies  absorbed  into  the  substance  of 
others." 

When  such  doctrines  had  prevailed  for  ages,  the  discovery  of  some 
of  the  worlds,  supposed  to  have  been  lost  (the  satellites  of  Jupiter,  for 
example),  by  aid  of  the  first  rude  telescope  invented  after  the  revival 
of  science,  would  not  dissipate  the  delusion,  for  the  whole  burden  of 
proof  would  now  be  thrown  on  those  who  insisted  on  the  stability  of 
the  system  from  a  remote  period,  and  these  philosophers  would  be  re- 
quired to  demonstrate  the  existence  of  all  the  worlds  said  to  have  been 
annihilated. 

Such  popular  prejudices  would  be  most  unfavorable  to  the  advance- 
ment of  astronomy ;  for,  instead  of  persevering  in  the  attempt  to  im- 
prove their  instruments,  and  laboriously  to  make  and  record  observa- 
tions, the  greater  number  would  despair  of  verifying  the  continued 
existence  of  the  heavenly  bodies  not  visible  to  the  naked  eye.  Instead 
of  confessing  the  extent  of  their  ignorance,  and  striving  to  remove  it  by 
bringing  to  light  new  facts,  they  would  indulge  in  the  more  easy  and 


CH.  V.]  ANCIENT   AND   MODERN   CAUSES.  71 

indolent  employment  of  framing  imaginary  theories  concerning  catastro- 
phes and  mighty  revolutions  in  the  system  of  the  universe. 

For  more  than  two  centuries  the  shelly  strata  of  the  Subapennine  hills 
afforded  matter  of  speculation  to  the  early  geologists  of  Italy,  and  few 
of  them  had  any  suspicion  that  similar  deposits  were  then  forming  in 
the  neighboring  sea.  They  were  as  unconscious  of  the  continued  action 
of  causes  still  producing  similar  effects,  as  the  astronomers,  in  the  case 
above  supposed,  of  the  existence  of  certain  heavenly  bodies  still  giving 
and  reflecting  light,  and  performing  their  movements  as  of  old.  Some 
imagined  that  the  strata,  so  rich  in  organic  remains,  instead  of  being 
due  to  secondary  agents,  had  been  so  created  in  the  beginning  of  things 
by  the  fiat  of  the  Almighty.  Others,  as  we  have  seen,  ascribed  the 
imbedded  fossil  bodies  to  some  plastic  power  which  resided  in  the  earth 
in  the  early  ages  of  the  world.  In  what  manner  were  these  dogmas  at 
length  exploded  ?  The  fossil  relics  were  carefully  compared  with  their 
living  analogues,  and  all  doubts  as  to  their  organic  origin  were  event- 
ually dispelled.  So,  also,  in  regard  to  the  nature  of  the  containing 
beds  of  mud,  sand,  and  limestone  :  those  parts  of  the  bottom  of  the  sea 
were  examined  where  shells  are  now  becoming  annually  entombed  in 
new  deposits.  Donati  explored  the  bed  of  the  Adriatic,  and  found  the 
closest  resemblance  between  the  strata  there  forming,  and  those  which 
constituted  hills  above  a  thousand  feet  high  in  various  parts  of  the 
Italian  peninsula.  He  ascertained  by  dredging  that  living  testacea 
were  there  grouped  together  in  precisely  the  same  manner  as  were 
their  fossil  analogues  in  the  inland  strata;  and  while  some  of  the  recent 
shells  of  the  Adriatic  were  becoming  incrusted  with  calcareous  rock,  he 
observed  that  others  had  been  newly  buried  in  sand  and  clay,  precisely 
as  fossil  shells  occur  in  the  Subapennine  hills.  This  discovery  of  the 
identity  of  modern  and  ancient  submarine  operations  was  not  made 
without  the  aid  of  artificial  instruments,  which,  like  the  telescope, 
brought  phenomena  into  view  not  otherwise  within  the  sphere  of  human 
observation. 

In  like  manner,  the  volcanic  rocks  of  the  Vicentin  had  been  studied 
in  the  beginning  of  the  last  century ;  but  no  geologist  suspected,  before 
the  time  of  Arduino,  that  these  were  composed  of  ancient  submarine  lavas. 
During  many  years  of  controversy,  the  popular  opinion  inclined  to  a  be- 
lief that  basalt  and  rocks  of  the  same  class  had  been  precipitated  from  a 
chaotic  fluid,  or  an  ocean  which  rose  at  successive  periods  over  the  con- 
tinents, charged  with  the  component  elements  of  the  rocks  in  question. 
Few  will  now  dispute  that  it  would  have  been  difficult  to  invent  a  theory 
more  distant  from  the  truth  ;  yet  we  must  cease  to  wonder  that  it  gained 
so  many  proselytes,  when  we  remember  that  its  claims  to  probability  arose 
partly  from  the  very  circumstance  of  its  confirming  the  assumed  want  of 
analogy  between  geological  causes  and  those  now  in  action.  By  what  train 
of  investigations  were  geologists  induced  at  length  to  reject  these  views, 
and  to  assent  to  the  igneous  origin  of  the  trappean  formations  ?  By  an 


72  UNIFORM   COURSE   OF  NATURE.  fCn.  V 

examination  of  volcanoes  now  active,  and  by  comparing  their  structure 
and  the  composition  of  their  lavas  with  the  ancient  trap-rocks. 

The  establishment,  from  time  to  time,  of  numerous  points  of  identifica- 
tion, drew  at  length  from  geologists  a  reluctant  admission,  that  there  was 
more  correspondence  between  the  condition  of  the  globe  at  remote  eras 
and  now,  and  more  uniformity  in  the  laws  which  have  regulated  the 
changes  of  its  surface,  than  they  at  first  imagined.  If,  in  this  state  of  the 
science,  they  still  despaired  of  reconciling  every  class  of  geological  phe- 
nomena to  the  operations  of  ordinary  causes,  even  by  straining  analogy  to 
the  utmost  limits  of  credibility,  we  might  have  expected,  at  least,  that  the 
balance  of  probability  would  now  have  been  presumed  to  incline  towards 
the  close  analogy  of  the  ancient  and  modern  causes.  But,  after  repeated 
experience  of  the  failure  of  attempts  to  speculate  on  geological  monuments, 
as  belonging  to  a  distinct  order  of  things,  new  sects  continued  to  perse- 
vere in  the  principles  adopted  by  their  predecessors.  They  still  began,  as 
each  new  problem  presented  itself,  whether  relating  to  the  animate  or  in- 
animate world,  to  assume  an  original  and  dissimilar  order  of  nature ;  and 
when  at  length  they  approximated,  or  entirely  came  round  to  an  opposite 
opinion,  it  was  always  with  the  feeling,  that  they  were  conceding  what  they 
had  been  justified  a  priori  in  deeming  improbable.  In  a  word,  the  same 
men  who,  as  natural  philosophers,  would  have  been  most  incredulous  re- 
specting any  extraordinary  deviations  from  the  known  course  of  nature,  if 
reported  to  have  happened  in  their  own  time,  were  equally  disposed,  as  ge- 
ologists, to  expect  the  proofs  of  such  deviations  at  every  period  of  the  past. 

I  shall  proceed  in  the  following  chapters  to  enumerate  some  of  the  prin- 
cipal difficulties  still  opposed  to  the  theory  of  the  uniform  nature  and  ener- 
gy of  the  causes  which  have  worked  successive  changes  in  the  crust  of  the 
earth,  and  in  the  condition  of  its  living  inhabitants.  The  discussion  of  so 
important  a  question  on  the  present  occasion  may  appear  premature,  but 
it  is  one  which  naturally  arises  out  of  a  review  of  the  former  history  of 
the  science.  It  is,  of  course,  impossible  to  enter  into  such  speculative 
topics,  without  occasionally  carrying  the  novice  beyond  his  depth,  and 
appealing  to  facts  and  conclusions  with  which  he  will  be  unacquainted, 
until  he  has  studied  some  elementary  work  on  geology,  but  it  may  be 
useful  to  excite  his  curiosity,  and  lead  him  to  study  such  works  by  call- 
ing his  attention  at  once  to  some  of  the  principal  points  of  controversy.* 

*  In  the  earlier  editions  of  this  work,  a  fourth  book  was  added  on  Geology 
Proper,  or  Systematic  Geology,  containing  an  account  of  the  former  changes  of 
the  animate  and  inanimate  creation,  brought  to  light  by  an  examination  of  the 
crust  of  the  earth.  This  I  afterwards  (in  1838)  expanded  into  a  separate  publi- 
cation called  the  Elements  or  Manual  Geology,  of  which  a  fourth  edition  ap- 
peared December,  1851. 


CHAPTER  VI. 

DOCTRINE    OF    THE    DISCORDANCE    OF    THE    ANCIENT    AND    MODERN 
CAUSES    OF    CHANGE    CONTROVERTED. 

Climate  of  the  Northern  Hemisphere  formerly  different — Direct  proofs  from  the 
organic  remains  of  the  Italian  strata — Proofs  from  analogy  derived  from  ex- 
tinct quadrupeds — Imbedding  of  animals  in  icebergs — Siberian  mammoths — 
Evidence  in  regard  to  temperature,  from  the  fossils  of  tertiary  and  secondary 
rocks — From  the  plants  of  the  coal  formation — Northern  limit  of  these  fossils — 
Whether  such  plants  could  endure  the  long  continuance  of  an  arctic  night. 

Climate  of  the  Northern  hemisphere  formerly  different. — PROOFS  of 
former  revolutions  in  climate,  as  deduced  from  fossil  remains,  have  af- 
forded one  of  the  most  popular  objections  to  the  theory  which  endeav- 
ors to  explain  all  geological  changes  by  reference  to  those  now  in 
progress  on  the  earth.  The  probable  causes,  therefore,  of  fluctuations 
in  climate,  may  first  be  treated  of. 

That  the  climate  of  the  Northern  hemisphere  has  undergone  an  im- 
portant change,  and  that  its  mean  annual  temperature  must  once  have 
more  nearly  resembled  that  now  experienced  within  the  tropics,  was  the 
opinion  of  some  of  the  first  naturalists  who  investigated  the  contents  of 
the  ancient  strata.  Their  conjecture  became  more  probable  when  the 
shells  and  corals  of  the  older  tertiary  and  many  secondary  rocks  were 
carefully  examined  ;  for  the  organic  remains  of  these  formations  were 
found  to  be  intimately  connected  by  generic  affinity  with  species  now 
living  in  warmer  latitudes.  At  a  later  period,  many  reptiles,  such  as 
turtles,  tortoises,  and  large  saurian  animals,  were  discovered  in  Euro- 
pean formations  in  great  abundance  ;  and  they  supplied  new  and  power- 
ful arguments,  from  analogy,  in  support  of  the  doctrine,  that  the  heat 
of  the  climate  had  been  great  when  our  secondary  strata  were  deposited. 
Lastly,  when  the  botanist  turned  his  attention  to  the  specific  determina- 
tion of  fossil  plants,  the  evidence  acquired  still  fuller  confirmation ;  for 
the  flora  of  a  country  is  peculiarly  influenced  by  temperature  :  and  the 
ancient  vegetation  of  the  earth  might  have  been  expected  more  readily 
than  the  forms  of  animals,  to  have  afforded  conflicting  proofs,  had  the 
popular  theory  been  without  foundation.  When  the  examination  of  fos- 
sil remains  was  extended  to  rocks  in  the  most  northern  parts  of  Europe 
and  North  America,  and  even  to  the  Arctic  regions,  indications  of  the 
same  revolution  in  climate  were  discovered. 

It  cannot  be  said,  that  in  this,  as  in  many  other  departments  of 
geology,  we  have  investigated  the  phenomena  of  former  eras,  and  neg- 
lected those  of  the  present  state  of  things.  On  the  contrary,  since  the 
first  agitation  of  this  interesting  question,  the  accessions  to  our  knowl- 
edge of  living  animals  and  plants  have  been  immense,  and  have  far 


74  CHANGE    OF    CLIMATE.  [On.  VI. 

surpassed  all  the  data  previously  obtained  for  generalizing  on  the  rela- 
tion of  certain  types  of  organization  to  particular  climates.  The  tropical 
and  temperate  zones  of  South  America  and  of  Australia  have  been  ex- 
plored ;  and,  on  close  comparison,  it  has  been  found  that  scarcely  any 
of  the  species  of  the  animate  creation  in  these  extensive  continents  are 
identical  with  those  inhabiting  the  old  world.  Yet  the  zoologist  and 
botanist,  well  acquainted  with  the  geographical  distribution  of  organic 
beings  in  other  parts  of  the  globe,  would  have  been  able,  if  distinct 
groups  of  species  had  been  presented  to  them  from  these  regions,  to 
recognize  those  which  had  been  collected  from  latitudes  within,  and 
those  which  were  brought  from  without  the  tropics. 

Before  I  attempt  to  explain  the  probable  causes  of  great  vicissitudes 
of  temperature  on  the  earth's  surface,  I  shall  take  a  rapid  view  of  some 
of  the  principal  data  which  appear  to  support  the  popular  opinions  now 
entertained  on  the  subject.  To  insist  on  the  soundness  of  these  infer- 
ences, is  the  more  necessary,  because  some  zoologists  have  undertaken  to 
vindicate  the  uniformity  of  the  laws  of  nature,  not  by  accounting  for 
former  fluctuations  in  climate,  but  by  denying  the  value  of  the  evidence 
in  their  favor.* 

Proofs  from  fossil  shells  in  tertiary  strata. — In  Sicily,  Calabria,  and 
in  the  neighborhood  of  Naples,  the  fossil  testacea  of  the  most  modern 
tertiary  formations  belong  almost  entirely  to  species  now  inhabiting  the 
Mediterranean  ;  but  as  we  proceed  northwards  in  the  Italian  peninsula 
we  find  in  the  strata  called  Subapennine  an  assemblage  of  fossil  shells 
departing  somewhat  more  widely  from  the  type  of  the  neighboring 
seas.  The  proportion  of  species  identifiable  with  those  now  living  in 
the  Mediterranean  is  still  considerable  ;  but  it  no  longer  predominates, 
as  in  the  South  of  Italy  and  part  of  Sicily,  over  the  unknown  species. 
Although  occurring  in  localities  which  are  removed  several  degrees  far- 
ther from  the  equator  (as  at  Sienna,  Parma,  Asti,  &c.),  the  shells  yield 
clear  indications  of  a  warmer  climate.  This  evidence  is  of  great  weight, 
and  is  not  neutralized  by  any  facts  of  a  conflicting  character  ;  such,  for 
instance,  as  the  association,  in  the  same  group,  of  individuals  referable 
to  species  now  confined  to  arctic  regions.  Whenever  any  of  the  fossil 
shells  are  identified  with  living  species  foreign  to  the  Mediterranean,  it 
is  not  in  the  Northern  Ocean,  but  nearer  the  tropics,  that  they  must  be 
sought :  on  the  other  hand,  the  associated  unknown  species  belong,  for 
the  most  part,  to  genera  which  are  now  most  largely  developed  in  equi- 
noctial regions,  as,  for  example,  the  genera  Cancellaria,  Cassidaria, 
Pleurotoma,  Conus,  and  Cypraea. 

On  comparing  the  fossils  of  the  tertiary  deposits  of  Paris  and  London 
with  those  of  Bourdeaux,  and  these  again  with  the  more  modern  strata 
of  Sicily,  we  should  at  first  expect  that  they  would  each  indicate  a 
higher  temperature  in  proportion  as  they  are  situated  farther  to  the 

*  See  two  articles  by  the  Rev.  Dr.  Fleming,  in  the  Edinburgh  New  Phil. 
.Tourn.  No.  xii.  p.  277,  April,  1829  ;  and  No.  xv.  p.  65,  Jan.  1830. 


CH.  VI.]  SIBERIAN    MAMMOTHS.  75 

south.  But  the  contrary  is  true  ;  of  the  shells  belonging  to  these  seve- 
ral groups,  whether  freshwater  or  marine,  some  are  of  extinct,  others  of 
living  species.  Those  found  in  the  older,  or  Eocene,  deposits  of  Paris 
and  London,  although  six  or  seven  degrees  to  the  north  of  the  Miocene 
strata  at  Bourdeaux,  afford  evidence  of  a  warmer  climate  ;  while  those 
of  Bourdeaux  imply  that  the  sea  in  which  they  lived  was  of  a  higher 
temperature  than  that  of  Sicily,  where  the  shelly  strata  were  formed  six 
or  seven  degrees  nearer  to  the  equator.  In  these  cases  the  greater  an- 
tiquity of  the  several  formations  (the  Parisian  being  the  oldest  and  the 
Sicilian  the  newest)  has  more  than  counterbalanced  the  influence  which 
latitude  would  otherwise  exert,  and  this  phenomenon  clearly  points  to  a 
gradual  and  successive  refrigeration  of  climate. 

Siberian  Mammoths. — It  will  naturally  be  asked,  whether  some  recent 
geological  discoveries  bringing  evidence  to  light  of  a  colder,  or  as  it  has 
been  termed  "  glacial  epoch,"  towards  the  close  of  the  tertiary  periods 
throughout  the  northern  hemisphere,  does  not  conflict  with  the  theory 
above  alluded  to,  of  a  warmer  temperature  having  prevailed  in  the  eras 
of  the  Eocene,  Miocene,  and  Pliocene  formations.  In  answer  to  this  in- 
quiry, it  may  certainly  be  affirmed,  that  an  oscillation  of  climate  has  oc- 
curred in  times  immediately  antecedent  to  the  peopling  of  the  earth  by 
man ;  but  proof  of  the  intercalation  of  a  less  genial  climate  at  an  era 
when  nearly  all  the  marine  and  terrestrial  testacea  had  already  become 
specifically  the  same  as  those  now  living,  by  no  means  rebuts  the  con- 
clusion previously  drawn,  in  favor  of  a  warmer  condition  of  the  globe, 
during  the  ages  which  elapsed  while  the  tertiary  strata  were  deposited. 
In  some  of  the  most  superficial  patches  of  sand,  gravel,  and  loam,  scat- 
tered very  generally  over  Europe,  and  containing  recent  shells,  the  re- 
mains of  extinct  species  of  land  quadrupeds  have  been  found,  especially 
in  places  where  the  alluvial  matter  appears  to  have  been  washed  into 
small  lakes,  or  into  depressions  in  the  plains  bordering  ancient  rivers. 
Similar  deposits  have  also  been  lodged  in  rents  and  caverns  of  rocks, 
where  they  may  have  been  swept  in  by  land  floods,  or  introduced  by 
engulphed  rivers  during  changes  in  the  physical  geography  of  these 
countries.  The  various  circumstances  under  which  the  bones  of  animals 
have  been  thus  preserved,  will  be  more  fully  considered  hereafter  ;*  I 
shall  only  state  here,  that  among  the  extinct  mammalia  thus  entombed, 
we  find  species  of  the  elephant,  rhinoceros,  hippopotamus,  bear,  hyaena, 
lion,  tiger,  monkey  (macacusf ),  and  many  others ;  consisting  partly  of 
genera  now  confined  to  warmer  regions. 

It  is  certainly  probable  that  when  some  of  these  quadrupeds  abounded 
in  Europe,  the  climate  was  milder  than  that  now  experienced.  The 
hippopotamus,  for  example,  is  now  only  met  with  where  the  temperature 
of  the  water  is  warm  and  nearly  uniform  throughout  the  year,  and 

*  Book  iii.  chaps.  46,  47,  <fec. 

f  Macacus  pliocenus,  Owen,  Brit.  Foss.  Mam.  Intr.  p.  37,  found  with  the  extinct 
elephant,  &c.  in  the  modern  freshwater  beds  at  Grays  Thurrock  (Essex),  in  the 
valley  of  the  Thames. 


76  CHANGE    OF    CLIMATE.  [On.  VI. 

where  the  rivers  are  never  frozen  over.  Yet  when  the  great  fossil  spe- 
cies (Hippopotamus  major,  Cuv.)  inhabited  England,  the  testacea  of  our 
country  were  nearly  the  same  as  those  now  existing,  and  the  climate 
cannot  be  supposed  to  have  been  very  hot.  The  bones  of  this  animal 
have  lately  been  found  by  Mr.  Strickland,  together  with  those  of  a  bear 
and  other  mammalia,  at  Cropthorn,  near  Evesham,  in  Worcestershire,  in 
alluvial  sand,  together  with  twenty-three  species  of  terrestrial  and  fresh- 
water shells,  all,  with  two  exceptions,  of  British  species.  The  bed  of 
sand,  containing  the  shells  and  bones,  reposes  on  lias,  and  is  covered  with 
alternating  strata  of  gravel,  sand,  and  loam.* 

The  mammoth  also  appears  to  have  existed  in  England  when  the 
temperature  of  our  latitudes  could  not  have  been  very  different  from 
that  which  now  prevails ;  for  remains  of  this  animal  have  been  found  at 
North  Cliff,  in  the  county  of  York,  in  a  lacustrine  formation,  in  which 
all  the  land  and  freshwater  shells,  thirteen  in  number,  can  be  identified 
with  species  and  varieties  now  existing  in  that  county.  Bones  of  the 
bison,  also,  an  animal  now  inhabiting  a  cold  or  temperate  climate,  have 
been  found  in  the  same  place.  That  these  quadrupeds,  and  the  idige- 
nous  species  of  testacea  associated  with  them,  were  all  contemporary 
inhabitants  of  Yorkshire,  has  been  established  by  unequivocal  proof. 
The  Rev.  W.  V.  Vernon  Harcourt  caused  a  pit  to  be  sunk  to  the  depth 
of  twenty-two  feet  through  undisturbed  strata,  in  which  the  remains  of 
the  mammoth  were  found  imbedded,  together  with  the  shells,  in  a  de- 
posit which  had  evidently  resulted  from  tranquil  waters.f 

In  the  valley  of  the  Thames,  as  at  Ilford  and  Grays,  in  Essex,  bones 
of  the  elephant  and  rhinoceros  occur  in  strata  abounding  in  freshwater 
shells  of  the  genera  Unio,  Cyclas,  Paludina,  Valvata,  Ancylus,  and 
others.  These  fossil  shells  belong  for  the  most  part  to  species  now  liv- 
ing in  the  same  district,  yet  some  few  of  them  are  extinct,  as,  for  exam- 
ple, a  species  of  Cyrena,  a  genus  no  longer  inhabiting  Europe,  and  now 
entirely  restricted  to  warmer  latitudes. 

When  reasoning  on  such  phenomena,  the  reader  must  always  bear  in 
mind  that  the  fossil  individuals  belonged  to  species  of  elephant,  rhinoce- 
ros, hippopotamus,  bear,  tiger,  and  hyaena,  distinct  from  those  which 
now  dwell  within  or  near  the  tropics.  Dr.  Fleming,  in  a  discussion  on 
this  subject,  has  well  remarked  that  a  near  resemblance  in  form  and  os« 
teological  structure  is  not  always  followed,  in  the  existing  creation,  by 
a  similarity  of  geographical  distribution ;  and  we  must  therefore  be  on 
our  guard  against  deciding  too  confidently,  from  mere  analogy  of  ana- 
tomical structure,  respecting  the  habits  and  physiological  peculiarities  of 
species  now  no  more.  "  The  zebra  delights  to  roam  over  the  tropical 
plains,  while  the  horse  can  maintain  its  existence  throughout  an  Iceland 
winter.  The  buffalo,  like  the  zebra,  prefers  a  high  temperature,  and 
cannot  thrive  even  where  the  common  ox  prospers.  The  musk-ox,  on 
the  other  hand,  though  nearly  resembling  the  buffalo,  prefers  the  stinted 

*  Geol.  Proceedings,  No.  xxxvi.  June,  1834. 
f  Phil.  Mag.,  Sept.  1829,  and  Jan.  1830. 


CH.  VI]  SIBEEIAN   MAMMOTHS.  77 

herbage  of  the  arctic  regions,  and  is  able,  by  its  periodical  migrations, 
to  outlive  a  northern  winter.  The  jackal  (Canis  aureus)  inhabits  Africa, 
the  warmer  parts  of  Asia,  and  Greece  ;  while  the  isatis  ( Canis  lagopus) 
resides  in  the  arctic  regions.  The  African  hare  and  the  polar  hare  have 
their  geographical  distribution  expressed  in  their  trivial  names  ;"*  and 
different  species  of  bears  thrive  in  tropical,  temperate,  and  arctic  lati- 
tudes. 

Recent  investigations  have  placed  beyond  all  doubt  the  important  fact 
that  a  species  of  tiger,  identical  with  that  of  Bengal,  is  common  in  the 
neighborhood  of  Lake  Aral,  near  Sussac,  in  the  forty-fifth  degree  of 
north  latitude  ;  and  from  time  to  time  this  animal  is  now  seen  in  Siberia, 
in  a  latitude  as  far  north  as  the  parallel  of  Berlin  and  Hamburgh. \ 
Humboldt  remarks  that  the  part  of  Southern  Asia  now  inhabited  by  this 
Indian  species  of  tiger  is  separated  from  the  Himalaya  by  two  great 
chains  of  mountains,  each  covered  with  perpetual  snow, — the  chain  of 
Kuenlun,  lat.  35°  N.,  and  that  of  Mouztagh,  lat.  42°,— so  that  it  is  im- 
possible that  these  animals  should  merely  have  made  excursions  from 
India,  so  as  to"  have  penetrated  in  summer  to  the  forty-eighth  and  fifty- 
third  degrees  of  north  latitude.  They  must  remain  all  the  winter  north 
of  the  Mouztagh,  or  Celestial  mountains.  The  last  tiger  killed,  in  1828, 
on  the  Lena,  in  lat.  52-J0,  was  in  a  climate  colder  than  that  of  Peters- 
burg and  Stockholm.]; 

We  learn  from  Mr.  Hodgson's  account  of  the  mammalia  of  Nepal, 
that  the  tiger  is  sometimes  found  at  the  very  edge  of  perpetual  snow  in 
the  Himalaya  ;§  and  Pennant  mentions  that  it  is  found  among  the  snows 
of  Mount  Ararat  in  Armenia.  The  jaguar,  also,  has  been  seen  in  Amer- 
ica, wandering  from  Mexico,  as  far  north  as  Kentucky,  lat.  37°  N.,||  and 
even  as  far  as  42°  S.  in  South  America, — a  latitude  which  corresponds 
to  that  of  the  Pyrenees  in  the  northern  hemisphere. ^[  The  range  of  the 
puma  is  still  wider,  for  it  roams  from  the  equator  to  the  Straits  of  Magel- 
lan, being  often  seen  at  Port  Famine,  in  lat.  53°  38'  S. 

A  new  species  of  panther  (Felis  irbis),  covered  with  long  hair,  has 
been  discovered  in  Siberia,  evidently  inhabiting,  like  the  tiger,  a  region 
north  of  the  Celestial  Mountains,  which  are  in  lat.  42°.** 

The  two-horned  African  rhinoceros  occurs  without  the  tropics  at  the 
Cape  of  Good  Hope,  in  lat.  34°  29'  S.,  where  it  is  accompanied  by  the 
elephant,  hippopotamus,  and  hyaena.  Here  the  migration  of  all  these 
species  towards  the  south  is  arrested  by  the  ocean  ;  but  if  the  continent 
had  been  prolonged  still  farther,  and  the  land  had  been  of  moderate  ele- 

*  Fleming,  Ed.  New  Phil,  Journ.,  No.  xii.  p.  282,  1829.  The  zebra,  however, 
inhabits  chiefly  the  extra-tropical  parts  of  Africa. 

f  Humboldt,  Fragmens  de  Gdologie,  «fec.,  tome  ii.  p.  388.  Ehrenberg,  Ann,  des 
Sci.  Nat.,  tome  xxi.  p.  387. 

1  Ehrenberg,  ibid.  p.  390.  §  Journ.  of  Asiat.  Soc.,  vol.  i.  p.  240. 

||  Rafinesque,  Atlantic  Journ.,  p.  18. 

*[[  Darwin's  Journal  of  Travels  in  South  America,  <fcc.,  1832  to  1886,  in  Voyage 
of  H.  M.  S.  Beagle,  p.  159. 

**  Ehrenberg,  ibid. 


78  CHANGE   OF   CLIMATE.  [Cn.  VI. 

vation,  it  is  very  probable  that  they  might  have  extended  their  range  to 
a  greater  distance  from  the  tropics. 

Now,  if  the  Indian  tiger  can  range  in  our  own  times  to  the  southern 
borders  of  Siberia,  or  skirt  the  snows  of  the  Himalaya,  and  if  the  puma 
can  reach  the  fifty-third  degree  of  latitude  in  South  America,  we  may 
easily  understand  how  large  species  of  the  same  genera  may  once  have 
inhabited  our  temperate  climates.  The  mammoth  (E.  -primigenius),  al- 
ready alluded  to,  as  occurring  fossil  in  England,  was  decidedly  different 
from  the  two  existing  species  of  elephants,  one  of  which  is  limited  to 
Asia,  south  of  the  31°  of  N.  lat.,  the  other  to  Africa,  where  it  extends, 
as  before  stated,  as  far  south  as  the  Cape  of  Good  Hope.  The  bones 
of  the  great  fossil  species  are  very  widely  spread  over  Europe  and  North 
America ;  but  are  nowhere  in  such  profusion  as  in  Siberia,  particularly 
near  the  shores  of  the  Frozen  Ocean.  Are  we,  then,  to  conclude  that  this 
animal  preferred  a  polar  climate  ?  If  so,  it  may  well  be  asked,  by  what 
food  was  it  sustained,  and  why  does  it  not  still  survive  near  the  arctic 
circle  ?* 

Pallas  and  other  writers  describe  the  bones  of  the  mammoth  as  abound- 
ing throughout  all  the  Lowlands  of  Siberia,  stretching  in  a  direction  west 
and  east,  from  the  borders  of  Europe  to  the  extreme  point  nearest  Amer- 
ica, and  south  and  north,  from  the  base  of  the  mountains  of  Central  Asia 
to  the  shores  of  the  Arctic  Sea.  (See  map,  fig.  1.)  Within  this  space, 
scarcely  inferior  in  area  to  the  whole  of  Europe,  fossil  ivory  has  been 
collected  almost  everywhere,  on  the  banks  of  the  Irtish,  Obi,  Yenesei, 
Lena,  and  other  rivers.  The  elephantine  remains  do  not  occur  in  the 
marshes  and  low  plains,  but  where  the  banks  of  the  rivers  present  lofty 
precipices  of  sand  and  clay,  from  which  circumstance  Pallas  very  justly 
inferred  that,  if  sections  could  be  obtained,  similar  bones  might  be  found 
in  all  the  elevated  lands  intervening  between  the  great  rivers.  Strahl en- 
berg,  indeed,  had  stated,  before  the  time  of  Pallas,  that  wherever  any  of 
the  great  rivers  overflowed  and  cut  out  fresh  channels  during  floods,  more 
fossil  remains  of  the  same  kind  were  invariably  disclosed. 

As  to  the  position  of  the  bones,  Pallas  found  them  in  some  places  im- 
bedded together  with  marine  remains  ;  in  others,  simply  with  fossil  wood, 
or  lignite,  such  as,  he  says,  might  have  been  derived  from  carbonized 
peat.  On  the  banks  of  the  Yenesei,  below  the  city  of  Krasnojarsk,  in 
lat.  56°,  he  observed  grinders,  and  bones  of  elephants,  in  strata  of  yel- 

*  The  speculations  which  follow,  on  the  ancient  physical  geography  of  Siberia, 
and  its  former  fitness  as  a  residence  for  the  mammoth,  were  first  given  in  their 
present  form  in  my  4th  edition,  June,  1835.  Recently  Sir  R.  Murchison  and  his 
companions  in  their  great  work  on  the  Geology  of  Russia,  1845  (vol.  i.  p.  497),  have, 
in  citing  this  chapter,  declared  that  their  investigations  have  led  them  to  similar 
conclusions.  Professor  Owen,  in  his  excellent  History  of  British  Fossil  Mammalia, 
1844,  p.  261,  et  seg.,  observes  that  the  teeth  of  the  mammoth  differ  from  those  of 
the  living  Asiatic  or  African  elephant  in  having  a  larger  proportion  of  dense  enamel, 
which  may  have  enabled  it  to  subsist  on  the  coarser  ligneous  tissues  of  trees  and 
shrubs.  In  short,  he  is  of  opinion,  that  the  structure  of  its  teeth,  as  well  as  the 
nature  of  its  epidermis  and  coverings,  may  have  made  it  "  a  meet  companion  for 
the  reindeer." 


OH.  VI.1 


SIBERIAN  MAMMOTHS. 


79 


Jf 
II 


low  and  red  loam,  alternating  with  coarse  sand  and  gravel,  in  which  was 
also  much  petrified  wood  of  the  willow  and  other  trees.  Neither  here 
nor  in  the  neighboring  country  were  there  any  marine  shells,  but  merely 
layers  of  black  coal.*  But  grinders  of  the  mammoth  were  collected 
much  farther  down  the  same  river,  near  the  sea,  in  lat,  70°,  mixed  with 
marine  petrifactions. f  Many  other  places  in  Siberia  are  cited  by  Pallas, 

*  Pallas,  Reise  in  Russ.  Reiche,  pp.  409,  410. 
f  Nov.  Com.  Petrop.  vol.  xvii.  p.  584. 


80  CHANGE   OF   CLIMATE.  [Cfl.  VI 

where  sea  shells  and  fishes'  teeth  accompany  the  bones  of  the  mammoth, 
rhinoceros,  and  Siberian  buffalo,  or  bison  (£os  priscus).  But  it  is  not 
on  the  Obi  nor  the  Yenesei,  but  on  the  Lena,  farther  to  the  east,  where, 
in  the  same  parallels  of  latitude,  the  cold  is  far  more  intense,  that  fossil 
remains  have  been  found  in  the  most  wonderful  state  of  preservation. 
In  1772,  Pallas  obtained  from  Wiljuiskoi,  in  lat.  64°,  from  the  banks  of 
the  Wiljui,  a  tributary  of  the  Lena,  the  carcass  of  a  rhinoceros  (JR. 
tichorhinus),  taken  from  the  sand  in  which  it  must  have  remained  con- 
gealed for  ages,  the  soil  of  that  region  being  always  frozen  to  within  a 
slight  depth  of  the  surface.  This  carcass  was  compared  to  a  natural 
mummy,  and  emitted  an  odor  like  putrid  flesh,  part  of  the  skin  being 
still  covered  with  black  and  gray  hairs.  So  great,  indeed,  was  the 
quantity  of  hair  on  the  foot  and  head  conveyed  to  St.  Petersburg,  that 
Pallas  asked  whether  the  rhinoceros  of  the  Lena  might  not  have  been 
an  inhabitant  of  the  temperate  regions  of  middle  A'sia,  its  clothing  being 
so  much  warmer  than  that  of  the  African  rhinoceros.* 

Professor  Brandt,  of  St.  Petersburg,  in  a  letter  to  Baron  Alex.  Von 
Humboldt,  dated  1846,  adds  the  following  particulars  respecting  this 
wonderful  fossil  relic  : — "  I  have  been  so  fortunate  as  to  extract  from 
cavities  in  the  molar  teeth  of  the  Wiljui  rhinoceros  a  small  quantity  of 
its  half-chewed  food,  among  which  fragments  of  pine  leaves,  one-half  of 
the  seed  of  a  polygonaceous  plant,  and  very  minute  portions  of  wood 
with  porous  cells  (or  small  fragments  of  coniferous  wood),  were  still 
recognizable.  It  was  also  remarkable,  on  a  close  investigation  of  the 
head,  that  the  blood-vessels  discovered  in  the  interior  of  the  mass 
appeared  filled,  even  to  the  capillary  vessels,  with  a  brown  mass 
(coagulated  blood),  which  in  many  places  still  showed  the  red  color  of 
blood."f 

After  more  than  thirty  years,  the  entire  carcass  of  a  mammoth  (or 
extinct  species  of  elephant)  was  obtained  in  1803,  by  Mr.  Adams,  much 
farther  to,  the  north.  It  fell  from  a  mass  of  ice,  in  which  it  had  been 
encased,  on  the  banks  of  the  Lena,  in  lat.  70°  ;  and  so  perfectly  had  the 
soft  parts  of  the  carcass  been  preserved,  that  the  flesh,  as  it  lay,  was 
devoured  by  wolves  and  bears.  This  skeleton  is  still  in  the  museum  of 
St.  Petersburg,  the  head  retaining  its  integument  and  many  of  the  liga- 
ments entire.  The  skin  of  the  animal  was  covered,  first,  with  black 
bristles,  thicker  than  horse  hair,  from  twelve  to  sixteen  inches  in  length  ; 
secondly,  with  hair  of  a  reddish  brown  color,  about  four  inches  long ; 
and  thirdly,  with  wool  of  the  same  color  as  the  hair,  about  an  inch  in 
length.  Of  the  fur,  upwards  of  thirty  pounds'  weight  were  gathered 
from  the  wet  sand-bank.  The  individual  was  nine  feet  high  and  sixteen 
feet  long,  without  reckoning  the  large  curved  tusks :  a  size  rarely  sur- 
passed by  the  largest  living  male  elephants.^ 

It  is  evident,  then,  that  the  mammoth,  instead  of  being  naked,  like  the 

*  Nov.  Com.  fVtrop.  vol.  xvii.  p.  591.     ' 

Quart.  Journ.  Geol.  Soc.  Lond.  vol.  iv.  p.  10,  Memoirs. 
Journal  du  Nord,  St.  Petersburg,  1807. 


CH.  VI]  SIBERIAN   MAMMOTHS.  81 

living  Indian  and  African  elephants,  was  enveloped  in  a  thick  shaggy 
covering  of  fur,  probably  as  impenetrable  to  rain  and  cold  as  that  of  the 
musk  ox.*  The  species  may  have  been  fitted  by  nature  to  withstand 
the  vicissitudes  of  a  northern  climate ;  and  it  is  certain  that,  from  the 
moment  when  the  carcasses,  both  of  the  rhinoceros  and  elephant,  above 
described,  were  buried  in  Siberia,  in  latitudes  64°  and  70°  N.,  the  soil 
must  have  remained  frozen,  and  the  atmosphere  nearly  as  cold  as  at 
this  day. 

The  most  recent  discoveries  made  in  1843  by  Mr.  Middendorf,  a  dis- 
tinguished Russian  naturalist,  and  which  he  communicated  to  me  in 
September,  1846,  afford  more  precise  information  as  to  the  climate  of 
the  Siberian  lowlands,  at  the  period  when  the  extinct  quadrupeds  were 
entombed.  One  elephant  was  found  on  the  Tas,  between  the  Obi  and 
Yenesei,  near  the  arctic  circle,  about  lat.  66°  30'  N.,  with  some  parts 
of  the  flesh  in  so  perfect  a  state  that  the  bulb  of  the  eye  is  now  pre- 
served in  the  museum  at  Moscow.  Another  carcass,  together  with  a 
young  individual  of  the  same  species,  was  met  with  in  the  same  year, 
1843,  in  lat.  75°  15'  N.,  near  the  river  Taimyr,  with  the  flesh  decayed. 
It  was  imbedded  in  strata  of  clay  and  sand,  with  erratic  blocks,  at  about 
15  feet  above  the  level  of  the  sea.  In  the  same  deposit  Mr.  Midden- 
dorf observed  the  trunk  of  a  larch  tree  (Pinus  larix),  the  same  wood 
as  that  now  carried  down  in  abundance  by  the  Taimyr  to  the  Arctic 
Sea.  There  were  also  associated  fossil  shells  of  living  northern  species, 
and  which  are  moreover  characteristic  of  the  drift  or  glacial  deposits  of 
Europe.  Among  these  Nucula  pygmcea,  Tellina  calcarea,  Mya  truncata, 
and  Saxicava  rugosa  were  conspicuous. 

So  fresh  is  the  ivory  throughout  northern  Russia,  that,  according  to 
Tilesius,  thousands  of  fossil  tusks  have  been  collected  and  used  in  turn- 
ing ;  yet  others  are  still  procured  and  sold  in  great  plenty.  He  declares 
his  belief  that  the  bones  still  left  in  northern  Russia  must  greatly  exceed 
in  number  all  the  elephants  now  living  on  the  globe. 

*  Fleming,  Ed.  New  Phil.  Journ.,  No.  xii.  p.  285. 

Bishop  Heber  informs  us  (Narr.  of  a  Journey  through  the  Upper  Provinces  of 
India,  vol.  ii.  p.  166 — 219),  that  in  the  lower  range  of  the  Himalaya  mountains, 
in  the  northeastern  borders  of  the  Delhi  territory,  between  lat.  29°  and  30°,  he  saw 
an  Indian  elephant  of  a  small  size,  covered  with  shaggy  hair.  But  this  variety  must 
bo  exceedingly  rare ;  for  Mr.  Royle  (late  superintendent  of  the  East  India  Com- 
pany's Botanic  Garden  at  Saharunpore)  has  assured  me,  that  being  in  India  when 
Heber's  Journal  appeared,  and  having  never  seen  or  heard  of  such  elephants,  he 
made  the  strictest  inquiries  respecting  the  fact,  and  was  never  able  to  obtain  any 
evidence  in  corroboration.  Mr.  Royle  resided  at  Saharunpore,  lat.  30°  N.,  upon 
the  extreme  northern  limits  of  the  range  of  the  elephant.  Mr.  Everest  also  de- 
clares that  he  has  been  equally  unsuccessful  in  finding  any  one  aware  of  the  exist- 
ence of  such  a  variety  or  breed  of  the  animal,  though  one  solitary  individual  was 
mentioned  to  him  as  having  been  seen  at  Delhi,  with  a  good  deal  of  long  hair  up- 
on it.  The  greatest  elevation,  says  Mr.  E.,  at  which  the  wild  elephant  is  found 
in  the  mountains  to  the  north  of  Bengal,  is  at  a  place  called  Nahun,  about  4000 
feet  above  the  level  of  the  sea,  and  in  the  31st  degree  of  N.  lat.,  where  the  mean 
yearly  temperature  may  be  about  64°  Fahrenheit,  and  the  difference  between 
winter  and  summer  very  great,  equal  to  about  36°  F.,  the  month  of  January 
averaging  45°,  and  Juno,  the  hottest  month,  81°  F.  (Everest  on  climate  of  Foss. 
Eleph.,  Journ.  of  Asiat.  Soc.,  No.  25,  p.  21.) 

6 


82  CHANGE  OF   CLIMATE.  [On.  VI 

We  are  as  yet  ignorant  of  the  entire  geographical  range  of  the  mam- 
moth ;  but  its  remains  have  been  recently  collected  from  the  cliffs  of 
frozen  mud  and  ice  on  the  east  side  of  Behring's  Straits,  in  Esch- 
scholtz's  Bay,  in  Russian  America,  lat.  66°  N.  As  the  cliffs  waste 
away  by  the  thawing  of  the  ice,  tusks  and  bones  fall  out,  and  a  strong 
odor  of  animal  matter  is  exhaled  from  the  mud.* 

On  considering  all  the  facts  above  enumerated,  it  seems  reasonable  to 
imagine  that  a  large  region  in  central  Asia,  including,  perhaps,  the 
southern  half  of  Siberia,  enjoyed,  at  no  very  remote  period  in  the  earth's 
history,  a  temperate  climate,  sufficiently  mild  to  afford  food  for  numer- 
ous herds  of  elephants  and  rhinoceroses,  of  species  distinct  from  those 
now  living.  It  has  usually  been  taken  for  granted  that  herbivorous 
animals  of  large  size  require  a  very  luxuriant  vegetation  for  their  sup- 
port ;  but  this  opinion  is,  according  to  Mr.  Darwin,  completely  errone- 
ous: — "It  has  been  derived,"  he  says,  "from  our  acquaintance  with 
India  and  the  Indian  islands,  where  the  mind  has  been  accustomed  to 
associate  troops  of  elephants  with  noble  forests  and  impenetrable  jun- 
gles. But  the  southern  parts  of  Africa,  from  the  tropic  of  Capricorn  to 
the  Cape  of  Good  Hope,  although  sterile  and  desert,  are  remarkable  for 
the  number  and  great  bulk  of  the  indigenous  quadrupeds.  We  there 
meet  with  an  elephant,  five  species  of  rhinoceros,  a  hippopotamus,  a 
giraffe,  the  bos  caffer,  the  elan,  two  zebras,  the  quagga,  two  gnus,  and 
several  antelopes.  Nor  must  we  suppose,  that  while  the  species  are 
numerous,  the  individuals  of  each  kind  are  few.  Dr.  Andrew  Smith 
saw,  in  one  day's  march,  in  lat.  24°  S.,  without  wandering  to  any  great 
distance  on  either  side,  about  150  rhinoceroses,  with  several  herds  of 
giraffes,  and  his  party  had  killed,  on  the  previous  night,  eight  hippopot- 
amuses. Yet  the  country  which  they  inhabited  was  thinly  covered 
with  grass  and  bushes  about  four  feet  high,  and  still  more  thinly  with 
mimosa-trees,  so  that  the  wagons  of  the  travellers  were  not  prevented 
from  proceeding  in  a  nearly  direct  line."f 

In  order  to  explain  how  so  many  animals  can  find  support  in  this  re- 
gion, it  is  suggested  that  the  underwood,  of  which  their  food  chiefly 
consists,  may  contain  much  nutriment  in  a  small  bulk,  and  also  that  the 
vegetation  has  a  rapid  growth ;  for  no  sooner  is  a  part  consumed  than 
its  place,  says  Dr.  Smith,  is  supplied  by  a  fresh  stock.  Nevertheless, 
after  making  every  allowance  for  this  successive  production  and  con- 
sumption, it  is  clear,  from  the  facts  above  cited,  that  the  quantity  of 
food  required  by  the  larger  herbivora  is  much  less  than  we  have  usually 
imagined.  Mr.  Darwin  conceives  that  the  amount  of  vegetation  sup- 
ported at  any  one  time  by  Great  Britain  may  exceed,  in  a  ten-fold  ratio, 
the  quantity  exfsting  on  an  equal  area  in  the  interior  parts  of  Southern 
Africa.};  It  is  remarked,  moreover,  in  illustration  of  the  small  connec- 

*  See  Dr.  Buckland's  description  of  these  bones,  Appen.  to  Beechy's  Voy. 
f  Darwin,  Journal  of  Travels  in  S.  America,  (fee.,  1832-36,  in  voyage  of  H.  M.  S, 
Beagle,  p.  98.     2d  Ed.  London,  1845,  p.  86. 

\  Darwin,  Journal  of  Travels  in  S.  America,  &c.,  p.  99,  2d  Ed.  p.  85. 


CH.  VI.]  SIBERIAN   MAMMOTHS.  83 

tion  discoverable  between  abundance  of  food  and  the  magnitude  of  in- 
digenous mammalia,  that  while  in  the  desert  part  of  Southern  Africa 
there  are  so  many  huge  animals ;  in  Brazil,  where  the  splendor  and  ex- 
uberance of  the  vegetation  are  unrivalled,  there  is  not  a  single  wild 
quadruped  of  large  size.* 

It  would  doubtless  be  impossible  for  herds  of  mammoths  and  rhino- 
ceroses to  subsist,  at  present,  throughout  the  year,  even  in  the  southern 
part  of  Siberia,  covered  as  it  is  with  snow  during  winter ;  but  there  is 
no  difficulty  in  supposing  a  vegetation  capable  of  nourishing  these  great 
quadrupeds  to  have  once  flourished  between  the  latitudes  40°  and 
60°  N. 

Dr.  Fleming  has  hinted,  that  "  the  kind  of  food  which  the  existing 
species  of  elephant  prefers,  will  not  enable  us  to  determine,  or  even  to 
offer  a  probable  conjecture,  concerning  that  of  the  extinct  species.  No 
one  acquainted  with  the  gramineous  character  of  the  food  of  our  fallow- 
deer,  stag,  or  roe,  would  have  assigned  a  lichen  to  the  reindeer." 

Travellers  mention  that,  even  now,  when  the  climate  of  eastern  Asia 
is  so  much  colder  than  the  same  parallels  of  latitude  farther  west,  there 
are  woods  not  only  of  fir,  but  of  birch,  poplar,  and  alder,  on  the  banks 
of  the  Lena,  as  far  north  as  latitude  60°. 

It  has,  moreover,  been  suggested,  that  as,  in  our  own  times,  the 
northern  animals  migrate,  so  the  Siberian  elephant  and  rhinoceros  may 
have  wandered  towards  the  north  in  summer.  The  musk  oxen  annually 
desert  their  winter  quarters  in  the  south,  and  cross  the  sea  upon  the  ice, 
to  graze  for  four  months,  from  May  to  September,  on  the  rich  pastur- 
age of  Melville  Island,  in  lat.  75°.  The  mammoths,  without  passing  so 
far  beyond  the  arctic  circle,  may  nevertheless  have  made  excursions, 
during  the  heat  of  a  brief  northern  summer,  from  the  central  or  temper- 
ate parts  of  Asia  to  the  sixtieth  parallel  of  latitude. 

Now,  in  this  case,  the  preservation  of  their  bones,  or  even  occasion- 
ally of  their  entire  carcasses,  in  ice  or  frozen  soil,  may  be  accounted  for, 
without  resorting  to  speculations  concerning  sudden  revolutions  in  the 
former  state  and  climate  of  the  earth's  surface.  We  are  entitled  to  as- 
sume, that,  in  the  time  of  the  extinct  elephant  and  rhinoceros,  the  Low- 
land of  Siberia  was  less  extensive  towards  the  north  than  now  ;  for  we 
have  seen  (p.  80)  that  the  strata  of  this  Lowland,  in  which  the  fossil 
bones  lie  buried,  were  originally  deposited  beneath  the  sea ;  and  we 
know,  from  the  facts  brought  to  light  in  Wrangle's  Voyage,  in  the  years 
1821,  1822,  and  1823,  that  a  slow  upheaval  of  the  land  along  the  bor- 
ders of  the  Icy  Sea  is  now  constantly  taking  place,  similar  to  that  ex- 
perienced in  part  of  Sweden.  In  the  same  manner,  then,  as  the  shores 
of  the  Gulf  of  Bothnia  are  extended,  not  only  by  the  influx  of  sediment 
brought  down  by  rivers,  but  also  by  the  elevation  and  consequent  dry- 
ing up  of  the  bed  of  the  sea,  so  a  like  combination  of  causes  may,  in 
modern  times,  have  been  extending  the  low  tract  of  land  where  marine 

*  Burchell,  cited  by  Darwin,  ibid.  p.  101.     2d  Ed.  p.  87. 


84  CHANGE   OF    CLIMATE.  CH.  VL 

shells  and  fossil  bones  occur  in  Siberia.*  Such  a  change  in  the  physi- 
cal geography  of  that  region,  implying  a  constant  augmentation  in  the 
quantity  of  arctic  land,  would,  according  to  principles  to  be  explained 
in  the  next  chapter,  tend  to  increase  the  severity  of  the  winters.  We 
may  conclude,  therefore,  that,  before  the  land  reached  so  far  to  the 
north,  the  temperature  of  the  Siberian  winter  and  summer  was  more 
nearly  equalized  ;  and  a  greater  degree  of  winter's  cold  may,  even  more 
than  a  general  diminution  of  the  mean  annual  temperature,  have  finally 
contributed  to  the  extermination  of  the  mammoth  and  its  contemporaries. 

On  referring  to  the  map  (p.  79),  the  reader  will  see  how  all  the 
great  rivers  of  Siberia  flow  at  present  from  south  to  north,  from  tem- 
perate to  arctic  regions,  and  they  are  all  liable,  like  the  Mackenzie,  in 
North  America,  to  remarkable  floods,  in  consequence  of  flowing  in  this 
direction.  For  they  are  filled  with  running  water  in  their  upper  or 
southern  course  when  completely  frozen  over  for  several  hundred  miles 
near  their  mouths,  where  they  remain  blocked  up  by  ice  for  six  months 
in  every  year.  The  descending  waters,  therefore,  finding  no  open  chan- 
nel, rush  over  the  ice,  often  changing  their  direction,  and  sweeping  along 
forests  and  prodigious  quantities  of  soil  and  gravel  mixed  with  ice. 
Now  the  rivers  of  Siberia  are  among  the  largest  in  the  world,  the 
Yenesei  having  a  course  of  2500,  the  Lena  of  2000  miles ;  so  that  we 
may  easily  conceive  that  the  bodies  of  animals  which  fall  into  their 
waters  may  be  transported  to  vast  distances  towards  the  Arctic  Sea, 
and,  before  arriving  there,  may  be  stranded  upon  and  often  frozen  into 
thick  ice.  Afterwards,  when  the  ice  breaks  up,  they  may  be  floated 
still  farther  towards  the  ocean,  until  at  length  they  become  buried  in 
fluviatile  and  submarine  deposits  near  the  mouths  of  rivers. 

Humboldt  remarks  that  near  the  mouths  of  the  Lena  a  considerable 
thickness  of  frozen  soil  may  be  found  at  all  seasons  at  the  depth  of  a 
few  feet ;  so  that  if  a  carcass  be  once  imbedded  in  mud  and  ice  in  such 
a  region  and  in  such  a  climate,  its  putrefaction  may  be  arrested  for  in- 
definite ages.f  According  to  Prof.  Yon  Baer  of  St.  Petersburg,  the 
ground  is  now  frozen  permanently  to  the  depth  of  400  feet,  at  the  town 
of  Yakutzt,  on  the  western  bank  of  the  Lena,  in  lat.  62°  N.,  600  miles 
distant  from  the  polar  sea.  Mr.  Hedenstrom  tells  us  that,  throughout 
a  wide  area  in  Siberia,  the  boundary  cliffs  of  the  lakes  and  rivers  consist 
of  alternate  layers  of  earthy  materials  and  ice,  in  horizontal  stratifica- 
tion;^ and  Mr.  Middendorf  informed  us,  in  1846,  that,  in  his  tour  there 
three  years  before,  he  had  bored  in  Siberia  to  the  depth  of  seventy  feet, 
and,  after  passing  through  much  frozen  soil  mixed  with  ice,  had  come 

*  Since  the  above  passage  was  first  printed  in  a  former  edition,  June,  1835,  it 
has  been  shown  by  the  observations  of  Sir  R.  Murchison,  M.  de  Verneuil,  and 
Count  Keyserling,  and  more  recently  by  M.  Middendorf  (see  above,  p.  81),  that 
the  Lowland  of  Siberia  has  actually  been  extended,  since  the  existing  species  of 
shells  inhabited  the  northern  seas. 

f  Humboldt,  Fragmens  Asiatiques,  torn.  ii.  p.  393. 

\  Reboul.  Geol.  de  la  Periode  Quaternaire,  who  cites  Observ.  sur  la  Siberie, 
BibL  Univ.,  Juillet,  1832. 


CH.  VI]  SIBERIAN    MAMMOTHS.  85 

down  upon  a  solid  mass  of  pure  transparent  ice,  the  thickness  of  which, 
after  penetrating  two  or  three  yards,  they  did  not  ascertain.  We  may 
conceive,  therefore,  that  even  at  the  period  of  the  mammoth,  when  the 
Lowland  of  Siberia  was  less  extensive  towards  the  north,  and  conse- 
quently the  climate  more  temperate  than  now,  the  cold  may  still  have 
been  sufficiently  intense  to  cause  the  rivers  flowing  in  their  present 
direction  to  sweep  down  from  south  to  north  the  bodies  of  drowned 
animals,  and  there  bury  them  in  drift  ice  and  frozen  mud. 

If  it  be  true  that  the  carcass  of  the  mammoth  was  imbedded  in  pure 
ice,  there  are  two  ways  in  which  it  may  have  been  frozen  in.  We  may 
suppose  the  animal  to  have  been  overwhelmed  by  drift  snow.  I  have 
been  informed  by  Dr.  Richardson,  that,  in  the  northern  parts  of  Amer- 
ica, comprising  regions  now  inhabited  by  many  herbivorous  quadru- 
peds, the  drift  snow  is  often  converted  into  permanent  glaciers.  It  is 
commonly  blown  over  the  edges  of  steep  cliffs,  so  as  to  form  an  inclined 
talus  hundreds  of  feet  high  ;  and  when  a  thaw  commences,  torrents 
rush  from  the  land,  and  throw  down  from  the  top  of  the  cliff  alluvial 
soil  and  gravel.  This  new  soil  soon  becomes  covered  with  vegetation, 
and  protects  the  foundation  of  snow  from  the  rays  of  the  sun.  Water 
occasionally  penetrates  into  the  crevices  and  pores  of  the  snow  ;  but, 
as  it  soon  freezes  again,  it  serves  the  more  rapidly  to  consolidate  the 
mass  into  a  compact  iceberg.  It  may  sometimes  happen  that  cattle 
grazing  in  a  valley  at  the  base  of  such  cliffs,  on  the  borders  of  a  sea  or 
river,  may  be  overwhelmed,  and  at  length  inclosed  in  solid  ice,  and 
then  transported  towards  the  polar  regions.  Or  a  herd  of  mammoths 
returning  from  their  summer  pastures  in  the  north,  may  have  been  sur- 
prised, while  crossing  a  stream,  by  the  sudden  congelation  of  the  waters. 
The  missionary  Hue  relates,  in  his  travels  in  Thibet  in  1846,  that,  after 
many  of  his  party  had  been  frozen  to  death,  they  pitched  their  tents 
on  the  banks  of  the  Mouroui-Ousson  (which  lower  down  becomes  the 
famous  Blue  River),  and  saw  from  their  encampment  "  some  black 
shapeless  objects  ranged  in  file  across  the  stream.  As  they  advanced 
nearer  no  change  either  in  form  or  distinctness  was  apparent ;  nor  was 
it  till  they  were  quite  close,  that  they  recognized  in  them  a  troop  of  the 
wild  oxen,  called  Yak  by  the  Thibetans.*  There  were  more  than  fifty 
of  them  incrusted  in  the  ice.  No  doubt  they  had  tried  to  swim  across 
at  the  moment  of  congelation,  and  had  been  unable  to  disengage  them- 
selves. Their  beautiful  heads,  surmounted  by  huge  horns,  were  still 
above  the  surface,  but  their  bodies  were  held  fast  in  the  ice,  which  was 
so  transparent  that  the  position  of  the  imprudent  beasts  was  easily  dis- 
tinguishable ;  they  looked  as  if  still  swimming,  but  the  eagles  and 
ravens  had  pecked  out  their  eyes."f 

The  foregoing  investigations,  therefore,  lead  us  to  infer  that  the  mam- 
moth, and  some  other  extinct  quadrupeds  fitted  to  live  in  high  latitudes, 

*  Conjectured  to  be  the  wild  stock  of  Bos  grunniens. 

f  Recollections  of  a  Journey  through  Tartary,  Thibet,  and  China  (ch.  xv.  p.  234), 
by  M.  Hue.  Longman,  1852. 


86  GEOLOGICAL   PROOFS    OF  [Cfl.  VI. 

were  inhabitants  of  Northern  Asia  at  a  time  when  the  geographical 
conditions  and  climate  of  that  continent  were  different  from  the  present. 
But  the  age  of  this  fauna  was  comparatively  modern  in  the  earth's  his- 
tory. It  appears  that  when  the  oldest  or  eocene  tertiary  deposits  were 
formed,  a  warm  temperature  pervaded  the  European  seas  and  lands. 
Shells  of  the  genus  Nautilus  and  other  forms  characteristic  of  tropical 
latitudes ;  fossil  reptiles,  such  as  the  crocodile,  turtle,  and  tortoise ; 
plants,  such  as  palms,  some  of  them  allied  to  the  cocoa-nut,  the  screw- 
pine,  the  custard-apple,  and  the  acacia,  all  lead  to  this  conclusion.  This 
flora  and  fauna  were  followed  by  those  of  the  miocene  formation,  in 
which  indications  of  a  southern,  but  less  tropical  climate  are  detected. 
Finally,  the  pliocene  deposits,  which  come  next  in  succession,  exhibit 
in  their  organic  remains  a  much  nearer  approach  to  the  state  of  things 
now  prevailing  in  corresponding  latitudes.  It  was  towards  the  close  of 
this  period  that  the  seas  of  the  northern  hemisphere  became  more  and 
more  filled  with  floating  icebergs  often  charged  with  erratic  blocks,  so 
that  the  waters  and  the  atmosphere  were  chilled  by  the  melting  ice,  and 
an  arctic  fauna  enabled,  for  a  time,  to  invade  the  temperate  latitudes 
both  of  N.  America  and  Europe.  The  extinction  of  a  considerable 
number  of  land  quadrupeds  and  aquatic  mollusca  was  gradually  brought 
about  by  the  increasing  severity  of  the  cold ;  but  many  species  survived 
this  revolution  in  climate,  either  by  their  capacity  of  living  under  a  va- 
riety of  conditions,  or  by  migrating  for  a  time  to  more  southern  lands 
and  seas.  At  length,  by  modifications  in  the  physical  geography  of  the 
northern  regions,  and  the  cessation  of  floating  ice  on  the  eastern  side  of 
the  Atlantic,  the  cold  was  moderated,  and  a  milder  climate  ensued, 
such  as  we  now  enjoy  in  Europe.* 

Proofs  from  fossils  in  secondary  and  still  older  strata. — A  great  in- 
terval of  time  appears  to  have  elapsed  between  the  formation  of  the 
secondary  strata,  which  constitute  the  principal  portion  of  the  elevated 
land  in  Europe,  and  the  origin  of  the  eocene  deposits.  If  we  examine 
the  rocks  from  the  chalk  to  the  new  red  sandstone  inclusive,  we  find 
many  distinct  assemblages  of  fossils  entombed  in  them,  all  of  unknown 
species,  and  many  of  them  referable  to  genera  and  families  now  most 
abundant  between  the  tropics.  Among  the  most  remarkable  are  rep- 
tiles of  gigantic  size ;  some  of  them  herbivorous,  others  carnivorous, 
and  far  exceeding  in  size  any  now  known  even  in  the  torrid  zone.  The 
genera  are  for  the  most  part  extinct,  but  some  of  them,  as  the  croco- 
dile and  monitor,  have  still  representatives  in  the  warmer  parts  of  the 
earth.  Coral  reefs  also  were  evidently  numerous  in  the  seas  of  the 
same  periods,  composed  of  species  often  belonging  to  genera  now  char- 
acteristic of  a  tropical  climate.  The  number  of  large  chambered  shells 

*  For  an  account  of  the  more  modern  changes  of  the  tertiary  fauna  and  flora  of 
the  British  Isles  and  adjoining  countries,  and  particularly  those  facts  which  relate 
to  the  "glacial  epoch,"  see  an  admirable  essay  by  Prof.  E.  Forbes.  Memoirs  of 
Geol.  Survey  of  Great  Brit.  vol.  i.  p.  336.  London,  1846.  To  this  important  me- 
moir I  shall  have  frequent  occasion  to  refer  in  the  sequel. 


CH.  VI.]  CHANGE    OF   CLIMATE.  87 

also,  including  the  nautilus,  leads  us  to  infer  an  elevated  temperature ; 
and  the  associated  fossil  plants,  although  imperfectly  known,  tend  to 
the  same  conclusion,  the  Cycadeae  constituting  the  most  numerous 
family. 

But  it  is  from  the  more  ancient  coal-deposits  that  the  most  extraordi- 
nary evidence  has  been  supplied  in  proof  of  the  former  existence  of  a 
very  different  climate — a  climate  which  seems  to  have  been  moist,  warm, 
and  extremely  uniform,  in  those  very  latitudes  which  are  now  the  colder, 
and  in  regard  to  temperature,  the  most  variable  regions  of  the  globe. 
We  learn  from  the  researches  of  Adolphe  Brongniart,  Goeppert,  and 
other  botanists,  that  in  the  flora  of  the  carboniferous  era  there  was  a 
great  predominance  of  ferns,  some  of  which  were  arborescent ;  as,  for 
example,  Caulopteris,  Protopteris,  and  Psarronius ;  nor  can  this  be  ac- 
counted for,  as  some  have  supposed,  by  the  greater  power  which  ferns 
possess  of  resisting  maceration  in  water.*  This  prevalence  of  ferns  in- 
dicates a  moist,  equable,  and  temperate  climate,  and  the  absence  of  any 
severe  cold ;  for  such  are  the  conditions  which,  at  the  present  day,  are 
found  to  be  most  favorable  to  that  tribe  of  plants.  It  is  only  in  the 
islands  of  the  tropical  oceans,  and  of  the  southern  temperate  zone,  such 
as  Norfolk  Island,  Otaheite,  the  Sandwich  Islands,  Tristan  d'Acunha,  and 
New  Zealand,  that  we  find  any  near  approach  to  that  remarkable  pre- 
ponderance of  ferns  which  is  characteristic  of  the  Carboniferous  flora. 
It  has  been  observed  that  tree  ferns  and  other  forms  of  vegetation  which 
flourished  most  luxuriantly  within  the  tropics,  extend  to  a  much  greater 
distance  from  the  equator  in  the  southern  hemisphere  than  in  the  nor- 
thern, being  found  even  as  far  as  46°  S.  latitude  in  New  Zealand. 
There  is  little  doubt  that  this  is  owing  to  the  more  uniform  and  moist 
climate  occasioned  by  the  greater  proportional  area  of  sea.  Next  to 
ferns  and  pines,  the  most  abundant  vegetable  forms  in  the  coal  formation 
are  the  Calamites,  Lepidodendra,  Sigillariae,  and  Stigmariae.  These 
were  formerly  considered  to  be  so  closely  allied  to  tropical  genera,  and 
to  be  so  much  greater  in  size  than  the  corresponding  tribes  now  inhabit- 
ing equatorial  latitudes,  that  they  were  thought  to  imply  an  extremely 
hot,  as  well  as  humid  and  equable  climate.  But  recent  discoveries  re- 
specting the  structure  and  relations  of  these  fossil  plants,  have  shown 
that  they  deviated  so  widely  from  all  existing  types  in  the  vegetable 
world,  that  we  have  more  reason  to  infer  from  this  evidence  a  widely 
different  climate  in  the  Carboniferous  era,  as  compared  to  that  now  pre- 
vailing, than  a  temperature  extremely  elevated. f  Palms,  if  not  entirely 

*  See  a  paper  by  Charles  J.  F.  Bunbury,  Esq.,  Journ.  of  Geol.  Soc.,  London, 
No.  6,  p.  88.  1846. 

f  The  Calamites  were  formerly  regarded  by  Adolphe  Brongniart  as  belonging 
to  the  tribe  of  Equisetaceae ;  but  he  is  now  inclined  to  refer  them  to  the  class  of 
gymnogens,  or  gymnospermous  exogens,  which  includes  the  Coniferae  and  Cyca- 
deae. Lepidodendron  appears  to  have  been  either  a  gigantic  form  of  the  lycopo- 
dium  tribe,  or,  as  Dr.  Lindley  thinks,  intermediate  between  the  lycopodia  and  the 
fir  tribe.  The  Sigillariae  were  formerly  supposed  by  Ad.  Brongniart,  to  be  arbo- 
rescent ferns ;  but  the  discovery  of  their  internal  structure,  and  of  their  leaves,  has 


88  FOSSIL   PLANTS.  [Cn.  VI. 

wanting  when  the  strata  of  the  carboniferous  group  were  deposited,  ap- 
pear to  have  been  exceedingly  rare.*  The  Coniferse,  on  the  other  hand, 
so  abundantly  met  with  in  the  coal,  resemble  Araucarise  in  structure,  a 
family  of  the  fir  tribe,  characteristic  at  present  of  the  milder  regions  of 
the  southern  hemisphere,  such  as  Chili,  Brazil,  New  Holland,  and  Nor- 
folk Island. 

"  In  regard  to  the  geographical  extent  of  the  ancient  vegetation,  it 
was  not  confined,"  says  M.  Brongniart,  "  to  a  small  space,  as  to  Europe, 
for  example ;  for  the  same  forms  are  met  with  again  at  great  distances. 
Thus,  the  coal- plants  of  North  America  are,  for  the  most  part,  identical 
with  those  of  Europe,  and  all  belong  to  the  same  genera.  Some  speci- 
mens, also,  from  Greenland,  are  referable  to  ferns,  analogous  to  those 
of  our  European  coal-mines. "f  The  fossil  plants  brought  from  Melville 
Island,  although  in  a  very  imperfect  state,  have  been  supposed  to  war- 
rant similar  conclusions  ;J  and  assuming  that  they  agree  with  those  of 
Baffin's  Bay,  mentioned  by  M.  Brongniart,  how  shall  we  explain  the 
manner  in  which  such  a  vegetation  lived  through  an  arctic  night  of  seve- 
ral months'  duration  ?§ 

It  may  seem  premature  to  discuss  this  question  until  the  true  nature 
of  the  fossil  flora  of  the  arctic  regions  has  been  more  accurately  deter- 
mined ;  yet,  as  the  question  has  attracted  some  attention,  let  us  assume 
for  a  moment  that  the  coal-plants  of  Melville  Island  are  strictly  analo- 
gous to  those  of  the  strata  .of  Northumberland — would  such  a  fact  pre- 
sent an  inexplicable  enigma  to  the  vegetable  physiologist  ? 

Plants,  it  is  affirmed,  cannot  remain  in  darkness,  even  for  a  week, 


since  proved  that  they  have  no  real  affinity  to  ferns.  According  to  the  view  now 
taken  of  their  structure,  their  nearest  allies  in  the  recent  world  are  the  genera 
Cycas  and  Zamia;  while  Corda,  on  the  other  hand,  maintains  that  they  were 
closely  related  to  the  succulent  euphorbias.  Stigmaria  is  now  generally  admitted 
to  have  been  merely  the  root  of  sigillaria.  The  scalariform  vessels  of  these  two 
genera  are  not  conclusive  in  proving  them  to  have  a  real  affinity  with  ferns,  as 
Mr.  Brown  has  discovered  the  same  structure  of  vessels  in  Myzodendron,  a  genus 
allied  to  the  mistletoe ;  and  Corda  has  lately  shown  that  in  two  species  of  Stig- 
maria, hardly  distinguishable  by  external  characters,  the  vessels  of  the  one  are 
scalariform,  and  of  the  other  dotted. 

*  Mr.  Lindley  endeavored  formerly  (1834)  to  show,  in  the  "Fossil  Flora,"  that 
Trigonocarpum  Noeggerathii,  a  fruit  found  in  the  coal  measures,  has  the  true 
structure  of  a  palm-fruit ;  but  Ad.  Brongniart  has  since  inclined  to  regard  it  as 
cycadeous ;  nor  is  the  French  botanist  satisfied  that  some  specimens  of  supposed 
palm  wood  from  the  coal-mines  of  Radnitz  in  Bohemia,  described  by  Corda,  really 
belong  to  palms.  On  the  other  hand,  Corda  has  proved  Flabellaria  borassi folia  oi 
Sternberg  to  be  an  exogenous  plant,  and  Brongniart  contends  that  it  was  allied  to 
the  Cycadese.  See  Tableau  des  Genres  de  Ve'getaux  Fossiles.  Paris,  1849. 

f  Prodrome  d'une  Hist,  des  Veget.  Foss.  p.  179.  See  also  a  late  paper,  Quart. 
Journ.  of  Geol.  Soc.  London,  1846,  in  which  coal-plants  of  Alabama,  lat.  33°  1ST., 
collected  by  the  author,  are  identified  by  Mr.  Bunbury  with  British  fossil  species, 
showing  the  great  southern  extension  of  this  flora. 

\  Konig,  Journ.  of  Sci.,  vol.  xv.  p.  20.  Mr.  Konig  informs  me  that  he  no  longer 
believes  any  of  these  fossils  to  be  tree  ferns,  as  he  at  first  stated,  but  that  they 
agree  generically  with  plants  in  our  English  coal-beds.  The  Melville  Island  spe- 
cimens, now  in  the  British  Museum,  are  very  obscure  impressions. 

§  Fossil  Flora  of  Great  Britain,  by  John  Lindley  and  William  Huttou,  Esqrs., 
No.  IV. 


CfL  VI]  CHANGE   OF   CLIMATE.  89 

without  serious  injury,  unless  in  a  torpid  state  ;  and  if  exposed  to  heat 
and  moisture  they  cannot  remain  torpid,  but  will  grow,  and  must  there- 
fore perish.  If,  then,  in  the  latitude  of  Melville  Island,  75°  N.,  a  high 
temperature,  and  consequent  humidity,  prevailed  at  that  period  when 
we  know  the  arctic  seas  were  filled  with  corals  and  large  multilocular 
shells,  how  could  plants  of  tropical  forms  have  flourished  ?  Is  not  the 
bright  light  of  equatorial  regions  as  indispensable  a  condition  of  their 
well-being  as  the  sultry  heat  of  the  same  countries  ?  and  how  could 
they  annually  endure  a  night  prolonged  for  three  months  ?* 

Now,  in  reply  to  this  objection,  we  must  bear  in  mind,  in  the  first 
place,  that,  so  far  as  experiments  have  been  made,  there  is  every  reason 
to  conclude,  that  the  range  of  intensity  of  light  to  which  living  plants 
can  accommodate  themselves  is  far  wider  than  that  of  heat.  No  palms 
or  tree  ferns  can  live  in  our  temperate  latitudes  without  protection  from 
the  cold  ;  but  when  placed  in  hot-houses  they  grow  luxuriantly,  even 
under  a  cloudy  sky,  and  where  much  light  is  intercepted  by  the  glass 
and  frame- work.  At  St.  Petersburg,  in  lat.  60°  N.,  these  plants  have 
been  successfully  cultivated  in  hot-houses,  although  there  they  must  ex- 
change the  perpetual  equinox  of  their  native  regions,  for  days  and  nights 
which  are  alternately  protracted  to  nineteen  hours  and  shortened  to 
five.  How  much  farther  towards  the  pole  they  might  continue  to  live, 
provided  a  due  quantity  of  heat  and  moisture  were  supplied,  has  not 
yet  been  determined ;  but  St.  Petersburg  is  probably  not  the  utmost 
limit,  and  we  should  expect  that  in  lat.  65°  at  least,  where  they  would 
never  remain  twenty-four  hours  without  enjoying  the  sun's  light,  they 
might  still  exist. 

It  should  also  be  borne  in  mind,  in  regard  to  tree  ferns,  that  they 
grow  in  the  gloomiest  and  darkest  parts  of  the  forests  of  warm  and 
temperate  regions,  even  extending  to  nearly  the  46th  degree  of  south 
latitude  in  New  Zealand.  In  equatorial  countries,  says  Humboldt,  they 
abound  chiefly  in  the  temperate,  humid,  and  shady  parts  of  mountains. 
As  we  know,  therefore,  that  elevation  often  compensates  for  the  effect 
of  latitude  in  the  geographical  distribution  of  plants,  we  may  easily  un- 
derstand that  a  class  of  vegetables,  which  grows  at  a  certain  height  in 
the  torrid  zone,  would  flourish  on  the  plains  at  greater  distances  from 
the  equator,  if  the  temperature,  moisture,  and  other  necessary  condi- 
tions, were  equally  uniform  throughout  the  year. 

Nor  must  we  forget  that  in  all  the  examples  above  alluded  to,  we 
have  been  speaking  of  living  species  ;  but  the  coal- plants  were  of  per- 
fectly distinct  species,  nay,  few  of  them  except  the  ferns  and  pines  can 
be  referred  to  genera  or  even  families  of  the  existing  vegetable  kingdom. 
Having  a  structure,  therefore,  and  often  a  form  which  appears  to  the 
botanist  so  anomalous,  they  may  also  have  been  endowed  with  a  diflfer- 


*  Fossil  Flora  of  Great  Britain,  by  John  Lindley  and  William  Hutton,  Esqrs. 


90  FOSSIL    PLANTS.  [On.  VI 

ent  constitution,  enabling  them  to  bear  a  greater  variation  of  circum- 
stances in  regard  to  light.  We  find  that  particular  species  of  plants 
and  tree  ferns  require  at  present  different  degrees  of  heat ;  and  that 
some  species  can  thrive  only  in  the  immediate  neighborhood  of  the 
equator,  others  only  a  distance  from  it.  In  the  same  manner  the  mini- 
mum of  light,  sufficient  for  the  now  existing  species,  cannot  be  taken 
as  the  standard  for  all  analogous  tribes  that  may  ever  have  flourished 
on  the  globe. 

But  granting  that  the  extreme  northern  point  to  which  a  flora  like 
that  of  the  Carboniferous  era  could  ever  reach,  may  be  somewhere  be- 
tween the  latitudes  of  65°  and  70°,  we  should  still  have  to  inquire 
whether  the  vegetable  remains  might  not  have  been  drifted  from  thence, 
by  rivers  and  currents,  to  the  parallel  of  Melville  Island,  or  still  farther. 
In  the  northern  hemisphere,  at  present,  we  see  that  the  materials  for 
future  beds  of  lignite  and  coal  are  becoming  amassed  in  high  latitudes, 
far  from  the  districts  where  the  forests  grew,  and  on  shores  where 
scarcely  a  stunted  shrub  can  now  exist.  The  Mackenzie,  and  other 
rivers  of  North  America,  carry  pines  with  their  roots  attached  for  many 
hundred  miles  towards  the  north,  into  the  Arctic  Sea,  where  they  are 
imbedded  in  deltas,  and  some  of  them  drifted  still  farther  by  currents 
towards  the  pole. 

Before  we  can  decide  on  this  question  of  transportation,  we  must 
know  whether  the  fossil  coal-plants  occurring  in  high  latitudes  bear  the 
marks  of  friction  and  of  having  decayed  previously  to  fossilization. 
Many  appearances  in  our  English  coal-fields  certainly  prove  that  the 
plants  were  not  floated  from  great  distances  ;  for  the  outline  of  the 
stems  of  succulent  species  preserve  their  sharp  angles,  and  others  have 
their  surfaces  marked  with  the  most  delicate  lines  and  streaks.  Long 
leaves,  also,  are  attached  in  many  instances  to  the  trunks  or  branches  ;* 
and  leaves,  we  know,  in  general,  are  soon  destroyed  when  steeped  in 
water,  although  ferns  will  retain  their  forms  after  an  immersion  of  many 
months.f  It  seems  fair  to  presume,  that  most  of  the  coal-plants  grew 
upon  the  same  land  which  supplied  materials  for  the  sandstones  and 
conglomerates  of  the  strata  in  which  they  are  imbedded.  The  coarse- 
ness of  the  particles  of  many  of  these  rocks  attests  that  they  were  not 
borne  from  very  remote  localities,  and  that  there  was  land  therefore  in 
the  vicinity  wasting  away  by  the  action  of  moving  waters.  The  pro- 
gress also  of  modern  discovery  has  led  to  the  very  general  admission  of 
the  doctrine  that  beds  of  coal  have  for  the  most  part  been  formed  of 
the  remains  of  trees  and  plants  that  grew  on  the  spot  where  the  coal 
now  exists ;  the  land  having  been  successively  submerged,  so  that  a 
covering  of  mud  and  sand"  was  deposited  upon  accumulations  of 
vegetable  mater.  That  such  has  been  the  origin  of  some  coal- 
seams  is  proved  by  the  upright  position  of  fossil  trees,  both  in 

*  Fossil  Flora,  No.  X. 

\  This  has  been  proved  by  Mr.  Lindley's  experiments,  ibid.  No.  XVII. 


CH.  VI.}  CHANGE   OF   CLIMATE.  91 

Europe  and  America,  in  which  the  roots  terminate  downwards  in  beds 
of  coal.* 

To  return,  therefore,  from  this  digression, — the  flora  of  the  coal  ap- 
pears to  indicate  a  uniform  and  mild  temperature  in  the  air,  while  the 
fossils  of  the  contemporaneous  mountain-limestone,  comprising  abundance 
of  lamelliferous  corals,  large  chambered  cephalopods,  and  crinoidea, 
naturally  lead  us  to  infer  a  considerable  warmth  in  the  waters  of  the 
northern  sea  of  the  Carboniferous  period.  So  also  in  regard  to  strata 
older  than  the  coal,  they  contain  in  high  northern  latitudes  mountain 
masses  of  corals  which  must  have  lived  and  grown  on  the  spot,  and  large 
chambered  univalves,  such  as  Orthocerata  and  Nautilus,  all  seeming  to 
indicate,  even  in  regions  bordering  on  the  arctic  circle,  the  former  prev- 
alence of  a  temperature  more  elevated  than  that  now  prevailing. 

The  warmth  and  humidity  of  the  air,  and  the  uniformity  of  climate, 
both  in  the  different  seasons  of  the  year,  and  in  different  latitudes,  ap- 
pears to  have  been  most  remarkable  when  some  of  the  oldest  of  the  fos- 
siliferous  strata  were  formed.  The  approximation  to  a  climate  similar  to 
that  now  enjoyed  in  these  latitudes  does  not  commence  till  the  era  of  the 
formations  termed  tertiary ;  and  while  the  different  tertiary  rocks  were 
deposited  in  succession,  from  the  eocene  to  the  pliocene,  the  temperature 
seems  to  have  been  lowered,  and  to  have  continued  to  diminish  even  after 
the  appearance  upon  the  earth  of  a  considerable  number  of  the  existing 
species,  the  cold  reaching  its  maximum  of  intensity  in  European  latitudes 
during  the  glacial  epoch,  or  the  epoch  immediately  antecedent  to  that  in 
which  all  the  species  now  contemporary  with  man  were  in  being. 

*  I  have  treated  of  this  subject  in  my  Manual  of  Geology,  and  still  more  fully 
in  my  Travels  in  N.  America,  vol.  ii.  p.  118.  For  a  full  account  of  the  facts  at 
present  known,  and  the  theories  entertained  by  the  most  eminent  geologists  and 
botanists  on  this  subject,  see  Mr.  Homer's  Anniversary  Address  to  the  Geological 
Society  of  London,  February,  1846.  Consult  also  Sir  H.  de  la  Beche,  on  the  for- 
mation of  rocks  in  South  Wales,  Memoirs  of  Geol.  Survey  of  Great  Britain,  1846, 
p.  1  to  296. 


92  CAUSES   OF   CHANGE  OF   CLIMATE.  fCn.  VII. 


CHAPTER   VII. 

FARTHER    EXAMINATION    OF    THE    QUESTION    AS  TO  THE  ASSUMED  DISCORD- 
ANCE   OF    THE    ANCIENT    AND    MODERN    CAUSES    OF    CHANGE. 

On  the  causes  of  vicissitudes  in  climate — Remarks  on  the  present  diffusion  of  heat 
over  the  globe — On  the  dependence  of  the  mean  temperature  on  the  relative 
position  of  land  and  sea — Isothermal  Lines — Currents  from  equatorial  regions — 
Drifting  of  icebergs — Different  temperature  of  Northern  and  Southern  hemi- 
spheres— Combination  of  causes  which  might  produce  the  extreme  cold  of  which 
the  earth's  surface  is  susceptible — Conditions  necessary  for  the  production  of 
the  extreme  of  heat,  and  its  probable  effects  on  organic  life. 

Causes  of  Vicissitudes  in  Climate* — As  the  proofs  enumerated  in  the 
last  chapter  indicate  that  the  earth's  surface  has  experienced  great  changes 
of  climate  since  the  deposition  of  the  older  sedimentary  strata,  we  have 
next  to  inquire  how  such  vicissitudes  can  be  reconciled  with  the  existing 
order  of  nature.  The  cosmogonist  has  availed  himself  of  this,  as  of  every 
obscure  problem  in  geology,  to  confirm  his  views  concerning  a  period 
when  the  planet  was  in  a  nascent  or  half-formed  state,  or  when  the  laws 
of  the  animate  and  inanimate  world  differed  essentially  from  those  now 
established  ;  and  he  has  in  this,  as  in  many  other  cases,  succeeded  so  far, 
as  to  divert  attention  from  that  class  of  facts  which,  if  fully  understood, 
might  probably  lead  to  an  explanation  of  the  phenomena.  At  first  it  was 
imagined  that  the  earth's  axis  had  been  for  ages  perpendicular  to  the 
plane  of  the  ecliptic,  so  that  there  was  a  perpetual  equinox,  and  unifor- 
mity of  seasons  throughout  the  year ; — that  the  planet  enjoyed  this 
"  paradisiacal"  state  until  the  era  of  the  great  flood ;  but  in  that  catas- 
trophe, whether  by  the  shock  of  a  comet,  or  some  other  convulsion,  it 
lost  its  equal  poise,  and  hence  the  obliquity  of  its  axis,  and  with  that  the 
varied  seasons  of  the  temperate  zone,  and  the  long  nights  and  days  of 
the  polar  circles. 

When  the  progress  of  astronomical  science  had  exploded  this  theory, 
it  was  assumed,  that  the  earth  at  its  creation  was  in  a  state  of  fluidity, 
and  red-hot,  and  that  ever  since  that  era,  it  had  been  cooling  down,  con- 
tracting its  dimensions,  and  acquiring  a  solid  crust, — an  hypothesis  hardly 
less  arbitrary,  yet  more  calculated  for  lasting  popularity  ;  because,  by  re- 
ferring the  mind  directly  to  the  beginning  of  things,  it  requires  no  sup- 
port from  observation,  nor  from  any  ulterior  hypothesis.  But  if,  instead 

*  The  theory  proposed  in  this  and  the  following  chapters,  to  account  for  former 
fluctuations  of  climate  at  successive  geological  periods,  agrees  in  every  essential 
particular,  and  has  indeed  been  reprinted  almost  verbatim  from  that  published  by 
me  twenty  years  ago  in  the  first  edition  of  my  Principles,  1830.  It  was  referred  to 
by  Sir  John  F.  W.  Herschel  in  his  Discourse  on  Natural  Philosophy,  published  in 
1830.  In  preceding  works  the  gradual  diminution  of  the  earth's  central  heat  was 
almost  the  only  cause  assigned  for  the  acknowledged  diminution  of  the  superficial 
temperature  of  our  planet, 


CH.  VII.]          LAWS   GOVERNING   THE   DIFFUSION    OF   HEAT.  93 

of  forming  vague  conjectures  as  to  what  might  have  been  the  state  of 
the  planet  at  the  era  of  its  creation,  we  fix  our  thoughts  on  the  connection 
at  present  existing  between  climate  and  the  distribution  of  land  and  sea ; 
and  then  consider  what  influence  former  fluctuations  in  the  physical 
geography  of  the  earth  must  have  had  on  superficial  temperature,  we  may 
perhaps  approximate  to  a  true  theory.  If  doubts  and  obscurities  still 
remain,  they  should  be  ascribed  to  our  limited  acquaintance  with  the 
laws  of  Nature,  not  to  revolutions  in  her  economy ; — they  should  stim- 
ulate us  to  farther  research,  not  tempt  us  to  indulge  our  fancies  respect- 
ing the  imaginary  changes  of  internal  temperature  in  an  embryo  world. 

Diffusion  of  Heat  over  the  Globe. — In  considering  the  laws  which  reg- 
ulate the  diffusion  of  heat  over  the  globe,  we  must  be  careful,  as  Hum- 
boldt  well  remarks,  not  to  regard  the  climate  of  Europe  as  a  type  of  the 
temperature  which  all  countries  placed  under  the  same  latitude  enjoy. 
The  physical  sciences,  observes  this  philosopher,  always  bear  the  impress 
of  the  places  where  they  began  to  be  cultivated ;  and  as,  in  geology,  an 
attempt  was  at  first  made  to  refer  all  the  volcanic  phenomena  to  those 
of  the  volcanoes  in  Italy,  so  in  meteorology,  a  small  part  of  the  old  world, 
the  centre  of  the  primitive  civilization  of  Europe,  was  for  a  long  time 
considered  a  type  to  which  the  climate  of  all  corresponding  latitudes 
might  be  referred.  But  this  region,  constituting  only  one-seventh  of  the 
whole  globe,  proved  eventually  to  be  the  exception  to  the  general  rule. 
For  the  same  reason,  we  may  warn  the  geologist  to  be  on  his  guard,  and 
not  hastily  to  assume  that  the  temperature  of  the  earth  in  the  present 
era  is  a  type  of  that  which  most  usually  obtains,  since  he  contemplates 
far  mightier  alterations  in  the  position  of  land  and  sea,  at  different  epochs, 
than  those  which  now  cause  the  climate  of  Europe  to  differ  from  that  of 
other  countries  in  the  same  parallels. 

It  is  now  well  ascertained  that  zones  of  equal  warmth,  both  in  the 
atmosphere  and  in  the  waters  of  the  ocean,  are  neither  parallel  to  the 
equator  nor  to  each  other.*  It  is  also  known  that  the  mean  annual 
temperature  may  be  the  same  in  two  places  which  enjoy  very  different 
climates,  for  the  seasons  may  be  nearly  uniform,  or  violently  contrasted, 
so  that  the  lines  of  equal  winter  temperature  do  not  coincide  with  those 
of  equal  annual  heat  or  isothermal  lines.  The  deviations  of  all  these 
lines  from  the  same  parallel  of  latitude  are  determined  by  a  multitude 
of  circumstances,  among  the  principal  of  which  are  the  position,  direc- 

*  We  are  indebted  to  Baron  Alex,  von  Humboldt  for  having  first  collected  to- 
gether the  scattered  data  on  which  he  founded  an  approximation  to  a  true  theory 
of  the  distribution  of  heat  over  the  globe.  Many  of  these  data  were  derived  from 
the  author's  own  observations,  and  many  from  the  works  of  M.  Pierre  Prevost,  of 
Geneva,  on  the  radiation  of  heat,  and  from  other  writers. — See  Humboldt  on  Iso- 
thermal Lines,  Memoires  d'Arcueil,  torn.  iii.  translated  in  the  Edin.  Phil.  Journ. 
vol.  iii.  July,  1820. 

The  map  of  Isothermal  Lines,  recently  published  by  Humboldt  and  Dove  (1848), 
supplies  a  large  body  of  well-established  data  for  such  investigations,  of  which  Mr. 
Hopkins  has  most  ably  availed  himself  in  an  essay  "  On  the  Causes  which  may  have 
produced  Changes  in  the  earth's  Superficial  Temperature." — Q.  Journ.  Geol.  Soc. 
1852,  p.  56. 


94  CAUSES   OF   CHANGE   OF   CLIMATE.  [Ca  VII 

tion,  and  elevation  of  the  continents  and  islands,  the  position  and  depths 
of  the  sea,  and  the  direction  of  currents  and  of  winds. 

On  comparing  the  two  continents  of  Europe  and  America,  it  is  found 
that  places  in  the  same  latitudes  have  sometimes  a  mean  difference  of 
temperature  amounting  to  11°,  or  even  in  a  few  cases  to  17°  Fahr. ;  and 
some  places  on  the  two  continents,  which  have  the  same  mean  tempera- 
ture, differ  from  7°  to  17°  in  latitude.  Thus,  Cumberland  House,  in 
North  America,  having  the  same  latitude  (54°  N.)  as  the  city  of  York 
in  England,  stands  on  the  isothermal  line  of  32°,  which  in  Europe  rises 
to  the  North  Cape,  in  lat.  71°,  but  its  summer  heat  exceeds  that  of 
Brussels  or  Paris.*  The  principal  cause  of  greater  intensity  of  cold  in 
corresponding  latitudes  of  North  America,  as  Contrasted  with  Europe, 
is  the  connection  of  America  with  the  polar  circle,  by  a  large  tract  of 
land,  some  of  which  is  from  three  to  five  thousand  feet  in  height ;  and, 
on  the  other  hand,  the  separation  of  Europe  from  the  arctic  circle  by  an 
ocean.  The  ocean  has  a  tendency  to  preserve  everywhere  a  mean  tem- 
perature, which  it  communicates  to  the  contiguous  land,  so  that  it  tem- 
pers the  climate,  moderating  alike  an  excess  of  heat  or  cold.  The  eleva- 
ted land,  on  the  other  hand,  rising  to  the  colder  regions  of  the  atmo- 
sphere, becomes  a  great  reservoir  of  ice  and  snow,  arrests,  condenses, 
and  congeals  vapor,  and  communicates  its  cold  to  the  adjoining  country. 
For  this  reason,  Greenland,  forming  part  of  a  continent  which  stretches 
northward  to  the  82d  degree  of  latitude,  experiences  under  the  60th 
parallel  a  more  rigorous  climate  than  Lapland  under  the  72d  parallel. 

But  if  land  be  situated  between  the  40th  parallel  and  the  equator,  it 
produces,  unless  it  be  of  extreme  height,  exactly  the  opposite  effect ; 
for  it  then  warms  the  tracts  of  land  or  sea  that  intervene  between  it  and 
the  polar  circle.  For  the  surface  being  in  this  case  exposed  to  the  ver- 
tical, or  nearly  vertical  rays  of  the  sun,  absorbs  a  large  quantity  of  heat, 
which  it  diffuses  by  radiation  into  the  atmosphere.  For  this  reason,  the 
western  parts  of  the  old  continent  derive  warmth  from  Africa,  "  which, 
like  an  immense  furnace,  distributes  its  heat  to  Arabia,  to  Turkey  in 
Asia,  and  to  Europe,  "f  On  the  contrary,  the  northeastern  extremity 
of  Asia  experiences  in  the  same  latitude  extreme  cold ;  for  it  has  land 
on  the  north  between  the  60th  and  70th  parallel,  while  to  the  south  it 
is  separated  from  the  equator  by  the  Pacific  Ocean. 

In  consequence  of  the  more  equal  temperature  of  the  waters  of  the 
ocean,  the  climate  of  islands  and  of  coasts  differs  essentially  from  that 
of  the  interior  of  continents,  the  more  maritime  climate  being  charac- 
terized by  mild  winters,  and  more  temperate  summers ;  for  the  sea-breezes 
moderate  the  cold  of  winter,  as  well  as  the  heat  of  summer.  When, 
therefore,  we  trace  round  the  globe  those  belts  in  which  the  mean  annual 
temperature  is  the  same,  we  often  find  great  differences  in  climate  ;  for 
there  are  insular  climates  in  which  the  seasons  are  nearly  equalized,  and 

*  Sir  J.  Richardson's  Appendix  to  Sir  G.  Bach's  Journal,  1843 — 1845,  p.  478. 
f  Malte-Brun,  Phys.  Geol.  book  xvil 


CH.  VII.]  EFFECTS   OF   GULF   STREAM.  95 

excessive  climates,  as  they  have  been  termed,  where  the  temperature  of 
winter  and  surryner  is  strongly  contrasted.  The  whole  of  Europe,  com- 
pared with  the  eastern  parts  of  America  and  Asia,  has  an  insular  climate. 
The  northern  part  of  China,  and  the  Atlantic  region  of  the  United  States, 
exhibit  "excessive  climates."  We  find  at  New  York,  says  Humboldt, 
the  summer  of  Rome  and  the  winter  of  Copenhagen  ;  at  Quebec,  the 
summer  of  Paris  and  the  winter  of  Petersburg.  At  Pekin,  in  China, 
where  the  mean  temperature  of  the  year  is  that  of  the  coasts  of  Brittany, 
the  scorching  heats  of  summer  are  greater  than  at  Cairo,  and  the  win- 
ters as  rigorous  as  at  Upsala.* 

If  lines  be  drawn  round  the  globe  through  all  those  places  which 
have  the  same  winter  temperature,  they  are  found  to  deviate  from  the 
terrestrial  parallels  much  farther  than  the  lines  of  equal  mean  annual 
heat.  The  lines  of  equal  winter  in  Europe,  for  example,  are  often 
curved  so  as  to  reach  parallels  of  latitude  9°  or  10°  distant  from  each 
other,  whereas  the  isothermal  lines,  or  those  passing  through  places 
having  the  same  mean  annual  temperature,  differ  only  from  4°  to  5° 
in  Europe. 

Influence  of  currents  and  drift  ice  on  temperature. — Among  other  in- 
fluential causes,  both  of  remarkable  diversity  in  the  mean  annual  heat, 
and  of  unequal  division  of  heat  in  the  different  seasons,  are  the  direc- 
tion of  currents  and  the  accumulation  and  drifting  of  ice  in  high  lati- 
tudes. The  temperature  of  the  Lagullas  current  is  10°  or  12°  Fahr. 
above  that  of  the  sea  at  the  Cape  of  Good  Hope ;  for  it  derives  the 
greater  part  of  its  waters  from  the  Mozambique  channel,  and  south- 
east coast  of  Africa,  and  from  regions  in  the  Indian  Ocean  much  nearer 
the  line,  and  much  hotter  than  the  Cape.f  An  opposite  effect  is  pro- 
duced by  the  "  equatorial"  current,  which  crosses  the  Atlantic  from 
Africa  to  Brazil,  having  a  breadth  varying  from  160  to  450  nautical 
miles.  Its  waters  are  cooler  by  3°  or  4°  Fahr.  than  those  of  the  ocean 
under  the  line,  so  that  it  moderates  the  heat  of  the  tropics.]; 

But  the  effects  of  the  Gulf  stream  on  the  climate  of  the  North  At- 
lantic Ocean  are  far  more  remarkable.  This  most  powerful  of  known 
currents  has  its  source  in  the  Gulf  or  Sea  of  Mexico,  which,  like  the 
Mediterranean  and  other  close  seas  in  temperate  or  low  latitudes,  is 
warmer  than  the  open  ocean  in  the  same  parallels.  The  temperature 
of  the  Mexican  sea  in  summer  is,  according  to  Rennell,  86°  Fahr.,  or  at 
least  7°  above  that  of  the  Atlantic  in  the  same  latitude.§  From  this 
great  reservoir  or  caldron  of  warm  water,  a  constant  current  pours 
forth  through  the  straits  of  Bahama  at  the  rate  of  3  or  4  miles  an  hour ; 
it  crosses  the  ocean  in  a  northeasterly  direction,  skirting  the  great 
bank  of  Newfoundland,  where  it  still  retains  a  temperature  of  8°  above 
that  of  the  surrounding  sea.  It  reaches  the  Azores  in  about  78  days, 
after  flowing  nearly  3000  geographical  miles,  and  from  thence  it  some- 

*  On  Isothermal  Lines,  <fec.         f  Rennell  on  Current?,  p.  96.     London,  1832. 
t  Ibid.  p.  153.  §  Ibid.  p.  25. 


96  INFLUENCE   OF  CURRENTS   ON   TEMPERATURE.        [Cn.  VII. 

times  extends  its  course  a  thousand  miles  farther,  so  as  to  reach  the 
Bay  of  Biscay,  still  retaining  an  excess  of  5°  above  the*  mean  tempera- 
ture of  that  sea.  As  it  has  been  known  to  arrive  there  in  the  months 
of  November  and  January,  it  may  tend  greatly  to  moderate  the  cold 
of  winter  in  countries  on  the  west  of  Europe. 

There  is  a  large  tract  in  the  centre  of  the  North  Atlantic,  between 
the  parallels  of  33°  and  45°  N".  lat.,  which  Rennell  calls  the  "  recipient 
of  the  gulf  water."  A  great  part  of  it  is  covered  by  the  weed  called 
sargasso  (Sargassum  bacciferum),  which  the  current  floats  in  abundance 
from  the  Gulf  of  Mexico.  This  mass  of  water  is  nearly  stagnant,  is 
warmer  by  7°  or  10°  than  the  waters  of  the  Atlantic,  and  may  be  com- 
pared to  the  fresh  water  of  a  river  overflowing  the  heavier  salt  water 
of  the  sea.  Rennell  estimates  the  area  of  the  "recipient,"  together 
with  that  covered  by  the  main  current,  as  being  2000  miles  in  length 
from  E.  to  W.,  and  350  in  breadth  from  N.  to  S.,  which,  he  remarks, 
is  a  larger  area  than  that  of  the  Mediterranean.  The  heat  of  this  great 
body  of  water  is  kept  up  by  the  incessant  and  quick  arrivals  of  fresh 
supplies  of  warm  water  from  the  south  ;  and  there  can  be  no  doubt 
that  the  general  climate  of  parts  of  Europe  and  America  is  materially 
affected  by  this  cause. 

It  is  considered  probable  by  Scoresby  that  the  influence  of  the  Gulf 
stream  extends  even  to  the  sea  near  Spitzbergen,  where  its  waters  may 
pass  under  those  of  melted  ice ;  for  it  has  been  found  that  in  the  neigh- 
borhood of  Spitzbergen,  the  water  is  warmer  by  6°  or  7°  at  the  depth 
of  one  hundred  and  two  hundred  fathoms  than  at  the  surface.  This 
might  arise  from  the  known  law  that  fresh  water  passes  the  point  of 
greatest  density  when  cooled  down  below  40°,  and  between  that  and 
the  freezing  point  expands  again.  The  water  of  melted  ice  might  be 
lighter,  both  as  being  fresh  (having  lost  its  salt  in  the  decomposing 
process  of  freezing),  and  because  its  temperature  is  nearer  the  freezing 
point  than  the  inferior  water  of  the  Gulf  stream. 

The  great  glaciers  generated  in  the  valleys  of  Spitzbergen,  in  the  79° 
of  north  latitude,  are  almost  all  cut  off  at  the  beach,  being  melted  by 
the  feeble  remnant  of  heat  still  retained  by  the  Gulf  stream.  In 
Baffin's  Bay,  on  the  contrary,  on  the  west  coast  of  Old  Greenland, 
where  the  temperature  of  the  sea  is  not  mitigated  by  the  same  cause, 
and  where  there  is  no  warmer  under-current,  the  glaciers  s-tretch  out 
from  the  shore,  and  furnish  repeated  crops  of  mountainous  masses  of 
ice  which  float  off  into  the  ocean.*  The  number  and  dimensions  of 
these  bergs  is  prodigious.  Captain  Sir  John  Ross  saw  several  of  them 
together  in  Baffin's  Bay  aground  in  water  fifteen  hundred  feet  deep ! 
Many  of  them  are  driven  down  into  Hudson's  Bay,  and  accumulating 
there,  diffuse  excessive  cold  over  the  neighboring  continent ;  so  that 
Captain  Franklin  reports,  that  at  the  mouth  of  Hayes'  River,  which 

*  Scoresby's  Arctic  Regions,  vol.  i.  p.  208. — Dr.  Latta's  Observations  on  the 
Glaciers  of  Spitzbergen,  <fcc.  Edin.  New  Phil.  Journ.  vol.  iii.  p.  97. 


CH.  VII.]  DIFFERENCE    OF   CLIMATE.  97 

lies  in  the  same  latitude  as  the  north  of  Prussia  or  the  south  of  Scot- 
land,  ice  is  found  everywhere  in  digging  wells,  in  summer,  at  the  depth 
of  four  feet !  Other  bergs  have  been  occasionally  met  with,  at  mid- 
summer, in  a  state  of  rapid  thaw,  as  far  south  as  lat.  40°  and  longitude 
about  60°  west,  where  they  cool  the  water  sensibly  to  the  distance  of 
forty  or  fifty  miles  around,  the  thermometer  sinking  sometimes  17°,  or 
even  18°,  Fahrenheit,  in  their  neighborhood.*  It  is  a  well-known  fact 
that  every  four  or  five  years  a  large  number  of  icebergs,  floating  from 
Greenland,  double  Cape  Langaness,  and  are  stranded  on  the  west  coast 
of  Iceland.  The  inhabitants  are  then  aware  that  their  crops  of  hay 
will  fail,  in  consequence  of  fogs  which  are  generated  almost  incessantly ; 
and  the  dearth  of  food  is  not  confined  to  the  land,  for  the  temperature 
of  the  water  is  so  changed  that  the  fish  entirely  desert  the  coast. 

Difference  of  climate  of  the  Northern  and  Southern  hemispheres. — 
When  we  compare  the  climate  of  the  northern  and  southern  hemispheres, 
we  obtain  still  more  instruction  in  regard  to  the  influence  of  the  distri- 
bution of  land  and  sea  on  climate.  The  dry  land  in  the  southern  hemi- 
sphere is  to  that  of  the  northern  in  the  ratio  only  of  one  to  three,  ex- 
cluding from  our  consideration  that  part  which  lies  between  the  pole  and 
the  78°  of  south  latitude,  which  has  hitherto  proved  inaccessible.  And 
whereas  in  the  northern  hemisphere,  between  the  pole  and  the  thirtieth 
parallel  of  north  latitude,  the  land  and  sea  occupy  nearly  equal  areas, 
the  ocean  in  the  southern  hemisphere  covers  no  less  than  fifteen  parts 
in  sixteen  of  the  entire  space  included  between  the  antarctic  circle  and 
the  thirtieth  parallel  of  south  latitude. 

This  great  extent  of  sea  gives  a  particular  character  to  climates  south 
of  the  equator,  the  winters  being  mild  and  the  summers  cool.  Thus,  in 
Van  Dieman's  Land,  corresponding  nearly  in  latitude  to  Rome,  the 
winters  are  more  mild  than  at  Naples,  and  the  summers  not  warmer  than 
those  at  Paris,  which  is  7°  farther  from  the  equator,  f  The  effects  on 
animal  and  vegetable  life  are  remarkable.  Capt.  King  observed  large 
shrubs  of  Fuchsia  and  Veronica,  which  in  England  are  treated  as  tender 
plants,  thriving  and  in  full  flower  in  Tierra  del  Fuego  with  the  tempera- 
ture at  36°.  He  states  also  that  humming  birds  were  seen  sipping  the 
sweets  of  the  flowers  "  after  two  or  three  days  of  constant  rain,  snow, 
and  sleet,  during  which  time  the  thermometer  had  been  at  the  freezing 
point."  Mr.  Darwin  also  saw  parrots  feeding  on  the  seeds  of  a  tree 
called  the  winter's  bark,  south  of  la.t.  55°,  near  Cape  Horn.J 

So  the  orchideous  plants  which  are  parasitical  on  trees,  and  are  gen- 
erally characteristic  of  the  tropics,  advance  to  the  38th  and  42d  degree 
of  S.  lat.,  and  even  beyond  the  45th  degree  in  New  Zealand,  where 
they  were  found  by  Forster.  In  South  America  also  arborescent  grasses 
abound  in  the  dense  forests  of  Chiloe,  in  lat.  42°  S.,  where  "they  en- 
twine the  trees  into  one  entangled  mass  to  the  height  of  thirty  or  forty 

*  Rennell  on  Currents,  p.  95.  f  Humboldt  on  Isothermal  Linea 

\  Journ.  of  Travels  in  S.  America,  <fcc.  p.  272. 

7 


98  DIFFERENCE   OF   CLIMATE   IN   NORTHERN  [Cn.  VII. 

feet  above  the  ground.  Palm-trees  in  the  same  quarter  of  the  globe 
grow  in  lat.  37°,  an  arborescent  grass  very  like  a  bamboo  in  40°,  and 
another  closely  allied  kind,  of  great  length,  but  not  erect,  even  as  far 
south  as  45°."* 

It  has  long  been  supposed  that  the  general  temperature  of  the  southern 
hemisphere  was  considerably  lower  than  that  of  the  northern,  and  that 
the  difference  amounted  to  at  least  10°  Fahrenheit.  Baron  Humboldt, 
after  collecting  and  comparing  a  great  number  of  observations,  came  to 
the  conclusion  that  even  a  much  larger  difference  existed,  but  that  none 
was  to  be  observed  within  the  tropics,  and  only  a  small  difference  as  far 
as  the  thirty-fifth  and  fortieth  parallel.  Captain  Cook  was  of  opinion 
that  the  ice  of  the  antarctic  predominated  greatly  over  that  of  the  arctic 
region,  that  encircling  the  southern  pole  coming  nearer  to  the  equator 
by  10°  than  the  ice  around  the  north  pole.  All  the  recent  voyages  of 
discovery  have  tended  to  confirm  this  opinion,  although  Capt.  Weddel 
penetrated,  in  1823,  three  degrees  farther  south  than  Capt.  Cook,  reach- 
ing lat.  74°  15'  South,  long.  34°  17'  West,  and  Sir  James  Ross,  in  1842, 
arrived  at  lat.  78°  10'  S.,  as  high  a  latitude,  within  three  degrees,  as 
the  farthest  point  attained  by  Captain  Parry  in  the  arctic  circle,  or  lat. 
81°  12'  North. 

The  description  given  by  ancient  as  well  as  modern  navigators  of  the 
sea  and  land  in  high  southern  latitudes,  clearly  attests  the  greater  se- 
verity of  the  climate  as  compared  to  arctic  regions.  In  Sandwich  Land, 
in  lat.  59°  S.,  or  in  nearly  the  same  parallel  as  the  north  of  Scotland, 
Capt.  Cook  found  the  whole  country,  from  the  summits  of  the  mountains 
down  to  the  very  brink  of  the  sea-cliffs,  "  covered  many  fathoms  thick 
with  everlasting  snow,"  and  this  on  the  1st  of  February,  the  hottest  time 
of  the  year ;  and  what  is  still  more  astonishing,  in  the  island  of  S.  Georgia, 
which  is  in  the  54°  south  latitude,  or  the  same  parallel  as  Yorkshire,  the 
line  of  perpetual  snow  descends  to  the  level  of  the  ocean. f  When  we 
consider  this  fact,  and  then  recollect  that  the  highest  mountains  in  Scot- 
land, which  ascend  to  an  elevation  of  nearly  5000  feet,  and  are  four  de- 
grees farther  to  the  north,  do  not  attain  the  limit  of  perpetual  snow  on 
our  side  of  the  equator,  we  learn  that  latitude  is  one  only  of  many  pow- 
erful causes,  which  determine  the  climate  of  particular  regions  of  the 
globe.  Capt.  Sir  James  Ross,  in  his  exploring  expedition  in  1841-3, 
found  that  the  temperature  south  of  the  60th  degree  of  latitude  seldom 
rose  above  32°  Fahr.  During  the  two  summer  months  of  the  year  1841 
(January  and  February)  the  range  of  the  thermometer  was  between  11° 
and  32°  Fahr. ;  and  scarcely  once  rose  above  the  freezing  point.  The 
permanence  of  snow  in  the  southern  hemisphere,  is  in  this  instance  partly 
due  to  the  floating  ice,  which  chills  the  atmosphere  and  condenses  the 

*  Darwin's  travels  in  S.  America,  p.  271. 

\  Mr.  Hopkins  raises  the  question  whether,  in  South  Georgia,  the  descent  of 
glaciers  to  the  margin  of  the  sea  might  noj  have  been  mistaken  by  Capt.  Cook  for 
the  descent  of  the  snow-line  to  the  sea*  level.  Quart.  Journ.  Geol.  Soc.  p.  85, 
1852.  The  great  navigator  is  generally  very,  accurate,  and  there  seem  to  be  no 
observations  of  more  recent  date  either  to  confirm  or  invalidate  his  statements. 


Cu.  VIL]  AND    SOUTHERN    HEMISPHERES.  99 

vapor,  so  that  in  summer  the  sun  cannot  pierce  through  the  foggy  air. 
But  besides  the  abundance  of  ice  which  covers  the  sea  to  the  south  of 
Georgia  and  Sandwich  Land,  we  may  also,  as  Humboldt  suggests,  as- 
cribe the  cold  of  those  countries  in  part  to  the  absence  of  land  between 
them  and  the  tropics. 

If  Africa  and  New  Holland  extended  farther  to  the  south,  a  diminu- 
tion of  ice  would  take  place  in  consequence  of  the  radiation  of  heat  from 
these  continents  during  summer,  which  would  warm  the  contiguous  sea 
and  rarefy  the  air.  The  heated  aerial  currents  would  then  ascend  and 
flow  more  rapidly  towards  the  south  pole,  and  moderate  the  winter. 
In  confirmation  of  these  views,  it  is  stated  that  the  ice,  which  extends  as 
far  as  the  68°  and  71°  of  south  latitude,  advances  more  towards  the 
equator  whenever  it  meets  an  open  sea  ;  that  is,  where  the  extremities 
of  the  present  continents  are  not  opposite  to  it ;  and  this  circumstance 
seems  explicable  only  on  the  principle  above  alluded  to,  of  the  radiation 
of  heat  from  the  lands  so  situated. 

The  cold  of  the  antarctic  regions  was  conjectured  by  Cook  to  be  due 
to  the  existence  of  a  large  tract  of  land  between  the  seventieth  degree 
of  south  latitude  and  the  pole.  The  justness  of  these  and  other  specu- 
lations of  that  great  navigator  have  since  been  singularly  confirmed  by 
the  investigation  made  by  Sir  James  Ross  in  1841.  He  found  Victoria 
Land,  extending  from  71°  to  79°  S.  latitude,  skirted  by  a  great  bar- 
rier of  ice,  the  height  of  the  land  ranging  from  4000  to  14,000  feet, 
the  whole  entirely  covered  with  snow,  except  a  narrow  ring  of  black 
earth  surrounding  the  huge  crater  of  the  active  volcano  of  Mount 
Erebus,  rising  12,400  feet  above  the  level  of  the  sea.  The  position  of 
a  mountainous  territory  of  such  altitude,  so  near  the  pole,  and  so  ob- 
vious a  source  of  intense  cold,  fully  explains  why  Graham's  and  Ender- 
by's  Land,  discovered  by  Captain  Biscoe  in  1831-2  (between  lat.  64°  and 
68°  S.),  presented  a  most  wintry  aspect,  covered  even  in  summer  with 
ice  and  snow,  and  nearly  destitute  of  animal  life.  In  corresponding 
latitudes  of  the  northern  hemisphere  we  not  only  meet  with  herds  of 
wild  herbivorous  animals,  but  with  land  which  man  himself  inhabits, 
and  where  he  has  even  built  ports  and  inland  villages.* 

The  distance  to  which  icebergs  float  from  the  polar  regions  On  the 
opposite  sides  of  the  line  is,  as  might  have  been  anticipated,  very  differ- 
ent. Their  extreme  limit  in  the  northern  hemisphere  is  lat.  40°,  as 
before  mentioned,  and  they  are  occasionally  seen  in  lat.  42°  N.,  near 
the  termination  of  the  great  bank  of  Newfoundland,  and  at  the  Azores, 
lat.  42°  N.,  to  which  they  are  sometimes  drifted  from  Baffin's  Bay. 
But  in  the  other  hemisphere  they  have  been  seen,  within  the  last  few 
years,  at  different  points  off  the  Cape  of  Good  Hope,  between  lat. 

*  After  all  these  modern  discoveries,  the  area  still  unexplored,  within  the  an- 
tarctic circle,  is  more  than  double  the  area  of  Europe.  The  surface  of  the  latter 
contains  about  2,793,000  square  geographical  miles.  The  unexplored  antarctic  re- 
gion, as  calculated  for  me  by  Mr.  Gardner,  in  1840,  equalled  about  7,620,000 
square  miles. 


100  DIFFERENCE   OF   CLIMATE   IN   NORTHERN  [Cn.  VII. 

Fig.  2. 


Iceberg  seen  off  the  Cape  of  Good  Hope,  April,  1829. 
Lat.  890  18'  S.    Long.  48°  46'  E. 

36°  and  39°.*  One  of  these  (see  fig.  2)  was  two  miles  in  circumfer- 
ence, and  150  feet  high,  appearing  like  chalk  when  the  sun  was  ob- 
scured, and  having  the  lustre  of  refined  sugar  when  the  sun  was  shining 
on  it.  Others  rose  from  250  to  300  feet  above  the  level  of  the  sea,  and 
were  therefore  of  great  volume  below ;  since  it  is  ascertained  by  experi- 
ments on  the  buoyancy  of  ice  floating  in  sea-water,  that  for  every  cubic 
foot  seen  above,  there  must  at  least  be  eight  cubic  feet  below  water.f 
If  ice  islands  from  the  north  polar  regions  floated  as  far,  they  might 
reach  Cape  St.  Vincent,  and  there,  being  drawn  by  the  current  that 
always  sets  in  from  the  Atlantic  through  the  Straits  of  Gibraltar,  be 
drifted  into  the  Mediterranean,  so  that  the  serene  sky  of  that  delightful 
region  might  soon  be  deformed  by  clouds  and  mists. 

Before  the  amount  of  difference  between  the  temperature  of  the  two 
hemispheres  was  ascertained,  it  was  referred  by  many  astronomers  to 
the  precession  of  the  equinoxes,  or  the  acceleration  of  the  earth's  mo- 
tion in  its  perihelium ;  in  consequence  of  which  the  spring  and  summer 
of  the  southern  hemisphere  are  now  shorter,  by  nearly  eight  days,  than 
those  seasons  north  of  the  equator.  But  Sir  J.  Herschel  reminds  us 
that  the  excess  of  eight  days  in  the  duration  of  the  sun's  presence  in 
the  northern  hemisphere  is  not  productive  of  an  excess  of  annual  light 
and  heat  ;  since,  according  to  the  laws  of  elliptic  motion,  it  is  demon- 
strable that  whatever  be  the  ellipticity  of  the  earth's  orbit,  the  two 
hemispheres  must  receive  equal  absolute  quantities  of  light  and  heat 
per  annum,  the  proximity  of  the  sun  in  perigee  exactly  compensating 
the  effect  of  its  swifter  motion. J  Humboldt,  however,  observes,  that 
there  must  be  a  greater  loss  of  heat  by  radiation  in  the  southern  hemi- 

*  On  icebergs  in  low  latitudes,  by  Capt.  Horsburgh,  by  whom  the  sketch  was 
made.  Phil.  Trans.  1830. 

f  Scoresby's  Arctic  Regions,  vol.  i.  p.  234. 

|  This  follows,  observes  Herschel,  from  a  very  simple  theorem,  which  may  be 
thus  stated : — "  The  amount  of  heat  received  by  the  earth  from  the  sun,  while  de- 
scribing any  part  of  its  orbit,  is  proportional  to  the  angle  described  round  the 
sun's  centre."  So  that  if  the  orbit  be  divided  into  two  portions  by  a  line  drawn 
in  any  direction  through  the  sun's  centre,  the  heat  received  in  describing  the  two 
unequal  segments  of  the  eclipse  so  produced  wvll  be  equal.  Geol.  Trans,  vol.  iii. 
part.  ii.  p.  298 ;  second  series. 


CH.  VIL]  AND   SOUTHERN   HEMISPHERES.  101 

sphere  during  a  winter  longer  by  eight  days  than  that  on  the  other  side 
of  the  equator.* 

Perhaps  no  very  sensible  effect  may  be  produced  by  this  source  of 
disturbance ;  yet  the  geologist  should  bear  in  mind  that  to  a  certain 
extent  it  operates  alternately  on  each  of  the  two  hemispheres  for  a 
period  of  upwards  of  10,000  years,  dividing  unequally  the  times  during 
which  the  annual  supply  of  solar  light  and  heat  is  received.  This 
cause  may  sometimes  tend  to  counterbalance  inequalities  of  temperature 
resulting  from  other  far  more  influential  circumstances ;  but,  on  the 
other  hand,  it  must  sometimes  tend  to  increase  the  extreme  of  deviation 
arising  from  particular  combinations  of  causes. 

But  whatever  may  be  at  present  the  inferiority  of  heat  in  the  temper- 
ate and  frigid  zones  south  of  the  line,  it  is  quite  evident  that  the  cold 
would  be  far  more  intense  if  there  happened,  instead  of  open  sea,  to  be 
tracts  of  elevated  land  between  the  55th  and  70th  parallel;  and,  on  the 
other  hand,  the  cold  would  be  moderated  if  there  were  more  land  be- 
tween the  line  and  the  forty-fifth  degree  of  south  latitude. 

Changes  in  the  position  of  land  and  sea  may  give  rise  to  vicissitudes 
in  climate. — Having  offered  these  brief  remarks  on  the  diffusion  of  heat 
over  the  globe  in  the  present  state  of  the  surface,  I  shall  now  proceed 
to  speculate  on  the  vicissitudes  of  climate,  which  must  attend  those 
endless  variations  in  the  geographical  features  of  our  planet  which  are 
contemplated  in  geology.  That  our  speculations  may  be  confined  with- 
in the  strict  limits  of  analogy,  I  shall  assume,  1st,  That  the  proportion 
of  dry  land  to  sea  continues  always  the  same.  2dly,  That  the  volume 
of  the  land  rising  above  the  level  of  the  sea  is  a  constant  quantity ;  and 
not  only  that  its  mean,  but  that  its  extreme  height,  is  liable  only  to 
trifling  variations.  3dly,  That  both  the  mean  and  extreme  depth  of 
the  sea  are  invariable ;  and  4thly,  It  may  be  consistent  with  due  cau- 
tion to  assume  that  the  grouping  together  of  the  land  in  continents  is  a 
necessary  part  of  the  economy  of  nature ;  for  it  is  possible  that  the 
laws  which  govern  the  subterranean  forces,  and  which  act  simulta- 
neously along  certain  lines,  cannot  but  produce,  at  every  epoch,  con- 
tinuous mountain-chains  ;  so  that  the  subdivision  of  the  whole  land  into 
innumerable  islands  may  be  precluded. 

If  it  be  objected,  that  the  maximum  of  elevation  of  land  and  depth 
of  sea  are  probably  not  constant,  nor  the  gathering  together  of  all  the 
land  in  certain  parts,  nor  even  perhaps  the  relative  extent  of  land 
and  water,  I  reply,  that  the  arguments  about  to  be  adduced  will  be 
strengthened  if,  in  these  peculiarities  of  the  surface,  there  be  consider- 
able deviations  from  the  present  type.  If,  for  example,  all  other  cir- 
cumstances being  the  same,  the  land  is  at  one  time  more  divided  into 
islands  than  at  another,  a  greater  uniformity  of  climate  might  be  pro- 
duced, the  mean  temperature  remaining  unaltered  ;  or  if,  at  another  era, 
there  were  mountains  higher  than  the  Himalaya,  these,  when  placed  in 

*  On  Isothermal  Lines. 


102  CAUSES   OF  [On.  VII. 

high  latitudes,  would  cause  a  greater  excess  of  cold.  Or,  if  we  suppose 
that  at  certain  periods  no  chain  of  hills  in  the  world  rose  beyond  the 
height  of  10,000  feet,  a  greater  heat  might  then  have  prevailed  than  is 
compatible  with  the  existence  of  mountains  thrice  that  elevation. 

However  constant  may  be  the  relative  proportion  of  sea  and  land,  we 
know  that  there  is  annually  some  small  variation  in  their  respective 
geographical  positions,  and  that  in  every  century  the  land  is  in  some 
parts  raised,  and  in  others  depressed  in  level,  and  so  likewise  is  the  bed 
of  the  sea.  By  these  and  other  ceaseless  changes,  the  configuration  of 
the  earth's  surface  has  been  remodelled  again  and  again,  since  it  was 
the  habitation  of  organic  beings,  and  the  bed  of  the  oceati  has  been 
lifted  up  to  the  height  of  some  of  the  loftiest  mountains.  The  imagina- 
tion is  apt  to  take  alarm  when  called  upon  to  admit  the  formation  of 
'such  irregularities  in  the  crust  of  the  earth,  after  it  had  once  become 
the  habitation  of  living. creatures ;  but,  if  time  be  allowed,  the  opera- 
tion need  not  subvert  the  ordinary  repose  of  nature  ;  and  the  result  is 
in  a  general  view  insignificant,  if  we  consider  how  slightly  the  highest 
mountain-chains  cause  our  globe  to  differ  from  a  perfect  sphere. 
Chimborazo,  though  it  rises  to  more  than  21,000  feet  above  the  sea, 
would  be  represented,  on  a  globe  of  about  six  feet  in  diameter,  by  a 
grain  of  sand  less  than  one-twentieth  of  an  inch  in  thickness. 

The  superficial  inequalities  of  the  earth,  then,  may  be  deemed  minute 
in  quantity,  and  their  distribution  at  any  particular  epoch  must  be  re- 
garded in  geology  as  temporary  peculiarities,  like  the  height  and  out- 
line of  the  cone  of  Vesuvius  in  the  interval  between  two  eruptions. 
But  although,  in  reference  to  the  magnitude  of  the  globe,  the  uneven- 
ness  of  the  surface  is  so  unimportant,  it  is  on  the  position  and  direction 
of  these  small  inequalities  that  the  state  of  the  atmosphere,  and  both 
the  local  and  general  climate,  are  mainly  dependent. 

Before  considering  the  effect  which  a  material  change  in  the  distribu- 
tion of  land  and  sea  must  occasion,  it  may  be  well  to  remark,  how 
greatly  organic  life  may  be  affected  by  those  minor  variations,  which 
need  not  in  the  least  degree  alter  the  general  temperature.  Thus,  for 
example,  if  we  suppose,  by  a  series  of  convulsions,  a  certain  part  of 
Greenland  to  become  sea,  and,  in  compensation,  a  tract  of  land  to  rise 
and  connect  Spitzbergen  with  Lapland, — an  accession  not  greater  in 
amount  than  one  which  the  geologist  can  prove  to  have  occurred  in  cer- 
tain districts  bordering  the  Mediterranean,  within  a  comparatively  mod- 
ern period, — this  altered  form  of  the  land  might  cause  an  interchange 
between  the  climate  of  certain  parts  of  North  America  and  of  Europe, 
which  lie  in  corresponding  latitudes.  Many  European  species  of  plants 
and  animals  would  probably  perish  in  consequence,  because  the  mean 
temperature  would  be  greatly  lowered  ;  and  others  would  fail  in  Amer- 
ica, because  it  would  there  be  raised.  On  the  other  hand,  in  places 
where  the  mean  annual  heat  remained  unaltered,  some  species  which 
flourish  in  Europe,  where  the  seasons  are  more  uniform,  would  be  una- 
ble to  resist  the  greater  heat  of  the  North  American  summer,  or  the 


CH.  VII.]  CHANGES    OF   TEMPERATURE.  103 

intenser  cold  of  the  winter ;  while  others,  now  fitted  by  their  habits  for 
the  great  contrast  of  the  American  seasons,  would  not  be  fitted  for  the 
insular  climate  of  Europe.  The  vine,  for  example,  according  to  Hum- 
boldt,  can  be  cultivated  with  advantage  10°  farther  north  in  Europe 
than  in  North  America.  Many  plants  endure  severe  frost,  but  cannot 
ripen  their  seeds  without  a  certain  intensity  of  summer  heat  and  a  cer- 
tain quantity  of  light ;  others  cannot  endure  a  similar  intensity  either  of 
heat  or  cold. 

It  is  now  established  that  many  of  the  existing  species  of  animals 
have  survived  great  changes  in  the  physical  geography  of  the  globe.  If 
such  species  be  termed  modern,  in  comparison  to  races  which  preceded 
them,  their  remains,  nevertheless,  enter  into  submarine  deposits  many 
hundred  miles  in  length,  and  which  have  since  been  raised  from  the  deep 
to  no  inconsiderable  altitude.  When,  therefore,  it  is  shown  that  changes 
in  the  temperature  of  the  atmosphere  may  be  the  consequence  of  such 
physical  revolutions  of  the  surface,  we  ought  no  longer  to  wonder  that 
we  find  the  distribution  of  existing  species  to  be  local,  in  regard  to  lon- 
gitude as  well  as  latitude.  If  all  species  were  now,  by  an  exertion  of 
creative  power,  to  be  diffused  uniformly  throughout  those  zones  where 
there  is  an  equal  degree  of  heat,  and  in  all  respects  a  similarity  of  cli- 
mate, they  would  begin  from  this  moment  to  depart  more  and  more  from 
their  original  distribution.  Aquatic  and  terrestrial  species  would  be  dis- 
placed, as  Hooke  long  ago  observed,  so  often  as  land  and  water  exchanged 
places  ;  and  there  would  also,  by  the  formation  of  new  mountains  and 
other  changes,  be  transpositions  of  climate,  contributing,  in  the  manner 
before  alluded  to,  to  the  local  extermination  of  species.* 

If  we  now  proceed  to  consider  the  circumstances  required  for  a  gen- 
eral change  of  temperature,  it  will  appear,  from  the  facts  and  principles 
already  laid  down,  that  whenever  a  greater  extent  of  high  land  is  col- 
lected in  the  polar  regions,  the  cold  will  augment ;  and  the  same  result 
will  be  produced  when  there  is  more  sea  between  or  near  the  tropics  ; 
while,  on  the  contrary,  so  often  as  the  above  conditions  are  reversed, 
the  heat  will  be  greater.  (See  figs.  5  and  6,  p.  111.)  If  this  be  admit- 
ted, it  will  follow,  that  unless  the  superficial  inequalities  of  the  earth  be 
fixed  and  permanent,  there  must  be  never-ending  fluctuations  in  the  mean 
temperature  of  every  zone  ;  and  that  the  climate  of  one  era  can  no  more 
be  a  type  of  every  other;  than  is  one  of  our  four  seasons  of  all  the  rest. 

It  has  been  well  said,  that  the  earth  is  covered  by  an  ocean,  in  the 
midst  of  which  are  two  great  islands,  and  many  smaller  ones ;  for  the 
whole  of  the  continents  and  islands  occupy  an  area  scarcely  exceeding 
one-fourth  of  the  whole  superficies  of  the  spheroid.  Now,  according  to 
this  analogy,  we  may  fairly  speculate  on  the  probability  that  there  would 
not  be  usually,  at  any  given  epoch  of  the  past,  more  than  about  one- 
fourth  dry  land  in  a  particular  region  ;  as,  for  example,  near  the  poles, 

*  A  full  consideration  of  the  effect  of  changes  in  physical  geography  on  the  dis- 
tribution and  extinction  of  species  is  given  in  book  iii. 


104  CAUSES   OF  [On.  VII. 

or  between  them  and  the  75th  parallels  of  N.  and  S.  latitude.  If,  there- 
fore, at  present  there  should  happen  to  be,  in  both  these  quarters  of  the 
globe,  much  more  than  this  average  proportion  of  land,  some  of  it  in  the 
arctic  region  being  above  five  thousand  feet  in  height,  and  if  in  antarctic 
latitudes  a  mountainous  country  has  been  found  varying  from  4000  to 
14,000  feet  in  height,  this  alone  affords  ground  for  concluding  that,  in 
the  present  state  of  things,  the  mean  heat  of  the  climate  is  below  that 
which  the  earth's  surface,  in  its  more  ordinary  state,  would  enjoy.  This 
presumption  is  heightened  when  we  reflect  on  the  results  of  the  recent 
soundings  made  by  Sir  James  Ross,  in  the  Southern  Ocean,  and  con- 
tinued for  four  successive  years,  eading  1844,  which  seem  to  prove  that 
the  mean  depth  of  the  Atlantic  and  Pacific  is  as  great  as  Laplace  and 
other  eminent  astronomers  had  imagined  ;*  for  then  we  might  look  not 
only  for  more  than  two-thirds  sea  in  the  frigid  zones,  but  for  water  of 
great  depth,  which  could  not  readily  be  reduced  to  the  freezing  point. 
The  same  opinion  is  confirmed,  when  we  compare  the  quantity  of  land 
lying  between  the  poles  and  the  30th  parallels  of  north  and  south  lati- 
tude, with  the  quantity  placed  between  those  parallels  and  the  equator ; 
for,  it  is  clear,  that  we  have  at  present  not  only  more  than  the  usual  de- 
gree of  cold  in  the  polar  regions,  but  also  less  than  the  average  quantity 
of  heat  within  the  tropics. 

*  For  calculations  founded  on  astronomical  data,  see  Young's  N"at.  Phil.,  Lect. 
xlvii.  ;  Mrs.  Somerville's  Connex.  of  Phys.  Sci.,  sect.  14,  p.  110.  Laplace,  endea- 
voring to  estimate  the  probable  depth  of  the  sea  from  some  of  the  phenomena  of 
the  tides,  says  of  the  ocean  generally,  "  que  sa  profondeur  moyenne  est  du  meme 
ordre  que  la  hauteur  moyenne  des  continens  et  des  isles  au-dessus  do  son  niveau, 
hauteur  qui  ne  surpasse  pas  mille  metres  (8280  ft.)"  Mec.  Celeste,  torn.  xi.  et 
Syst.  du  Monde,  p.  254.  The  expression  "  du  meme  ordre"  admits  in  mathemati- 
cal language  of  considerable  latitude  of  signification,  and  does  not  mean  that  the 
depth  of  the  water  below  the  level  of  the  sea  corresponds  exactly  to  the  height 
of  the  land  above  it. 

It  appeared  from  the  observations  of  Sir  James  Ross,  communicated  to  me  in 
1849,  by  himself,  and  his  fellow-voyager,  Dr.  Joseph  Hooker,  that  in  latitude  15° 
3'  S.,  longitude  23°  14'  W.  (the  island  of  Trinidad,  the  nearest  land,  being  486 
miles  distant,  and  bearing  S.  47  W.),  they  sounded  with  a  weight  of  76  Ibs.,  and 
4600  fathoms  of  line,  which  ran  out  to  the  very  end,  without  finding  bottom. 
Here  therefore  in  mid-ocean  the  depth  exceeded  27,600  feet.  One  of  the  shallow- 
est soundings  ever  obtained  in  the  open  sea  during  the  same  survey,  struck  bottom 
with  2677  fathoms,  or  16,062  feet,  latitude  33°  21'  S.,  longitude  9°  4'  E,  The 
surveyors  arrived  at  the  conclusion,  that  at  a  moderate  distance  from  the  shore, 
the  depth  of  the  great  ocean  always  exceeds  4000  feet. 

During  the  American  survey  in  1849,  a  much  greater  depth,  or  5700  fathoms 
(34,200  feet),  was  sounded  in  the  Atlantic  by  Lieut.  Walsh,  without  reaching  the 
bottom,  in  lat.  31°  59'  N.,  long.  58°  43'  W.,  or  between  the  Bermudas  and  the 
Azores.  But  the  deepest  soundings  yet  published  were  taken  Oct.  30th  1852,  by 
Capt.  Henry  M.  Denham,  R.  N.,  who  reached  bottom  at  7706  fathoms  (46,236  feet), 
lat.  36°  49'  S.,  long.  37°  6'  W.,  the  nearest  land  being  at  the  mouth  of  the  River 
Plate.  A  weight  of  9  Ibs.  was  attached  to  the  line,  which  was  one-tenth  of  an  inch  in 
diameter ;  the  day  was  calm,  and  the  line  took  9  hours  24  minutes  to  run  out. 
When  the  bottom  was  struck  the  line  was  raised  50  fathoms,  and  then  allowed 
to  run  out  again.  It  struck  at  the  same  point  as  before,  verifying  the  observa- 
tions. Nevertheless  some  experienced  surveyors  have  remarked  that  the  experi- 
ment would  have  been  more  satisfactory  had  the  weight  been  greater.  The  high- 
est summits  of  the  Himalaya  are  about  28,000  feet ;  the  Pacific,  according  to  this 
sounding,  is  probably  at  some  points  twice  as  deep  as  the  Himalaya  are  high. 


CH.  VII.]  CHANGES  OF  TEMPERATURE.  105 

Position  of  land  and  sea  which  might  produce  the'  extreme  of  cold  of 
which  the  earths  surface  is  susceptible. — To  simplify  our  view  of  the 
various  changes  in  climate,  which  different  combinations  of  geographical 
circumstances  may  produce,  we  shall  first  consider  the  conditions  neces- 
sary for  bringing  about  the  extreme  of  cold,  or  what  would  have  been 
termed  in  the  language  of  the  old  writers  the  winter  of  the  "  great 
year,"  or  geological  cycle,  and  afterwards,  the  conditions  requisite  to 
produce  the  maximum  of  heat,  or  the  summer  of  the  same  year. 

To  begin  with  the  northern  hemisphere.  Let  us  suppose  those  hills 
of  the  Italian  peninsula  and  of  Sicily,  which  are  of  comparatively  mod- 
ern origin,  and  contain  many  fossil  shells  identical  with  living  species,  to 
subside  again  into  the  sea,  from  which  they  have  been  raised,  and  that  an 
extent  of  land  of  equal  area  and  height  (varying  from  one  to  three 
thousand  feet)  should  rise  up  in  the  Arctic  Ocean  between  Siberia  and 
the  north  pole.  In  speaking  of  such  changes,  I  shall  not  allude  to  the 
manner  in  which  I  conceive  it  possible  that  they  may  be  brought  about, 
nor  of  the  time  required  for  their  accomplishment — reserving  for  a  future 
occasion,  not  only  the  proofs  that  revolutions  of  equal  magnitude  have 
taken  place,  but  that  analogous  operations  are  still  in  gradual  progress. 
The  alteration  now  supposed  in  the  physical  geography  of  the  northern 
regions,  would  cause  additional  snow  and  ice  to  accumulate  where  now 
there  is  usually  an  open  sea ;  and  the  temperature  of  the  greater  part 
of  Europe  would  be  somewhat  lowered,  so  as  to  resemble  more  nearly 
that  of  corresponding  latitudes  of  North  America :  or,  in  other  words, 
it  might  be  necessary  to  travel  about  10°  farther  south  in  order  to  meet 
with  the  same  climate  which  we  now  enjoy.  No  compensation  would 
be  derived  from  the  disappearance  of  land  in  the  Mediterranean  coun- 
tries ;  but  the  contrary,  since  the  mean  heat  of  the  soil  in  those  lati- 
tudes probably  exceeds  that  which  would  belong  to  the  sea,  by  which 
we  imagine  it  to  be  replaced. 

But  let  the  configuration  of  the  surface  be  still  farther  varied,  and  let 
some  large  district  within  or  near  the  tropics,  such  as  Brazil,  with  its 
plains  and  hills  of  moderate  height,  be  converted  into  sea,  while  lands 
of  equal  elevation  and  extent  rise  up  in  the  arctic  circle.  From  this 
change  there  would,  in  the  first  place,  result  a  sensible  diminution  of 
temperature  near  the  tropic,  for  the  Brazilian  soil  would  no  longer  be 
heated  by  the  sun ;  so  that  the  atmosphere  would  be  less  warm,  as  also 
the  neighboring  Atlantic.  On  the  other  hand,  the  whole  of  Europe, 
Northern  Asia,  and  North  America,  would  be  chilled  by  the  enormous 
quantity  of  ice  and  snow,  thus  generated  on  the  new  arctic  continent. 
If,  as  we  have  already  seen,  there  are  now  some  points  in  the  southern 
hemisphere  where  snow  is  perpetual  down  to  the  level  of  the  sea,  in 
latitudes  as  low  as  central  England,  such  might  assuredly  be  the  case 
throughout  a  great  part  of  Europe,  under  the  change  of  circumstances 
above  supposed :  and  if  at  present  the  extreme  range  of  drifted  icebergs 
is  the  Azores,  they  might  easily  reach  the  equator  after  the  assumed 
alteration.  But  to  pursue  the  subject  still  farther,  let  the  Himalaya 


106  CAUS1-.S    OF  [CH.VH 

mountains,  with  the  whole  of  Hindostan,  sink  down,  and  their  place  be 
occupied  by  the  Indian  Ocean,  while  an  equal  extent  of  territory  and 
mountains,  of  the  same  vast  height,  rise  up  between  North  Greenland 
and  the  Orkney  Islands.  It  seems  difficult  to  exaggerate  the  amount 
to  which  the  climate  of  the  northern  hemisphere  would  then  be  cooled.* 

But  the  refrigeration  brought  about  at  the  same  time  in  the  southern 
hemisphere,  would  be  nearly  equal,  and  the  difference  of  temperature 
between  the  arctic  and  equatorial  latitudes  would  not  be  much  greater 
than  at  present ;  for  no  important  disturbance  can  occur  in  the  climate 
of  a  particular  region  without  its  immediately  affecting  all  other  lati- 
tudes, however  remote.  The  heat  and  cold  which  surround  the  globe 
are  in  a  state  of  constant  and  universal  flux  and  reflux.  The  heated 
and  rarefied  air  is  always  rising  and  flowing  from  the  equator  towards 
the  poles  in  the  higher  regions  of  the  atmosphere  ;  while  in  the  lower, 
the  colder  air  is  flowing  back  to  restore  the  equilibrium.  That  this  cir- 
culation is  constantly  going  on  in  the  aerial  currents  is  not  disputed  ;  it 
is  often  proved  by  the  opposite  course  of  the  clouds  at  different  heights, 
and  the  fact  has  been  farther  illustrated  in  a  striking  manner  by  two 
recent  events.  The  trade  wind  continually  blows  with  great  force  from 
the  island  of  Barbadoes  to  that  of  St.  Vincent ;  notwithstanding  which, 
during  the  eruption  of  the  volcano  in  the  island  of  St.  Vincent,  in  1812, 
ashes  fell  in  profusion  from  a  great  height  in  the  atmosphere  upon 
Barbadoes. f  In  like  manner,  during  the  great  eruption  of  Sumbawa, 
in  1815,  ashes  were  carried  to  the  islands  of  Amboyna  and  Banda, 
which  last  is  about  800  miles  east  from  the  site  of  the  volcano.  Yet 
the  southeast  monsoon  was  then  at  its  height. J  This  apparent  trans- 
position of  matter  against  the  wind,  confirmed  the  opinion  of  the  exist- 
ence of  a  counter-current  in  the  higher  regions,  which  had  previously 
rested  on  theoretical  conclusions  only. 

That  a  corresponding  interchange  takes  place  in  the  seas,  is  demon- 
strated, according  to  Humboldt,  by  the  cold  which  is  found  to  exist  at 
great  depths  within  the  tropics ;  and,  among  other  proofs,  may  be  men- 
tioned the  mass  of  warmer  water  which  the  Gulf  stream  is  constantly 
bearing  northwards,  while  a  cooler  current  flows  from  the  north  along 
the  coast  of  Greenland  and  Labrador,  and  helps  to  restore  the  equi- 
librium. S 


*  Mr.  Hopkins,  reasoning  on  data  furnished  by  Dove's  Isothermal  maps,  has 
arrived  at  the  very  interesting  conclusion,  that  both  on  Snowdon  and  the  lower 
mountains  of  the  West  of  Ireland  the  snow-line  would  descend  to  within  1000 
feet  of  the  sea  level,  and  glaciers  reach  the  sea,  if  we  could  simply  assume  the 
three  following  geographical  changes : — 

1st,  The  diversion  of  the  Gulf  stream  from  its  present  northerly  course  ;  2dly, 
the  depression  of  the  existing  land  of  Northern  and  Western  Europe,  to  the 
amount  of  no  more  than  500  feet ;  and  3dly,  a  cold  current  from  the  North  sweep- 
ing over  the  submerged  area.  Quart.  Journ.  Geol.  Soc.  1852,  p.  85. 

f  Daniell's  Meteorological  Essays,  p.  108. 

\  Observed  by  J.  Crawfurd,  Esq. 

§  In  speaking  of  the  circulation  of  air  and  water  in  this  chapter,  no  allusion  is 
made  to  the  trade  winds,  or  to  irregularities  in  the  direction  of  currents,  caused 


CH.  VIL]  CHANGES  OF  TEMPERATURE.  107 

Currents  of  colder  and  therefore  specifically  heavier  water  pass  from 
the  poles  towards  the  equator,  which  cool  the  inferior  parts  of  the 
ocean  ;  so  that  the  heat  of  the  torrid  zone  and  the  cold  of  the  polar 
circle  balance  each  other.  The  refrigeration,  therefore,  of  the  polar  re- 
gions, resulting  from  the  supposed  alteration  in  the  distribution  of  land 
and  sea,  would  be  immediately  communicated  to  the  tropics,  and  from 
them  its  influence  would  extend  to  the  antarctic  circle,  where  the  atmos- 
phere and  the  ocean  would  be  cooled,  so  that  ice  and  snow  would  aug- 
ment. Although  the  mean  temperature  of  higher  latitudes  in  the 
southern  hemisphere  is,  as  before  stated,  for  the  most  part,  lower  than 
that  of  the  same  parallels  in  the  northern,  yet,  for  a  considerable  space 
on  each  side  of  the  line,  the  mean  annual  heat  of  the  waters  is  found 
to  be  the  same  in  corresponding  parallels.  If,  therefore,  by  the  new 
position  of  the  land,  the  formation  of  icebergs  had  become  of  common 
occurrence  in  the  northern  temperate  zone,  and  if  these  were  frequently 
drifted  as  far  as  the  equator,  the  same  degree  of  cold  which  they  gener- 
ated would  immediately  be  communicated  as  far  as  the  tropic  of  Capri- 
corn, and  from  thence  to  the  lands  or  ocean  to  the  south. 

The  freedom,  then,  of  the  circulation  of  heat  and  cold  from  pole  to 
pole  being  duly  considered,  it  will  be  evident  that  the  mean  tempera- 
ture which  may  prevail  at  the  same  point  at  two  distinct  periods,  may 
differ  far  more  widely  than  that  of  any  two  points  in  the  same  parallels 
of  latitude,  at  one  and  the  same  period.  For  the  range  of  temperature, 
or  in  other  words,  the  curvature  of  the  isothermal  lines  in  a  given  zone, 
and  at  a  given  period,  must  always  be  circumscribed  within  narrow 
limits,  the  climate  of  each  place  in  that  zone  being  controlled  by  the 
combined  influence  of  the  geographical  peculiarities  of  all  other  parts 
of  the  earth.  Whereas,  if  we  compare  the  state  of  things  at  two  dis- 
tinct and  somewhat  distant  epochs,  a  particular  zone  may  at  one  time 
be  under  the  influence  of  one  class  of  disturbing  causes,  and  at  another 
time  may  be  affected  by  an  opposite  combination.  The  lands,  for  ex- 
ample, to  the  north  of  Greenland  cause  the  present  climate  of  North 
America  to  be  colder  than  that  of  Europe  in  the  same  latitudes ;  but 
the  excess  of  cold  is  not  so  great  as  it  would  have  been  if  the  western 
hemisphere  had  been  entirely  isolated,  or  separated  from  the  eastern 
like  a  distinct  planet.  For  not  only  does  the  refrigeration  produced  by 
Greenland  chill  to  a  certain  extent  the  atmosphere  of  northern  and  west- 
ern Europe,  but  the  mild  climate  of  Europe  reacts  also  upon  North  Amer- 
ica, and  moderates  the  chilling  influence  of  the  adjoining  polar  lands. 

To  return  to  the  state  of  the  earth  after  the  changes  above  supposed, 
we  must  not  omit  to  dwell  on  the  important  effects  to  which  a  wide 
expanse  of  perpetual  snow  would  give  rise.  It  is  probable  that  nearly 
the  whole  sea,  from  the  poles  to  the  parallels  of  45°,  would  be  frozen 
over  ;  for  it  is  well  known  that  the  immediate  proximity  of  land  is  not 

by  the  rotary  motion  of  the  earth.  These  causes  prevent  the  movements  from 
being  direct  from  north  to  south,  or  from  south  to  north,  but  they  do  not  affect 
the  theory  of  a  constant  circulation. 


108  CAUSES   OF  [Cn.  VII. 

essential  to  the  formation  and  increase  of  field  ice,  provided  there  be  in 
some  part  of  the  same  zone  a  sufficient  quantity  of  glaciers  generated 
on  or  near  the  land,  to  cool  down  the  sea.  Captain  Scoresby,  in  his 
account  of  the  arctic  regions,  observes,  that  when  the  sun's  rays  "  fall 
upon  the  snow-clad  surface  of  the  ice  or  land,  they  are  in  a  great  meas- 
ure reflected,  without  producing  any  material  elevation  of  temperature ; 
but  when  they  impinge  on  the  black  exterior  of  a  ship,  the  pitch  on 
one  side  occasionally  becomes  fluid  while  ice  is  rapidly  generated  at 
the  other."* 

Now  field  ice  is  almost  always  covered  with  snow  \\  and  thus  not 
only  land  as  extensive  as  our  existing  continents,  but  immense  tracts  of 
sea  in  the  frigid  and  temperate  zones,  might  present  a  solid  surface 
covered  with  snow,  and  reflecting  the  sun's  rays  for  the  greater  part  of 
the  year.  Within  the  tropics,  moreover,  where  the  ocean  now  pre- 
dominates, the  sky  would  no  longer  be  serene  and  clear,  as  in  the  pres- 
ent era ;  but  masses  of  floating  ice  would  cause  quick  condensations  of 
vapor,  so  that  fogs  and  clouds  would  deprive  the  vertical  rays  of  the 
sun  of  half  their  power.  The  whole  planet,  therefore,  would  receive 
annually  a  smaller  portion  of  the  solar  influence,  and  the  external  crust 
would  part,  by  radiation,  with  some  of  the  heat  which  had  been  accu- 
mulated in  it,  during  a  different  state  of  the  surface.  This  heat  would 
be  dissipated  in  the  spaces  surrounding  our  atmosphere,  which,  accord- 
ing to  the  calculations  of  M.  Fourier,  have  a  temperature  much  inferior 
to  that  of  freezing  water. 

After  the  geographical  revolution  above  assumed,  the  climate  of 
equinoctial  lands  might  be  brought  at  last  to  resemble  that  of  the  pres- 
ent temperate  zone,  or  perhaps  be  far  more  wintry.  They  who  should 
then  inhabit  such  small  isles  and  coral  reefs  as  are  now  seen  in  the 
Indian  Ocean  and  South  Pacific,  would  wonder  that  zoophytes  of  large 
dimensions  had  once  been  so  prolific  in  their  seas  ;  or  if,  perchance, 
they  found  the  wood  and  fruit  of  the  cocoa-nut  tree  or  the  palm  silici- 
fied  by  the  waters  of  some  ancient  mineral  spring,  or  incrusted  with 
calcareous  matter,  they  would  muse  on  the  revolutions  which  had  anni- 
hilated such  genera,  and  replaced  them  by  the  oak,  the  chestnut,  and 
the  pine.  With  equal  admiration  would  they  compare  the  skeletons  of 
their  small  lizards  with  the  bones  of  fossil  alligators  and  crocodiles  more 
than  twenty  feet  in  length,  which,  at  a  former  epoch,  had  multiplied 
between  the  tropics :  and  when  they  saw  a  pine  included  in  an  iceberg, 
drifted  from  latitudes  which  we  now  call  temperate,  they  would  be  as- 
tonished at  the  proof  thus  afforded,  that  forests  had  once  grown  where 
nothing  could  be  seen  in  their  own  times  but  a  wilderness  of  snow. 

If  the  reader  hesitate  to  suppose  so  extensive  an  alteration  of  temper- 
ature as  the  probable  consequence  of  geographical  changes,  confined  to 
one  hemisphere,  he  should  remember  how  great  are  the  local  anomalies 
in  climate  now  resulting  from  the  peculiar  distribution  of  land  and  sea 

*  See  Scoreby's  Arctic  Regions,  vol.  i.  p.  378.  f  Ibid.  p.  320. 


OH,  VII.]  CHANGES  OF  TEMPERATURE.  109 

in  certain  regions.  Thus,  in  the  island  of  South  Georgia,  before  men- 
tioned (p.  98),  Captain  Cook  found  the  everlasting  snows  descending 
to  the  level  of  the  sea,  between  lat.  54°  and  55°  S. ;  no  trees  or  shrubs 
were  to  be  seen,  and  in  summer  a  few  rocks  only,  after  a  partial  melt- 
ing of  the  ice  and  snow,  were  scantily  covered  with  moss  and  tufts  of 
grass.  If  such  a  climate  can  now  exist  at  the  level  of  the  sea  in  a  lati- 
tude corresponding  to  that  of  Yorkshire  in  spite  of  all  those  equalizing 
causes  before  enumerated,  by  which  the  mixture  of  the  temperatures  of 
distant  regions  is  facilitated  throughout  the  globe,  what  rigors  might 
we  not  anticipate  in  a  winter  generated  by  the  transfer  of  the  mountains 
of  India  to  our  arctic  circle  ! 

But  we  have  still  to  contemplate  the  additional  refrigeration  which 
might  be  effected  by  changes  in  the  relative  position  of  land  and  sea  in 
the  southern  hemisphere.  If  the  remaining  continents  were  transferred 
from  the  equatorial  and  contiguous  latitudes  to  the  south  polar  regions, 
the  intensity  of  cold  produced  might,  perhaps,  render  the  globe  unin- 
habitable. We  are  too  ignorant  of  the  laws  governing  the  direction  of 
subterranean  forces,  to  determine  whether  such  a  crisis  be  within  the 
limits  of  possibility.  At  the  same  time,  it  may  be  observed,  that  no 
distribution  of  land  can  well  be  imagined  more  irregular,  or,  as  it  were, 
capricious,  than  that  which  now  prevails ;  for  at  present,  the  globe  may 
be  divided  into  two  equal  parts,  in  such  a  manner,  that  one  hemisphere 
shall  be  almost  entirely  covered  with  water,  while  the  other  shall  con- 
tain less  water  than  land  (see  figs.  3  and  4)  ;*  and,  what  is  still  more 
extraordinary,  on  comparing  the  extratropical  lands  in  the  northern  and 
southern  hemispheres,  the  lands  in  the  northern  are  found  to  be  to  those 
in  the  southern  in  the  proportion  of  thirteen  to  one  !f  To  imagine  all 
the  lands,  therefore,  in  high,  and  all  the  sea  in  low  latitudes,  as  deline- 
ated in  fig.  6,  p.  Ill,  would  scarcely  be  a  more  anomalous  state  of  the 
surface. 

Position  of  land  and  sea  which  might  give  rise  to  the  extreme  of  heat. — 
Let  us  now  turn  from  the  contemplation  of  the  winter  of  the  "great  year," 
and  consider  the  opposite  train  of  circumstances  which  would  bring  on 
the  spring  and  summer.  To  imagine  all  the  lands  to  be  collected  to- 
gether in  equatorial  latitudes,  and  a  few  promontories  only  to  project 

*  This  is  shown  by  projecting  a  map  on  the  horizon  of  London,  that  is  to  say, 
by  supposing  the  eye  of  the  observer  to  be  placed  above  that  city,  and  to  see  from 
thence  one  half  of  the  globe.  For  it  so  happens  that  from  that  point,  and  no  other, 
we  should  behold  the  greatest  possible  quantity  of  land  ;  and  if  we  are  then  trans- 
ferred to  the  opposite  or  antipodal  point,  we  should  see  the  greatest  possible  quan- 
tity of  water.  (See  figs.  3  and  4.)  A  singular  fact,  first  pointed  out  by  Mr.  James 
Gardner,  namely,  that  only  one  twenty-seventh  part  of  the  dry  land  has  any  land 
opposite  to  it,  is  intimately  connected  with  this  excess  of  land  in  one  of  the  two 
hemispheres  above  alluded  to.  Thus,  in  fig.  3,  the  land  shaded  black  in  part  of 
China  answers  to  that  portion  of  the  extremity  of  South  America  and  Tierra  del 
Fuego  which  is  opposite  or  antipodal  to  it,  whilst  the  dark  spots  in  the  northern 
and  central  parts  of  South  America  represent  Borneo,  Sumatra,  and  other  antipo- 
dal islands  in  the  Eastern  Archipelago.  See  Gardner,  Geol.  Soc.  Proceeding^ 
1833,  vol.  i.  p.  488. 

f  Humboldt  on  Isothermal  Lines 


110 


CAUSES   OF 


[On.  VIL 


MAP  showing  the  present  unequal  Distribution  of  LAND  and  WATER  on  the 
Surface  of  the  GLOBE. 


Fig.  3. 


Fig.  4. 


Fig.  3.  Here  London  is  taken  as  a  centre,  and  we  behold  the  greatest  quantity  of  land 
existing  in  one  hemisphere". 

Fig.  4  Here  the  centre  is  the  antipodal  point  to  London,  and  we  see  the  greatest 
quancity  of  water  existing  in  one  hemisphere. 


The  black  shading  expresses  land  having  land  opposite  or  antipodal  to  it 


CH.  VII] 


CHANGES  OF  TEMPERATURE. 


Ill 


MAPS  showing  the  position  of  LAND  and  SEA  which  might  produce  the  Extremes 
of  HEAT  and  COLD  in  the  Climates  of  the  GLOBE. 


Fig.  5. 


Extreme  of  Heat. 


Fig.  6. 


Extreme  of  Cold. 


OBSERVATIONS.— These  maps  are  intended  to.show  that  continents  and  islands  having  the  same 
shape  and  relative  dimensions  as  those  now  existing,  might  be  placed  so  as  to  occupy  either  the 
equatorial  or  polar  regions. 

In  fig.  5,  scarcely  any  of  the  land  extends  from  the  equator  towards  the  poles  beyond  the  80th 
parallel  of  latitude ;  and  fig.  6,  a  very  small  proportion  of  it  extends  from  the  poles  towards  the 
Equator  beyond  the  40th  parallel  of  latitude. 


112  CAUSES   OF  [On.  VII. 

beyond  the  thirtieth  parallel,  as  represented  in  the  annexed  maps  (figs. 
5  and  6),  would  be  undoubtedly  to  suppose  an  extreme  result  of  geo- 
logical change.  But  if  we  consider  a  mere  approximation  to  such  a  state 
of  things,  it  would  be  sufficient  to  cause  a  general  elevation  of  tempera- 
ture. Nor  can  it  be  regarded  as  a  visionary  idea,  that  amidst  the  revo- 
lutions of  the  earth's  surface,  the  quantity  of  land  should,  at  certain  pe- 
riods, have  been  simultaneously  lessened  in  the  vicinity  of  both  the  poles, 
and  increased  within  the  tropics.  We  must  recollect  that  even  now  it 
is  necessary  to  ascend  to  the  height  of  fifteen  thousand  feet  in  the  Andes 
under  the  line,  and  in  the  Himalaya  mountains,  which  are  without  the  tropic, 
to  seventeen  thousand  feet,  before  we  reach  the  limit  of  perpetual  snow. 
On  the  northern  slope,  indeed,  of  the  Himalaya  range,  where  the  heat  ra- 
diated from  a  great  continent  moderates  the  cold,  there  are  meadows  and 
cultivated  land  at  an  elevation  equal  to  the  height  of  Mont  Blanc.*  If  then 
there  were  no  arctic  lands  to  chill  the  atmosphere,  and  freeze  the  sea,  and 
if  the  loftiest  chains  were  near  the  line,  it  seems  reasonable  to  imagine  that 
the  highest  mountains  might  be  clothed  with  a  rich  vegetation  to  their 
summits,  and  that  nearly  all  signs  of  frost  would  disappear  from  the  earth. 

When  the  absorption  of  the  solar  rays  was  in  no  region  impeded,  even 
in  winter,  by  a  coat  of  snow,  the  mean  heat  of  the  earth's  crust  would 
augment  to  considerable  depths,  and  springs,  which  we  know  to  be  in 
general  an  index  of  the  mean  temperature  of  the  climate,  would  be 
warmer  in  all  latitudes.  The  waters  of  lakes,  therefore,  and  rivers, 
would  be  much  hotter  in  winter,  and  would  be  never  chilled  in  summer 
by  melted  snow  and  ice.  A  remarkable  uniformity  of  climate  would  pre- 
vail amid  the  archipelagoes  of  the  temperate  and  polar  oceans,  where  the 
tepid  waters  of  equatorial  currents  would  freely  circulate.  The  general  hu- 
midity of  the  atmosphere  would  far  exceed  that  of  the  present  period,  for 
increased  heat  would  promote  evaporation  in  all  parts  of  the  globe.  The 
winds  would  be  first  heated  in  their  passage  over  the  tropical  plains,  and 
would  then  gather  moisture  from  the  surface  of  the  deep,  till,  charged  with 
vapor,  they  arrived  at  extreme  northern  and  southern  regions,  and  there 
encountering  a  cooler  atmosphere,  discharged  their  burden  in  warm  rain. 
If,  during  the  long  night  of  a  polar  winter,  the  snows  should  whiten  the 
summits  of  some  arctic  islands,  they  would  be  dissolved  as  rapidly  by  the 
returning  sun,  as  are  the  snows  of  Etna  by  the  blasts  of  the  sirocco. 

We  learn  from  those  who  have  studied  the  geographical  distribution  of 
plants,  that  in  very  low  latitudes,  at  present,  the  vegetation  of  small  islands  re- 
mote from  continents  has  a  peculiar  character ;  the  ferns  and  allied  families, 
in  particular,  bearing  a  great  proportion  to  the  total  number  of  other  plants. 
Other  circumstances  being  the  same,  the  more  remote  the  isles  are  from 
the  continents,  the  greater  does  this  proportion  become.  Thus,  in  the  con- 
tinent of  India,  and  the  tropical  parts'  of  New  Holland,  the  proportion  of 
ferns  to  the  phaenogamous  plants  is  only  as  one  to  twenty-six  ;  whereas, 
in  the  South-Sea  Islands,  it  is  as  one  to  four,  or  even  as  one  to  three. f 

*  Humboldt,  Tableaux  de  la  Nature,  torn.  i.  p.  112. 

f  Ad.  Brongniart,  Consid.  Generates  sur  la  Nat.  de  la  Vege"  t.  tfcc.  Ann.  dea  Sciences 
Nat.,  Nov.  1828. 


CH.  VII.]  CHANGES   OF   TEMPERATURE.  113 

We  might  expect,  therefore,  in  the  summer  of  the  "  great  year,"  or 
cycle  of  climate,  that  there  would  be  a  predominance  of  tree  ferns  and 
plants  allied  to  genera  now  called  tropical,  in  the  islands  of  the  wide 
ocean,  while  many  forms  now  confined  to  arctic  and  temperate  regions, 
or  only  found  near  the  equator  on  the  summit  of  the  loftiest  mountains, 
would  almost  disappear  from  the  earth.  Then  might  those  genera  of 
animals  return,  of  which  the  memorials  are  preserved  in  the  ancient  rocks 
of  our  continents.  The  pterodactyle  might  flit  again  through  the  air, 
the  huge  iguanodon  reappear  in  the  woods,  and  the  ichthyosaurs  swarm 
once  more  in  the  sea.  Coral  reefs  might  be  prolonged  again  beyond 
the  arctic  circle,  where  the  whale  and  the  narwal  now  abound ;  and 
droves  of  turtles  might  begin  again  to  wander  through  regions  now  ten- 
anted by  the  walrus  and  the  seal. 

But  not  to  indulge  too  far  in  these  speculations,  I  may  observe,  in 
conclusion,  that  however  great,  during  the  lapse  of  ages,  may  be  the 
vicissitudes  of  temperature  in  every  zone,  it  accords  with  this  theory  that 
the  general  climate  should  not  experience  any  sensible  change  in  the 
course  of  a  few  thousand  years  ;  because  that  period  is  insufficient  to 
affect  the  leading  features  of  the  physical  geography  of  the  globe. 

Notwithstanding  the  apparent  uncertainty  of  the  seasons,  it  is  found 
that  the  mean  temperature  of  particular  localities  is  very  constant,  when 
observations  made  for  a  sufficient  series  of  years  are  compared. 

Yet  there  must  be  exceptions  to  this  rule  ;  and  even  the  labors  of 
man  have,  by  the  drainage  of  lakes  and  marshes,  and  the  felling  of  ex- 
tensive forests,  caused  such  changes  in  the  atmosphere  as  greatly  to  raise 
our  conception  of  the  more  important  influence  of  those  forces  to  which, 
in  certain  latitudes,  even  the  existence  of  land  or  water,  hill  or  valley, 
lake  or  sea,  must  be  ascribed.  If  we  possessed  accurate  information  of 
the  amount  of  local  fluctuation  in  climate  in  the  course  of  twenty  cen- 
turies, it  would  often,  undoubtedly,  be  considerable.  Certain  tracts,  for 
example,  on  the  coast  of  Holland  and  of  England  consisted  of  cultivated 
land  in  the  time  of  the  Romans,  which  the  sea,  by  gradual  encroach- 
ments, has  at  length  occupied.  Here,  at  least,  a  slight  alteration  has 
been  effected ;  for  neither  the  distribution  of  heat  in  the  different  seasons, 
nor  the  mean  annual  temperature  of  the  atmosphere  investing  the  sea,  is 
precisely  the  same  as  that  which  rests  upon  the  land. 

In  those  countries,  also,  where  earthquakes  and  volcanoes  are  in  full 
activity,  a  much  shorter  period  may  produce  a  sensible  variation.  The 
climate  of  the  great  table-land  of  Malpais  in  Mexico,  must  differ  mate- 
rially from  that  which  prevailed  before  the  middle  of  the  last  century ;  for, 
since  that  time,  six  mountains,  the  highest  of  them  rising  sixteen  hun- 
dred feet  above  the  plateau,  have  been  thrown  up  by  volcanic  eruptions. 
It  is  by  the  repetition  of  an  indefinite  number  of  such  local  revolutions, 
and  by  slow  movements  extending  simultaneously  over  wider  areas,  as 
will  be  afterwards  shown,  that  a  general  change  of  climate  may  finally 
be  brought  about. 

8 


CHAPTER  VIII. 

ON    FORMER    CHANGES    IN    PHYSICAL    GEOGRAPHY    AND    CLIMATE. 

Geographical  features  of  the  northern  hemisphere,  at  the  period  of  the  oldest  fos- 
siliferous  strata — State  of  the  surface  when  the  mountain  limestone  and  coal 
were  deposited — Changes  in  physical  geography,  between  the  carboniferous 
period  and  the  chalk — Abrupt  transition  from  the  secondary  to  the  tertiary  fos- 
sils— Accession  of  land,  and  elevation  of  mountain  chains,  after  the  consolida- 
tion of  the  secondary  rocks — Explanation  of  Map,  showing  the  area  covered  by 
sea,  since  the  commencement  of  the  tertiary  period — Astronomical  theories  of 
the  causes  of  variations  in  climate — Theory  of  the  diminution  of  the  supposed 
primitive  heat  of  the  globe. 

IN  the  sixth  chapter,  I  stated  the  arguments  derived  from  organic  re- 
mains for  concluding  that  in  the  period  when  the  carboniferous  strata 
were  deposited,  the  temperature  of  the  ocean  and  the  air  was  more  uni- 
form in  the  different  seasons  of  the  year,  and  in  different  latitudes,  than 
at  present,  and  that  there  was  a  remarkable  absence  of  cold  as  well  as 
great  moisture  in  the  atmosphere.  It  was  also  shown  that  the  climate 
had  been  modified  more  than  once  since  that  epoch,  and  that  it  had  been 
reduced,  by  successive  changes,  more  and  more  nearly  to  that  now  pre- 
vailing in  the  same  latitudes.  Farther,  I  endeavored,  in  the  last  chap- 
ter, to  prove  that  vicissitudes  in  climate  of  no  less  importance  may  be 
expected  to  recur  in  future,  if  it  be  admitted  that  causes  now  active  in 
nature  have  power,  in  the  lapse  of  ages,  to  produce  considerable  varia- 
tions in  the  relative  position  of  land  and  sea.  It  remains  to  inquire 
whether  the  alterations,  which  the  geologist  can  prove  to  have  actually 
taken  place  at  former  periods,  in  the  geographical  features  of  the  northern 
hemisphere,  coincide  in  their  nature,  and  in  the  time  of  their  occurrence, 
with  such  revolutions  in  climate  as  might  naturally  have  resulted,  ac- 
cording to  the  meteorological  principles  already  explained. 

Period  of  the  primary  fossiliferous  rocks. — The  oldest  system  of  strata 
which  afford  by  their  organic  remains  any  evidence  as  to  climate,  or  the 
former  position  of  land  and  sea,  are  those  former]  v  known  as  the  tran- 
sition rocks,  or  what  have  since  been  termed  Lower  Silurian  or  "  pri- 
mary fossiliferous"  formations.  These  have  been  found  in  England, 
France,  Germany,  Sweden,  Russia,  and  other  parts  of  central  and  north- 
ern Europe,  as  also  in  the  great  Lake  district  of  Canada  and  the  United 
States.  The  multilocular  or  chambered  univalves,  including  the  Nauti- 
lus, and  the  corals,  obtained  from  the  limestones  of  these  ancient  groups, 
have  been  compared  to  forms  now  most  largely  developed  in  tropical 
seas.  The  corals,  however,  have  been  shown  by  M.  Milne  Edwards  to 
differ  generally  from  all  living  zoophytes ;  so  that  conclusions  as  to  a 
warmer  climate  drawn  from  such  remote  analogies  must  be  received  with 


CH.  VIII.]        FORMER   CHANGES   IN    PHYSICAL   GEOGRAPHY.  115 

caution.  Hitherto,  few,  if  any,  contemporaneous  vegetable  remains  have 
been  noticed ;  but  such  as  are  mentioned  agree  more  nearly  with  the 
plants  of  the  carboniferous  era  than  any  other,  and  would  therefore 
imply  a  warm  and  humid  atmosphere  entirely  free  from  intense  cold 
throughout  the  year. 

This  absence  or  great  scarcity  of  plants  as  well  as  of  freshwater  shells 
and  other  indications  of  neighboring  land,  coupled  with  the  wide  extent 
of  marine  strata  of  this  age  in  Europe  and  North  America,  are  facts 
which  imply  such  a  state  of  physical  geography  (so  far  at  least  as  re- 
gards the  northern  hemisphere)  as  would,  according  to  the  principles 
before  explained,  give  rise  to  such  a  moist  and  equable  climate.  (See  p. 
109,  and  fig.  5,  p.  111.) 

Carboniferous  group. — This  group  comes  next  in  the  order  of  succes- 
sion ;  and  one  of  its  principal  members,  the  mountain  limestone,  was 
evidently  a  marine  formation,  as  is  shown  by  the  shells  and  corals  which 
it  contains.  That  the  ocean  of  that  period  was  of  considerable  extent  in 
our  latitudes,  we  may  infer  from  the  continuity  of  these  calcareous  strata 
over  large  areas  in  Europe,  Canada,  and  the  United  States.  The  same 
group  has  also  been  traced  in  North  America,  towards  the  borders  of 
the  arctic  sea.* 

There  are  also  several  regions  in  Scotland,  and  in  the  central  and 
northern  parts  of  England,  as  well  as  in  the  United  States,  where  ma- 
rine carboniferous  limestones  alternate  with  strata  containing  coal,  in  such 
a  manner  as  to  imply  the  drifting  down  of  plants  by  rivers  into  the  sea, 
and  the  alternate  occupation  of  the  same  space  by  fresh  and  salt  water. 

Since  the  time  of  the  earlier  writers,  no  strata  have  been  more  exten- 
sively investigated,  both  in  Europe  and  North  America,  than  those  of 
the  ancient  carboniferous  group,  and  the  progress  of  science  has  led  to 
a  general  belief  that  a  large  portion  of  the  purest  coal  has  been  formed, 
not,  as  was  once  imagined,  by  vegetable  matter  floated  from  a  distance, 
but  by  plants  which  grew  on  the  spot,  and  somewhat  in  the  manner  of 
peat  on  the  spaces  now  covered  by  the  beds  of  coal.  The  former  ex- 
istence of  land  in  some  of  these  spaces  has  been  proved,  as  already 
stated,  by  the  occurrence  of  numerous  upright  fossil  trees,  with  their 
roots  terminating  downwards  in  seams  of  coal ;  and  still  more  generally 
by  the  roots  of  trees  (stigmarise)  remaining  in  their  natural  position  in 
the  clays  which  underlie  almost  every  layer  of  coal. 

As  some  nearly  continuous  beds  of  such  coal  have  of  late  years  been 
traced  in  North  America,  over  areas  100  or  200  miles  and  upwards  in 
diameter,  it  may  be  asked  whether  the  large  tracts  of  ancient  land  im- 
plied by  this  fact  are  not  inconsistent  with  the  hypothesis  of  the  general 
prevalence  of  islands  at  the  period  under  consideration  ?  In  reply,  I 
may  observe  that  the  coal-fields  must  originally  have  been  low  alluvial 
grounds,  resembling  in  situation  the  cypress-swamps  of  the  Mississippi, 
or  the  sunderbunds  of  the  Ganges,  being  liable  like  them  to  be  inun- 

*  Sir  J.  Richardson,  Proceedings  of  Geol.  Soc.  No.  7,  p.  68,  March,  1828. 


116  PROOFS   OF   FORMER  [Cm  VIIL 

dated  at  certain  periods  by  a  river  or  by  the  sea,  if  the  land  should  be 
depressed  a  few  feet.  All  the  phenomena,  organic  and  inorganic,  imply 
conditions  nowhere  to  be  met  with  except  in  the  deltas  of  large  rivers. 
We  have  to  account  for  an  abundant  supply  of  fluviatile  sediment,  car- 
ried for  ages  towards  one  and  the  same  region,  and  capable  of  forming 
strata  of  mud  and  sand  thousands  of  feet,  or  even  fathoms,  in  thickness, 
many  of  them  consisting  of  laminated  shale,  inclosing  the  leaves  of  ferns 
and  other  terrestrial  plants.  We  have  also  to  explain  the  frequent  in- 
tercalations of  root-beds,  and  the  interposition  here  and  there  of  brack- 
ish and  marine  deposits,  demonstrating  the  occasional  presence  of  the 
neighboring  sea.  But  these  forest- covered  deltas  could  only  have  been 
formed  at  the  termination  of  large  hydrographical  basins,  each  drained 
by  a  great  river  and  its  tributaries ;  and  the  accumulation  of  sediment 
bears  testimony  to  contemporaneous  denudation  on  a  large  scale,  and, 
therefore,  to  a  wide  area  of  land,  probably  containing  within  it  one  or 
more  mountain  chains. 

In  the  case  of  the  great  Ohio  or  Appalachian  coal-field,  the  largest 
in  the  world,  it  seems  clear  that  the  uplands  drained  by  one  or  more 
great  rivers  were  chiefly  to  the  eastward,  or  they  occupied  a  space  now 
filled  by  part  of  the  Atlantic  Ocean,  for  the  mechanical  deposits  of  mud 
and  sand  increase  greatly  in  thickness  and  coarseness  of  material  as  we 
approach  the  eastern  borders  of  the  coal-field,  or  the  southeast  flanks 
of  the  Alleghany  mountains,  near  Philadelphia.  In  that  region  numer- 
ous beds  of  pebbles,  often  of  the  size  of  a  hen's  egg,  are  seen  to  alter- 
nate with  beds  of  pure  coal. 

But  the  American  coal-fields  are  all  comprised  within  the  30th  and 
50th  degrees  of  north  latitude  ;  and  there  is  no  reason  to  presume  that 
the  lands  at  the  borders  of  which  they  originated  ever  penetrated  so  far 
or  in  such  masses  into  the  colder  and  arctic  regions,  so  as  to  generate  a 
cold  climate.  In  the  southern  hemisphere,  where  the  predominance  of 
sea  over  land  is  now  the  distinguishing  geographical  feature,  we  never- 
theless find  a  large  part  of  the  continent  of  Australia,  as  well  as  New 
Zealand,  placed  between  the  30th  and  50th  degrees  of  S.  latitude.  The 
two  islands  of  New  Zealand  taken  together,  are  between  800  and  900 
miles  in  length,  with  a  breadth  in  some  parts  of  ninety  miles,  and  they 
stretch  as  far  south  as  the  46th  degree  of  latitude.  They  afford,  there- 
fore, a  wide  area  for  the  growth  of  a  terrestrial  vegetation,  and  the  bot- 
any of  this  region  is  characterized  by  abundance  of  ferns,  one  hundred 
and  forty  species  of  which  are  already  known,  some  of  them  attaining 
the  size  of  trees.  In  this  respect  the  southern  shores  of  New  Zealand 
in  the  46th  degree  of  latitude  almost  vie  with  tropical  islands.  Another 
point  of  resemblance  between  the  Flora  of  New  Zealand  and  that  of  the 
ancient  carboniferous  period  is  the  prevalence  of  the  fir  tribe  or  of 
coniferous  wood. 

An  argument  of  some  weight  in  corroboration  of  the  theory  above 
explained  respecting  the  geographical  condition  of  the  temperate  and 
arctic  latitudes  of  the  northern  hemisphere  in  the  carboniferous  period 


CH.  VIIL]  CHANGES   IN   PHYSICAL   GEOGRAPHY.  117 

may  also  be  derived  from  an  examination  of  those  groups  of  strata  which 
immediately  preceded  the  coal.  The  fossils  of  the  Devonian  and  Silu- 
rian strata  in  Europe  and  North  America  have  led  to  the  conclusion, 
that  they  were  formed  for  the  most  part  in  deep  seas,  far  from  land. 
In  those  older  strata  land  plants  are  almost  as  rare  as  they  are  abun- 
dant or  universal  in  the  coal  measures.  Those  ancient  deposits,  there- 
fore, may  be  supposed  to  have  belonged  to  an  epoch  when  dry  land  had 
only  just  begun  to  be  upraised  from  the  deep  ;  a  theory  which  would 
imply  the  existence  during  the  carboniferous  epoch  of  islands,  instead  of 
an  extensive  continent,  in  the  area  where  the  coal  was  formed. 

Such  a  state  of  things  prevailing  in  the  north,  from  the  pole  to  the 
30th  parallel  of  latitude,  if  not  neutralized  by  circumstances  of  a  con- 
trary tendency  in  corresponding  regions  south  of  the  line,  would  give 
rise  to  a  general  warmth  and  uniformity  of  climate  throughout  the  globe. 

Changes  in  physical  geography  between  the  formation  of  the  carbonif- 
erous strata  and  the  chalk. — We  have  evidence  in  England  that  the 
strata  of  the  ancient  carboniferous  group,  already  adverted  to,  were,  in 
many  instances,  fractured  and  contorted,  and  often  thrown  into  a  vertical 
position,  before  the  deposition  of  some  even  of  the  oldest  known  second- 
ary rocks,  such  as  the  new  red  sandstone. 

Fragments  of  the  older  formations  are  sometimes  included  in  the  con- 
glomerates of  the  more  modern ;  and  some  of  these  fragments  still  retain 
their  fossil  shells  and  corals,  so  as  to  enable  us  to  determine  the  parent 
rocks  from  whence  they  were  derived.  There  are  other  proofs  of  the 
disturbance  at  successive  epochs  of  different  secondary  rocks  before  the 
deposition  of  others ;  and  satisfactory  evidence  that,  during  these  re- 
iterated convulsions,  the  geographical  features  of  the  northern  hemi- 
sphere were  frequently  modified,  and  that  from  time  to  time  new  lands 
emerged  from  the  deep.  The  vegetation,  during  some  parts  of  the  pe- 
riod in  question  (from  the  lias  to  the  chalk  inclusive),  when  genera  allied 
to  Cycas  and  Zamia  were  abundant,  appears  to  have  approached  to  that 
of  the  larger  islands  of  the  equatorial  zone ;  such,  for  example,  as  we 
now  find  in  the  West  Indian  archipelago.*  These  islands  appear  to 
have  been  drained  by  rivers  of  considerable  size,  which  were  inhabited 
by  crocodiles  and  gigantic  oviparous  reptiles,  both  herbivorous  and  car- 
nivorous, belonging  for  the  most  part  to  extinct  genera.  Of  the  con- 
temporary inhabitants  of  the  land  we  have  as  yet  acquired  but  scanty 
information,  but  we  know  that  there  were  flying  reptiles,  insects,  and 
small  mammifers,  allied  to  the  marsupial  tribes. 

A  freshwater  deposit,  called  the  Wealden,  occurs  in  the  upper  part 
of  the  secondary  series  of  the  south  of  England,  which,  by  its  extent 
and  fossils,  attests  the  existence  in  that  region  of  a  large  river  draining 
a  continent  or  island  of  considerable  dimensions.  We  know  that  this 
land  was  clothed  with  wood,  and  inhabited  by  huge  terrestrial  reptiles 
and  birds.  Its  position  so  far  to  the  north  as  the  counties  of  Surrey  and 

*  Ad.  Brongniart,  Consid.  G6n£rales  sur  la  Nat.  de  la  V£g6t.  <fec.,  Ann.  des  Sci. 
Nat.,  Nov.  1828. 


118  CHANGES   OF   THE   SURFACE  [Cfl.  VIH. 

Sussex,  at  a  time  when  the  mean  temperature  of  the  climate  is  supposed 
to  have  been  much  hotter  than  at  present,  may  at  first  sight  appear  in- 
consistent with  the  theory  before  explained,  that  the  heat  was  caused 
by  the  gathering  together  of  all  the  great  masses  of  land  in  low  latitudes, 
while  the  northern  regions  were  almost  entirely  sea.  But  it  must  not 
be  taken  for  granted  that  the  geographical  conditions  already  described 
(p.  109,  and  fig.  5,  p.  Ill)  as  capable  of  producing  the  extreme  of  heat 
were  ever  combined  at  any  geological  period  of  which  we  have  yet  ob- 
tained information.  It  is  more  probable,  from  what  has  been  stated  in 
the  preceding  chapters,  that  a  slight  approximation  to  such  an  extreme 
state  of  things  would  be  sufficient ;  in  other  words,  if  most  of  the  dry 
land  were  tropical,  and  scarcely  any  of  it  arctic  or  antarctic,  a  prodigious 
elevation  of  temperature  must  ensue,  even  though  a  part  of  some  conti- 
nents should  penetrate  far  into  the  temperate  zones. 

Changes  during  the  tertiary  periods. — The  secondary  and  tertiary  for- 
mations of  Europe,  when  considered  separately,  may  be  contrasted  as 
having  very  different  characters  ;  the  secondary  appearing  to  have  been 
deposited  in  open  seas,  the  tertiary  in  regions  where  dry  land,  lakes, 
bays,  and  perhaps  inland  seas,  abounded.  The  secondary  series  is  al- 
most exclusively  marine ;  the  tertiary,  even  the  oldest  part,  contains  la- 
custrine strata,  and  not  unfrequently  freshwater  and  marine  beds  alter- 
nating. In  fact  there  is  evidence  of  important  geographical  changes- 
having  occurred  between  the  deposition  of  the  cretaceous  system,  or 
uppermost  of  the  secondary  series,  and  that  of  the  oldest  tertiary  group, 
and  still  more  between  the  era  of  the  latter  and  that  of  the  newer  ter- 
tiary formations.  This  change  in  the  physical  geography  of  Europe 
and  North  America  was  accompanied  by  an  alteration  no  less  remark- 
able in  organic  life,  scarcely  any  species  being  common  both  to  the  sec- 
ondary and  tertiary  rocks,  and  the  fossils  of  the  latter  affording  evidence 
of  a  different  climate. 

On  the  other  hand,  when  we  compare  the  tertiary  formations  of  suc- 
cessive ages,  we  trace  a  gradual  approximation  in  the  imbedded  fossils, 
from  an  assemblage  in  which  extinct  species  predominate,  to  one  where 
the  species  agree  for  the  most  part  with  those  now  existing.  In  other 
words,  we  find  a  gradual  increase  of  animals  and  plants  fitted  for  our 
present  climates,  in  proportion  as  the  strata  which  we  examine  are  more 
modern.  Now,  during  all  these  successive  tertiary  periods,  there  are 
signs  of  a  great  increase  of  land  in  European  and  North  American  lati- 
tudes. By  reference  to  the  map  (PL  1),  and  its  description,  p.  121, 
the  reader  will  see  that  about  two-thirds  of  the  present  European  lands 
have  emerged  since  the  earliest  tertiary  group  originated.  Nor  is  this 
the  only  revolution  which  the  same  region  has  undergone  within  the 
period  alluded  to,  some  tracts  which  were  previously  land  having  gained 
in  altitude,  others,  on  the  contrary,  having  sunk  below  their  former  level. 

That  the  existing  lands  were  not  all  upheaved  at  once  into  their 
present  position  is  proved  by  the  most  striking  evidence.  Several  Ital- 
ian geologists,  even  before  the  time  of  Brocchi,  had  justly  inferred  that 


CH.  VIIL]  AND    CLIMATE    CONTEMPORANEOUS.  119 

the  Apennines  were  elevated  several  thousand  feet  above  the  level  of 
the  Mediterranean  before  the  deposition  of  the  modern  Subapennine 
beds  which  flank  them  on  either  side.  What  now  constitutes  the  cen- 
tral calcareous  chain  of  the  Apennines  must  for  a  long  time  have  been  a 
narrow  ridgy  peninsula,  branching  off,  at  its  northern  extremity,  from 
the  Alps  near  Savona.  This  peninsula  has  since  been  raised  from  one 
to  two  thousand  feet,  by  which  movement  the  ancient  shores,  and,  for  a 
certain  extent,  the  bed  of  the  contiguous  sea,  have  been  laid  dry,  both 
on  the  side  of  the  Mediterranean  and  the  Adriatic. 

The  nature  of  these  vicissitudes  will  be  explained  by  the  accompany- 
ing diagram,  which  represents  a  transverse  section  across  the  Italian 
peninsula.  The  inclined  strata  A  are  the  disturbed  formations  of  the 

Fig.  7.  A 


Apennines,  into  which  the  ancient  igneous  rocks  a  are  supposed  to  have 
intruded  themselves.  At  a  lower  level  on  each  flank  of  the  chain  are 
the  more  recent  shelly  beds  6  6,  which  often  contain  rounded  pebbles 
derived  from  the  waste  of  contiguous  parts  of  the  older  Apennine  lime- 
stone. These,  it  will  be  seen,  are  horizontal,  and  lie  in  what  is  termed 
"  unconformable  stratification"  on  the  more  ancient  series.  They  now 
constitute  a  line  of  hills  of  moderate  elevation  between  the  sea  and  the 
Apennines,  but  never  penetrate  to  the  higher  and  more  ancient  valleys 
of  that  chain. 

The  same  phenomena  are  exhibited  in  the  Alps  on  a  much  grander 
scale  ;  those  mountains  being  composed  in  some  even  of  their  higher  re- 
gions of  the  newer  secondary  and  oldest  tertiary  formations,  while  they 
are  encircled  by  a  great  zone  of  more  modern  tertiary  rocks  both  on 
their  southern  flank  towards  the  plains  of  the  Po,  and  on  the  side  of 
Switzerland  and  Austria,  and  at  their  eastern  termination  towards  Styria 
and  Hungary.*  This  newer  tertiary  zone  marks  the  position  of  former 
seas  or  gulfs,  like  the  Adriatic,  wherein  masses  of  strata  accumulated, 
some  single  groups  of  which  are  not  inferior  in  thickness  to  the  most 
voluminous  of  our  secondary  formations  in  England.  Some  even  of 
these  newer  groups  have  been  raised  to  the  height  of  three  or  four  thou- 
sand feet,  and  in  proportion  to  their  antiquity,  they  generally  rise  to 
greater  heights,  the  older  of  them  forming  interior  zones  nearest  to  the 
central  ridges  of  the  Alps.  We  have  already  ascertained  that  the  Alps 
gained  accessions  to  their  height  and  width  at  several  successive  peri- 

*  See  a  Memoir  on  the  Alps,  by  Professor  Sedgwick  and  Sir  Rod.  Murchison, 
Trans,  of  Geol.  Soc.  second  ser.  vol.  iii.  accompanied  by  a  map. 


120  CHANGES    OF   THE   SURFACE  [Cfi.  VIIL 

ods,  and  that  the  last  series  of  improvements  occurred  when  the  seas 
were  inhabited  by  many  existing  species  of  animals. 

We  may  imagine  some  future  series  of  convulsions  once  more  to  heave 
up  this  stupendous  chain,  together  with  the  adjoining  bed  of  the  sea,  so 
that  the  mountains  of  Europe  may  rival  the  Andes  in  elevation  ;  in 
which  case  the  deltas  of  the  Po,  Adige,  and  Brenta,  now  encroaching 
upon  the  Adriatic,  might  be  uplifted  so  as  to  form  another  exterior  belt 
of  considerable  height  around  the  southeastern  flank  of  the  Alps. 

The  Pyrenees,  also,  have  acquired  their  present  altitude,  which  in 
Mont  Perdu  exceeds  eleven  thousand  feet,  since  the  deposition  of  the 
nummulitic  or  Eocene  division  of  the  tertiary  series.  Some  of  the  ter- 
tiary strata  at  the  base  of  the  chain  are  raised  to  the  height  of  only  a 
few  hundred  feet  above  the  sea,  and  retain  a  horizontal  position,  with- 
out partaking  in  general  in  the  disturbance  to  which  the  older  series 
has  been  subjected  ;  so  that  the  great  barrier  between  France  and  Spain 
was  almost  entirely  upheaved  in  the  interval  between  the  deposition  of 
certain  groups  of  tertiary  strata. 

The  remarkable  break  between  the  most  modern  of  the  known  sec- 
ondary rocks  and  the  oldest  tertiary,  may  be  apparent  only,  and  ascriba- 
ble  to  the  present  deficiency  of  our  information.  Already  the  marles  and 
green  sand  of  Heers  near  Tongres,  in  Belgium,  observed  by  M.  Dumont, 
and  the  "  pisolitic  limestone"  of  the  neighborhood  of  Paris,  both  inter- 
mediate in  age  between  the  Maestricht  chalk  and  the  lower  Eocene 
strata,  begin  to  afford  us  signs  of  a  passage  from  one  state  of  things  to 
another.  Nevertheless,  it  is  far  from  impossible  that  the  interval  be- 
tween the  chalk  and  tertiary  formations  constituted  an  era  in  the  earth's 
history,  when  the  transition  from  one  class  of  organic  beings  to  another 
was,  comparatively  speaking,  rapid.  For  if  the  doctrines  above  ex- 
plained in  regard  to  vicissitudes  of  temperature  are  sound,  it  will  follow 
that  changes  of  equal  magnitude  in  the  geographical  features  of  the 
globe  may  at  different  periods  produce  very  unequal  effects  on  climate  ; 
and,  so  far  as  the  existence  of  certain  animals  and  plants  depends 
on  climate,  the  duration  of  species  would  be  shortened  or  pro- 
tracted, according  to  the  rate  at  which  the  change  of  temperature 
proceeded. 

For  even  if  we  assume  that  the  intensity  of  the  subterranean  disturb- 
ing forces  is  uniform  and  capable  of  producing  nearly  equal  amounts  of 
alteration  on  the  surface  of  the  planet,  during  equal  periods  of  time,  still 
the  rate  of  alteration  in  climate  would  be  by  no  means  uniform.  Let  us 
imagine  the  quantity  of  land  between  the  equator  and  the  tropic  in  one 
hemisphere  to  be  to  that  in  the  other  as  thirteen  to  one,  which,  as  before 
stated,  represents  the  unequal  proportion  of  the  extra-tropical  lands  in 
the  two  hemispheres  at  present.  (See  figs.  3  and  4,  p.  110.)  Then 
let  the  first  geographical  change  consist  in  the  shifting  of  this  preponder- 
ance of  land  from  one  side  of  the  line  to  the  other ;  from  the  southern 
hemisphere,  for  example,  to  the  northern.  Now  this  need  not  affect  the 
general  temperature  of  the  earth.  But  if,  at  another  epoch,  we  suppose 


CH.  VIIL]  AND    CLIMATE    CONTEMPORANEOUS.  121 

a  continuance  of  the  same  agency  to  transfer  an  equal  volume  of  land 
from  the  torrid  zone  to  the  temperate  and  arctic  regions  of  the  northern 
and  southern  hemispheres,  or  into  one  of  them,  there  might  be  so  great 
a  refrigeration  of  the  mean  temperature  in  all  latitudes,  that  scarcely 
any  of  the  pre-existing  races  of  animals  would  survive  ;  and,  unless  it 
pleased  the  Author  of  Nature  that  the  planet  should  be  uninhabited, 
new  species,  and  probably  of  widely  different  forms,  would  then  be  sub- 
stituted in  the  room  of  the  extinct.  We  ought  not,  therefore,  to  infer 
that  equal  periods  of  time  are  always  attended  by  an  equal  amount  of 
change  in  organic  life,  since  a  great  fluctuation  in  the  mean  temperature 
of  the  earth,  the  most  influential  cause  which  can  be  conceived  in  exter- 
minating whole  races  of  animals  and  plants,  must,  in  different  epochs, 
require  unequal  portions  of  time  for  its  completion. 


PLATE  I.  Map  showing  the  extent  of  surface  in  Europe  which  has  at  one  period  or 
another  been  covered  by  the  sea  since  the  commencement  of  the  deposition  of  the 
older  or  Eocene  Tertiary  strata. 

THIS  map  will  enable  the  reader  to  perceive  at  a  glance  the  great  extent 
of  change  in  the  physical  geography  of  Europe,  which  can  be  proved 
to  have  taken  place  since  some  of  the  older  tertiary  strata  began  to  be 
deposited.  The  proofs  of  submergence,  during  some  part  or  other  of 
this  period,  in  all  the  districts  distinguished  by  ruled  lines,  are  of  a  most 
unequivocal  character ;  for  the  area  thus  described  is  now  covered  by 
deposits  containing  the  fossil  remains  of  animals  which  could  only  have 
lived  in  salt  water.  The  most  ancient  part  of  the  period  referred  to  can- 
not be  deemed  very  remote,  considered  geologically ;  because  the  de- 
posits of  the  Paris  and  London  basins,  and  many  other  districts  belong- 
ing to  the  older  tertiary  epoch,  are  newer  than  the  greater  part  of  the 
sedimentary  rocks  (those  commonly  called  secondary  and  primary  fos- 
siliferous  or  paleozoic)  of  which  the  crust  of  the  globe  is  composed. 
The  species,  moreover,  of  marine  testacea,  of  which  the  remains  are 
found  in  these  older  tertiary  formations,  are  not  entirely  distinct  from 
such  as  now  live.  Yet,  notwithstanding  the  comparatively  recent  epoch 
to  which  this  retrospect  is  carried,  the  variations  in  the  distribution  of 
land  and  sea  depicted  on  the  map  form  only  a  part  of  those  which  must 
have  taken  place  during  the  period  under  consideration.  Some  approx- 
imation has  merely  been  made  to  an  estimate  of  the  amount  of  sea  con- 
verted into  land  in  parts  of  Europe  best  known  to  geologists ;  but  we 
cannot  determine  how  much  land  has  become  sea  during  the  same  period  ; 
and  there  may  have  been  repeated  interchanges  of  land  and  water  in  the 
same  places,  changes  of  which  no  account  is  taken  in  the  map,  and  re- 
specting the  amount  of  which  little  accurate  information  can  ever  be  ob- 
tained. 

I  have  extended  the  sea  in  some  instances  beyond  the  limits  of  the 
land  now  covered  by  tertiary  formations,  and  marine  drift,  because  other 
geological  data  have  been  obtained  for  inferring  the  submergence  of  these 


122  EXPLANATION    OF   MAP,   SHOWING  [On.  VIII 

tracts  after  the  deposition  of  the  Eocene  strata  had  begun.  Thus,  for 
example,  there  are  good  reasons  for  concluding  that  part  of  the  chalk  of 
England  (the  North  and  South  Downs,  for  example,  together  with  the 
intervening  secondary  tracts)  continued  beneath  the  sea  until  the  oldest 
tertiary  beds  had  begun  to  accumulate. 

A  strait  of  the  sea  separating  England  and  Wales  has  also  been  in- 
troduced, on  the  evidence  afforded  by  shells  of  existing  species  found  in 
a  deposit  of  gravel,  sand,  loam,  and  clay,  called  the  northern  drift,  by 
Sir  R.  Murchison.*  And  Mr.  Trimmer  has  discovered  similar  recent 
marine  shells  on  the  northern  coast  of  North  Wales,  and  on  Moel  Try- 
fane,  near  the  Menai  Straits,  at  the  height  of  1392  feet  above  the  level 
of  the  sea ! 

Some  raised  sea-beaches,  and  drift  containing  marine  shells,  which  I 
examined  in  1843,  between  Limerick  and  Dublin,  and  which  have  been 
traced  over  other  parts  of  Ireland  by  different  geologists,  have  required 
an  extension  of  the  dark  lines  so  as  to  divide  that  island  into  several. 
In  improving  this  part  of  my  map  I  have  been  especially  indebted  to 
the  assistance  of  Mr.  Oldham,  who  in  1843  announced  to  the  British  As- 
sociation at  Cork  the  fact  that  at  the  period  when  the  drift  or  glacial  beds 
were  deposited,  Ireland  must  have  formed  an  archipelago  such  as  is  here 
depicted.  A  considerable  part  of  Scotland  might  also  have  been  repre- 
sented in  a  similar  manner  as  under  water  when  the  drift  originated. 

A  portion  of  Brittany  is  divided  into  islands,  because  it  is  known  to 
be  covered  with  patches  of  marine  tertiary  strata  chiefly  miocene.  When 
I  examined  these  in  1830  and  1843,  I  convinced  myself  that  the  sea 
must  have  covered  much  larger  areas  than  are  now  occupied  by  these 
small  and  detached  deposits.  The  former  connection  of  the  White  Sea 
and  the  Gulf  of  Finland  is  proved  by  the  fact  that  a  multitude  of  huge 
erratic  blocks  extend  over  the  intervening  space,  and  a  large  portion  of 
Norway,  Sweden,  and  Denmark,  as  well  as  Germany  and  Russia,  are 
represented  as  sea,  on  the  same  evidence,  strengthened  by  the  actual 
occurrence  of  fossil  sea-shells,  of  recent  species,  in  the  drift  of  various 
portions  of  those  countries.  The  submergence  of  considerable  areas 
under  large  bodies  of  fresh  water,  during  the  tertiary  period,  of  which 
there  are  many  striking  geological  proofs  in  Auvergne,  and  elsewhere, 
has  not  been  expressed  by  ruled  lines.  They  bear  testimony  to  the 
former  existence  of  neighboring  lands,  and  a  certain  elevation  of  the 
areas  where  they  occur  above  the  level  of  the  ocean ;  they  are  there- 
fore left  blank,  together  with  all  the  space  that  cannot  be  demonstrated 
to  have  been  part  of  the  sea  at  some  time  or  other,  since  the  commence- 
ment of  the  Eocene  epoch. 

In  compiling  this  map,  which  has  been  entirely  recast  since  the  first 
edition,  I  have  availed  myself  of  the  latest  geological  maps  of  the  British 
isles,  and  north  of  Europe  ;  also  of  those  published  by  the  government 
surveyors  of  France,  MM.  de  Beaumont  and  Dufresnoy ;  the  map  of 

*  See  Proceedings  of  Geol.  Soc.  voL  ii.  p.  334. 


CH.  VIIL]  CHANGES    IN    PHYSICAL    GEOGRAPHY.  123 

Germany  and  part  of  Europe,  by  Yon  Dechen,  and  that  of  Italy  by 
M.  Tchihatchoff  (Berlin,  1842).  Lastly,  Sir  R.  Murchison's  important 
map  of  Russia,  and  the  adjoining  countries,  has  enabled  me  to  mark  out 
not  only  a  considerable  area,  previously  little  known,  in  which  tertiary 
formations  occur ;  but  also  a  still  wider  expanse,  over  which  the  north- 
ern drift,  and  erratic  blocks  with  occasional  marine  shells,  are  traceable. 
The  southern  limits  of  these  glacial  deposits  in  Russia  and  Germany  in- 
dicate the  boundary,  so  far  as  we  can  now  determine  it,  of  the  northern 
ocean,  at  a  period  immediately  antecedent  to  that  of  the  human  race. 

I  was  anxious,  even  in  the  title  of  this  map,  to  guard  the  reader  against 
the  supposition  that  it  was  intended  to  represent  the  state  of  the  physi- 
cal geography  of  part  of  Europe  at  any  one  point  of  time.  The  difficulty, 
or  rather  the  impossibility,  of  restoring  the  geography  of  the  globe  as  it 
may  have  existed  at  any  former  period,  especially  a  remote  one,  consists 
in  this,  that  we  can  only  point  out  where  part  of  the  sea  has  been  turned 
into  land,  and  are  almost  always  unable  to  determine  what  land  may 
have  become  sea.  All  maps,  therefore,  pretending  to  represent  the 
geography  of  remote  geological  epochs  must  be  ideal.  The  map  under 
consideration  is  not  a  restoration  of  a  former  state  of  things,  at  any  par- 
ticular moment  of  time,  but  a  synoptical  view  of  a  certain  amount  of  one 
kind  of  change  (the  conversion  of  sea  into  land)  known  to  have  been 
brought  about  within  a  given  period. 

It  may  be  proper  to  remark  that  the  vertical  movements  to  which  the 
land  is  subject  in  certain  regions,  occasion  alternately  the  subsidence  and 
the  uprising  of  the  surface  ;  and  that,  by  such  oscillations  at  successive 
periods,  a  great  area  may  have  been  entirely  covered  with  marine  de- 
posits, although  the  whole  may  never  have  been  beneath  the  waters  at 
one  time  ;  nay,  even  though  the  relative  proportion  of  land  and  sea  may 
have  continued  unaltered  throughout  the  whole  period.  I  believe,  how- 
ever, that  since  the  commencement  of  the  tertiary  period,  the  dry  land 
in  the  northern  hemisphere  has  been  continually  on  the  increase,  both 
because  it  is  now  greatly  in  excess  beyond  the  average  proportion  which 
land  generally  bears  to  water  on  the  globe,  and  because  a  comparison 
of  the  secondary  and  tertiary  strata  affords  indications,  as  I  have  already 
shown,  of  a  passage  from  the  condition  of  an  ocean  interspersed  with 
islands  to  that  of  a  large  continent. 

But  supposing  it  were  possible  to  represent  all  the  vicissitudes  in  the 
distribution  of  land  and  sea  that  have  occurred  during  the  tertiary  pe- 
riod, and  to  exhibit  not  only  the  actual  existence  of  land  where  there 
was  once  sea,  but  also  the  extent  of  surface  now  submerged  which  may 
once  have  been  land,  the  map  would  still  fail  to  express  all  the  import 
ant  revolutions  in  physical  geography  which  have  taken  place  within  the 
epoch  under  consideration.  For  the  oscillations  of  level,  as  was  before 
stated,  have  not  merely  been  such  as  to  lift  up  the  land  from  below  the 
water,  but  in  some  cases  to  occasion  a  rise  of  many  thousand  feet  above 
the  sea.  Thus  the  Alps  have  acquired  an  additional  altitude  of  4000, 
and  even  in  some  places  10,000  feet ;  and  the  Apennines  owe  a  con- 


124  CHANGES   IN    PHYSICAL   GEOGRAPHY  [On.  VIII. 

siderable  part  of  their  present  height  to  subterranean  convulsions  which 
have  happened  within  the  tertiary  epoch. 

On  the  other  hand,  some  mountain  chains  may  have  been  lowered 
during  the  same  series  of  ages,  in  an  equal  degree,  and  shoals  may  have 
been  converted  into  deep  abysses.*  Since  this  map  was  recast  in  1847, 
geologists  have  very  generally  come  to  the  conclusion  that  the  nummu- 
litic  limestone,  together  with  the  overlying  fucoidal  grit  and  shale,  called 
"  Flysch,"  in  the  Alps,  belongs  to  the  older  tertiary  or  Eocene  group. 
As  these  nummulitic  rocks  enter  into  the  structure  of  some  of  the  most 
lofty  and  disturbed  parts  of  the  Alps,  Apennines,  Carpathians,  Pyrenees, 
and  other  mountain  chains,  and  form  many  of  the  elevated  lands  of  Af- 
rica and  Asia,  their  position  almost  implies  the  ubiquity  of  the  post- 
Eocene  ocean,  not,  indeed,  by  the  simultaneous,  but  by  the  successive, 
occupancy  of  the  whole  ground  by  its  waters. f 

Concluding  remarks  on  changes  in  physical  geography. — The  foregoing 
observations,  it  may  be  said,  are  confined  chiefly  to  Europe,  and  there- 
fore merely  establish  the  increase  of  dry  land  in  a  space  which  consti- 
tutes but  a  small  portion  of  the  northern  hemisphere  ;  but  it  was  stated 
in  the  preceding  chapter,  that  the  great  Lowland  of  Siberia,  lying  chiefly 
between  the  latitudes  55°  and  75°  N.  (an  area  nearly  equal  to  all  Eu- 
rope), is  covered  for  the  most  part  by  marine  strata,  which,  from  the 
account  given  by  Pallas,  and  more  recently  by  Sir  R.  Murchison,  belongs 
to  a  period  when  all  or  nearly  all  the  shells  were  of  a  species  still  living 
in  the  north.  The  emergence,  therefore,  of  this  area  from  the  deep  is, 
comparatively  speaking,  a  very  modern  event,  and  must,  as  before  re- 
marked, have  caused  a  great  increase  of  cold  throughout  the  globe. 

Upon  a  review,  then,  of  all  the  facts  above  enumerated,  respecting 
the  ancient  geography  of  the  globe  as  attested  by  geological  monuments, 
there  appear  good  grounds  for  inferring  that  changes  of  climate  coin- 
cided with  remarkable  revolutions  in  the  former  position  of  sea  and  land.  A 
wide  expanse  of  ocean,  interspersed  with  islands,  seems  to  have  pervaded 
the  northern  hemisphere  at  the  periods  when  the  Silurian  and  carbonif- 
erous rocks  were  formed,  and  a  warm  and  very  uniform  temperature 
then  prevailed.  Subsequent  modifications  in  climate  accompanied  the 
deposition  of  the  secondary  formations,  when  repeated  changes  were  ef- 
fected in  the  physical  geography  of  our  northern  latitudes.  Lastly,  the 
refrigeration  became  most  decided,  and  the  climate  most  nearly  assimila- 
ted to  that  now  enjoyed,  when  the  lands  in  Europe  and  northern  Asia  had 
attained  their  full  extension,  and  the  mountain  chains  their  actual  height. 

Soon  after  the  first  publication  of  this  theory  of  climate,  an  objection 
was  made  by  an  anonymous  German  critic  in  1833  that  there  are  no 
geological  proofs  of  the  prevalence  at  any  former  period  of  a  temperature 

*  It  may  be  observed,  that  the  facts  and  inferences  exhibited  in  this  map  bear 
not  merely  on  the  theory  of  climate  above  proposed,  but  serve  also  to  illustrate 
the  views  explained  in  the  third  book  respecting  the  migration  of  animals  and 
plants  and  the  gradual  extinction  of  species. 

f  See  Sir  R.  Murchison's  Paper  on  the  Alps,  Quart.  Journ.  Geol.  Soc.  vol.  v. 
and  my  Anniversary  Address  for  1850,  ibid.  vol.  vi. 


CH.  VIII.]  AND   CLIMATE   CONTEMPORANEOUS.  125 

lower  than  that  now  enjoyed  ;  whereas,  if  the  causes  above  assigned 
were  the  true  ones,  it  might  reasonably  have  been  expected  that  fossil 
remains  would  sometimes  indicate  colder  as  well  as  hotter  climates  than 
those  now  established.*  In  answer  to  this  objection,  I  may  suggest, 
that  our  present  climates  are  probably  far  more  distant  from  the  extreme 
of  possible  heat  than  from  its  opposite  extreme  of  cold.  A  glance  at 
the  map  (fig.  6,  p.  Ill)  will  show  that  all  the  existing  lands  might  be 
placed  between  the  30th  parallels  of  latitude  on  each  side  of  the  equator, 
and  that  even  then  they  would  by  no  means  fill  that  space.  In  no  other 
position  would  they  give  rise  to  so  high  a  temperature.  But  the  present 
geographical  condition  of  the  earth  is  so  far  removed  from  such  a  state 
of  things,  that  the  land  lying  between  the  poles  and  the  parallels  of  30, 
is  in  great  excess ;  so  much  so  that,  instead  of  being  to  the  sea  in  the 
proportion  of  1  to  3,  which  is  as  near  as  possible  'the  average  general 
ratio  throughout  the  globe,  it  is  9  to  23.f  Hence  it  ought  not  to  sur- 
prise us  if,  in  our  geological  retrospect,  embracing  perhaps  a  small  part 
only  of  a  complete  cycle  of  change  in  the  terrestrial  climates,  we  should 
happen  to  discover  everywhere  the  signs  of  a  higher  temperature.  The 
strata  hitherto  examined  may  have  originated  when  the  quantity  of  equa- 
torial land  was  always  decreasing  and  the  land  in  regions  nearer  the 
poles  augmenting  in  height  and  area,  until  at  length  it  attained  its  pres- 
ent excess  in  high  latitudes.  There  is  nothing  improbable  in  supposing 
that  the  geographical  revolutions  of  which  we  have  hitherto  obtained 
proofs  had  this  general  tendency ;  and  in  that  case  the  refrigeration  must 
have  been  constant,  although,  for  reasons  before  explained,  the  rate  of 
cooling  may  not  have  been  uniform. 

It  may,  however,  be  as  well  to  recall  the  reader's  attention  to  what 
was  before  said  of  the  indication  brought  to  light  of  late  years,  of  a  con- 
siderable oscillation  of  temperature,  in  the  period  immediately  preceding 
the  human  era.  We  have  seen  that  on  examining  some  of  the  most 
northern  deposits,  those  commonly  called  the  northern  drift  in  Scotland, 
Ireland,  and  Canada,  in  which  nearly  all,  in  some  cases,  perhaps  all,  the 
fossil  shells  are  of  recent  species,  we  discover  the  signs  of  a  climate  colder 
than  that  now  prevailing  in  corresponding  latitudes  on  both  sides  the 
Atlantic.  It  appears  that  an  arctic  fauna  specifically  resembling  that 
of  the  present  seas,  extended  farther  to  the  south  than  now.  This  opin- 
ion is  derived  partly  from  the  known  habitations  of  the  corresponding 
living  species,  and  partly  from  the  abundance  of  certain  genera  of  shells 

*  Allgemeine  Literatur  Zeitung,  No.  cxxxix.     July,  1833. 

f  In  this  estimate,  the  space  within  the  antarctic  circle  is  not  taken  into  ac- 
count :  if  included,  it  would  probably  add  to  the  excess  of  dry  land  ;  for  the  late 
discoveries  of  Capt.  Sir  James  Ross,  who  penetrated  to  lat.  78°  10'  S.,  confirm  the 
conjecture  of  Captain  Cook  that  the  accumulation  of  antarctic  ice  implies  the  pres- 
ence of  a  certain  quantity  of  terra  firina.  The  number  of  square  miles  on  the  sur- 
face of  the  globe  are  148,522,000,  the  part  occupied  by  the  sea  being  110,849,000, 
and  that  by  land,  37,673,000 ;  so  that  the  land  is  very  nearly  to  the  sea  as  1  part 
in  4.  I  am  informed  by  Mr.  Gardner  that,  according  to  a  rough  approximation,  the 
land  between  the  30°  N.  lat.  and  the  pole  occupies  a  space  about  equal  to  that  of 
the  sea,  and  the  land  between  the  30°  S.  lat.  and  the  antarctic  circle  about  one- 
sixteenth  of  that  zone. 


126  ASTRONOMICAL   CAUSES    OF  [On.  VIII. 

and  the  absence  of  others.*  The  date  of  the  refrigeration  thus  inferred 
appears  to  coincide  very  nearly  with  the  era  of  the  dispersion  of  erratic 
blocks  over  Europe  and  North  America,  a  phenomenon  which  will  be  as- 
cribed in  the  sequel  (ch.  16)  to  the  cold  then  prevailing  in  the  northern 
hemisphere.  The  force,  moreover,  of  the  German  critic's  objection  has 
been  since  in  a  great  measure  destroyed,  by  the  larger  and  more  profound 
knowledge  acquired  in  the  last  few  years  of  the  ancient  carboniferous  flora, 
which  has  led  the  ablest  botanists  to  adopt  the  opinion,  that  the  climate 
of  the  coal  period  was  remarkable  for  its  warmth,  moisture,  equability, 
and  freedom  from  cold,  rather  than  the  intensity  of  its  tropical  heat.  We 
are  therefore  no  longer  entitled  to  assume  that  there  has  been  a  constant 
and  gradual  decline  in  the  absolute  amount  of  heat  formerly  contained 
in  the  atmosphere  and  waters  of  the  ocean,  such  as  it  was  conjectured 
might  have  emanated  from  the  incandescent  central  nucleus  of  a  new 
and  nearly  fluid  planet,  before  the  interior  had  lost,  by  radiation  into 
surrounding  space,  a  great  part  of  its  original  high  temperature. 

Astronomical  causes  of  fluctuations  in  climate. — Sir  John  Herschel 
has  lately  inquired,  whether  there  are  any  astronomical  causes  which 
may  offer  a  possible  explanation  of  the  difference  between  the  actual 
climate  of  the  earth's  surface,  and  those  which  formerly  appear  to  have 
prevailed.  He  has  entered  upon  this  subject,  he  says,  "impressed  with 
the  magnificence  of  that  view  of  geological  revolutions,  which  regards 
them  rather  as  regular  and  necessary  effects  of  great  and  general  causes, 
than  as  resulting  from  a  series  of  convulsions  and  catastrophes,  regulated 
by  no  laws,  and  reducible  to  no  fixed  principles."  Geometers,  he  adds, 
have  demonstrated  the  absolute  invariability  of  the  mean  distance  of  the 
earth  from  the  sun ;  whence  it  would  at  first  seem  to  follow,  that  the 
mean  annual  supply  of  light  and  heat  derived  from  that  luminary  would 
be  alike  invariable  :  but  a  closer  consideration  of  the  subject  will  show, 
that  this  would  not  be  a  legitimate  conclusion ;  but  that  on  the  contrary, 
the  mean  amount  of  solar  radiation  is  dependent  on  the  eccentricity  of 
the  earth's  orbit,  and  therefore  liable  to  variation.! 

Now  the  eccentricity  of  the  orbit,  he  continues,  is  actually  diminish- 
ing, and  has  been  so  for  ages  beyond  the  records  of  history.  In  conse- 
quence, the  ellipse  is  in  a  state  of  approach  to  a  circle,  and  the  annual 
average  of  solar  heat  radiated  to  the  earth  is  actually  on  the  decrease.  So 
far  this  is  in  accordance  with  geological  evidence,  which  indicates  a  gen- 
eral refrigeration  of  climate  ;  but  the  question  remains,  whether  the  amount 
of  diminution  which  the  eccentricity  may  have  ever  undergone  can  be  sup- 
posed sufficient  to  account  for  any  sensible  refrigeration.  The  calcula- 

*  See  papers  by  Mr.  Smith  of  Jordanhill,  F.  G.  S.,  and  the  author,  Proceedings 
Geol.  Soc.  No.  63,  1839,  also  that  of  Prof.  E.  Forbes,  before  cited,  p.  86,  note. 

f  The  theorem  is  thus  stated  : — "  The  eccentricity  of  the  orbit  varying,  the  total 
quantity  of  heat  received  by  the  earth  from  the  sun  in  one  revolution  is  inversely 
proportional  to  the  minor  axis  of  the  orbit.  The  major  axis  is  invariable,  and  there- 
fore, of  course,  the  absolute  length  of  the  year :  hence  it  follows  that  the  mean  an- 
nual average  of  heat  will  also  be  in  the  same  inverse  ratio  of  the  minor  axis." — 
Geol.  Trans,  second  series,  vol.  iil  p.  295. 


CH.  VIII.]  CHANGES   IN    CLIMATE.  127 

tions  necessary  to  determine  this  point,  though  practicable,  have  never 
yet  been  made,  and  would  be  extremely  laborious  ;  for  they  must  em- 
brace all  the  perturbations  which  the  most  influential  planets,  Venus, 
Mars,  Jupiter,  and  Saturn,  would  cause  in  the  earth's  orbit,  and  in  each 
other's  movements  round  the  sun. 

The  problem  is  also  very  complicated,  inasmuch  as  it  depends  not 
merely  on  the  ellipticity  of  the  earth's  orbit,  but  on  the  assumed  tem- 
perature of  the  celestial  spaces  beyond  the  earth's  atmosphere  ;  a  mat- 
ter still  open  to  discussion,  and  on  which  M.  Fourier  and  Sir  J.  Herschel 
have  arrived  at  very  different  opinions.  But  if,  says  Herschel,  we  sup- 
pose an  extreme  case,  as  if  the  earth's  orbit  should  ever  become  as  ec- 
centric as  that  of  the  planet  Juno  or  Pallas,  a  great  change  of  climate 
might  be  conceived  to  result,  the  winter  and  summer  temperatures 
being  sometimes  mitigated,  and  at  others  exaggerated,  in  the  same  lati- 
tudes. 

It  is  much  to  be  desired  that  the  calculations  alluded  to  were  exe- 
cuted, as  even  if  they  should  demonstrate,  as  M.  Arago  thinks  highly 
probable,*  that  the  mean  amount  of  solar  radiation  can  never  be  mate- 
rially affected  by  irregularities  in  the  earth's  motion,  it  would  still  be 
satisfactory  to  ascertain  the  point.  Such  inquiries,  however,  can  never 
supersede  the  necessity  of  investigating  the  consequences  of  the  varying 
position  of  continents,  shifted  as  we  know  them  to  have  been  during 
successive  epochs,  from  one  part  of  the  globe  to  the  other. 

Another  astronomical  hypothesis  respecting  the  possible  cause  of  sec- 
ular variations  in  climate,  has  been  proposed  by  a  distinguished  mathe- 
matician and  philosopher,  M.  Poisson.  He  begins  by  assuming,  1st, 
that  the  sun  and  our  planetary  system  are  not  stationary,  but  carried 
onward  by  a  common  movement  through  space  ;  2dly,  that  every  point 
in  space  receives  heat  as  well  as  light  from  innumerable  stars  surround- 
ing it  on  all  sides,  so  that  if  a  right  line  of  indefinite  length  be  produced 
in  any  direction  from  such  a  point,  it  must  encounter  a  star  either  visible 
or  invisible  to  us.  3dly,  He  then  goes  on  to  assume,  that  the  different 
regions  of  space,  which  in  the  course  of  millions  of  years  are  traversed 
by  our  system,  must  be  of  very  unequal  temperature,  inasmuch  as  some 
of  them  must  receive  a  greater,  others  a  less,  quantity  of  radiant  heat 
from  the  great  stellary  inclosure.  If  the  earth,  he  continues,  or  any 
other  large  body,  pass  from  a  hotter  to  a  colder  region,  it  would  not 
readily  lose  in  the  second  all  the  heat  which  it  has  imbibed  in  the  first 
region,  but  retain  a  temperature  increasing  downwards  from  the  surface, 
as  in  the  actual  condition  of  our  planet,  f 

Now  the  opinion  originally  suggested  by  Sir  W.  Herschel,  that  our 
sun  and  its  attendant  planets  were  all  moving  onward  through  space, 
in  the  direction  of  the  constellation  Hercules,  is  very  generally  thought 
by  eminent  astronomers  to  be  confirmed.  But  even  if  its  reality  be 

*  Ann.  du  Bur.  des  Long.  1834. 

f  Poisson,  Theorie  Mathemat.  de  la  Chaleur,  Comptes  Rendus  de  1'Acad  des 
Sci.,  Jan.  30,  1837. 


128  ASTRONOMICAL   CAUSES   OF  [On.  VIII. 

no  longer  matter  of  doubt,  conjectures  as  to  its  amount  are  still  vague 
and  uncertain  ;  and  great,  indeed,  must  be  the  extent  of  the  movement 
before  this  cause  alone  can  work  any  material  alteration  in  the  terrestrial 
climates.  Mr.  Hopkins,  when  treating  of  this  theory,  remarked,  that  so 
far  as  we  were  acquainted  with  the  position  of  the  stars  not  very  remote 
from  the  sun,  they  seem  to  be  so  distant  from  each  other,  that  there  are 
no  points  in  space  among  them,  where  the  intensity  of  radiating  heat 
would  be  comparable  to  that  which  the  earth  derives  from  the  sun,  ex- 
cept at  points  very  near  to  each  star.  Thus,  in  order  that  the  earth 
should  derive  a  degree  of  heat  from  stellar  radiation  comparable  to  that 
now  derived  from  the  sun,  she  must  be  in  close  proximity  to  some  par- 
ticular star,  leaving  the  aggregate  effect  of  radiation  from  the  other  stars 
nearly  the  same  as  at  present.  This  approximation,  however,  to  a  sin- 
gle star  could  not  take  place  consistently  with  the  preservation  of  the 
motion  of  the  earth  about  the  sun,  according  to  its  present  laws. 

Suppose  our  sun  should  approach  a  star  within  the  present  distance 
of  Neptune.  That  planet  could  no  longer  remain  a  member  of  the  solar 
system,  and  the  motions  of  the  other  planets  would  be  disturbed  in  a 
degree  which  no  one  has  ever  contemplated  as  probable  since  the  exist- 
ence of  the  solar  system.  But  such  a  star,  supposing  it  to  be  no  larger 
than  the  sun,  and  to  emit  the  same  quantity  of  heat,  would  not  send  to 
the  earth  much  more  than  one-thousandth  part  of  the  heat  which  she 
derives  from  the  sun,  and  would  therefore  produce  only  a  very  small 
change  in  terrestrial  temperature.* 

Variable  splendor  of  stars. — There  is  still  another  astronomical  sug- 
gestion respecting  the  possible  causes  of  secular  variations  in  the  terres- 
trial climates  which  deserves  notice.  It  has  long  been  known  that  cer- 
tain stars  are  liable  to  great  and  periodical  fluctuations  in  splendor,  and 
Sir  J.  Herschel  has  lately  ascertained  (Jan.  1840),  that  a  large  and 
brilliant  star,  called  alpha  Orionis,  sustained,  in  the  course  of  six  weeks, 
a  loss  of  nearly  half  its  light.  "  This  phenomenon,"  he  remarks,  "  can- 
not fail  to  awaken  attention,  and  revive  those  speculations  which  were 
first  put  forth  by  my  father  Sir  W.  Herschel,  respecting  the  possibility 
of  a  change  in  the  lustre  of  our  sun  itself.  If  there  really  be  a  commu- 
nity of  nature  between  the  sun  and  fixed  stars,  every  proof  that  we  ob- 
tain of  the  extensive  prevalence  of  such  periodical  changes  in  those  re- 
mote bodies,  adds  to  the  probability  of  finding  something  of  the  kind 
nearer  home."  Referring  then  to  the  possible  bearing  of  such  facts  on 
ancient  revolutions,  in  terrestrial  climates,  he  says,  that  "  it  is  a  matter 
of  observed  fact,  that  many  stars  have  undergone,  in  past  ages,  within 
the  records  of  astronomical  "history,  very  extensive  changes  in  apparent 
lustre,  without  a  change  of  distance  adequate  to  producing  such  an  •  ef- 
fect. If  our  sun  were  even  intrinsically  much  brighter  than  at  present, 
the  mean  temperature  of  the  surface  of  our  globe  would,  of  course,  be 
proportionally  greater.  I  speak  now  not  of  periodical,  but  of  secular 

*  Quart.  Journ.  Geol.  Soc.  1852,  p.  62, 


Cn.  VIII.]  PRIMITIVE    HEAT    OF    THE    EARTH.  129 

changes.  But  the  argument  is  complicated  with  the  consideration  of 
the  possibly  imperfect  transparency  of  the  celestial  spaces,  and  with  the 
cause  of  that  imperfect  transparency,  which  may  be  due  to  material 
non-luminous  particles  diffused  irregularly  in  patches  analogous  to  neb- 
ulae, but  of  greater  extent — to  cosmical  clouds,  in  short — of  whose  ex- 
istence we  have,  I  think,  some  indication  in  the  singular  and  apparently 
capricious  phenomena  of  temporary  stars,  and  perhaps  in  the  recent 
extraordinary  sudden  increase  and  hardly  less  sudden  diminution  of 
f\  Argus"* 

More  recently  (1852)  Schwabe  has  observed  that  the  spots  on  the 
sun  alternately  increase  and  decrease  in  the  course  of  every  ten  years, 
and  Captain  Sabine  has  pointed  out  that  this  variable  obscuration  coin- 
cides in  time  both  as  to  its  maximum  and  minimum  with  changes  in  all 

O 

those  terrestrial  magnetic  variations  which  arc  caused  by  the  sun. 
Hence  he  infers  that  the  period  of  alteration  in  the  spots  is  a  solar  mag- 
netic period.  Assuming  such  to  be  the  case,  the  variable  light  of  some 
stars  may  indicate  a  similar  phenomenon,  or  they  may  be  stellar  mag- 
netic periods,  differing  only  in  the  degree  of  obscuration  and  its  dura- 
tion. And  as  hitherto  we  have  perceived  no  fluctuation  in  the  heat 
received  by  the  earth  from  the  sun  coincident  with  the  solar  magnetic 
period,  so  the  fluctuations  in  the  brilliancy  of  the  stars  may  not  per- 
haps be  attended  with  any  perceptible  alteration  in  their  power  of  ra- 
diating heat.  But  before  we  can  speculate  with  advantage  in  this  new 
and  interesting  field  of  inquiry,  we  require  more  facts  and  observations. 

Supposed  gradual  diminution  of  the  earth's  primitive  heat. — The 
gradual  diminution  of  the  supposed  primitive  heat  of  the  globe  has  been 
resorted  to  by  many  geologists  as  the  principal  cause  of  alterations  of 
climate.  The  matter  of  our  planet  is  imagined,  in  accordance  with  the 
conjectures  of  Leibnitz,  to  have  been  originally  in  an  intensely  heated 
state,  and  to  have  been  parting  ever  since  with  portions  of  its  heat,  and 
at  the  same  time  contracting  its  dimensions.  There  are,  undoubtedly, 
good  grounds  for  inferring  from  recent  observation  and  experiment,  that 
the  temperature  of  the  earth  increases  as  we  descend  from  the  surface 
to  that  slight  depth  to  which  man  can  penetrate  :  but  there  are  no 
positive  proofs  of  a  secular  decrease  of  internal  heat  accompanied  by 
contraction.  On  the  contrary,  La  Place  has  shown,  by  reference  to 
astronomical  observations  made  in  the  time  of  Hipparchus,  that  in  the 
last  two  thousand  years  at  least  there  has  been  no  sensible  contraction 
of  the  globe  by  cooling  ;  for  had  this  been  the  case,  even  to  an  ex- 
tremely small  amount,  the  day  would  have  been  shortened,  whereas  its 
length  has  certainly  not  diminished  during  that  period  by  3- J^th  of  a 
second. 

Baron  Fourier,  after  making  a  curious  series  of  experiments  on  the 
cooling  of  incandescent  bodies,  considers  it  to  be. proved  mathematically, 
that  the  actual  distribution  of  heat  in  the  earth's  envelope  is  precisely 

*  Proceedings  Roy.  Astronom.  Soc.  No.  iii.  Jan.  1840. 

9  J 


130  THEOKY    OF    PROGRESSIVE   DEVELOPMENT  [Cn.  IX.. 

that  which  would  have  taken  place  if  the  globe  had  been  formed  in  a 
medium  of  a  very  high  temperature,  and  had  afterwards  been  constantly 
cooled.*  He  contends,  that  although  no  contraction  can  be  demon- 
strated to  have  taken  place  within  the  historical  period  (the  operation 
being  slow  and  the  time  of  observation  limited),  yet  it  is  no  less  certain 
that  heat  is  annually  passing  out  by  radiation  from  the  interior  of  the 
globe  into  the  planetary  spaces.  He  even  undertook  to  demonstrate 
that  the  quantity  of  heat  thus  transmitted  into  space  in  the  course  of 
every  century,  through  every  square  metre  of  the  earth's  surface,  would 
suffice  to  melt  a  column  of  ice  having  a  square  metre  for  its  base,  and 
being  three  metres  (or  9  feet  10  inches)  high. 

It  is  at  the  same  time  denied,  that  there  is  any  assignable  mode  in 
which  the  heat  thus  lost  by  radiation  can  be  again  restored  to  the  earth, 
and  consequently  the  interior  of  our  planet  must,  from  the  moment  of 
its  creation,  have  been  subject  to  refrigeration,  and  is  destined  together 
with  the  sun  and  stars  forever  to  grow  colder.  But  I  shall  point  out 
in  the  sequel  (chapter  31)  many  objections  to  these  views,  and  to  the 
theory  of  the  intense  heat  of  the  earth's  central  nucleus,  and  shall  then 
inquire  how  far  the  observed  augmentation  of  temperature,  as  we  de- 
scend below  the  surface,  may  be  referable  to  other  causes  unconnected 
with  the  supposed  pristine  fluidity  of  the  entire  globe. 


CHAPTER  IX. 

THEORY    OF    THE    PROGRESSIVE    DEVELOPMENT    OF    ORGANIC    LIFE    AT 
SUCCESSIVE    GEOLOGICAL    PERIODS. 

Theory  of  the  progressive  development  of  organic  life — Evidence  in  its  support 
inconclusive — Vertebrated  animals,  and  plants  of  the  most  perfect  organization, 
in  strata  of  very  high  antiquity — Differences  between  the  organic  remains  of 
successive  formations — Comparative  modern  origin  of  the  human  race — The 
popular  doctrine  of  successive  development  not  established  by  the  admission 
that  man  is  of  modern  origin — Introduction  of  man,  to  what  extent  a  change  in 
the  system. 

Progressive  development  of  organic  life. — IN  the  preceding  chapters  I 
have  considered  whether  revolutions  in  the  general  climate  of  the  globe 
afford  any  just  ground  of  opposition  to  the  doctrine  that  the  former 
changes  of  the  earth  which  are  treated  of  in  geology  belong  to  one  un- 
interrupted series  of  physical  events  governed  by  ordinary  causes. 
Against  this  doctrine  some  popular  arguments  have  been  derived  from 
the  great  vicissitudes  of  the  organic  creation  in  times  past ;  I  shall 

*  See  a  Memoir  on  the  Temperature  of  the  Terrestrial  Globe,  and  the  Planet- 
arv  Spaces,  Ann.  de  Chimie  et  Phys.  torn,  xxvii.  p.  136.  Oct.  1824. 


CH.  IX.]  AT   SUCCESSIVE   PERIODS.  131 

therefore  proceed  to  the  discussion  of  such  objections,  which  have  been 
thus  formally  advanced  by  the  late  Sir  Humphrey  Davy.  "  It  is  im- 
possible," he  affirms,  "  to  defend  the  proposition,  that  the  present  order 
of  things  is  the  ancient  and  constant  order  of  nature,  only  modified  by 
existing  laws :  in  those  strata  which  are  deepest,  and  which  must,  con- 
sequently, be  supposed  to  be  the  earliest  deposited,  forms  even  of  ve- 
getable life  are  rare  ;  shells  and  vegetable  remains  are  found  in  the  next 
order  ;  the  bones  of  fishes  and  oviparous  reptiles  exist  in  the  following 
class  ;  the  remains  of  birds,  with  those  of  the  same  genera  mentioned 
before,  in  the  next  order ;  those  of  quadrupeds  of  extinct  species  in  a 
still  more  recent  class  ;  and  it  is  only  in  the  loose  and  slightly  consoli- 
dated strata  of  gravel  and  sand,  and  which  are  usually  called  'diluvian 
formations,  that  the  remains  of  animals  such  as  now  people  the  globe 
are  found,  with  others  belonging  to  extinct  species.  But,  in  none  of 
these  formations,  whether  called  secondary,  tertiary,  or  diluvial,  have 
the  remains  of  man,  or  any  of  his  works,  been  discovered  ;  and  who- 
ever dwells  upon  this  subject  must  be  convinced,  that  the  present  order 
of  things,  and  the  comparatively  recent  existence  of  man  as  the  mastei 
of  the  globe,  is  as  certain  as  the  destruction  of  a  former  and  a  different 
order,  and  the  extinction  of  a  number  of  living  forms  which  have  no 
types  in  being.  In  the  oldest  secondary  strata  there  are  no  remains  of 
such  animals  as  now  belong  to  the  surface ;  and  in  the  rocks,  which 
may  be  regarded  as  more  recently  deposited,  these  remains  occur  but 
rarely,  and  with  abundance  of  extinct  species  ; — there  seems,  as  it  were, 
a  gradual  approach  to  the  present  system  of  things,  and  a  succession  of 
destructions  and  creations  preparatory  to  the  existence  of  man."* 

In  the  above  passages,  the  author  deduces  two  important  conclusions 
from  geological  data :  first,  that  in  the  successive  groups  of  strata, 
from  the  oldest  to  the  most  recent,  there  is  a  progressive  development 
of  organic  life,  from  the  simplest  to  the  most  complicated  forms  ; — 
secondly,  that  man  is  of  comparatively  recent  origin,  and  these  conclu- 
sions he  regards  as  inconsistent  with  the  doctrine,  "  that  the  present 
order  of  things  is  the  ancient  and  constant  order  of  nature  only  modified 
by  existing  laws." 

With  respect,  then,  to  the  first  of  these  propositions,  we  may  ask 
whether  the  theory  of  the  progressive  development  of  animal  and  vege- 
table life,  and  their  successive  advancement  from  a  simple  to  a  more 
perfect  state,  has  any  secure  foundation  in  fact  ?  No  geologists  who 
are  in  possession  of  all  the  data  now  established  respecting  fossil  re- 
mains, will  for  a  moment  contend  for  the  doctrine  in  all  its  detail,  as 
laid  down  by  the  distinguished  philosopher  to  whose  opinions  we  hare 
referred :  but  naturalists,  who  are  not  unacquainted  with  recent  discov- 
eries, continue  to  defend  it  in  a  modified  form.  They  say  that  in  the 
first  period  of  the  world  (by  which  they  mean  the  earliest  of  which  we 
have  yet  brought  to  light  any  memorials),  the  vegetation  was  charac- 
terized by  a  predominance  of  cryptogamic  plants,  while  the  animals 
*  Sir  H.  Davy,  Consolations  in  Travel :  Dialogue  III.  "  The  Unknown." 


132         THEORY  OF  PROGRESSIVE  DEVELOPMENT      [CH.  IX. 

which  coexisted  were  almost  entirely  confined  to  zoophytes,  testacea, 
and  a  few  fish.  Plants  of  a  less  simple  structure,  coniferae  and  cyca- 
dese,  flourished  largely  in  the  next  epoch,  when  oviparous  reptiles  began 
also  to  abound.  Lastly,  the  terrestrial  flora  became  most  diversified 
and  most  perfect  when  the  highest  orders  of  animals,  the  mammalia 
and  birds,  were  called  into  existence. 

Now  in  the  first  place,  it  may  be  observed,  that  many  naturalists  are 
guilty  of  no  small  inconsistency  in  endeavoring  to  connect  the  phe- 
nomena of  the  earliest  vegetation  with  a  nascent  condition  of  organic  life, 
and  at  the  same  time  to  deduce  from  the  numerical  predominance  of 
certain  forms,  the  greater  heat  or  uniformity  of  the  ancient  climate. 
The  arguments  in  favor  of  the  latter  conclusion  are  without  any  force, 
unless  we  can  assume  that  the  rules  followed  by  the  Author  of  Nature 
in  the  creation  and  distribution  of  organic  beings  were  the  same  for- 
merly as  now ;  and  that,  as  certain  families  of  animals  and  plants  are 
now  most  abundant  in,  or  exclusively  confined  to  regions  where  there  is 
a  certain  temperature,  a  certain  degree  of  humidity,  a  certain  intensity 
of  light,  and  other  conditions,  so  also  analogous  phenomena  were  ex- 
hibited at  every  former  era. 

If  this  postulate  be  denied,  and  the  prevalence  of  particular  families 
be  declared  to  depend  on  a  certain  order  of  precedence  in  the  introduc- 
tion of  different  classes  into  the  earth,  and  if  it  be  maintained  that  the 
standard  of  organization  was  raised  successively,  we  must  then  ascribe 
the  numerical  preponderance,  in  the  earlier  ages,  of  plants  of  simpler 
structure,  not  to  the  heat,  or  other  climatal  conditions,  but  to  those  dif- 
ferent laws  which  regulate  organic  life  in  newly  created  worlds. 

Before  we  can  infer  a  warm  and  uniform  temperature  in  high  lati- 
tudes, from  the  presence  of  250  species  of  ferns,  some  of  them  arbo- 
rescent, accompanied  by  lycopadiacse  of  large  size,  and  araucaria3,  we 
must  be  permitted  to  assume,  that  at  all  times,  past,  present,  and 
future,  a  heated  and  moist  atmosphere  pervading  the  northern  hemi- 
sphere has  a  tendency  to  produce  in  the  vegetation  a  predominance  of 
analogous  forms. 

It  should  moreover  be  borne  in   mind,  when  we  are  considering  the 

t3 

question  of  development  from  a  botanical  point  of  view,  that  naturalists 
are  by  no  means  agreed  as  to  the  existence  of  an  ascending  scale  of 
organization  in  the  vegetable  world  corresponding  to  that  which  is  very 
generally  recognized  in  animals.  "  From  the  sponge  to  man,"  in  the 
language  of  De  Blainville,  there  may  be  a  progressive  chain  of  being, 
although  often  broken  and  imperfect ;  but  if  we  seek  to  classify  plants 
according  to  a  linear  arrangement,  ascending  gradually  from  the  lichen 
to  the  lily  or  the  rose,  we  encounter  incomparably  greater  difficulties. 
Yet  the  doctrine  of  a  more  highly  developed  organization  in  the  plants 
created  at  successive  periods  presupposes  the  admission  of  such  a 
graduated  scale. 

We  have  as  yet  obtained  but  scanty  information  respecting  the  state 
of  the  terrestrial  flora  at  periods  antecedent  to  the  coal.  In  the  carbon- 


CH.  IX.]  AT   SUCCESSIVE   PERIODS.  133 

iferous  epoch,  about  500  species  of  fossil  plants  are  enumerated  by 
Adolphe  Brongniart,  which  we  may  safely  regard  as  a  mere  fragment  of 
an  ancient  flora ;  since,  in  Europe  alone,  there  are  now  no  less  than 
11,000  living  species.  I  have  already  hinted  that  the  plants  which 
produced  coal  were  not  drifted  from  a  distance,  but  that  nearly  all  of 
them  grew  on  the  spots  where  they  became  fossil.  They  appear  to 
have  belonged,  as  before  explained  (p.  115),  to  a  peculiar  class  of  sta- 
tions,— to  low  level  and  swampy  regions,  in  the  deltas  of  large  rivers, 
slightly  elevated  above  the  level  of  the  sea.  From  the  study,  there- 
fore, of  such  a  vegetation,  we  can  derive  but  little  insight  into  the  na- 
ture of  the  contemporaneous  upland  flora,  still  less  of  the  plants  of  the 
mountainous  or  Alpine  country  ;  and  if  so,  we  are  enabled  to  account 
for  the  apparent  monotony  of  the  vegetation,  although  its  uniform 
character  was  doubtless  in  part  owing  to  a  greater  uniformity  of  climate 
then  prevailing  throughout  the  globe.  Some  of  the  commonest  trees  of 
this  period,  such  as  the  sigillarise,  which  united  the  structure  of  ferns 
and  of  cycadese,  departed  very  widely  from  all  known  living  types. 
The  coniferae  and  ferns,  on  the  contrary,  were  very  closely  allied  to 
living  genera.  It  is  remarkable  that  none  of  the  exogens  of  Lindley 
(dicotyledonous  angiosperms  of  Brongniart),  which  comprise  four- 
fifths  of  the  living  flora  of  the  globe,  and  include  all  the  forest  trees  of 
Europe  except  the  fir-tribe,  have  yet  been  discovered  in  the  coal  meas- 
ures, and  a  very  small  number — fifteen  species  only — of  monocotyle- 
dons. If  several  of  these  last  are  true  plants,  an  opinion  to  which  Messrs. 
Lindley,  Unger,  Corda,  and  other  botanists  of  note  incline,  the  question 
whether  any  of  the  most  highly  organized  plants  are  to  be  met  with  in 
ancient  strata  is  at  once  answered  in  the  affirmative.  But  the  determi- 
nation of  these  palms  being  doubtful,  we  have  as  yet  in  the  coal  no 
positive  proofs  either  of  the  existence  of  the  most  perfect,  or  of  the 
most  simple  forms  of  flowering  or  flowerless  vegetation.  We  have  no 
fungi,  lichens,  hepatici  or  mosses :  yet  this  latter  class  may  have  been 
as  fully  represented  then  as  now. 

In  the  flora  of  the  secondary  eras,  all  botanists  agree  that  palms 
existed,  although  in  Europe  plants  of  the  family  of  zamia  and  cycas 
together  with  coniferae  predominated,  and  must  have  given  a  peculiar 
aspect  to  the  flora.  As  only  200  or  300  species  of  plants  are  known 
in  all  the  rocks  ranging  from  the  Trias  to  the  Oolite  inclusive,  our  data 
are  too  scanty  as  yet  to  affirm  whether  the  vegetation  of  this  second 
epoch  was  or  was  not  on  the  whole  of  a  simpler  organization  than  that 
of  our  own  times. 

In  the  Lower  Cretaceous  formation,  near  Aix-la-Chapelle,  the  leaves 
of  a  great  many  dicotyledonous  trees  have  lately  been  discovered  by 
Dr.  Debey,  establishing  the  important  fact  of  the  coexistence  of  a  large 
number  of  angiosperms  with  cycadece,  and  with  that  rich  reptilian  fauna 
comprising  the  ichthyosaur,  plesiosaur,  and  pterodactyl,  which  some  had 
supposed  to  indicate  a  state  of  the  atmosphere  unfavorable  to  a  dicoty- 
ledonous vegetation. 


134         THEORY  OF  PROGRESSIVE  DEVELOPMENT       [Cn.  IX. 

The  number  of  plants  hitherto  obtained  from  tertiary  strata  of  differ- 
ent ages  is  very  limited,  but  is  rapidly  increasing.  T.hey  are  referable 
to  a  much  greater  variety  of  families  and  classes  than  an  equal  number 
of  fossil  species  taken  from  secondary  or  primary  rocks,  the  angio- 
sperms  bearing  the  same  proportion  to  the  gymnosperms  and  acrogens 
as  in  the  present  flora  of,  the  globe.  This  greater  variety  may,  doubtless, 
be  partly  ascribed  to  the  greater  diversity  of  stations  in  which  the  plants 
grew,  as  we  have  in  this  case  an  opportunity,  rarely  enjoyed  in  study- 
ing the  secondary  fossils,  of  investigating  inland  or  lacustrine  deposits 
accumulated  at  different  heights  above  the  sea,  and  containing  the  me- 
morials of  plants  washed  down  from  adjoining  mountains. 

In  regard,  then,  to  the  strata  from  the  cretaceous  to  the  uppermost 
tertiary  inclusive,  we  may  affirm  that  we  find  in  them  all  the  principal 
classes  of  living  plants,  and  during  this  vast  lapse  of  time  four  or  five 
complete  changes  in  the  vegetation  occurred,  yet  no  step  whatever  was 
made  in  advance  at  any  of  these  periods  by  the  addition  of  more  highly 
organized  species. 

If  we  next  turn  to  the  fossils  of  the  animal  kingdom,  we  may  inquire 
whether,  when  they  are  arranged  by  the  geologists  in  a  chronological 
series,  they  imply  that  beings  of  more  highly  developed  structure  and 
greater  intelligence  entered  upon  the  earth  at  successive  epochs,  those 
of  the  simplest  organization  being  the  first  created,  and  those  more 
highly  organized  being  the  last. 

Our  knowledge  of  the  Silurian  fauna  is  at  present  derived  entirely 
from  rocks  of  marine  origin,  no  fresh- water  strata  of  such  high  antiquity 
having  yet  been  met  with.  The  fossils,  however,  of  these  ancient  rocks 
at  once  reduce  the  theory  of  progressive  development  to  within  very 
narrow  limits,  for  already  they  comprise  a  very  full  representation  of  the 
radiata,  mollusca,  and  articulata  proper  to  the  sea.  Thus,  in  the  great 
division  of  radiata,  we  find  asteriod  and  helianthoid  zoophytes,  be- 
sides crinoid  and  cystidean  echinoderms.  In  the  mollusca,  between 
200  and  300  species  of  cephalopoda  are  enumerated.  In  the  articulata 
we  have  the  crustaceans  represented  by  more  than  200  species  of  trilo- 
bites,  besides  other  genera  of  the  same  class.  The  remains  of  fish  are 
as  yet  confined  to  the  upper  part  of  the  Silurian  series  ;  but  some  of 
these  belong  to  placoid  fish,  which  occupy  a  high  grade  in  the  scale  of 
organization.  Some  naturalists  have  assumed  that  the  earliest  fauna 
was  exclusively  marine,  because  we  have  not  yet  found  a  single  Silurian 
helix,  insect,  bird,  terrestrial  reptile  or  mammifer ;  but  when  we  carry 
back  our  investigation  to  a  period  so  remote  from  the  present,  we  ought 
not  to  be  surprised  if  the  only  accessible  strata  should  be  limited  to 
deposits  formed  far  from  land,  because  the  ocean  probably  occupied 
then,  as  now,  the  greater  part  of  the  earth's  surface.  After  so  many 
entire  geographical  revolutions,  the  chances  are  nearly  three  to  one  in 
favor  of  our  finding  that  such  small  portions  of  the  existing  continents 
and  islands  as  expose  Silurian  strata  to  view,  should  coincide  in  position 
with  the  ancient  ocean  rather  than  the  land.  We  must  not,  therefore, 


Cn.  IX.]  AT   SUCCESSIVE   PERIODS.  135 

too  hastily  infer,  from  the  absence  of  fossil  bones  of  mammalia  in  the 
older  rocks,  that  the  highest  class  of  vertebrated  animals  did  not  exist 
in  remoter  ages.  There  are  regions  at  present,  in  the  Indian  and  Pacific 
Oceans,  coextensive  in  area  with  the  continents  of  Europe  and  North 
America,  where  we  might  dredge  the  bottom  and  draw  up  thousands 
of  shells  and  corals,  without  obtaining  one  bone  of  a  land  quadruped. 
Suppose  our  mariners  were  to  report,  that,  on  sounding  in  the  Indian 
Ocean  near  some  coral  reefs,  and  at  some  distance  from  the  land,  they 
drew  up  on  hooks  attached  to  their  line  portions  of  a  leopard,  elephant, 
or  tapir,  should  we  not  be  skeptical  as  to  the  accuracy  of  their  state- 
ments ?  and  if  we  had  no  doubt  of  their  veracity,  might  we  not  suspect 
them  to  be  unskilful  naturalists  ?  or,  if  the  fact  were  unquestioned, 
should  we  not  be  disposed  to  believe  that  some  vessel  had  been  wreck- 
ed on  the  spot  ? 

The  casualties  must  always  be  rare  by  which  land  quadrupeds  are 
swept  by  rivers  far  out  into  the  open  sea,  and  still  rarer  the  contingency 
of  such  a  floating  body  not  being  devoured  by  sharks  or  other  preda- 
ceous  fish,  such  as  were  those  of  which  we  find  the  teeth  preserved  in 
some  of  the  carboniferous  strata.  But  if  the  carcass  should  escape,  and 
should  happen  to  sink  where  sediment  was  in  the  act  of  accumulating, 
and  if  the  numerous  causes  of  subsequent  disintegration  should  not  ef- 
face all  traces  of  the  body,  included  for  countless  ages  in  solid  rock,  is 
it  not  contrary  to  all  calculation  of  chances  that  we  should  hit  upon  the 
exact  spot — that  mere  point  in  the  bed  of  an  ancient  ocean,  where  the 
precious  relic  was  entombed  ?  Can  we  expect  for  a  moment,  when  we 
have  only  succeeded,  amidst  several  thousand  fragments  of  corals  and 
shells,  in  finding  a  few  bones  of  aquatic  or  amphibious  animals,  that  we 
should  meet  with  a  single  skeleton  of  an  inhabitant  of  the  land  ? 

Clarence,  in  his  dream,  saw,  "  in  the  slimy  bottom  of  the  deep," 

a  thousand  fearful  wrecks  ; 

A  thousand  men,  that  fishes  gnaw'd  upon : 
Wedges  of  gold,  great  anchors,  heaps  of  pearl. 

Had  he  also  beheld,  amid  "  the  dead  bones  that  lay  scattered  by,"  the 
carcasses  of  lions,  deer,  and  the  other  wild  tenants  of  the  forest  and  the 
plain,  the  fiction  would  have  been  deemed  unworthy  of  the  genius  of 
Shakspeare.  So  daring  a  disregard  of  probability  and  violation  of  anal- 
ogy would  have  been  condemned  as  unpardonable,  even  where  the  poet 
was  painting  those  incongruous  images  which  present  themselves  to  a 
disturbed  imagination  during  the  visions  of  the  night. 

Until  lately  it  was  supposed  that  the  old  red  sandstone,  or  Devonian 
rocks,  contained  no  vertebrate  remains  except  those  of  fish,  but  in  1850 
the  footprints  of  a  chelonian,  and  in  1851  the  skeleton  of  a  reptile,  al- 
lied both  to  the  batrachians  and  lizards,  were  found  in  a  sandstone  of 
that  age  near  Elgin  in  Scotland.*  Up  to  the  year  1844  it  was  laid 

*  Quart.  Journ.  Geol.  Soc.  1852. 


136          THEORY  OF  PROGRESSIVE  DEVELOPMENT      [On.  IX. 

down  as  a  received  dogma  in  many  works  of  high  authority  in  geology, 
that  reptiles  were  not  created  until  after  the  close  of  the  carboniferous 
epoch.  In  the  course  of  that  year,  however,  Hermann  Von  Meyer  an- 
nounced the  discovery,  in. the  coal  measures  of  Rhenish  Bavaria,  of  a 
reptile,  called  by  him  Apateon,  related  to  the  salamanders ;  and  in 
1847  three  species  of  another  genus,  called  archegosaurus  by  Goldfuss, 
were  obtained  from  the  coal  of  Saarbriick,  between  Treves  and  Stras- 
burg.  The  footprints  of  a  large  quadruped,  probably  batrachian,  had 
also  been  observed  by  Dr.  King  in  the  carboniferous  rocks  of  Pennsyl- 
vania in  1844.  The  first  example  of  the  bones  of  a  reptile  in  the  Coal 
of  North  America  was  detected  so  lately  as  September,  1852,  by  Mr. 
Gr.  W.  Dawson  and  myself  in  Nova  Scotia.  These  remains,  referred  by 
Messrs.  Wyman  and  Owen  to  a  perennibranchiate  batrachian,  were  met 
with  in  the  interior  of  an  erect  fossil  tree,  apparently  a  sigillaria.  They 
seem  clearly  to  have  been  introduced  together  with  sediment  into  the 
tree,  during  its  submergence  and  after  it  had  decayed  and  was  standing 
as  a  hollow  cylinder  of  bark,  this  bark  being  now  converted  into  coal. 

When  Agassiz,  in  his  great  work  on  fossil  fish,  described  152  species 
of  ichthyolites  from  the  Coal,  he  found  them  to  consist  of  94  placoids, 
belonging  to  the  families  of  shark  and  ray,  and  58  ganoids.  One  fam- 
ily of  the  latter  he  called  "  sauroid  fish,"  including  the  megalicthys  and 
holoptychius,  often  of  great  size,  and  all  predaceous.  Although  true 
fish,  and  not  intermediate  between  that  class  and  reptiles,  they  seem  to 
have  been  more  highly  organized  than  any  living  fish,  reminding  us  of 
the  skeletons  of  saurians  by  the  close  suture  of  their  cranial  bones,  their 
large  conical  teeth,  striated  longitudinally,  and  the  articulation  of  the 
spinous  processes  with  the  vertebrae.  Among  living  species  they  are 
most  nearly  allied  to  the  lepidosteus,  or  bony  pike  of  the  North  Ameri- 
can rivers.  Before  the  recent  progress  of  discovery  above  alluded  to 
had  shown  the  fallacy  of  such  ideas,  it  was  imagined  by  some  geolo- 
gists that  this  ichthyic  type  was  the  more  highly  developed,  because  it 
took  the  lead  at  the  head  of  nature  before  the  class  of  reptiles  had  been 
created.  The  confident  assumption  indulged  in  till  the  year  1844,  that 
reptiles  were  first  introduced  into  the  earth  in  the  Permian  period,  shows 
the  danger  of  taking  for  granted  that  the  date  of  the  creation  of  any 
family  of  animals  or  plants  in  past  time  coincides  with  the  age  of  the 
oldest  stratified  rock  in  which  the  geologist  has  detected  its  remains. 
Nevertheless,  after  repeated  disappointments,  we  find  some  naturalists 
as  much  disposed  as  ever  to  rely  on  such  negative  evidence,  and  to  feel 
now  as  sure  that  reptiles  were  not  introduced  into  the  earth  till  after 
the  Silurian  epoch,  as  they  were  in  1844,  that  they  appeared  for  the 
first  time  at  an  era  subsequent  to  the  carboniferous. 

Scanty  as  is  the  information  hitherto  obtained  in  regard  to  the  articu- 
lata  of  the  coal  formation,  we  have  at  least  ascertained  that  some  in- 
sects winged  their  way  through  the  ancient  forests.  In  the  ironstone 
of  Coalbrook  Dale,  two  species  of  coleoptera  of  the  Linnsean  genus  cur- 
culio  have  been  met  with  :  and  a  neuropterous  insect  resembling  a  co- 


OH.  IX.]  AT   SUCCESSIVE   PERIODS.  137 

rydalis,  together  with  another  of  the  same  order  related  to  the  phas- 
midae.  As  an  example  of  the  insectivorous  arachnidae,  I  may  niention 
the  scorpion  of  the  Bohemian  coal,  figured  by  Count  Sternberg,  in  which 
even  the  eyes,  skin,  and  minute  hairs  were  preserved.*  We  need  not 
despair,  therefore,  of  obtaining  eventually  fossil  representatives  of  all 
the  principal  orders  of  hexapods  and  arachnidse  in  carboniferous  strata. 

Next  in  chronological  order  above  the  Coal  comes  the  allied  Magne- 
sian  Limestone,  or  Permian  group,  and  the  secondary  formations  from 
the  Trias  to  the  Chalk  inclusive.  These  rocks  comprise  the  monuments 
of  a  long  series  of  ages  in  which  reptiles  of  every  variety  of  size,  form, 
and  structure  peopled  the  earth  ;  so  that  the  whole  period,  and  especially 
that  of  the  Lias  and  Oolite,  has  been  sometimes  called  "  the  age  of  rep- 
tiles." As  there  are  now  mammalia  entirely  confined  to  the  land  ;  others 
which,  like  the  bat  and  vampire,  fly  in  the  air ;  others,  again,  of  amphibi- 
ous habits,  frequenting  rivers,  like  the  hippopotamus,  otter,  and  beaver ; 
others  exclusively  aquatic  and  marine,  like  the  seal,  whale,  and  narwal ; 
so  in  the  early  ages  under  consideration,  there  were  terrestrial,  winged, 
and  aquatic  reptiles.  There  were  iguanodons  walking  on  the  land,  ptero- 
dactyls winging  their  way  through  the  air,  monitors  and  crocodiles  in 
the  rivers,  and  ichthyosaurs  and  plesiosaurs  in  the  ocean.  It  appears 
also  that  some  of  these  ancient  saurians  approximated  more  nearly  in 
their  organization  to  the  type  of  living  mammalia  than  do  any  of  the 
reptiles  now  existing. \ 

In  the  vast  range  of  strata  above  alluded  to,  comprising  the  Permian, 
the  Upper  New  Red  Sandstone  and  Muschelkalk,  the  Lias,  Oolite, 
Wealden,  Green-sand,  and  Chalk,  scarcely  any  well-authenticated  in- 
stances of  the  occurrence  of  fossil  birds  in  Europe  are  on  record,  and 
only  two  or  three  of  fossil  mammalia. 

In  regard  to  the  absence  of  birds,  they  are  usually  wanting,  for  rea- 
sons afterwards  to  be  explained  (see  chap.  47),  in  deposits  of  all  ages, 
even  in  the  tertiary  periods,  where  we  know  that  birds  as  well  as  land 
quadrupeds  abounded.  Some  at  least  of  the  fossil  remains  formerly  re- 
ferred to  this  class  in  the  Wealden  (a  great  freshwater  deposit  below 
the  chalk),  have  been  recently  shown  by  Mr.  Owen  to  belong  to  ptero- 
dactyls.]; But  in  North  America  still  more  ancient  indications  of  the 
existence  of  the  feathered  tribe  have  been  detected,  the  fossil  foot-marks 
of  a  great  variety  of  species,  of  various  sizes,  some  larger  than  the  ostrich, 
others  smaller  than  the  plover,  having  been  observed.  These  bipeds 
have  left  marks  of  their  footsteps  on  strata  of  an  age  decidedly  interme- 
diate between  the  Lias  and  the  Coal.§ 

The  examples  of  mammalia,  above  alluded  to,  are  confined  to  the  Trias 
and  the  Oolite.  In  the  former,  the  evidence  is  as  yet  limited  to  two 
small  molar  teeth,  described  by  Professor  Plieninger  in  1847,  under  the 

*  Buckland's  Brklgewater  Treatise,  p.  409. 

f  Owen's  Report  on  "British  Fossil  Reptiles,  to  Brit.  Soc."  1841,  p.  200. 
t  Quart,  Journ.  Geol.  Soc.  No.  6,  p.  96. 

§  See  Hitchcock's  Report  on  Geol.  of  Massachusetts,  and  Lyell's  Travels  in 
North  America,  chap.  12. 


138  THEORY   OF   PROGRESSIVE   DEVELOPMENT  [Cll.  IX. 

generic  name  of  Microlestes.  They  were  found  near  Stuttgart,  and  pos- 
sess the  double  fangs  so  characteristic  of  mammalia.*  The  other  fossil 
remains  of  the  same  class  were  derived  from  one  of  the  inferior  members 
of  the  oolitic  series  in  Oxfordshire,  and  afford  more  full  and  satisfactory 
evidence,  consisting  of  the  lower  jaws  of  three  species  of  small  quadru- 
peds about  the  size  of  a  mole.  Cuvier,  when  he  saw  one  of  them  (during 

Fig.  8.  Natural  Size. 


Thylacotherium  Prevostii  (  Valenciennes).    Amphitherium  (Owen).    Lower  jaw,  from  the 
slate  of  Stonesfield,  near  Oxford.t 

a  visit  to  Oxford  in  1818),  referred  it  to  the  marsupial  order,  stating, 
however,  that  it  differed  from  all  known  carnivora  in  having  ten  molar 
teeth  in  a  row.  Professor  Owen  afterwards  pointed  out  that  the  jaw 
belonged  to  an  extinct  genus,  having  considerable  affinity  to  a  newly 
discovered  Australian  mammifer,  the  Myrmecobius  of  Waterhouse,  which 
has  nine  molar  teeth  in  the  lower  jaw.  (Fig.  9.)  A  more  perfect  speci- 
men enabled  Mr.  Owen  in  1846  to 

- 9-  prove  that  the  inflection  of  the  an- 

gular process  of  the  lower  jaw  was 
not  sufficiently  marked  to  entitle 
the  osteologist  to  infer  that  this 
quadruped  was  marsupial,  as  the 

Myrmecobius  fasciatus  ( Waterliouse).    Eecent  .  .  .  , 

from  Swan  Eiver.    Lower  jaw  of  the  natural      prOCCSS    IS   not   bent   inwards    in    a 

greater  degree  than  in  the  mole  or 

hedgehog.     Hence  the  genus  amphitherium,  of  which  there  are  two 
species  from  Stonesfield,  must  be  referred  to  the  ordinary  or  placental 

*  See  Manual  of  Geol.  by  the  Author,  index  Microlestes. 

f  This  figure  (No.  8)  is  from  a  drawing  by  Professor  C.  Prevost,  published  Ann. 
des  Sci.  Nat.  Avril,  1825.  The  fossil  is  a  lower  jaw,  adhering  by  its  inner  side  to 
the  slab  of  oolite,  in  which  it  is  sunk.  The  form  of  the  condyle,  or  posterior  pro- 
cess of  the  jaw,  is  convex,  agreeing  with  the  mammiferous  type,  and  is  distinctly 
seen,  an  impression  of  it  being  left  on  the  stone,  although  in  this  specimen  the  bone 
is  wanting.  The  anterior  part  of  the  jaw  has  been  partially  broken  away,  so  that 
the  double  fangs  of  the  molar  teeth  are  seen  fixed  in  their  sockets,  the  form  of  the 
fangs  being  characteristic  of  the  mammalia.  Ten  molars  are  preserved,  and  the 
place  of  an  eleventh  is  believed  to  be  apparent.  The  enamel  of  some  of  the  teeth 
is  well  preserved. 

\  A  colored  figure  of  this  small  and  elegant  quadruped  is  given  in  the  Trans. 
Zool.  Soc.  vol.  ii.  pi.  28.  It  is  insectivorous,  and  was  taken  in  a  hollow  tree,  in  a 
country  abounding  in  ant-hills,  ninety  miles  to  the  southeast  of  the  mouth  of  Swan 
River  in  Australia. — It  is  the  first  living  marsupial  species  known  to  have  nine 
molar  teeth  in  the  lower  jaw,  and  some  of  the  teeth  are  widely  separated  from 
others,  one  of  the  peculiarities  in  the  thylacotherium  of  Stonesfield,  which  at  first 
induced  M.  Blainville  to  refer  that  creature  to  the  class  of  reptiles. 


CH.  IX.]  AT   SUCCESSIVE   PERIODS.  139 

type  of  insectivorous  mammals,  although  it  approximates  in  some  points 
of  structure  to  the  myrmecobius  and  allied  marsupials  of  Australia.  The 
other  contemporary  genus,  called  phascolotherium,  agrees  much  more 
nearly  in  osteological  character  and  precisely  in  the  number  of  the  teeth 
with  the  opossums ;  and  is  believed  to  have  been  truly  marsupial. 
(Fig.  10.) 

2  Fig.  10. 


Natural  size, 

Phascolotherium  Bncklandi,  Owen.    (St/n.  Didelphis  Bucklandi,  Brod.) 
Lower  jaw,  from  Stonesfield.* 

1.  The  jaw  magnified  twice  in  length.       2.  The  second  molar  tooth  magnified  six  times. 

The  occurrence  of  these  most  ancient  memorials  of  the  mammiferous 
lype,  in  so  low  a  member  of  the  oolitic  series,  while  no  other  repre- 
sentatives of  the  same  class  (if  we  except  the  microlestes)  have  yet  been 
found  in  any  other  of  the  inferior  or  superior  secondary  strata,  is  a 
striking  fact,  and  should  serve  as  a  warning  to  us  against  hasty  general- 
izations, founded  solely  on  negative  evidence.  So  important  an  excep- 
tion to  a  general  rule  may  be  perfectly  consistent  with  the  conclusion, 
that  a  small  number  only  of  mammalia  inhabited  European  latitudes 
when  our  secondary  rocks  were  formed ;  but  it  seems  fatal  to  the  theory 
of  progressive  development,  or  to  the  notion  that  the  order  of  prece- 
dence in  the  creation  of  animals,  considered  chronologically,  has  pre- 
cisely coincided  with  the  order  in  which  they  would  be  ranked  accord- 
ing to  perfection  or  complexity  of  structure. 

It  was  for  many  years  suggested  that  the  marsupial  order  to  which 
the  fossil  animals  of  Stonesfield  were  supposed  exclusively  to  belong 
constitutes  the  lowest  grade  in  the  class  Mammalia,  and  that  this  order, 
of  which  the  brain  is  of  more  simple  form,  evinces  an  inferior  degree  of 

*  This  figure  (No.  10)  was  taken  from  the  orignal,  formerly  in  Mr.  Broderip's 
collection,  and  now  in  the  British  Museum.  It  consists  of  the  right  half  of  a  lower 
jaw,  of  which  the  inner  side  is  seen.  The  jaw  contains  seven  molar  teeth,  one 
canine,  and  three  incisors  ;  but  the  end  of  the  jaw  is  fractured,  and  traces  of  the 
alveolus  of  a  fourth  incisor  are  seen.  With  this  addition,  the  number  of  teeth 
would  agree  exactly  with  those  of  a  lower  jaw  of  a  didelphis.  The  fossil  is  well 
preserved  in  a  slab  of  oolitic  structure  containing  shells  of  trigonise  and  other  ma- 
rine remains.  Two  or  three  other  similar  jaws,  besides  those  above  represented, 
have  been  procured  from  the  quarries  of  Stonesfield. — See  Broderip,  Zool.  Journ. 
vcl  \L  p.  408.  Owen,  Proceedings  Geol.  Soc.,  November,  1838. 


140          THEORY  OF  PROGRESSIVE  DEVELOPMENT       [Cu.  IX 

intelligence.  If,  therefore,  in  the  oolitic  period  the  marsupial  tribes 
were  the  only  warm-blooded  quadrupeds  which  had  as  yet  appeared 
upon  our  planet,  the  fact,  it  was  said,  confirmed  the  theory  which 
teaches  that  the  creation  of  the  more  simple  forms  in  each  division  of 
the  animal  kingdom  preceded  that  of  the  more  complex.  But  on  how 
slender  a  support,  even  if  the  facts  had  continued  to  hold  true,  did  such 
important  conclusions  hang  !  The  Australian  continent,  so  far  as  it  has 
been  hitherto  explored,  contains  no  indigenous  quadrupeds  save  those 
of  the  marsupial  order,  with  the  exception  of  a  few  small  rodents,  while 
some  neighboring  islands  to  the  north,  and  even  southern  Africa,  in  the 
same  latitude  as  Australia,  abound  in  mammalia  of  every  tribe  except 
the  marsupial.  We  are  entirely  unable  to  explain  on  what  physiologi- 
cal or  other  laws  this  singular  diversity  in  the  habitations  of  living  mam- 
malia depends  ;  but  nothing  is  more  clear  than  that  the  causes  which 
stamp  so  peculiar  a  character  on  two  different  provinces  of  wide  extent 
are  wholly  independent  of  time,  or  of  the  age  or  maturity  of  the  planet. 

The  strata  of  the  Wealden,  although  of  a  later  date  than  the  oolite  of 
Stonesfield,  and  although  filled  with  '.he  remains  of  large  reptiles,  both 
terrestrial  and  aquatic,  have  not  yielded  as  yet  a  single  marsupial  bone. 
Were  we  to  assume  on  such  scanty  data  that  no  warm-blooded  quadru- 
peds were  then  to  be  found  throughout  the  northern  hemisphere,  there 
would  still  remain  a  curious  subject  of  speculation,  whether  the  entire 
suppression  of  one  important  class  of  vertebrata,  such  as  the  mammifer- 
ous,  and  the  great  development  of  another,  such  as  the  reptilian,  implies 
a  departure  from  fixed  and  uniform  rules  governing  the  fluctuations  of 
the  animal  world  ;  such  rules,  for  example,  as  appear  from  one  century 
to  another  to  determine  the  growth  of  certain  tribes  of  plants  and  ani- 
mals in  arctic,  and  of  other  tribes  in  tropical  regions. 

In  Australia,  New  Zealand,  and  many  other  parts  of  the  southern 
hemisphere,  where  the  indigenous  land  quadrupeds  are  comparatively 
few,  and  of  small  dimensions,  the  reptiles  do  not  predominate  in  number 
or  size.  The  deposits  formed  at  the  mouth  of  an  Australian  river,  within 
the  tropics,  might  contain  the  bones  of  only  a  few  small  marsupial  an- 
imals, which,  like  those  of  Stonesfield,  might  hereafter  be  discovered 
with  difficulty  by  geologists  ;  'but  there  would,  at  the  same  time,  be  no 
megalosauri  and  other  fossil  remains,  showing  that  large  saurians  were 
plentiful  on  the  land  and  in  the  waters  at  a  time  when  mammalia  were 
scarce.  This  example,  therefore,  would  afford  a  very  imperfect  parallel 
to  the  state  of  the  animal  kingdom,  supposed  to  have  prevailed  during 
the  secondary  periods,  when  a  high  temperature  pervaded  European 
latitudes. 

It  may  nevertheless  be  advantageous  to  point  to  some  existing  anom- 
alies in  the  geographical  development  of  distinct  classes  of  vertebrata 
which  may  be  comparable  to  former  conditions  of  the  animal  creation 
brought  to  light  by  geology.  Thus  in  the  arctic  regions,  at  present, 
reptiles  are  small,  and  sometimes  wholly  wanting,  where  birds,  large 
land  quadrupeds,  and  cetaeea  abound.  We  meet  with  bears,  wolves, 


OH.  IX.]  AT   SUCCESSIVE   PERIODS.  141 

foxes,  musk  oxen,  and  deer,  walruses,  seals,  whales,  and  narwals,  in  re- 
gions of  ice  and  snow,  where  the  smallest  snakes,  efts,  and  frogs  are 
rarely,  if  ever,  seen. 

A  still  more  anomalous  state  of  things  presents  itself  in  the  southern 
hemisphere.  Even  in  the  temperate  zone,  between  the  latitudes  52° 
and  56°  8.,  as,  for  example,  in  Tierra  del  Fuego,  as  well  as  in  the 
woody  region  immediately  north  of  the  Straits  of  Magellan,  and  in  the 
Falkland  Islands,  no  reptiles  of  any  kind  are  met  with,  not  even  a  snake, 
lizard,  or  frog  ;  but  in  these  same  countries  we  find  the  guanaco  (a  kind 
of  llama),  a  deer,  the  puma,  a  large  species  of  fox,  many  small  rodentia, 
besides  the  seal  and  otter,  together  with  the  porpoise,  whale,  and  other 
cetacea. 

On  what  grand  laws  in  the  animal  physiology  these  remarkable  phe- 
nomena depend,  cannot  in  the  present  state  of  science  be  conjectured  ; 
nor  could  we  predict  whether  any  opposite  condition  of  the  atmosphere, 
in  respect  to  heat,  moisture,  and  other  circumstances,  would  bring  about 
a  state  of  animal  life  which  might  be  called  the  converse  of  that  above 
described,  namely,  a  state  in  which  reptiles  of  every  size  and  order 
might  abound,  and  mammalia  disappear. 

The  nearest  approximation  to  such  a  fauna  is  found  in  the  Galapagos 
Archipelago.  These  islands,  situated  under  the  equator,  and  nearly 
600  miles  west  of  the  coast  of  Peru,  have  been  called  "  the  land  of  rep- 
tiles," so  great  is  the  number  of  snakes,  large  tortoises,  and  lizards, 
which  they  support.  Among  the  lizards,  the  first  living  species  proper 
to  the  ocean  has  been  discovered.  Yet,  although  some  of  these  islands 
are  from  3000  to  4000  feet  high,  and  one  of  them  75  miles  long,  they 
contain,  with  the  exception  of  one  small  mouse,  no  indigenous  mammi- 
fer.  Even  here,  however,  it  is  true  that  in  the  neighboring  sea  there 
are  seals,  and  several  kinds  of  cetacea.* 

It  m?iy  be  unreasonable  to  look  for  a  nearer  analogy  between  the 
fauna  now  existing  in  any  part  of  the  globe,  and  that  which  we  can 
show  to  have  prevailed  when  our  secondary  strata  were  deposited,  be- 
cause we  must  always  recollect  that  a  climate  like  that  now  experienced 
at  the  equator,  coexisting  with  the  unequal  days  and  nights  of  Euro- 
pean latitudes,  was  a  state  of  things  to  which  there  is  now  no  counter- 
part on  the  globe.  Consequently,  the  type  of  animal  and  vegetable 
existence  required  for  such  a  climate  might  be  expected  to  deviate 
almost  as  widely  from  that  now  established,  as  do  the  flora  and  fauna 
of  our  tropical  differ  from  those  of  our  arctic  regions. 

In  the  Tertiary  strata. — The  tertiary  formations  were  deposited  when 
the  physical  geography  of  the  northern  hemisphere  had  been  entirely 
altered.  Large  inland  lakes  had  become  numerous,  as  in  central  France 
and  other  countries.  There  were  gulfs  of  the  sea,  into  which  consider- 
able rivers  emptied  themselves,  and  where  strata  like  those  of  the  Paris 
basin  were  accumulated.  There  were  also  formations  in  progress,  in 

*  Darwin's  Journal,  chap.  19.     Lyell's  Manual  of  Geol.  chap.  21,  p.  279. 


142  THEORY  OF   PROGRESSIVE   DEVELOPMENT  [Cfl.  IX. 

shallow  seas  not  far  from  shore,  such  as  are  indicated  by  portions  of  the 
Faluns  of  the  Loire,  and  the  English  Crag. 

The  proximity,  therefore,  of  large  tracts  of  dry  land  to  the  seas  and 
lakes  then  existing,  may,  in  a  great  measure,  explain  why  the  remains 
of  land  animals,  so  rare  in  the  older  strata,  are  not  uncommon  in  these 
more  modern  deposits.  Yet  even  these  have  sometimes  proved  en- 
tirely destitute  of  mammiferous  relics  for  years  after  they  had  become 
celebrated  for  the  abundance  of  their  fossil  testacea,  fish,  and  reptiles. 
Thus  the  calcaire  grossier,  a  marine  limestone  of  the  district  round  Paris, 
had  afforded  to  collectors  more  than  1100  species  of  shells,  besides 
many  zoophytes,  echinodermata,  and  the  teeth  of  fish,  before  the  bones 
of  one  or  two  land  quadrupeds  were  met  with  in  the  same  rock.  The 
strata  called  London  and  Plastic  clay  in  England  have  been  studied  for 
more  than  half  a  centuiy,  and  about  400  species  of  shells,  50  or  more 
of  fish,  besides  several  kinds  of  chelonian  and  saurian  reptiles,  were 
known  before  a  single  mammifer  was  detected.  At  length,  in  the  year 
1839,  there  were  found  in  this  formation  the  remains  of  a  monkey,  an 
opossum,  a  bat,*  and  a  species  of  the  extinct  genus  Hyracotherium, 
allied  to  the  Peccary  or  hog  tribe. 

If  we  examine  the  strata  above  the  London  clay  in  England,  we  first 
meet  with  mammiferous  remains  in  the  Isle  of  Wight,  in  beds  also  be- 
longing to  the  Eocene  epoch,  such  as  the  remains  of  the  Palseotherium, 
Anoplotherium,  and  other  extinct  quadrupeds,  agreeing  very  closely 
with  those  first  found  by  Cuvier,  near  Paris,  in  strata  of  the  same  age, 
and  of  similar  freshwater  origin. 

In  France  we  meet  with  another  fauna,  both  conchological  and  mam- 
malian in  the  Miocene  "faluns"  of  the  Loire;  above  which  in  the 
ascending  series  in  Great  Britain  we  arrive  at  the  coralline  crag  of  Suf- 
folk, a  marine  formation  which  has  yielded  three  or  four  hundred  species 
of  shells,  very  different  from  the  Eocene  testacea,  and  of  which  a  large 
proportion,  although  a  minority  of  the  whole  number,  are  recent,  be- 
sides many  corals,  echini,  foraminifera,  and  fish,  but  as  yet  no  relic  de- 
cidedly mammalian  except  the  ear-bone  of  a  whale. 

In  the  shelly  sand,  provincially  termed  "Red  Crag,"  in  Suffolk, 
which  immediately  succeeds  the  coralline,  constituting  a  newer  member 
of  the  same  tertiary  group,  about  250  species  of  shells  have  been  rec- 
ognized, of  which  a  still  larger  proportion  are  recent.  They  are  as- 
sociated with  numerous  teeth  of  fish  ;  but  no  signs  of  a  warm-blooded 
quadruped  had  been  detected  until  1839,  when  the  teeth  of  a  leopard, 
a  bear,  a  hog,  and  a  species  of  ruminant,  were  found  at  Newbourn,  in 
Suffolk,  and  since  that  time,  several  other  genera  of  mammalia  have 
been  met  with  in  the  same  formation,  or  in  the  Red  Crag.f 

Of  a  still  newer  date  is  the  Norwich  Crag,  a  fluvio  marine  deposit  of 
the  Pleiocene  epoch,  containing  a  mixture  of  marine,  fluviatile,  and  land 

*  Taylor'8  Annals  of  Nat.  Hist.  Nov.  1839. 

f  See  notice  by  the  Author,  and  Professor  Owen,  Taylor's  Annals  of  Nat.  Hist 
Nov.  1839. 


CH.  IX.]  AT   SUCCESSIVE   PERIODS.  143 

shells,  of  which  90  per  cent,  or  more  are  recent.  These  beds,  since  the 
time  of  their  first  investigation,  have  yielded  a  supply  of  mammalian 
bones  of  the  genera  mastodon,  elephant,  rhinoceros,  pig,  horse,  deer,  ox, 
and  others,  the  bodies  of  which  may  have  been  washed  down  into  the 
sea  by  rivers  draining  land,  of  which  the  contiguity  is  indicated  by  the 
occasional  presence  of  terrestrial  and  freshwater  shells. 

Our  acquaintance  with  the  newer  Pleiocene  mammalia  in  Europe, 
South  America,  and  Australia,  is  derived  chiefly  from  cavern  deposits,  a 
fact  which  we  ought  never  to  forget  if  we  desire  to  appreciate  the  supe- 
rior facilities  we  enjoy  for  studying  the  more  modern  as  compared  to  the 
more  ancient  terrestrial  faunas.  We  know  nothing  of  the  fossil  bones 
which  must  have  been  inclosed  in  the  stalagmite  of  caverns  in  the  older 
Pleiocene,  or  in  the  Miocene  or  Eocene  epochs,  much  less  can  we  derive 
any  information  respecting  the  inhabitants  of  the  land  from  a  similar 
source,  when  we  carry  back  our  inquiries  to  the  Wealden  or  carboniferous 
epochs.  We  are  as  well  assured  that  land  and  rivers  then  existed,  as  that 
they  exist  now  ;  but  it  is  evident  that  even  a  slight  geographical  revolution, 
accompanied  by  the  submergence  and  denudation  of  land,  would  reduce 
to  an  extreme  improbability  the  chance  of  our  hitting  on  those  minute 
points  of  space  where  caves  may  once  have  occurred  in  limestone  rocks. 

Fossil  quadrumana. — Until  within  a  few  years  (1836,  1837),  not  a 
single  bone  of  any  quadrumanous  animal,  such  as  the  orang,  ape,  baboon, 
and  monkey,  had  been  discovered  in  a  fossil  state,  although  so  much 
progress  had  been  made  in  bringing  to  light  the  extinct  mammalia  of 
successive  tertiary  eras,  both  carnivorous  and  herbivorous.  The  total 
absence  of  these  anthropomorphous  tribes  among  the  records  of  a  former 
world,  had  led  some  to  believe  that  the  type  of  organization  most  nearly 
resembling  the  human,  came  so  late  in  the  order  of  creation,  as  to  be 
scarcely,  if  at  all,  anterior  to  that  of  man.  That  such  generalizations 
were  premature,  I  endeavored  to  point  out  in  the  first  edition  of  this 
work,*  in  which  I  stated  that  the  bones  of  quadrupeds  hitherto  met  with 
in  tertiary  deposits  were  chiefly  those  which  frequent  marshes,  rivers,  or 
the  borders  of  lakes,  as  the  elephant,  rhinoceros,  hippopotamus,  tapir, 
hog,  deer,  and  ox,  while  species  which  live  in  trees  are  extremely  rare  in 
a  fossil  state.  I  also  hinted,  that  we  had  as  yet  no  data  for  determining 
how  great  a  number  of  the  one  kind  we  ought  to  find,  before  we  have 
a  right  to  expect  a  single  individual  of  the  other.  Lastly,  I  observed 
that  the  climate  of  the  more  modern  (or  Post-Eocene)  tertiary  periods 
in  England  was  not  tropical,  and  that  in  regard  to  the  London  clay,  of 
which  the  crocodiles,  turtles,  and  fossil  fruits  implied  a  climate  hot  enough 
for  the  quadrumana,  we  had  as  yet  made  too  little  progress  in  ascertain- 
ing what  were  the  Eocene  pachydermata  of  England,  to  entitle  us  to  ex- 
pect to  have  discovered  any  quadrumana  of  the  same  date. 

Since  those  remarks  were  first  written,  in  1829,  a  great  number  of 
extinct  species  have  been  added  to  our  collections  of  tertiary  mammalia 

*  See  Principles  of  Geology,  1st  ed.  1830,  vol.  i.  p.  162. 


144          THEORY  OF  PROGRESSIVE  DEVELOPMENT       [On.  IX. 

from  Great  Britain  and  other  parts  of  the  world.  At  length,  between 
the  years  1836  and  1839,  a  few  remains  of  quadrumana  were  found  in 
France  and  England,  India  and  Brazil.  Those  of  India,  belonging  to 
more  than  one  extinct  species  of  monkey,  were  first  discovered  near  the 
Sutlej,  in  lat.  30°  N.,  in  tertiary  strata,  of  which  the  age  is  not  yet  de- 
termined ;  the  Brazilian  fossil,  brought  from  the  basin  of  the  Rio  das 
Velhas,  about  lat.  18°  S.,  is  referable  to  a  form  now  peculiar  in  America, 
allied  to  the  genus  Callithrix,  the  species  being  extinct.  The  skull  and 
other  bones  met  with  in  the  South  of  France  belong  to  a  gibbon,  or  one 
of  the  tailless  apes,  which  stand  next  in  the  scale  of  organization  to  the 
orang.  It  occurred  at  Sansan,  about  forty  miles  west  of  Toulouse,  in 
lat.  43°  40'  N.,  in  freshwater  strata,  probably  of  the  Miocene  or  middle 
tertiary  period.  Lastly,  the  English  quadrumane  first  met  with,  occurred 
in  a  more  ancient  stratum  than  the  rest,  and  at  a  point  more  remote 
from  the  equator.  It  belongs  to  the  genus  Macacus,  is  an  extinct  species, 
and  was  found  in  Suffolk,  in  lat.  52°,*  in  the  London  clay,  the  fossils  of 
which,  such  as  crocodiles,  turtles,  shells  of  the  genus  Nautilus,  and  many 
curious  fruits,  had  already  led  geologists  to  the  conclusion  that  .the 
climate  of  that  era  (the  Eocene)  was  warm  and  nearly  tropical. 

Some  years  later  (in  1846)  the  jaw  of  another  British  species  of  fos- 
sil monkey,  Macacus  pliocenus,  was  announced  by  Mr.  Owen  as  having 
been  met  with  in  the  newer  Pleiocene  strata,  on  the  banks  of  the 
Thames,  at  Grays,  in  Essex,  accompanying  the  remains  of  hippopotamus, 
elephant,  and  other  quadrupeds,  and  associated  with  freshwater  and 
land  shells,  most  of  which  are  now  inhabitants  of  the  British  Isles. f 

When  we  consider  the  small  area  of  the  earth's  surface  hitherto  ex- 
plored geologically,  and  the  new  discoveries  brought  to  light  daily, 
even  in  the  environs  of  great  European  capitals,  we  must  feel  that 
it  would  be  rash  to  assume  that  the  Lower  Eocene  deposits  mark  the 
era  of  the  first  creation  of  quadrumana.  It  would,  however,  be  still 

*  The  first  quadrumanous  fossils  discovered  in  India  were  observed  in  1836  in  the 
Sewalik  Hills,  a  lower  range  of  the  Himalayan  Mountains,  by  Lieutenants  Baker 
and  Durond,  by  whom  their  osteological  characters  were  determined  (Jourri.  of 
Asiat.  Soc.  of  Bengal,  vol.  v.  p.  739),  and  in  the  year  following,  other  fossils  of  the 
same  class  were  brought  to  light  and  described  by  Capt.  Cautley  and  Dr.  Falconer. 
These  were  imbedded,  like  the  former,  in  tertiary  strata  of  conglomerate,  sand, 
marl,  and  clay,  in  the  Sub-Himalayan  Mountains.  (Ibid.  vol.  v.  p.  379.  Nov. 
1836  ;  and  vol.  vi.  p.  354.  May,  1837.) 

The  Brazilian  quadrumane  was  found,  with  a  great  many  other  extinct  species 
of  animals,  by  a  Danish  naturalist,  Dr.  Lund,  between  the  rivers  Francisco  and 
Velhas,  in  1837. 

The  gibbon  of  the  South  of  France  was  found  by  M.  Lartet  in  the  beginning  of 
1837,  and  determined  by  M.  de.Blainville.  It  occurred  near  Auch,  in  the  depart- 
ment of  Gers,  about  forty  miles  west  of  Toulouse,  in  freshwater  marl,  limestone, 
and  sand.  They  were  accompanied  by  the  remains  of  the  mastodon,  dinotheriinn, 
palseotherium,  rhinoceros,  gigantic  sloth,  and  other  extinct  quadrupeds.  (Bulletin 
de  la  Soc.  Geol.  de  France,  torn.  viii.  p.  92.) 

The  British  quadrumane  was  discovered  in  1839,  by  Messrs.  William  Colchester 
and  Searles  Wood,  at  Kyson,  near  Woodbridge,  in  Suffolk,  and  was  referred  by  Pro- 
fessor Owen  to  the  penna  Macacus.  (Mag.  of  Nat.  Hist.  Sept.  1839.  Taylor, 
Annals  of  Nat.  Hist.  No.  xxiii.  Nov.  1839.) 

f  Owen's  Introduction  to  British  Fossil  Mammals,  p.  46. 


Cli.  IX.]  AT    SUCCESSIVE   PERIODS.  145 

more  unphilosophical  to  infer,  as  some  writers  have  done,  from  a  single 
extinct  species  of  this  family  obtained  in  a  latitude  far  from  the  tropics, 
that  the  Eocene  quadrumana  did  not  attain  as  high  a  grade  of  organiza- 
tion as  they  do  in  our  own  times.  What  would  the  naturalist  know  of 
the  apes  and  orangs  now  contemporary  with  man,  if  our  investigations 
were  restricted  to  such  northern  latitudes  as  those  where  alone  the  geol- 
ogist has  hitherto  found  all  the  fossil  quadrumana  of  Europe  ? 

Cetacea. — The  absence  of  Cetacea  from  rocks  older  than  the  Eocene 
has  been  frequently  adduced  as  lending  countenance  to  the  theory  of 
the  very  late  appearance  of  the  highest  class  of  Vertebrata  on  the 
earth.  Professor  Sedgwick  possesses  in  the  Cambridge  Museum  a  mass 
of  anchylosed  cervical  vertebras  of  a  whale,  which  he  found  in  drift 
clay  near  Ely,  and  which  he  has  no  doubt  was  washed  out  of  the  Kim- 
meridge  clay,  an  upper  member  of  the  Oolite.  According  to  Professor 
Owen,  it  exhibits  well-marked  specific  characters,  distinguishing  it  from 
all  other  known  recent  or  fossil  cetacea.  Dr.  Leidy,  of  Philadelphia, 
has  lately  described  (1851)  two.  species  of  cetacea  of  a  new  genus, 
which  he  has  called  Priscodelphinus  from  the  green  sand  of  New  Jer- 
sey, which  corresponds  in  age  with  the  English  Chalk  or  the  cretaceous 
strata  above  the  gault.  The  specimens  consist  of  dorsal  and  cervical 
vertebras.*  Even  in  the  Eocene  strata  of  Europe,  the  discovery  of 
cetaceans  has  never  kept  pace  with  that  of  land  quadrupeds.  The  only 
instance  cited  in  Great  Britain  is  a  species  of  Monodon,  from  the  Lon- 
don clay,  of  doubtful  authenticity  as  to  its  geological  position.  On  the 
other  hand,  the  gigantic  Zeuglodon  of  North  America  occurs  abundantly 
in  the  Middle  Eocene  strata  of  Georgia  and  Alabama,  from  which  as 
yet  no  bones  of  land  quadrupeds  have  been  obtained. 

In  the  present  imperfect  state  then  of  our  information,  we  can  scarcely 
say  more  than  that  the  cetacea  seem  to  have  been  scarce  in  the  secondary 
and  primary  periods.  It  is  quite  conceivable  that  when  aquatic  saurians, 
some  of  them  carnivorous,  like  the  Ichthyosaurus,  were  swarming  in  the 
sea,  and  when  there  were  large  herbivorous  reptiles,  like  the  Iguanodon, 
on  the  land,  the  class  of  reptiles  may,  to  a  certain  extent,  have  super- 
seded the  cetacea,  and  discharged  their  functions  in  the  animal  economy. 

That  mammalia  had  been  created  long  before  the  epoch  of  the  Kim- 
meridge  clay,  is  shown  by  the  Microlestes  of  the  Trias  before  alluded 
to,  and  by  the  Stonesfield  quadrupeds  from  the  Inferior  Oolite.  And 
we  are  bound  to  remember,  whenever  we  infer  the  poverty  of  the  flora 
or  fauna  of  any  given  period  of  the  past,  from  the  small  number  of  fos- 
sils occurring  in  ancient  rocks,  that  it  has  been  evidently  no  part  of  the 
plan  of  Nature  to  hand  down  to  us  a  complete  or  systematic  record  of 
the  former  history  of  the  animate  world.  We  may  have  failed  to  dis- 
cover a  single  shell,  marine  or  freshwater,  or  a  single  coral  or  bone  in 
certain  sandstones,  such  as  that  of  the  valley  of  the  Connecticut,  where 
the  footprints  of  bipeds  and  quadrupeds  abound  ;  but  such  failure  may 

*  Proceedings  of  Acad.  Nat.  ScL  Philad.  Dec.  9,  1851. 
10 


146  THEORY   OF   PROGRESSIVE   DEVELOPMENT.  [Gfl.  IX. 

have  arisen,  not  because  the  population  of  the  land  or  sea  was  scanty  at 
that  era,  but  because  in  general  the  preservation  of  any  relics  of  the 
animals  or  plants  of  former  times  is  the  exception  to  a  general  rule. 
Time  so  enormous  as  that  contemplated  by  the  geologist  may  multiply 
exceptional  cases  till  they  seem  to  constitute  the  rule,  and  so  impose  on 
the  imagination  as  to  lead  us  to  infer  the  non-existence  of  creatures  of 
which  no  monuments  happen  to  remain.  Professor  Forbes  has  re- 
marked, that  few  geologists  are  aware  how  large  a  proportion  of  all 
known  species  of  fossils  are  founded  on  single  specimens,  while  a  still 
greater  number  are  founded  on  a  few  individuals  discovered  in  one  spot. 
This  holds  true  not  only  in  regard  to  animals  and  plants  inhabiting  the 
land,  the  lake,  and  the  river,  but  even  to  a  surprising  number  of  the 
marine  mollusca,  articulata,  and  radiata.  Our  knowledge,  therefore,  of 
the  living  creation  of  any  given  period  of  the  past  may  be  said  to  de- 
pend in  a  great  degree  on  what  we  commonly  call  chance,  and  the  cas- 
ual discovery  of  some  new  localities  rich  in  peculiar  fossils  may  modify 
or  entirely  overthrow  all  our  previous  generalizations. 

Upon  the  whole  then  we  derive  this  result  from  a  general  review  of 
the  fossils  of  the  successive  tertiary  strata,  namely,  that  since  the  Eocene 
period,  there  have  been  several  great  changes  in  the  land  quadrupeds 
inhabiting  Europe,  probably  not  less  than  five  complete  revolutions, 
during  which  there  has  been  no  step  whatever  made  in  advance,  no  ele- 
vation in  the  scale  of  being ;  so  that  had  man  been  created  at  the  com- 
mencement of  the  Eocene  era,  he  would  not  have  constituted  a  greater 
innovation  on  the  state  of  the  animal  creation  previously  established  than 
now,  when  we  believe  him  to  have  begun  to  exist  at  the  close  of  the 
Pleiocene.  The  views,  therefore,  which  I  proposed  in  the  first  edition 
of  this  work,  January,  1830,  in  opposition  to  the  theory  of  progressive 
development,  do  not  seem  to  me  to  require  material  modification,  not- 
withstanding the  large  additions  since  made  to  our  knowledge  of  fossil 
remains. 

These  views  may  be  thus  briefly  stated.  From  the  earliest  period  at 
which  plants  and  animals  can  be  proved  to  have  existed,  there  ha's  been 
a  continual  change  going  on  in  the  position  of  land  and  sea,  accompanied 
by  great  fluctuations  of  climate.  To  these  ever-varying  geographical 
and  climatal  conditions  the  state  of  the  animate  world  has  been  un- 
ceasingly adapted.  No  satisfactory  proof  has  yet  been  discovered  of 
the  gradual  passage  of  the  earth  from  a  chaotic  to  a  more  habitable 
state,  nor  of  any  law  of  progressive  development  governing  the  extinc- 
tion and  renovation  of  species,  and  causing  the  fauna  and  flora  to  pass 
from  an  embryonic  to  a  more"  perfect  condition,  from  a  simple  to  a  more 
complex  organization. 

The  principle  of  adaptation  to  which  I  have  alluded,  appears  to  have 
been  analogous  to  that  which  now  peoples  the  arctic,  temperate,  and 
tropical  regions  contemporaneously  with  distinct  assemblages  of  species 
and  genera,  or  which,  independently  of  mere  temperature,  gives  rise  to 
a  predominance  of  the  marsupial  or  didelphous  tribe  of  quadrupeds  in 


CH.  IX.]  RECENT    ORIGIN   OF   MAN.  147 

Australia,  of  the  placcntal  or  monodelphous  tribe  in  Asia  and  Europe, 
or  which  causes  a  profusion  of  reptiles  without  mammalia  in  the  Gala- 
pagos Archipelago,  and  of  mammalia  without  reptiles  in  Greenland. 

Recent  origin  of  man. — If,  then,  the  popular  theory  of  the  successive 
development  of  the  animal  and  vegetable  world,  from  the  simplest  to 
the  most  perfect  forms,  rests  on  a  very  insecure  foundation ;  it  may 
be  asked,  whether  the  recent  origin  of  man  lends  any  support  to  the 
same  doctrine,  or  how  far  the  influence  of  man  may  be  considered  as 
such  a  deviation  from  the  analogy  of  the  order  of  things  previously  es- 
tablished, as  to  weaken  our  confidence  in  the  uniformity  of  the  course 
of  nature. 

Antecedently  to  investigation,  we  might  reasonably  have  anticipated 
that  the  vestiges  of  man  would  have  been  traced  back  at  least  as  far  as 
those  modern  strata  in  which  all  the  testacea  and  a  certain  number  of 
the  mammalia  are  of  existing  species,  for  of  all  the  mammalia  the  hu- 
man species  is  the  most  cosmopolite,  and  perhaps  more  capable  than 
any  other  of  surviving  considerable  vicissitudes  in  climate,  and  in  the 
physical  geography  of  the  globe. 

No  inhabitant  of  the  land  exposes  himself  to  so  many  dangers  on  the 
waters  as  man,  whether  in  a  savage  or  a  civilized  state  ;*  and  there  is 
no  animal,  therefore,  whose  skeleton  is  so  liable  to  become  imbedded  in 
lacustrine  or  submarine  deposits ;  nor  can  it  be  said  that  his  remains 
are  more  perishable  than  those  of  other  animals ;  for  in  ancient  fields 
of  battle,  as  Cuvier  has  observed,  the  bones  of  men  have  suffered 
as  little  decomposition  as  those  of  horses  which  were  buried  in  the 
same  grave. f  But  even  if  the  more  solid  parts  of  our  species  had  dis- 
appeared, the  impression  of  their  form  would  have  remained  engraven 
on  the  rocks,  as  have  the  traces  of  the  tenderest  leaves  of  plants,  and 
the  soft  integuments  of  many  animals.  Works  of  art,  moreover,  com- 
posed of  the  most  indestructible  materials,  would  have  outlasted  al- 
most all  the  organic  contents  of  sedimentary  rocks.  Edifices,  and  even 
entire  cities,  have,  within  the  times  of  history,  been  buried  under  vol- 
canic ejections,  submerged  beneath  the  sea,  or  engulfed  by  earthquakes  ; 
and  had  these  catastrophes  been  repeated  throughout  an  indefinite 
lapse  of  ages,  the  high  antiquity  of  man  would  have  been  inscribed  in 
far  more  legible  characters  on  the  framework  of  the  globe  than  are  the 
forms  of  the  ancient  vegetation  which  once  covered  the  islands  of  the 
northern  ocean,  or  of  those  gigantic  reptiles  which  at  still  later  periods 
peopled  the  seas  and  rivers  of  the  northern  hemisphere.^ 

Dr.  Prichard  has  argued  that  the  human  race  have  not  always  ex- 
isted on  the  surface  of  the  earth,  because  "  the  strata  of  which  our  con- 
tinents are  composed  were  once  a  part  of  the  ocean's  bed" — "  mankind 
had  a  beginning,  since  we  can  look  back  to  the  period  when  the  surface 
on  which  they  lived  began  to  exist.  "§  This  proof,  however,  is  insuffi- 

*  See  ch.  48.  f  Ibid.  \  Ibid. 

§  Phys.  Hist,  of  Mankind,  vcl.  ii.  p.  594. 


14:8  RECENT   ORIGIN   OF  MAN.  [On.  IX. 

cient,  for  many  thousands  of  human  beings  now  dwell  in  various  quar- 
ters of  the  globe  where  marine  species  lived  within  the  times  of  history, 
and,  on  the  other  hand,  the  sea  now  prevails  permanently  over  large 
districts  once  inhabited  by  thousands  of  human  beings.  Nor  can  this 
interchange  of  sea  and  land  ever  cease  while  the  present  causes  are  in 
existence.  Terrestrial  species,  therefore,  might  be  older  than  the  con- 
tinents which  they  inhabit,  and  aquatic  species  of  higher  antiquity  than 
the  lakes  and  seas  which  they  now  people. 

But  so  far  as  our  interpretation  of  physical  movements  has  yet  gone, 
we  have  every  reason  to  infer  that  the  human  race  is  extremely  mod- 
ern, even  when  compared  to  the  larger  number  of  species  now  our  con- 
temporaries on  the  earth,  ard  we  may,  therefore,  ask  whether  his  crea- 
tion can  be  considered  as  one  step  in  a  supposed  progressive  system,  by 
which  the  organic  world  has  advanced  slowly  from  a  more  simple  to  a 
more  complex  and  perfect  state  ?  If  we  concede,  for  a  moment,  the 
truth  of  the  proposition,  that  the  sponge,  the  cephalopod,  the  fish,  the 
reptile,  the  bird,  and  the  mammifer,  have  followed  each  other  in  reg- 
ular chronological  order,  the  creation  of  each  class  being  separated  from 
the  other  by  vast  intervals  of  time,  should  we  be  able  to  recognize,  in 
man's  entrance  upon  the  earth,  the  last  term  of  one  and  the  same  series 
of  progressive  developments  ? 

In  reply  to  this  question  it  should  first  be  observed,  that  the  superi- 
ority of  man  depends  not  on  those  faculties  and  attributes  which  he 
shares  in  common  with  the  inferior  animals,  but  on  his  reason,  by  which 
he  is  distinguished  from  them.  When  it  is  said  that  the  human  race 
is  of  far  higher  dignity  than  were  any  pre-existing  beings  on  the  earth, 
it  is  the  intellectual  and  moral  attributes  of  our  race,  rather  than  the 
physical,  which  are  considered ;  and  it  is  by  no  means  clear  that  the 
organization  of  man  is  such  as  would  confer  a  decided  pre-eminence 
upon  him,  if,  in  place  of  his  reasoning  powers,  he  was  merely  provided 
with  such  instincts  as  are  possessed  by  the  lower  animals. 

If  this  be  admitted,  it  would  not  follow,  even  if  there  were  sufficient 
geological  evidence  in  favor  of  the  theory  of  progressive  development, 
that  the  creation  of  man  was  the  last  link  in  the  same  chain.  For  the 
sudden  passage  from  an  irrational  to  a  rational  animal,  is  a  phenome- 
non of  a  distinct  kind  from  the  passage  from  the  more  simple  to  the 
more  perfect  forms  of  animal  organization  and  instinct.  To  pretend 
that  such  a  step,  or  rather  leap,  can  be  part  of  a  regular  series  ol 
changes  in  the  animal  world,  is  to  strain  analog}?"  beyond  all  reasonable 
bounds. 

Introduction  of  man,  to  what  extent  a  change  in  the  system. — But 
setting  aside  the  question  of  progressive  development,  another  and  a 
far  more  difficult  one  may  arise  out  of  the  admission  that  man  is  com- 
paratively of  modern  origin.  Is  not  the  interference  of  the  human  spe- 
cies, it  may  be  asked,  such  a  deviation  from  the  antecedent  course  oi 
physical  events,  that  the  knowledge  of  such  a  fact  tends  to  destroy  all 
our  confidence  in  the  uniformity  of  the  order  of  nature,  both  in  regard 


CH.  IX.]  UNIFORMITY    OF    THE   SYSTEM.  14:9 

to  time  past  and  future  ?  If  such  an  innovation  could  take  place  after 
the  earth  had  been  exclusively  inhabited  for  thousands  of  ages  by  infe- 
rior animals,  why  should  not  other  changes  as  extraordinary  and  unpre- 
cedented happen  from  time  to  time  ?  If  one  new  cause  was  permitted 
to  supervene,  differing  in  kind  and  energy  from  any  before  in  operation, 
why  may  not  others  have  come  into  action  at  different  epochs  ?  Or 
what  security  have  we  that  they  may  not  arise  hereafter  ?  And  if  such 
be  the  case,  how  can  the  experience  of  one  period,  even  though  we  are 
acquainted  with  all  the  possible  effects  of  the  then  existing  causes,  be  a 
standard  to  which  we  can  refer  all  natural  phenomena  of  other  periods  ? 
Now  these  objections  would  be  unanswerable,  if  adduced  against  one 
who  was  contending  for  the  absolute  uniformity  throughout  all  time  of 
the  succession  of  sublunary  events — if,  for  example,  he  was  disposed  to 
indulge  in  the  philosophical  reveries  of  some  Egyptian  and  Greek  sects, 
who  represented  all  the  changes  both  of  the  moral  and  material  world 
as  repeated  at  distant  intervals,  so  as  to  follow  each  other  in  their  for- 
mer connection  of  place  and  time.  For  they  compared  the  course  of 
events  on  our  globe  to  astronomical  cycles  ;  and  not  only  did  they  con- 
sider all  sublunary  affairs  to  be  under  the  influence  of  the  celestial  bod- 
ies, but  they  taught  that  on  the  earth,  as  well  as  in  the  heavens,  the 
same  identical  phenomena  recurred  again  and  again  in  a  perpetual  vicis- 
situde. The  same  individual  men  were  doomed  to  be  re-born,  and  to 
perform  the  same  actions  as  before  ;  the  same  arts  were  to  be  invented, 
and  the  same  cities  built  and  destroyed.  The  Argonautic  expedition 
was  destined  to  sail  again  with  the  same  heroes,  and  Achilles  with  his 
Myrmidons  to  renew  the  combat  before  the  walls  of  Troy. 

Alter  erit  turn  Tiphys,  et  altera  quse  vehat  Argo 

Dilectos  heroas  ;  erunt  etiam  altera  bella, 

Atque  iterum  ad  Trojam  magnus  mittetur  Achilles.* 

The  geologist,  however,  may  condemn  these  tenets  as  absurd,  with- 
out running  into  the  opposite  extreme,  and  denying  that  the  order  of 
nature  has,  from  the  earliest  periods,  been  uniform  in  the  same  sense  in 
which  we  believe  it  to  be  uniform  at  present,  and  expect  it  to  remain  so 
in  future.  We  have  no  reason  to  suppose,  that  when  man  first  became 
master  of  a  small  part  of  the  globe,  a  greater  change  took  place  in  its 
physical  condition  than  is  now  experienced  when  districts,  never  before 
inhabited,  become  successively  occupied  by  new  settlers.  When  a 
powerful  European  colony  lands  on  the  shores  of  Australia,  and  intro- 
duces at  once  those  arts  which  it  has  required  many  centuries  to  ma- 
ture ;  when  it  imports  a  multitude  of  plants  and  large  animals  from  the 
opposite  extremity  of  the  earth,  and  begins  rapidly  to  extirpate  many  of 
the  indigenous  species,  a  mightier  revolution  is  effected  in  a  brief  period 
than  the  first  entrance  of  a  savage  horde,  or  their  continued  occupation 

*  Virgil,  Eclog.  iv.  For  an  account  of  these  doctrines,  see  Dugald  Stewart's 
Elements  of  the  Philosophy  of  the  Human  Mind,  vol.  ii.  chap.  ii.  sect.  4,  and  Prich- 
ard's  Egypt.  Mythol.  p.  177. 


150  EECENT   OKIGIN   OF  MAN.  [On.  IX. 

of  the  country  for  many  centuries,  can  possibly  be  imagined  to  have 
produced.  If  there  be  no  impropriety  in  assuming  that  the  system  is 
uniform  when  disturbances  so  unprecedented  occur  in  certain  localities, 
we  can  with  much  greater  confidence  apply  the  same  language  to  those 
primeval  ages  when  the  aggregate  number  and  power  of  the  human 
race,  or  the  rate  of  their  advancement  in  civilization,  must  be  supposed 
to  have  been  far  inferior.  In  reasoning  on  the  state  of  the  globe  imme- 
diately before  our  species  was  called  into  existence,  we  must  be  guided 
by  the  same  rules  of  induction  as  when  we  speculate  on  the  state  of 
America  in  the  interval  that  elapsed  between  the  introduction  of  man 
into  Asia,  the  supposed  cradle  of  our  race,  and  the  arrival  of  the  first 
adventurers  on  the  shores  of  the  New  World.  In  that  interval,  we  im- 
agine the  state  of  things  to  have  gone  on  according  to  the  order  now 
observed  in  regions  unoccupied  by  man.  Even  now,  the  waters  of 
lakes,  seas,  and  the  great  ocean,  which  teem  with  life,  may  be  said  to 
have  no  immediate  relation  to  the  human  race — to  be  portions  of  the 
terrestrial  system  of  which  man  has  never  taken,  nor  ever  can  take  pos- 
session ;  so  that  the  greater  part  of  the  inhabited  surface  of  the  planet 
may  still  remain  as  insensible  to  our  presence  as  before  any  isle  or  con- 
tinent was  appointed  to  be  our  residence. 

If  the  barren  soil  around  Sydney  had  at  once  become  fertile  upon  the 
landing  of  our  first  settlers ;  if,  like  the  happy  isles  whereof  the  poets 
have  given  such  glowing  descriptions,  those  sandy  tracts  had  begun  to 
yield  spontaneously  an  annual  supply  of  grain,  we  might  then,  indeed, 
have  fancied  alterations  still  more  remarkable  in  the  economy  of  nature 
to  have  attended  the  first  coming  of  our  species  into  the  planet.  Or  if, 
when  a  volcanic  island  like  Ischia  was,  for  the  first  time,  brought  under 
cultivation  by  the  enterprise  and  industry  of  a  Greek  colony,  the  inter- 
nal fire  had  become  dormant,  and  the  earthquake  had  remitted  its  de- 
structive violence,  there  would  then  have  been  some  ground  for  specu- 
lating on  the  debilitation  of  the  subterranean  forces,  when  the  earth  was 
first  placed  under  the  dominion  of  man.  But  after  a  long  interval  of 
rest,  the  volcano  bursts  forth  again  with  renewed  energy,  annihilates 
one  half  of  the  inhabitants,  and  compels  the  remainder  to  emigrate. 
The  course  of  nature  remains  evidently  unchanged ;  and,  in  like  manner, 
we  may  suppose  the  general  condition  of  the  globe,  immediately  before 
and  after  the  period  when  our  species  first  began  to  exist,  to  have  been 
the  same,  with  the  exception  only  of  man's  presence. 

The  modifications  in  the  system  of  which  man  is  the  instrument  do 
not,  perhaps,  constitute  so  great  a  deviation  from  previous  analogy  as 
we  usually  imagine ;  we  often,  for  example,  form  an  exaggerated  esti- 
mate of  the  extent  of  our  power  in  extirpating  some  of  the  inferior  ani- 
mals, and  causing  others  to  multiply  ;  a  power  which  is  circumscribed 
within  certain  limits,  and  which,  in  all  likelihood,  is  by  no  means  exclu- 
sively exerted  by  our  species.*  The  growth  of  human  population  can- 

*  See  ch.  41. 


CH.  IX.]  UNIFORMITY    OF   THE   SYSTEM.  151 

not  take  place  without  diminishing  the  numbers,  or  causing  the  entire 
destruction,  of  many  animals.  The  larger  beasts  of  prey,  in  particular, 
give  way  before  us  ;  but  other  quadrupeds  of  smaller  size,  and  innumer- 
able birds,  insects,  and  plants,  which  are  inimical  to  our  interests,  in- 
crease in  spite  of  us,  some  attacking  our  food,  others  our  raiment  and 
persons,  and  others  interfering  with  our  agricultural  and  horticultural 
labors.  We  behold  the  rich  harvest  which  we  have  raised  by  the  sweat 
of  our  brow,  devoured  by  myriads  of  insects,  and  are  often  as  incapable 
of  arresting  their  depredations,  as  of  staying  the  shock  of  an  earthquake, 
or  the  course  of  a  stream  of  lava. 

A  great  philosopher  has  observed,  that  we  can  command  nature  only 
by  obeying  her  laws  ;  and  this  principle  is  true  even  in  regard  to  the 
astonishing  changes  which  are  superinduced  in  the  qualities  of  certain 
animals  and  plants  by  domestication  and  garden  culture.  I  shall  point 
out  in  the  third  book  that  we  can  only  effect  such  surprising  alterations 
by  assisting  the  development  of  certain  instincts,  or  by  availing  ourselves 
of  that  mysterious  law  of  their  organization,  by  which  individual' pecu- 
liarities are  transmissible  from  one  generation  to  another.* 

It  is  probable  from  these  and  many  other  considerations,  that  as  we 
enlarge  our  knowledge  of  the  system,  we  shall  become  more  and  more 
convinced,  that  the  alterations  caused  by  the  interference  of  man  devi- 
ate far  less  from  the  analogy  of  those  effected  by  other  animals  than  is 
usually  supposed. j*  We  are  often  misled,  when  we  institute  such  com- 
parisons, by  our  knowledge  of  the  wide  distinction  between  the  instincts 
of  animals  and  the  reasoning  power  of  man  ;  and  we  are  apt  hastily  to 
infer,  that  the  effects  of  a  rational  and  irrational  species,  considered 
merely  as  physical  agents,  will  differ  almost  as  much  as  the  faculties  by 
which  their  actions  are  directed. 

It  is  not,  however,  intended  that  a  real  departure  from  the  antecedent 
course  of  physical  events  cannot  be  traced  in  the  introduction  of  man. 
If  that  latitude  of  action  which  enables  the  brutes  to  accommodate 
themselves  in  some  measure  to  accidental  circumstances  could  be  im- 
agined to  have  been  at  any  former  period  so  great,  that  the  operations 
of  instinct  were  as  much  diversified  as  are  those  of  human  reason,  it 
might,  perhaps,  be  contended,  that  the  agency  of  man  did  not  consti- 
tute an  anomalous  deviation  from  the  previously  established  order  of 
things.  It  might  then  have  been  said,  that  the  earth's  becoming  at  a 
particular  period  the  residence  of  human  beings,  was  an  era  in  the 
moral,  not  in  the  physical  world — that  our  study  and  contemplation 
of  the  earth,  and  the  laws  which  govern  its  animate  productions,  ought 
no  more  to  be  considered  in  the  light  of  a  disturbance  or  deviation  from 
the  system,  than  the  discovery  of  the  satellites  of  Jupiter  should  be 
regarded  as  a  physical  event  affecting  those  heavenly  bodies.  Their 
influence  in  advancing  the  progress  of  science  among  men,  and  in  aid- 
ing navigation  and  commerce,  was  accompanied  by  no  reciprocal  action 

*  See  ch.  35.  f  See  ch.  37,  38,  39,  41. 


152  RECENT   ORIGIN   OF  MAN.  [Cn.  IX. 

of  the  human  mind  upon  the  economy  of  nature  in  those  distant  planets ; 
and  so  the  earth  might  be  conceived  to  have  become,  at  a  certain  pe- 
riod, a  place  of  moral  discipline  and  intellectual  improvement  to  man, 
without  the  slightest  derangement  of  a  previously  existing  order  of 
change  in  its  animate  and  inanimate  productions. 

The  distinctness,  however,  of  the  human  from  all  other  species,  con- 
sidered merely  as  an  efficient  cause  in  the  physical  world,  is  real ;  for 
we  stand  in  a  relation  to  contemporary  species  of  animals  and  plants 
widely  different  from  that  which  other  irrational  animals  can  ever  be 
supposed  to  have  held  to  each  other.  We  modify  their  instincts,  rel- 
ative numbers,  and  geographical  distribution,  in  a  manner  superior  in 
degree,  and  in  some  respects  very  different  in  kind  from  that  in  which 
any  other  species  can  affect  the  rest.  Besides,  the  progressive  move- 
ment of  each  successive  generation  of  men  causes  the  human  species 
to  differ  more  from  itself  in  power  at  two  distant  periods,  than  any 
one  species  of  the  higher  order  of  animals  differs  from  another.  The 
establishment,  therefore,  by  geological  evidence,  of  the  first  interven- 
tion of  such  a  peculiar  and  unprecedented  agency,  long  after  other  parts 
of  the  animate  and  inanimate  world  existed,  affords  ground  for  con- 
cluding that  the  experience  during  thousands  of  ages  of  all  the  events 
which  may  happen  on  this  globe,  would  not  enable  a  philosopher  to 
speculate  with  confidence  concerning  future  contingencies. 

If,  then,  an  intelligent  being,  after  observing  the  order  of  events 
for  an  indefinite  series  of  ages,  had  witnessed  at  last  so  wonderful  an 
innovation  as  this,  to  what  extent  would  his  belief  in  the  regularity  of 
the  system  be  weakened  ? — would  he  cease  to  assume  that  there  was 
permanency  in  the  laws  of  nature  ? — would  he  no  longer  be  guided 
in  his  speculations  by  the  strictest  rules  of  induction  ?  To  these  ques- 
tions it  may  be  answered,  that,  had  he  previously  presumed  to  dog- 
matize respecting  the  absolute  uniformity  of  the  order  of  nature,  he 
would  undoubtedly  be  checked  by  witnessing  this  new  and  unexpected 
event,  and  would  form  a  more  just  estimate  of  the  limited  range  of  his 
own  knowledge,  and  the  unbounded  extent  of  the  scheme  of  the  uni- 
verse. But  he  would  soon  perceive  that  no  one  of  the  fixed  and  con- 
stant laws  of  the  animate  or  inanimate  world  was  subverted  by  human 
agency,  and  that  the  modifications  now  introduced  for  the  first  time 
were  the  accompaniments  of  new  and  extraordinary  circumstances, 
and  those  not  of  a  physical  but  a  moral  nature.  The  deviation  per- 
mitted would  also  appear  to  be  as  slight  as  was  consistent  with  the 
accomplishment  of  the  new  moral  ends  proposed,  and  to  be  in  a  great 
degree  temporary  in  its  nature,  so  that,  whenever  the  power  of  the 
new  agent  was  withheld,  even  for  a  brief  period,  a  relapse  would  take 
place  to  the  ancient  state  of  things ;  the  domesticated  animal,  for  ex- 
ample, recovering  in  a  few  generations  its  wild  instinct,  and  the  garden- 
flower  and  fruit-tree  reverting  to  the  likeness  of  the  parent  stock. 

Now,  if  it  would  be  reasonable  to  draw  such  inferences  with  respect 
to  the  future,  we  cannot  but  apply  the  same  rules  of  induction  to  the 


CH.  X.]  INTENSITY   OF   AQUEOUS   CAUSES.  153 

past.  We  have  no  right  to  anticipate  any  modifications  in  the  results 
of  existing  causes  in  time  to  come,  which  are  not  conformable  to  analogy, 
unless  they  be  produced  by  the  progressive  development  of  human 
power,  or  perhaps  by  some  other  new  relations  which  may  hereafter 
spring  up  between  the  moral  and  material  worlds.  In  the  same  man- 
ner, when  we  speculate  on  the  vicissitudes  of  the  animate  and  inanimate 
creation  in  former  ages,  we  ought  not  to  look  for  any  anomalous  results, 
unless  where  man  has  interfered,  or  unless  clear  indications  appear  of 
some  other  moral  source  of  temporary  derangement. 


CHAPTER  X. 

SUPPOSED    INTENSITY    OF    AQUEOUS    FORCES    AT    REMOTE    PERIODS. 

Intensity  of  aqueous  causes — Slow  accumulation  of  strata  proved  by  fossils — Rate 
of  denudation  can  only  keep  pace  with  deposition — Erratics,  and  effects  of  ice — 
Deluges,  and  the  causes  to  which  they  are  referred — Supposed  universality  of 
ancient  deposits. 

Intensity  of  aqueous  causes. — THE  great  problem  considered  in  the 
preceding  chapters,  namely,  whether  the  former  changes  of  the  earth 
made  known  to  us  by  geology,  resemble  in  kind  and  degree  those  now 
in  daily  progress,  may  still  be  contemplated  from  several  other  points  of 
view.  We  may  inquire,  for  example,  whether  there  are  any  grounds 
for  the  belief  entertained  by  many,  that  the  intensity  both  of  aqueous 
and  of  igneous  forces,  in  remote  ages,  far  exceeded  that  which  we  wit- 
ness in  our  own  times. 

First,  then,  as  to  aqueous  causes  :•  it  has  been  shown,  in  our  history 
of  the  science,  that  Woodward  did  not  hesitate,  in  1695,  to  teach  that 
the  entire  mass  of  fossiliferous  strata  contained  in  the  earth's  crust  had 
been  deposited  in  a  few  months ;  and,  consequently,  as  their  mechanical 
and  derivative  origin  was  already  admitted,  the  reduction  of  rocky 
masses  into  mud,  sand,  and  pebbles,  the  transportation  of  the  same  to 
a  distance,  and  their  accumulation  elsewhere  in  regular  strata,  were  all 
assumed  to  have  taken  place  with  a  rapidity  unparalleled  in  modern 
times.  This  doctrine  was  modified  by  degrees,  in  proportion  as  different 
classes  of  organic  remains,  such  as  shells,  corals,  and  fossil  plants,  had 
been  studied  with  attention.  Analogy  led  every  naturalist  to  assume, 
that  each  full-grown  individual  of  the  animal  or  vegetable  kingdom,  had 
required  a  certain  number  of  months  or  years  for  the  attainment  of  ma- 
turity, and  the  perpetuation  of  its  species  by  generation ;  and  thus  the 


154:  SUPPOSED  FORMER  INTENSITY  [On.  X. 

first  approach  was  made  to  the  conception  of  a  common  standard  of 
time,  without  which  there  are  no  means  whatever  of  measuring  the 
comparative  rate  at  which  any  succession  of  events  has  taken  place  at 
two  distinct  periods.  This  standard  consisted  of  the  average  duration 
of  the  lives  of  individuals  of  the  same  genera  or  families  in  the  animal 
and  vegetable  kingdoms ;  and  the  multitude  of  fossils  dispersed  through 
successive  strata  implied  the  continuance  of  the  same  species  for  many 
generations.  At  length  the  idea  that  species  themselves  had  had  a 
limited  duration,  arose  out  of  the  observed  fact  that  sets  of  strata  of  dif- 
ferent ages  contained  fossils  of  distinct  species.  Finally,  the  opinion 
became  general,  that  in  the  course  of  ages,  one  assemblage  of  animals 
and  plants  had  disappeared  after  another  again  and  again,  and  new 
tribes  had  started  into  life  to  replace  them. 

Denudation. — In  addition  to  the  proofs  derived  from  organic  remains, 
the  forms  of  stratification  led  also,  on  a  fuller  investigation,  to  the  belief 
that  sedimentary  rocks  had  been  slowly  deposited ;  but  it  was  still  sup- 
posed that  denudation,  or  the  power  of  running  water,  and  the  waves 
and  currents  of  the  ocean,  to  strip  off  superior  strata,  and  lay  bare  the 
rocks  below,  had  formerly  operated  with  an  energy  wholly  unequalled 
in  our  times.  These  opinions  were  both  illogical  and  inconsistent,  be- 
cause deposition  and  denudation  are  parts  of  the  same  process,  and 
what  is  true  of  the  one  must  be  true  of  the  other.  Their  speed  must 
be  always  limited  by  the  same  caus.es,  and  the  conveyance  of  solid  mat- 
ter to  a  particular  region  can  only  keep  pace  with  its  removal  from  an- 
other, so  that  the  aggregate  of  sedimentary  strata  in  the  earth's  crust 
can  never  exceed  in  volume  the  amount  of  solid  matter  which  has  been 
ground  down  and  washed  away  by  running  water.  How  vast,  then, 
must  be  the  spaces  which  this  abstraction  of  matter  has  left  vacant ! 
how  far  exceeding  in  dimensions  all  the  valleys,  however  numerous,  and 
the  hollows,  however  vast,  which  we  can  prove  to  have  been  cleared  out 
by  aqueous  erosion  !  The  evidences  of  the  work  of  denudation  are  de- 
fective, because  it  is  the  nature  of  every  destroying  cause  to  obliterate 
the  signs  of  its  own  agency ;  but  the  amount  of  reproduction  in  the  form 
of  sedimentary  strata  must  always  afford  a  true  measure  of  the  minimum 
of  denudation  which  the  earth's  surface  has  undergone. 

Erratics. — The  next  phenomenon  to  which  the  advocates  of  the 
excessive  power  of  running  water  in  times  past  have  appealed,  is  the 
enormous  size  of  the  blocks  called  erratic,  which  lie  scattered  over  the 
northern  parts  of  Europe  and  North  America.  Unquestionably  a  large 
proportion  of  these  blocks  have  been  transported  far  from  their  original 
position,  for  between  them  and  the  parent  rocks  we  now  find,  not  unfre- 
quently,  deep  seas  and  valleys  intervening,  or  hills  more  than  a  thousand 
feet  high.  To  explain  the  present  situation  of  such  travelled  fragments, 
a  deluge  of  mud  has  been  imagined  by  some  to  have  come  from  the 
north,  bearing  along  with  it  sand,  gravel,  and  stony  fragments,  some  of 
them  hundreds  of  tons  in  weight.  This  flood,  in  its  transient  passage 
over  the  continents,  dispersed  the  boulders  irregularly  over  hill,  valley, 


Cn.  X.]  OF   AQUEOUS    CAUSES.  155 

and  plain ;  or  forced  them  along  over  a  surface  of  hard  rock,  so  as  to 
polish  it  and  leave  it  indented  with  parallel  scratches  and  grooves — such 
markings  as  are  still  visible  in  the  rocks  of  Scandinavia,  Scotland,  Can- 
ada, and  many  other  countries. 

There  can  be  no  doubt  that  the  myriads  of  angular  and  rounded  blocks 
above  alluded  to,  cannot  have  been  borne  along  by  ordinary  rivers  or 
marine  currents,  so  great  is  their  volume  and  weight,  and  so  clear  are 
the  signs,  in  many  places,  of  time  having  been  occupied  in  their  succes- 
sive deposition  ;  for  they  are  often  distributed  at  various  depths  through 
heaps  of  regularly  stratified  sand  and  gravel.  No  waves  of  the  sea 
raised  by  earthquakes,  nor  the  bursting  of  lakes  dammed  up  for  a  time 
by  landslips  or  by  avalanches  of  snow,  can  account  for  the  observed 
facts ;  but  I  shall  endeavor  to  show,  in  the  next  book,  chap.  15,*  that 
a  combination  of  existing  causes  may  have  conveyed  erratics  into  their 
present  situations. 

The  causes  which  will  be  referred  to  are,  first,  the  carrying  power  of 
ice,  combined  with  that  of  running  water ;  and  second,  the  upward 
movement  of  the  bed  of  the  sea,  converting  it  gradually  into  land. 
Without  entering  at  present  into  any  details  respecting  these  causes, 
I  may  mention  that  the  transportation  of  blocks  by  ice  is  now  simulta- 
neously in  progress  in  the  cold  and  temperate  latitudes,  both  of  the 
northern  and  southern  hemisphere,  as,  for  example,  on  the  coasts  of  Can- 
ada and  Gulf  of  St.  Lawrence,  and  also  in  Chili,  Patagonia,  and  the 
island  of  South  Georgia.  In  those  regions  the  uneven  bed  of  the  ocean 
is  becoming  strewed  over  with  ice-drifted  fragments,  which  have  either 
stranded  on  shoals,  or- been  dropped  in  deep  water  by  melting  bergs.  The 
entanglement  of  boulders  in  drift-ice  will  also  be  shown  to  occur  annually 
in  North  America,  and  these  stones,  when  firmly  frozen  into  ice,  wander 
year  after  year  from  Labrador  to  the  St.  Lawrence,  and  reach  points  of 
the  western  hemisphere  farther  south  than  any  part  of  Great  Britain. 

The  general  absence  of  erratics  in  the  warmer  parts  of  the  equatorial 
regions  of  Asia,  Africa,  and  America,  confirms  the  same  views.  As  to 
the  polishing  and  grooving  of  hard  rocks,  it  has  lately  been  ascertained 
that  glaciers  give  rise  to  these  effects  when  pushing  forward  sand,  peb- 
bles, and  rocky  fragments,  and  causing  them  to  grate  along  the  bottom. 
Nor  can  there  be  any  reasonable  doubt  that  icebergs,  when  they  run 
aground  on  the  floor  of  the  ocean,  must  imprint  similar  marks  upon  it. 

It  is  unnecessary,  therefore,  to  refer  to  deluges,  or  even  to  speculate 
on  the  former  existence  of  a  climate  more  severe  than  that  now  prevail- 
ing in  the  western  hemisphere,  to  explain  the  geographical  distribution 
of  most  of  the  European  erratics. 

Deluges. — As  deluges  have  been  often  alluded  to,  I  shall  say  some- 
thing of  the  causes  which  may  be  supposed  to  give  rise  to  these  grand 
movements  of  water  in  addition  to  those  already  alluded  to  (p.  9). 
Geologists  who  believe  that  mountain-chains  have  been  thrown  up  sud- 

*  See  also  Manual  of  Geology,  ch.  11,  12. 


156  SUPPOSED   FORMER   INTENSITY  [Cfl.  X. 

denly  at  many  successive  epochs,  imagine  that  the  waters  of  the  ocean 
may  be  raised  by  these  convulsions,  and  then  break  in  terrific  waves  upon 
the  land,  sweeping  over  whole  continents,  hollowing  out  valleys,  and 
transporting  sand,  gravel,  and  erratics,  to  great  distances.  The  sudden 
rise  of  the  Alps  or  Andes,  it  is  said,  may  have  produced  a  flood  even 
subsequently  to  the  time  when  the  earth  became  the  residence  of  man. 
But  it  seems  strange  that  none  of  the  writers  who  have  indulged  their 
imaginations  in  conjectures  of  this  kind,  should  have  ascribed  a  deluge 
to  the  sudden  conversion  of  part  of  the  unfathomable  ocean  into  a  shoal 
rather  than  to  the  rise  of  mountain-chains.  In  the  latter  case,  the 
mountains  themselves  could  do  no  more  than  displace  a  certain  quantity 
of  atmospheric  air,  whereas,  the  instantaneous  formation  of  the  shoal 
would  displace  a  vast  body  of  water,  which  being  heaved  up  to  a  great 
height  might  roll  over  and  permanently  submerge  a  large  portion  of  a 
continent. 

If  we  restrict  ourselves  to  combinations  of  causes  at  present  known, 
it  would  seem  that  the  two  principal  sources  of  extraordinary  inunda- 
tions are,  first,  the  escape  of  the  waters  of  a  large  lake  raised  far  above 
the  sea ;  and,  secondly,  the  pouring  down  of  a  marine  current  into  lands 
depressed  below  the  mean  level  of  the  ocean. 

As  an  example  of  the  first  of  these  cases,  we  may  take  Lake  Superior, 
which  is  more  than  400  geographical  miles  in  length  and  about  150  in 
breadth,  having  an  average  depth  of  from  500  to  900  feet.  The  sur- 
face of  this  vast  body  of  fresh  water  is  no  less  than  600  feet  above  the 
level  of  the  ocean  ;  the  lowest  part  of  the  barrier  which  separates  the 
lake  on  its  southwest  side  from  those  streams  which  flow  into  the  head 
waters  of  the  Mississippi  being  about  600  feet  high.  If,  therefore,  a 
series  of  subsidences  should  lower  any  part  of  this  barrier  600  feet,  any 
subsequent  rending  or  depression,  even  of  a  few  yards  at  a  time,  would 
allow  the  sudden  escape  of  vast  floods  of  water  into  a  hydrographical 
basin  of  enormous  extent.  If  the  event  happened  in  the  dry  season, 
when  the  ordinary  channels  of  the  Mississippi  and  its  tributaries  are  in  a 
great  degree  empty,  the  inundation  might  not  be  considerable  ;  but  if  in 
the  flood-season,  a  region  capable  of  supporting  a  population  of  many 
millions  might  be  suddenly  submerged.  But  even  this  event  would  be 
insufficient  to  cause  a  violent  rush  of  water,  and  to  produce  those  effects 
usually  called  diluvial ;  for  the  difference  of  level  of  600  feet  between 
Lake  Superior  and  the  Gulf  of  Mexico,  when  distributed  over  a  distance 
of  1800  miles,  would  give  an  average  fall  of  only  four  inches  per  mile. 

The  second  case  before  adverted  to  is  where  there  are  large  tracts  of 
dry  land  beneath  the  mean  level  of  the  ocean.  It  seems,  after  much 
controversy,  to  be  at  length  a  settled  point,  that  the  Caspian  is  really 
83  feet  6  inches  lower  than  the  Black  Sea.  As  the  Caspian  covers  an 
area  about  equal  to  that  of  Spain,  and  as  its  shores  are  in  general  low 
and  flat,  there  must  be  many  thousand  square  miles  of  country  less  than 
83  feet  above  the  level  of  that  inland  sea,  and  consequently  depressed 
below  the  Black  Sea  and  Mediterranean.  This  area  includes  the  site  of 


Cu.  X.]  OF   AQUEOUS   CAUSES.  157 

the  populous  city  of  Astrakhan  and  other  towns.  Into  this  region  the 
ocean  would  pour  its  waters,  if  the  land  now  intervening  between  the 
Sea  of  Azof  and  the  Caspian  should  subside.  Yet  even  if  this  event 
should  occur,  it  is  most  probable  that  the  submergence  of  the  whole 
region  would  not  be  accomplished  simultaneously,  but  by  a  series  of 
minor  floods,  the  sinking  of  the  barrier  being  gradual.* 

Supposed  universality  of  ancient  deposits. — The  next  fallacy  which 
has  helped  to  perpetuate  the  doctrine  that  the  operations  of  water  were 
on  a  different  and  grander  scale  in  ancient  times,  is  founded  on  the  indef- 
inite areas  over  which  homogeneous  deposits  were  supposed  to  extend. 
No  modern  sedimentary  strata,  it  is  said,  equally  identical  in  mineral 
character  and  fossil  contents,  can  be  traced  continuously  from  one  quar- 
ter of  the  globe  to  another.  But  the  first  propagators  of  these  opinions 
were  very  slightly  acquainted  with  the  inconstancy  in  mineral  composi- 
tion of  the  ancient  formations,  and  equally  so  of  the  wide  spaces  over 
which  the  same  kind  of  sediment  is  now  actually  distributed  by  rivers 
and  currents  in  the  course  of  centuries.  The  persistency  of  character 
in  the  older  series  was  exaggerated,  its  extreme  variability  in  the  newer 
was  assumed  without  proof.  In  the  chapter  which  treats  of  river-deltas 
and  the  dispersion  of  sediment  by  currents,  and  in  the  description  of 
reefs  of  coral  now  growing  over  areas  many  hundred  miles  in  length,  I 
shall  have  opportunities  of  convincing  the  reader  of  the  danger  of  hasty 
generalizations  on  this  head. 

In  regard  to  the  imagined  universality  of  particular  rocks  of  ancient 
date,  it  was  almost  unavoidable  that  this  notion,  when  once  em- 
braced, should  be  perpetuated  ;  for  the  same  kinds  of  rock  have  occa- 
sionally been  reproduced  at  successive  epochs;  and  when  once  the 
agreement  or  disagreement  in  mineral  character  alone  was  relied  on  as 
the  test  of  age,  it  followed  that  similar  rocks,  if  found  even  at  the 
antipodes,  were  referred  to  the  same  era,  until  the  contrary  could  be 
shown. 

*  It  has  been  suspected  ever  since  the  middle  of  the  last  century,  that  the 
Caspian  was  lower  than  the  ocean,  it  being  known  that  in  Astrakhan  the  mercury 
in  the  barometer  generally  stands  above  thirty  inchea  In  1811,  MM.  Engelhardt 
and  Parrot  attempted  to  determine  the  exact  amount  of  difference  by  a  series  of 
levellings  and  barometrical  measurements  across  the  isthmus  at  two  different 
places  near  the  foot  of  Mount  Caucasus.  The  result  of  their  operations  led  them, 
to  the  opinion  that  the  Caspian  was  more  than  300  feet  below  the  Black  Sea. 
But  the  correctness  of  the  observations  having  afterwards  been  called  in  question, 
M.  Parrot  revisited  the  ground  in  1829  and  1830,  and  inferred  from  new  level- 
lings,  that  the  mouth  of  the  Don  was  between  three  and  four  feet  lower  than 
that  of  the  Wolga ;  in  other  words,  that  the  sea  of  Azof,  which  communicates 
with  the  Black  Sea,  was  actually  lower  than  the  Caspian  !  Other  statements, 
no  less  Contradictory,  having  been  made  by  other  observers,  the  Russian  govern- 
ment at  length  directed  the  Academy  of  St.  Petersburg  to  send  an  expedition, 
in  1836,  to  decide  the  point  by  a  trigonometrical  survey,  from  which  it  appeared 
that  the  Caspian  is  101  Russian,  or  108  English,  feet  lower  than  the  Black  Sea. 
(For  authorities,  see  Journ.  Roy.  Geograph.  Soc.  vol.  viii.  p.  135).  Sir  R.  Murchi- 
son,  however,  concludes,  in  1845,  from  the  best  Russian  authorities,  that  the  de- 
pression of  the  Caspian  is  only  83  feet  6  inches. 

The  measurements  of  Major  Anthonv  Symonds,  since  confirmed  by  French 
authorities,  make  the  Dead  Sea  to  be  1200  feet  below  the  Mediterranean. 


158  SUPPOSED   FORMER   INTENSITY  [Cn.  X. 

Now  it  is  usually  impossible  to  combat  such  an  assumption  on  geo- 
logical grounds,  so  long  as  we  are  imperfectly  acquainted  with  the  order 
of  superposition  and  the  organic  remains  of  these  same  formations. 
Thus,  for  example,  a  group  of  red  marl  and  red  sandstone,  containing 
salt  and  gypsum,  being  interposed  in  England  between  the  Lias  and  the 
Coal,  all  other  red  marls  and  sandstones,  associated  some  of  them  with 
salt,  and  others  with  gypsum,  and  occurring  not  only  in  different  parts  of 
Europe,  but  in  North  America,  Peru,  India,  the  salt  deserts  of  Asia, 
those  of  Africa — in  a  word,  in  every  quarter  of  the  globe,  were  referred 
to  one  and  the  same  period.  The  burden  of  proof  was  not  supposed  to 
rest  with  those  who  insisted  on  the  identity  in  age  of  all  these  groups — 
their  identity  in  mineral  composition  was  thought  sufficient.  It  was  in 
vain  to  urge  as  an  objection  the  improbability  of  the  hypothesis  which 
implies  that  all  the  moving  waters  on  the  globe  were  once  simultaneously 
charged  with  sediment  of  a  red  color. 

But  the  rashness  of  pretending  to  identify,  in  age,  all  the  red  sand- 
stones and  marls  in  question,  has  at  length  been  sufficiently  exposed,  by 
the  discovery  that,  even  in  Europe,  they  belong  decidedly  to  many  dif- 
ferent epochs.  It  is  already  ascertained,  that  the  red  sandstone  and  red 
marl  containing  the  rock-salt  of  Cardona  in  Catalonia  is  newer  than  the 
Oolitic,  if  not  more  modern  than  the  Cretaceous  period.  It  is  also 
known  that  certain  red  marls  and  variegated  sandstones  in  Auvergne 
which  are  undistinguishable  in  mineral  composition  from  the  New  Red 
Sandstone  of  English  geologists,  belong,  nevertheless,  to  the  Eocene 
period  ;  and,  lastly,  the  gypseous  red  marl  of  Aix,  in  Provence,  for- 
merly supposed  to  be  a  marine  secondary  group,  is  now  acknowledged 
to  be  a  tertiary  freshwater  formation.  In  Nova  Scotia  one  great  de- 
posit of  red  marl,  sandstone,  and  gypsum,  precisely  resembling  in  min- 
eral character  the  "New  Red"  of  England,  occurs  as  a  member  of  the 
Carboniferous  group,  and  in  the  United  States  near  the  Falls  of  Niagara, 
a  similar  formation  constitutes  a  subdivision  of  the  Silurian  series.* 

Nor  was  the  nomenclature  commonly  adopted  in  geology  without  its 
influence  in  perpetuating  the  erroneous  doctrine  of  universal  formations. 
Such  names,  for  example,  as  Chalk,  Green  Sand,  Oolite,  Red  Marl,  Coal, 
and  others,  were  given  to  some  of  the  principal  fossiliferous  groups  in 
consequence  of  mineral  peculiarities  which  happened  to  characterize 
them  in  the  countries  where  they  were  first  studied.  When  geologists 
had  at  length  shown,  by  means  of  fossils  and  the  order  of  superposition, 
that  other  strata,  entirely  dissimilar  in  color,  texture,  and  composition, 
were  of  contemporaneous  date,  it  was  thought  convenient  still  to  retain 
the  old  names.  That  these  were  often  inappropriate  was  admitted  ; 
but  the  student  was  taught  to  understand  them  in  no  other  than  a 
chronological  sense  ;  so  that  the  Chalk  might  not  be  a  white  cretaceous 
rock,  but  a  hard  dolomitic  limestone,  as  in  the  Alps,  or  a  brown  sand- 
stone or  green  marl,  as  in  New  Jersey,  U.  S.  In  like  manner,  the 

*  See  Lyell's  Travels  in  N.  America,  ch.  2  and  25. 


CH.  X.]  OF   AQUEOUS    CAUSES.  159 

Green  Sand,  it  was  said,  might  in  some  places  be  represented  by  red 
sandstone,  red  marl,  salt,  and  gypsum,  as  in  the  north  of  Spain.  So 
the  oolitic  texture  was  declared  to  be  rather  an  exception  than  other- 
wise to  the  general  rule  in  rocks  of  the  Oolitic  period  ;  and  it  often 
became  necessary  to  affirm  that  no  particle  of  carbonaceous  matter 
could  be  detected  in  districts  where  the  true  Coal  series  abounded.  In 
spite  of  every  precaution  the  habitual  use  of  this  language  could  scarcely 
fail  to  instil  into  the  mind  of  the  pupil  an  idea  that  chalk,  coal,  salt,  red 
marl,  or  the  Oolitic  structure  were  far  more  widely  characteristic  of 
the  rocks  of  a  given  age  than  was  really  the  case. 

There  is  still  another  cause  of  deception,  disposing  us  to  ascribe  a 
more  limited  range  to  the  newer  sedimentary  formations  as  compared 
to  the  older,  namely,  the  very  general  concealment  of  the  newer  strata 
beneath  the  waters  of  lakes  and  seas,  and  the  wide  exposure  above 
waters  of  the  more  ancient.  The  Chalk,  for  example,  now  seen  stretch- 
ing for  thousands  of  miles  over  different  parts  of  Europe,  has  become 
visible  to  us  by  the  effect,  not  of  one,  but  of  many  distinct  series  of  sub- 
terranean movements.  Time  has  been  required,  and  a  succession  of 
geological  periods,  to  raise  it  above  the  waves  in  so  many  regions ;  and 
if  calcareous  rocks  of  the  middle  and  upper  tertiary  periods  have  been 
formed,  as  homogeneous  in  mineral  composition  throughout  equally  ex- 
tensive regions,  it  may  require  convulsions  as  numerous  as  all  those 
which  have  occurred  since  the  origin  of  the  Chalk  to  bring  them  up 
within  the  sphere  of  human  observation.  Hence  the  rocks  of  more 
modern  periods  may  appear  partial,  as  compared  to  those  of  remoter 
eras,  not  because  of  any  original  inferiority  in  their  extent,  but  because 
there  has  not  been  sufficient  time  since  their  origin  for  the  development 
of  a  great  series  of  elevatory  movements. 

In  regard,  however,  to  one  of  the  most  important  characteristics  of 
sedimentary  rocks,  their  organic  remains,  many  naturalists  of  high  au- 
thority have  maintained  that  the  same  species  of  fossils  are  more  uni- 
formly distributed  through  formations  of  high  antiquity  than  in  those  of 
more  modern  date,  and  that  distinct  zoological  and  botanical  provinces, 
as  they  are  called,  which  form  so  striking  a  feature  in  the  living  crea- 
tion, were  not  established  at  remote  eras.  Thus  the  plants  of  the  Coal, 
the  shells,  the  trilobites  of  the  Silurian  rocks,  and  the  ammonites  of  the 
Oolite,  have  been  supposed  to  have  a  wider  geographical  range  than 
any  living  species  .of  plants,  crustaceans,  or  mollusks.  This  opinion 
seems  in  certain  cases  to  be  well  founded,  especially  in  relation  to  the 
plants  of  the  Carboniferous  epoch,  owing  probably  to  the  more  uniform 
temperature  of  the  globe,  at  a  time  when  the  position  of  sea  and  land 
was  less  favorable  to  variations  in  climate,  according  to  principles 
already  explained  in  the  seventh  and  eighth  chapters.  But  a  recent 
comparison  of  the  fossils  of  North  American  rocks  with  those  of  corre- 
sponding ages  in  the  European  series,  has  proved  that  the  terrestrial 
vegetation  of  the  Carboniferous  epoch  is  an  exception  to  the  general 
rule,  and  that  the  fauna  and  flora  of  the  earth  at  successive  periods, 


160  SUPPOSED    FOEMEE   INTENSITY  [On.  XL 

from  the  oldest  Silurian  to  the  newest  Tertiary  was  as  diversified  as 
now.  The  shells,  corals,  and  other  classes  of  organic  remains  demon- 
strate the  fact  that  the  earth  might  then  have  been  divided  into  separate 
zoological  provinces,  in  a  manner  analogous  to  that  observed  in  the  geo- 
graphical distribution  of  species  now  living. 


CHAPTER  XL 

ON    THE    SUPPOSED    FORMER    INTENSITY    OF    THE    IGNEOUS    FORCES. 

Volcanic  action  at  successive  geological  periods — Plutonic  rocks  of  different  ages — 
Gradual  development  of  subterranean  movements — Faults — Doctrine  of  the 
sudden  upheaval  of  parallel  mountain-chains — Objections  to  the  proof  of  the 
suddenness  of  the  upheaval,  and  the  contemporaneousness  of  parallel  chains — 
Trains  of  active  volcanoes  not  parallel — As  large  tracts  of  land  are  rising  or 
sinking  slowly,  so  narrow  zones  of  land  may  be  pushed  up  gradually  to  great 
heights — Bending  of  strata  by  lateral  pressure — Adequacy  of  the  volcanic 
power  to  effect  this  without  paroxysmal  convulsions. 

WHEN  reasoning  on  the  intensity  of  volcanic  action  at  former  periods, 
as  well  as  on  the  power  of  moving  water,  already  treated  of,  geologists 
have  been  ever  prone  to  represent  Nature  as  having  been  prodigal  of 
violence  and  parsimonious  of  time.  Now,  although  it  is  less  easy  to 
determine  the  relative  ages  of  the  volcanic  than  of  the  fossiliferous  for- 
mations, it  is  undeniable  that  igneous  rocks  have  been  produced  at  all 
geological  periods,  or  as  often  as  we  find  distinct  deposits  marked  by 
peculiar  animal  and  vegetable  remains.  It  can  be  shown  that  rocks 
commonly  called  trappean  have  been  injected  into  fissures,  and  ejected 
at  the  surface,  both  before  and  during  the  deposition  of  the  Carbon- 
iferous series,  and  at  the  time  when  the  Magnesian  Limestone,  and 
when  the  Upper  New  Red  Sandstone  were  formed,  or  when  the  Lias, 
Oolite,  Green  Sand,  Chalk,  and  the  several  tertiary  groups  newer  than 
the  chalk,  originated  in  succession.  Nor  is  this  all :  distinct  volcanic 
products  may  be  referred  to  the  subordinate  divisions  of  each  period, 
such  as  the  Carboniferous,  as  in  the  county  of  Fife,  in  Scotland,  where 
certain  masses  of  contemporaneous  trap  are  associated  with  the  Lower, 
others  with  the  Upper  Coal  measures.  And  if  one  of  these  masses  is 
more  minutely  examined,  we  find  it  to  consist  of  the  products  of  a  great 
many  successive  outbursts,  by  which  scorise  and  lava  were  again  and 
again  emitted,  and  afterwards  consolidated,  then  fissured,  and  finally 
traversed  by  melted  matter,  constituting  what  are  called  dikes.*  As 
we  enlarge,  therefore,  our  knowledge  of  the  ancient  rocks  formed  by 

*  See  Manual  of  Geology,  chap.  29  to  33,  inclusive. 


CH.  XL]  OF   IGNEOUS    FORCES.  ,  161 

subterranean  heat,  we  find  ourselves  compelled  to  regard  them  as  the 
aggregate  effects  of  innumerable  eruptions,  each  of  which  may  have 
been  comparable  in  violence  to  those  now  experienced  in  volcanic 
regions. 

It  may  indeed  be  said  that  we  have  as  yet  no  data  for  estimating  the 
relative  volume  of  matter  simultaneously  in  a  state  of  fusion  at  two 
given  periods,  as  if  we  were  to  compare  the  columnar  basalt  of  Staffa 
and  its  environs  with  the  lava  poured  out  in  Iceland  in  1783  ;  but  for 
this  very  reason  it  would  be  rash  and  unphilosophical  to  assume  an  ex- 
cess of  ancient  as  contrasted  with  modern  outpourings  of  melted  matter 
at  particular  periods  of  time.*  It  would  be  still  more  presumptuous  to 
take  for  granted  that  the  more  deep-seated  effects  of  subterranean  heat 
surpassed  at  remote  eras  the  corresponding  effects  of  internal  heat  in 
our  own  times.  Certain  porphyries  and  granites,  and  all  the  rocks  com- 
monly called  plutonic,  are  now  generally  supposed  to  have  resulted  from 
the  slow  cooling  of  materials  fused  and  solidified  under  great  pressure ; 
and  we  cannot  doubt  that  beneath  existing  volcanoes  there  are  large 
spaces  filled  with  melted  stone,  which  must  for  centuries  remain  in  an 
incandescent  state,  and  then  cool  and  become  hard  and  crystalline  when 
the  subterranean  heat  shall  be  exhausted.  That  lakes  of  lava  are  con- 
tinuous for  hundreds  of  miles  beneath  the  Chilian  Andes,  seems  estab- 
lished by  observations  made  in  the  year  1835.f 

Now,  wherever  the  fluid  contents  of  such  reservoirs  are  poured  out 
successively  from  craters  in  the  open  air,  or  at  the  bottom  of  the  sea, 
the  matter  so  ejected  may  afford  evidence  by  its  arrangement  of  having 
originated  at  different  periods ;  but  if  the  subterranean  residue  after  the 
withdrawal  of  the  heat  be  converted  into  crystalline  or  plutonic  rock, 
the  entire  mass  may  seem  to  have  been  formed  at  once,  however  count- 
less the  ages  required  for  its  fusion  and  subsequent  refrigeration.  As 
the  idea  that  all  the  granite  in  the  earth's  crust  was  produced  simulta- 
neously, and  in  a  primitive  state  of  the  planet,  has  now  been  universally 
abandoned  ;  so  the  suggestion  above  adverted  to,  may  put  us  on  our 
guard  against  too  readily  adopting  another  opinion,  namely,  that  each 
large  mass  of  granite  was  generated  in  a  brief  period  of  time. 

Modern  writers  indeed,  of  authority,  seem  more  and  more  agreed  that 
in  the  case  of  granitic  rocks,  the  passage  from  a  liquid  or  pasty  to  a 
solid  and  crystalline  state  must  have  been  an  extremely  gradual  process. 

The  doctrine  so  much  insisted  upon  formerly,  that  crystalline  rocks, 
such  as  granite,  gneiss,  mica- schist,  quartzite,  and  others  were  produced 
in  the  greatest  abundance  in  the  earlier  ages  of  the  planet,  and  that 
their  formation  has  ceased  altogether  in  our  own  times,  will  be  contro- 
verted in  the  next  chapter. 

Gradual  development  of  subterranean  movements. — The  extreme  vio- 
lence of  the  subterranean  forces  in  remote  ages  has  been  often  inferred 
from  the  facts  that  the  older  rocks  are  more  fractured  and  dislocated 

*  See  ch.  26,  infra.  f  See  ch.  27,  infra. 

11 


162  SUPPOSED   FORMER   INTENSITY  [On.  XI. 

than  the  newer.  But  what  other  result  could  we  have  anticipated  if  the 
quantity  of  movement  had  been  always  equal  in  equal  periods  of  time  ? 
Time  must,  in  that  case,  multiply  the  derangement  of  strata  in  the  ratio 
of  their  antiquity.  Indeed  the  numerous  exceptions  to  the  above  rule 
which  we  find  in  nature,  present  at  first  sight  the  only  objection  to  the 
hypothesis  of  uniformity.  For  the  more  ancient  formations  remain  in 
many  places  horizontal,  while  in  others  much  newer  strata  are  curved 
and  vertical.  This  apparent  anomaly,  however,  will  be  seen  in  the  next 
chapter  to  depend  on  the  irregular  manner  in  which  the  volcanic  and 
subterranean  .agency  affect  different  parts  of  the  earth  in  succession,  be- 
ing often  renewed  again  and  again  in  certain  areas,  while  others  remain 
during  the  whole  time  at  rest. 

O 

That  the  more  impressive  effects  of  subterranean  power,  such  as  the 
upheaval  of  mountain- chains,  may  have  been  due  to  multiplied  convul- 
sions of  moderate  intensity  rather  than  to  a  few  paroxysmal  explosions, 
will  appear  the  less  improbable  when  the  gradual  and  intermittent  de- 
velopment of  volcanic  eruptions  in  times  past  is  once  established.  It  is 
now  very  generally  conceded  that  these  eruptions  have  their  source  in 
the  same  causes  as  those  which  give  rise  to  the  permanent  elevation  and 
sinking  of  land ;  the  admission,  therefore,  that  one  of  the  two  volcanic 
or  subterranean  processes  has  gone  on  gradually,  draws  with  it  the  con- 
clusion that  the  effects  of  the  other  have  been  elaborated  by  successive 
and  gradual  efforts. 

Faults.- — The  same  reasoning  is  applicable  to  great  faults,  or  those 
striking  instances  of  the  upthrow  or  downthrow  of  large  masses  of  rock, 
which  have  been  thought  by  some  to  imply  tremendous  catastrophes 
wholly  foreign  to  the  ordinary  course  of  nature.  Thus  we  have  in 
England  faults,  in  which  the  vertical  displacement  is  between  600  and 
3000  feet,  and  the  horizontal  extent  thirty  miles  or  more,  the  width  of 
the  fissures  since  filled  up  with  rubbish  varying  from  ten  to  fifty  feet. 
But  when  we  inquire  into  the  proofs  of  the  mass  having  risen  or  fallen 
suddenly  on  the  one  side  of  these  great  rents,  several  hundreds  or  thou- 
sands of  feet  above  or  below  the  rock  with  which  it  was  once  continuous 
on  the  other  side,  we  find  the  evidence  defective.  There  are  grooves,  it 
is  said,  and  scratches  on  the  rubbed  and  polished  walls,  which  have 
often  one  common  direction,  favoring  the  theory  that  the  movement  was 
accomplished  by  a  single  stroke,  and  not  by  a  series  of  interrupted  move- 
ments. But,  in  fact,  the  striae  are  not  always  parallel  in  such  cases,  but 
often  irregular,  and  sometimes  the  stones  and  earth  which  are  in  the  mid- 
dle of  the  fault,  or  fissure,  have  been  polished  and  striated  by  friction  in 
different  directions,  showing  that  there  have  been  slidings  subsequent  to 
the  first  introduction  of  the  fragmentary  matter.  Nor  should  we  forget 
that  the  last  movement  must  always  tend  to  obliterate  the  signs  of  pre- 
vious trituration,  so  that  neither  its  instantaneousness  nor  the  uniformity 
of  its  direction  can  be  inferred  from  the  parallelism  of  the  strise  that 
have  been  last  produced. 

When  rocks  have  been  once  fractured,  and  freedom  of  motion  com- 


CH.  XL]  OF  IGNEOUS   FORCES.  163 

municated  to  detached  portions  of  them,  these  will  naturally  continue 
to  yield  in  the  same  direction,  if  the  process  of  upheaval  or  of  under- 
mining be  repeated  again  and  again.  The  incumbent  mass  will  always 
give  way  along  the  lines  of  least  resistance,  or  where  it  was  formerly 
rent  asunder.  Probably,  the  effects  of  reiterated  movement,  whether 
upward  or  downward,  in  a  fault,  may  be  undistinguishable  from  those 
of  a  single  and  instantaneous  rise  or  subsidence ;  and  the  same  may  be 
said  of  the  rising  or  falling  of  continental  masses,  such  as  Sweden  or 
Greenland,  which  we  know  to  take  place  slowly  and  insensibly. 

Doctrine  of  the  sudden  upheaval  of  parallel  mountain-chains. — The 
doctrine  of  the  suddenness  of  many  former  revolutions  in  the  physical 
geography  of  the  globe  has  been  thought  by  some  to  derive  additional 
confirmation  from  a  theory  respecting  the  origin  of  mountain-chains,  ad- 
vanced in  1833  by  a  distinguished  geologist,  M.  Elie  de  Beaumont.  In 
several  essays  on  this  subject,  the  last  published  in  1852,  he  has  at- 
tempted to  establish  two  points;  first,  that  a  variety  of  independent 
chains  of  mountains  have  been  thrown  up  suddenly  at  particular  periods ; 
and,  secondly,  that  the  contemporaneous  chains  thus  thrown  up,  pre- 
serve a  parallelism  the  one  to  the  other. 

These  opinions,  and  others  by  which  they  are  accompanied,  are  so 
adverse  to  the  method  of  interpreting  the  history  of  geological  changes 
which  I  have  recommended  in  this  work,  that  I  am  desirous  of  explain- 
ing the  grounds  of  my  dissent,  a  course  which  I  feel  myself  the  more 
called  upon  to  adopt,  as  the  generalizations  alluded  to  are  those  of  a 
skilful  writer,  and  an  original  observer  of  great  talent  and  experience. 
I  shall  begin,  therefore,  by  giving  a  brief  summary  of  the  principal  prop- 
ositions laid  down  in  the  works  above  referred  to.* 

1st.  M.  de  Beaumont  supposes  "that  in  the  history  of  the  earth 
there  have  been  long  periods  of  comparative  repose,  during  which  the 
deposition  of  sedimentary  matter  has  gone  on  in  regular  continuity  ;  and 
there  have  also  been  short  periods  of  paroxysmal  violence,  during  which 
that  continuity  was  broken. 

"  2dly.  At  each  of  these  periods  of  violence  or  'revolution,'  in  the 
state  of  the  earth's  surface,  a  great  number  of  mountain-chains  have 
been  formed  suddenly. 

"  3dly.  The  chains  thrown  up  by  a  particular  revolution  have  one 
uniform  direction,  being  parallel  to  each  other  within  a  few  degrees  of 
the  compass,  even  when  situated  in  remote  regions  ;  whilst  the  chains 
thrown  up  at  different  periods  have,  for  the  most  part,  different  di- 
rections. 

"4thly.  Each  'revolution,'  or  'great  convulsion,'  has  fallen  in  with 
the  date  of  another  geological  phenomenon ;  namely,  '  the  passage  from 

*  Ann.  des  Sci.  Nat.,  Septembre,  Novembre,  et  Decembre,  1829.  Revue  Fran- 
9aise,  No.  15,  May,  1830.  Bulletin  de  la  Societe  Geol.  de  France,  p.  864,  May, 
1847.  The  latest  edition  of  M.  de  Beaumont's  theory  will  be  found  in  the  12th 
vol.  of  the  Dictionnaire  Universel  d'Hist.  Nat.  1852,  art.  "Systemes  des  Mon- 
tagues ;"  also  the  same  printed  separately. 


164  SUPPOSED   CONTEMPORANEOUS   UPHEAVAL  [On.  XL 

one  Independent  sedimentary  formation  to  another/  characterized  by  a 
considerable  difference  in  '  organic  types.' 

"  Sthly.  There  has  been  a  recurrence  of  these  paroxysmal  movements 
from  the  remotest  geological  periods  ;  and  they  may  still  be  reproduced, 
and  the  repose  in  which  we  live  may  hereafter  be  broken  by  the  sudden 
upthrow  of  another  system  of  parallel  chains  of  mountains. 

"  6thly.  The  origin  of  these  chains  depends  not  on  partial  volcanic 
action,  or  a  reiteration  of  ordinary  earthquakes,  but  on  the  secular  re- 
frigeration of  the  entire  planet.  For  the  whole  globe,  with  the  excep- 
tion of  a  thin  envelope,  much  thinner  in  proportion  than  the  shell  to  an 
egg,  is  a  fused  mass,  kept  fluid  by  heat,  but  constantly  cooling  and 
contracting  its  dimensions.  The  external  crust  does  not  gradually  col- 
lapse and  accommodate  itself  century  after  century  to  the  shrunken 
nucleus,  subsiding  as  often  as  there  is  a  slight  failure  of  support,  but  it 
is  sustained  throughout  whole  geological  periods,  so  as  to  become  par- 
tially separated  from  the  nucleus,  until  at  last  it  gives  way  suddenly, 
cracking  and  falling  in  along  determinate  lines  of  fracture.  During  such 
a  crisis  the  rocks  are  subjected  to  great  lateral  pressure,  the  unyielding 
ones  are  crushed,  and  the  pliant  strata  bent,  and  are  forced  to  pack 
themselves  more  closely  into  a  smaller  space,  having  no  longer  the 
same  room  to  spread  themselves  out  horizontally.  At  the  same  time, 
a  large  portion  of  the  mass  is  squeezed  upwards,  because  it  is  in  the 
upward  direction  only  that  the  excess  in  size  of  the  envelope,  as  com- 
pared to  the  contracted  nucleus,  can  find  relief.  This  excess  produces 
one  or  more  of  those  folds  or  wrinkles  in  the  earth's  crust  which  we  call 
mountain-chains. 

"  Lastly,  some  chains  are  comparatively  modern ;  such  as  the  Alps, 
which  were  partly  upheaved  after  the  middle  tertiary  period.  The 
elevation  of  the  Andes  was  much  more  recent,  and  was  accompanied  by 
the  simultaneous  outburst  for  the  first  time  of  270  of  the  principal  vol- 
canoes now  active.* 

"  The  agitation  of  the  waters  of  the  ocean  caused  by  this  convulsion 
probably  occasioned  that  transient  and  general  deluge  which  is  noticed 
in  the  traditions  of  so  many  nations. "f 

Several  of  the  topics  enumerated  in  the  above  summary,  such  as  the 
cause  of  interruptions  in  the  sedimentary  series,  will  be  discussed  in  the 
thirteenth  chapter,  and  I  shall  now  confine  myself  to  what  I  conceive 
to  be  the  insufficiency  of  the  proofs  adduced  in  favor  of  the  suddenness 
of  the  upthrow,  and  the  contemporaneousness  of  the  origin  of  the  paral- 
lel chains  referred  to.  At  the  same  time  I  may  remark,  that  the  great 
body  of  facts  collected  together  by  M.  de  Beaumont  will  always  form 
a  most  valuable  addition  to  our  knowledge,  tending  as  they  do  to  con- 
firm the  doctrine  that  different  mountain-chains  have  been  formed  in 
succession,  and,  as  Werner  first  pointed  out,  that  there  are  certain  de- 
terminate lines  of  direction  or  strike  in  the  strata  of  various  countries. 

•  *  Systfeme  de  Mont.  p.  762.  f  Ibid.  pp.  761  and  773. 


CH.  XL]  PARALLEL   MOUNTAIN-CHAINS.  165 

The  following  may  serve  as  an  analysis  of  the  evidence  on  which 
the  theory  above  stated  depends.  "  We  observe,"  says  M.  de  Beau- 
mont, "  when  we  attentively  examine  nearly  all  mountain-  chains,  that 
the  most  recent  rocks  extend  horizontally  up  to  the  foot  of  such  chains, 
as  we  should  expect  would  be  the  case  if  they  were  deposited  in  seas 
or  lakes,  of  which  these  mountains  have  partly  formed  the  shores  ; 
whilst  the  other  sedimentary  beds,  tilted  up,  and  more  or  less  contorted, 
on  the  flanks  of  the  mountains,  rise  in  certain  points  even  to  their  high- 
est crests."*  There  are,  therefore,  in  and  adjacent  to  each  chain,  two 
classes  of  sedimentary  rocks,  the  ancient  and  inclined  beds,  and  the 
newer  or  horizontal.  It  is  evident  that  the  first  appearance  of  the  chain 
itself  was  an  event  "  intermediate  between  the  period  when  the  beds 
now  upraised  were  deposited,  and  the  period  when  the  strata  were  pro- 
duced horizontally  at  its  feet." 


Fig. 


Thus  the  chain  A  assumed  its  present  position  after  the  deposition 
of  the  strata  b,  which  have  undergone  great  movements,  and  before 
the  deposition  of  the  group  c,  in  which  the  strata  have  not  suffered 
derangement. 

If  we  then  discover  another  chain  B,  in  which  we  find  not  only  the 

Fig.  12.  B 


formation  b,  but  the  group  c  also,  disturbed  and  thrown  on  its  edges, 
we  may  infer  that  the  latter  chain  is  of  subsequent  date  to  A  ;  for  B 
must  have  been  elevated  after  the  deposition  of  c,  and  before  that  of 
the  group  d  ;  whereas  A  had  originated  before  the  strata  c  were  formed. 

It  is  then  argued,  that  in  order  to  ascertain  whether  other  mountain 
ranges  are  of  contemporaneous  date  with  A  and  B,  or  are  referable  to 
distinct  periods,  we  have  only  to  inquire  whether  the  inclined  and  un- 
disturbed sets  of  strata  in  each  range  correspond  with  or  differ  from 
those  in  the  typical  chain  A  and  B. 

Now  all  this  reasoning  is  perfectly  correct,  so  long  as  the  period  of 
time  required  for  the  deposition  of  the  strata  b  and  c  is  not  made  iden- 

*  Phil.  Mag.  and  Annals,  No.  58.    New  Series,  p.  242. 


166  THEORY   OF   SUDDEN   RISE   OF  [Ca  XL 

tical  in  duration  with  the  period  of  time  during  which  the  animals  and 
plants  found  fossil  in  b  and  c  may  have  flourished ;  for  the  latter,  that 
is  to  say,  the  duration  of  certain  groups  of  species,  may  have  greatly 
exceeded,  and  probably  did  greatly  exceed,  the  former,  or  the  time 
required  for  the  accumulation  of  certain  local  deposits,  such  as  b  and  c 
(figs.  11  and  12).  In  order,  moreover,  to  render  the  reasoning  cor- 
rect, due  latitude  must  be  given  to  the  term  contemporaneous ;  for 
this  term  must  be  understood  to  allude,  not  to  a  moment  of  time,  but 
to  the  interval,  whether  brief  or  protracted,  which  elapsed  between 
two  events,  namely,  between  the  accumulation  of  the  inclined  and  that 
of  the  horizontal  strata. 

But,  unfortunately,  no  attempt  has  been  made  in  the  treatises  under 
review  to  avoid  this  manifest  source  of  confusion,  and  hence  the  very 
terms  of  each  proposition  are  equivocal ;  and  the  possible  length  of 
some  of  the  intervals  is  so  vast,  that  to  affirm  that  all  the  chains  raised 
in  such  intervals  were  contemporaneous  is  an  abuse  of  language. 

In  order  to  illustrate  this  argument,  I  shall  select  the  Pyrenees  as  an 
example.  Originally  M.  E.  de  Beaumont  spoke  of  this  range  of  moun- 
tains as  having  been  uplifted  suddenly  (a  un  seul  jet),  but  he  has  since 
conceded  that  in  this  chain,  in  spite  of  the  general  unity  and  simplicity 
of  its  structure,  six,  if  not  seven,  systems  of  dislocation  of  different  dates 
can  be  recognized.*  In  reference,  however,  to  the  latest,  and  by  far 
the  most  important  of  these  convulsions,  the  chain  is  said  to  have  at- 
tained its  present  elevation  at  a  certain  epoch  in  the  earth's  history, 
namely,  between  the  deposition  of  the  chalk,  or  rocks  of  about  that 
age,  and  that  of  certain  tertiary  formations  "as  old  as  the  plastic  clay ;" 
for  the  chalk  is  seen  in  vertical,  curved,  and  distorted  beds  on  the  flanks 
of  the  chain,  as  the  beds  6,  fig.  11,  while  the  tertiary  formations  rest 
upon  them  in  horizontal  strata  at  its  base,  as  c,  ibid. 

The  proof,  then,  of  the  extreme  suddenness  of  the  convulsion  is  sup- 
posed to  be  the  shortness  of  the  time  which  intervened  between  the 
formation  of  the  chalk  and  the  origin  of  certain  tertiary  strata.f  Even 
if  the  interval  were  deducible  within  these  limits,  it  might  comprise  an 
indefinite  lapse  of  time.  In  strictness  of  reasoning,  however,  the  author 
cannot  exclude  the  Cretaceous  or  Tertiary  periods  from  the  possible 
duration  of  the  interval  during  which  the  elevation  may  have  taken 
place.  For,  in  the  first  place,  it  cannot  be  assumed  that  the  move- 
ment of  upheaval  took  place  after  the  close  of  the  Cretaceous  period  ; 
we  can  merely  say,  that  it  occurred  after  the  deposition  of  certain 
strata  of  that  period ;  secondly,  although  it  were  true  that  the  event 
happened  before  the  formation  of  all  the  tertiary  strata  now  at  the  base 
of  the  Pyrenees,  it  would  by  no  means  follow  that  it  preceded  the 
whole  Tertiary  epoch. 

The  age  of  the  strata,  both  of  the  inclined  and  horizontal  series,  may 

*  Systfeme  de  Montagnes,  1852,  p.  429. 

f  Phil.  Mag.  and  Annals,  No.  58.    New  series,  p.  243. 


CH.  XL]  PARALLEL    MOUNTAIN-CHAINS.  167 

have  been  accurately  determined  by  M.  De  Beaumont,  and  still  the  up- 
heaving of  the  Pyrenees  may  have  been  going  on  before  the  animals  of 
the  Chalk  period,  such  as  are  found  fossil  in  England,  had  ceased  to  ex- 
ist, or  when  the  Maastricht  beds  were  in  progress,  or  during  the  indefi- 
nite ages  which  may  have  elapsed  between  the  extinction  of  the  Maes- 
tricht  animals  and  the  introduction  of  the  Eocene  tribes,  or  during  the 
Eocene  epoch,  or  the  rise,  may  have  been  going  on  throughout  one,  or 
several,  or  all  of  these  periods. 

It  would  be  a  purely  gratuitous  assumption  to  say  that  the  inclined 
cretaceous  strata  (6,  fig.  1 1 )  on  the  flanks  of  the  Pyrenees,  were  the 
very  last  which  were  deposited  during  the  Cretaceous  period,  or  that, 
as  soon  as  they  were  upheaved,  all  or  nearly  all  the  species  of  animals 
and  plants  now  found  fossil  in  them  were  suddenly  exterminated ;  yet, 
unless  this  can  be  affirmed,  we  cannot  say  that  the  Pyrenees  were  not 
upheaved  during  the  Cretaceous  period.  Consequently,  another  range 
of  mountains,  at  the  base  of  which  cretaceous  rocks  may  lie  in  horizontal 
stratification,  may  have  been  elevated,  like  the  chain  A,  fig.  12,  during 
some  part  of  the  same  great  period. 

There  are  mountains  in  Sicily  two  or  three  thousand  feet  high,  the 
tops  of  which  are  composed  of  limestone,  in  which  a  large  proportion  of 
the  fossil  shells  agree  specifically  with  those  now  inhabiting  the  Medi- 
terranean. Here,  as  in  many  other  countries,  the  deposits  now  in  pro- 
gress in  the  sea  must  inclose  shells  and  other  fossils  specifically  identical 
with  those  of  the  rocks  constituting  the  contiguous  land.  So  there  are 
islands  in  the  Pacific  where  a  mass  of  dead  coral  has  emerged  to  a  con- 
siderable altitude,  while  other  portions  of  the  mass  remain  beneath  the 
sea,  still  increasing  by  the  growth  of  living  zoophytes  and  shells.  The 
chalk  of  the  Pyrenees,  therefore,  may  at  a  remote  period  have  been 
raised  to  an  elevation  of  several  thousand  feet,  while  the  species  found 
fossil  in  the  same  chalk  still  continued  to  be  represented  in  the  fauna  of 
the  neighboring  ocean.  In  a  word,  we  cannot  assume  that  the  origin  of 
a  new  range  of  mountains  caused  the  Cretaceous  period  to  cease,  and 
served  as  the  prelude  to  a  new  order  of  things  in  the  animate  creation. 

To  illustrate  the  grave  objections  above  advanced,  against  the  theory 
considered  in  the  present  chapter,  let  us  suppose,  that  in  some  country 
three  styles  of  architecture  had  prevailed  in  succession,  each  for  a  period 
of  one  thousand  years ;  first  the  Greek,  then  the  Roman,  and  then  the 
Gothic  ;  and  that  a  tremendous  earthquake  was  known  to  have  occurred 
in  the  same  district  during  one  of  the  three  periods — a  convulsion  of 
such  violence  as  to  have  levelled  to  the  ground  all  the  buildings  then 
standing.  If  an  antiquary,  desirous  of  discovering  the  date  of  the  catas- 
trophe, should  first  arrive  at  a  city  where  several  Greek  temples  were 
lying  in  ruins  and  half  engulphed  in  the  earth,  while  many  Gothic  edi- 
fices were  standing  uninjured,  could  he  determine  on  these  data  the  era 
of  the  shock  ?  Could  he  even  exclude  any  one  of  the  three  periods, 
and  decide  that  it  must  have  happened  during  one  of  the  other  two  ? 
Certainly  not.  He  could  merely  affirm  that  it  happened  at  some  period 


168  THEORY   OF   SUDDEN    KISE    OF  [ClI.  XL 

after  the  introduction  of  the  Greek  style,  and  before  the  Gothic  had 
fallen  into  disuse.  Should  he  pretend  to  define  the  date  of  the  convul- 
sion with  greater  precision,  and  decide  that  the  earthquake  must  have 
occurred  after  the  Greek  and  before  the  Gothic  period,  that  is  to  say, 
when  the  Roman  style  was  in  use,  the  fallacy  in  his  reasoning  would  be 
too  palpable  to  escape  detection  for  a  moment. 

Yet  such  is  the  nature  of  the  erroneous  induction  which  I  am  now 
exposing.  For  as,  in  the  example  above  proposed,  the  erection  of  a 
particular  edifice  is  perfectly  distinct  from  the  period  of  architecture  in 
which  it  may  have  been  raised,  so  is  the  deposition  of  chalk,  or  any 
other  set  of  strata,  from  the  geological  epochs  characterized  by  certain 
fossils  to  which  they  may  belong. 

It  is  almost  superfluous  to  enter  into  any  farther  analysis  of  the  theory 
of  parallelism,  because  the  whole  force  of  the  argument  depends  on  the 
accuracy  of  the  data  by  which  the  contemporaneous  or  non-contempo- 
raneous date  of  the  elevation  of  two  independent  chains  can  be  demon- 
strated. In  every  case,  this  evidence,  as  stated  by  M.  de  Beaumont,  is 
equivocal,  because  he  has  not  included  in  the  possible  interval  of  time 
between  the  depositions  of  the  deranged  and  the  horizontal  formations, 
part  of  the  periods  to  which  each  of  those  classes  of  formations  are  ref- 
erable. Even  if  all  the  geological  facts,  therefore,  adduced  by  the  au- 
thor were  true  and  unquestionable,  yet  the  conclusion  that  certain  chains 
were  or  were  not  simultaneously  upraised  is  by  no  means  a  legitimate 
consequence. 

In  the  third  volume  of  my  first  edition  of  the  Principles,  which  ap- 
peared in  April,  1833,  I  controverted  the  views  of  M.  de  Beaumont, 
then  just  published,  in  the  same  terms  as  I  have  now  restated  them. 
At  that  time  I  took  for  granted  that  the  chronological  date  of  the  new- 
est rocks  entering  into  the  disturbed  series  of  the  Pyrenees  had  been 
correctly  ascertained.  It  now  appears,  however,  that  some  of  the  most 
modern  of  those  disturbed  strata  belong  to  the  nummulitic  formation, 
which  are  regarded  by  the  majority  of  geologists  as  Eocene  or  older 
tertiary,  an  opinion  not  assented  to  by  M.  E.  de  Beaumont,  and  which 
I  cannot  discuss  here  without  being  led  into  too  long  a  digression.* 

Perhaps  a  more  striking  illustration  of  the  difficulties  we  encounter, 
when  we  attempt  to  apply  the  theory  under  consideration  even  to  the 
best  known  European  countries,  is  afforded  by  what  is  called  "  The  Sys- 
tem of  the  Longmynds."  This  small  chain,  situated  in  Shropshire,  is 
the  third  of  the  typical  systems  to  which  M.  E.  de  Beaumont  compares 
other  mountain  ranges  corresponding  in  strike  and  structure.  The  date 
assigned  to  its  upheaval  is  "  after  the  unfossiliferous  grey  wacke,  or  Cam- 
brian strata,  and  before  the  Silurian."  But  Sir  R.  I.  Murchison  had 
shown  in  1838,  in  his  "Silurian  System,"  and  the  British  government 
surveyors,  since  that  time,  in  their  sections  (about  1845),  that  the  Long- 
mynds and  other  chains  of  similar  composition  in  North  Wales  are  post- 

*  Systfeme  de  Montagnee,  1852,  p.  429. 


CH.  XL]  PAEALLEL   MOUNTAIN-CHAINS.  169 

Silurian.  In  all  of  them  fossiliferous  beds  of  the  lower  Silurian  forma- 
tion, or  Llandeilo  flags  are  highly  inclined,  and  often  vertical.  In  one 
limited  region  the  Caradoc  sandstone,  a  member  of  the  lower  Silurian, 
rests  unconformably  on  the  denuded  edges  of  the  inferior  (or  Llandeilo) 
member  of  the  same  group ;  whilst  in  some  cases  both  of  these  sets  of 
strata  are  upturned.  When,  therefore,  so  grave  an  error  is  detected  in 
regard  to  the  age  of  a  typical  chain,  we  are  entitled  to  inquire  with  sur- 
prise, by  what  means  nine  other  parallel  chains  in  France,  Germany, 
and  Sweden,  assumed  to  be  "  ante-Silurian,"  have  been  made  to  agree 
precisely  in  date  with  the  Longmynds  ?  If  they  are  correctly  repre- 
sented as  having  been  all  deposited  before  the  deposition  of  the  Silurian 
strata,  they  cannot  be  contemporaneous  with  the  Longmynds,  and  they 
only  prove  how  little  reliance  can  be  placed  on  parallelism  as  a  test  of 
simultaneousness  of  upheaval.  But  in  truth  it  is  impossible,  for  reasons 
already  given,  to  demonstrate  that  each  of  those  nine  chains  coincide  in 
date  with  one  another,  any  more  than  with  the  Longmynds. 

The  reader  will  see  in  the  sequel  (chap.  31*)  that  Mr.  Hopkins  has 
inferred  from  astronomical  calculations,  that  the  solid  crust  of  the  earth 
cannot  be  less  than  800  or  1000  miles  thick,  and  may  be  more.  Even 
if  it  be  solid  to  the  depth  of  100  miles,  such  a  thickness  would  be  in- 
consistent with  M.  E.  de  Beaumont's  hypothesis,  which  requires  a  shell 
not  more  than  thirty  miles  thick,  or  even  less.  Mr.  Hopkins  admits 
that  the  exterior  of  the  planet,  though  solid  as  a  whole,  may  contain 
within  it  vast  lakes  or  seas  of  lava.  If  so,  the  gradual  fusion  of  rocks, 
and  the  expansive  power  of  heat  exerted  for  ages,  as  well  as  the  subse- 
quent contraction  of  the  same  during  slow  refrigeration,  may  perhaps 
account  for  the  origin  of  mountain-chains,  for  these,  as  Dolomieu  has 
remarked,  are  "  far  less  important,  proportionally  speaking,  than  the  in- 
equalities on  the  surface  of  an  egg-shell,  which  to  the  eye  appears 
smooth."  A  "  centripetal  force"  affecting  the  whole  planet  as  it  cools, 
seems  a  mightier  cause  than  is  required  to  produce  wrinkles  of  such 
insignificant  size. 

In  pursuing  his  investigations,  M.  E.  de  Beaumont  has  of  late  greatly 
multiplied  the  number  of  successive  periods  of  instantaneous  upheaval, 
admitting  at  the  same  time  that  occasionally  new  lines  of  upthrow  have 
taken  the  direction  of  older  ones.f  These  admissions  render  his  views 
much  more  in  harmony  with  the  principles  advocated  in  this  work,  but 
they  impair  the  practical  utility  of  parallelism  considered  as  a  chrono- 
logical test ;  for  no  rule  is  laid  down  for  limiting  the  interval,  whether  in 
time  or  space,  which  may  separate  two  parallel  lines  of  upheaval  of 
different  dates. J 

*  For  page,  see  Index,  "Hopkins."         f  Art.  Systeme  de  Montagnes,  p.  775. 

\  M.  E.  de  Beaumont  in  his  later  inquiries  (Comptes  rendus,  Sept.  1850,  and 
Systemes  des  Montagnes)  has  come  to  the  conclusion,  that  the  principal  mountain 
ranges,  if  prolonged,  would  intersect  each  other  at  certain  angles,  so  as  to  produce 
a  regular  geometric  arrangement,  which  he  calls  "  a  pentagonal  network."  This 
theory  has  been  ably  discussed  and  controverted  by  Mr.  Hopkins,  in  his  Anniver- 
sary Address  as  President  of  the  Geol.  Soc.,  Feb.  1853. 


170  UPHEAVAL  AND  SUBSIDENCE  [On.  XL 

Among  the  various  propositions  above  laid  down  (p.  164),  it  will  be 
seen  that  the  sudden  rise  of  the  Andes  is  spoken  of  as  a  modern  event, 
but  Mr.  Darwin  has  brought  together  ample  data  in  proof  of  the  local 
persistency  of  volcanic  action  throughout  a  long  succession  of  geological 
periods,  beginning  with  times  antecedent  to  the  deposition  of  the  oolitic 
and  cretaceous  formations  of  Chili,  and  continuing  to  the  historical 
epoch.  It  appears  that  some  of  the  parallel  ridges  which  compose  the 
Cordilleras,  instead  of  being  contemporaneous,  were  successively  and 
slowly  upheaved  at  widely  different  epochs.  The  whole  range,  after 
twice  subsiding  some  thousands  of  feet,  was  brought  up  again  by  a  slow 
movement  in  mass,  during  the  era  of  the  Eocene  tertiary  formations, 
after  which  the  whole  sank  down  once  more  several  hundred  feet,  to  be 
again  uplifted  to  its  present  level  by  a  slow  and  often  interrupted  move- 
ment.* In  a  portion  of  this  latter  period  the  "  Pampean  mud"  was 
formed,  in  which  the  Megatherium  mylodon  and  other  extinct  quadru- 
peds are  buried.  This  mud  contains  in  it  recent  species  of  shells,  some 
of  them  proper  to  brackish  water,  and  is  believed  by  Mr.  Darwin  to  be 
an  estuary  or  delta  deposit.  M.  A.  d'Orbigny,  however,  has  advanced 
an  hypothesis  referred  to  by  M.  E.  de  Beaumont,  that  the  agitation  and 
displacement  of  the  waters  of  the  ocean,  caused  by  the  elevation  of  the 
Andes,  gave  rise  to  a  deluge,  of  which  this  Pampean  mud,  which  rises 
sometimes  to  the  height  of  12,000  feet,  is  the  result  and  monument. f 

In  studying  many  chains  of  mountains,  we  find  that  the  strike  or  line 
of  outcrop  of  continuous  sets  of  strata,  and  the  general  direction  of  the 
chain,  may  be  far  from  rectilinear.  Curves  forming  angles  of  20°  or  30° 
may  be  found  in  the  same  range  as  in  the  Alleghanies  ;  just  as  trains 
of  active  volcanoes  and  the  zones  throughout  which  modern  earthquakes 
occur  are  often  linear,  without  running  in  straight  lines.  Nor  are  all  of 
these,  though  contemporaneous  or  belonging  to  our  own  epoch,  by  any 
means  parallel,  but  some  at  right  angles,  the  one  to  the  other. 

Slow  upheaval  and  subsidence. — Recent  observations  have  disclosed 
to  us  the  wonderful  fact,  that  not  only  the  west  coast  of  South 
America,  but  also  other  large  areas,  some  of  them  several  thousand 
miles  in  circumference,  such  as  Scandinavia,  and  certain  archipelagoes  in 
the  Pacific,  are  slowly  and  insensibly  rising  ;  while  other  regions,  such 
as  Greenland,  and  parts  of  the  Pacific  and  Indian  Oceans,  in  which 
atolls  or  circular  coral  islands  abound,  are  as  gradually  sinking.  That 
all  the  existing  continents  and  submarine  abysses  may  have  originated 
in  movements  of  this  kind,  continued  throughout  incalculable  periods  of 
time,  is  undeniable,  and  the  denudation  which  the  dry  land  appears 
everywhere  to  have  suffered,  favors  the  idea  that  it  was  raised  from 
the  deep  by  a  succession  of  upward  movements,  prolonged  throughout 
indefinite  periods.  For  the  action  of  waves  and  currents  on  land  slowly 
emerging  from  the  deep,  affords  the  only  power  by  which  we  can  con- 

*  Darwin's  Geology  of  South  America,  p.  248.    London,  1846. 
f  Systfeme  de  Montagues,  p.  748. 


CH.  XL]  OF   MOUNTAIN-CHAINS.  171 

ceive  so  many  deep  valleys  and  wide  spaces  to  have  been  denuded  as 
those  which  are  unquestionably  the  effects  of  running  water. 

But  perhaps  it  may  be  said  that  there  is  no  analogy  between  the  slow 
upheaval  of  broad  plains  or  table-lands,  and  the  manner  in  which  we 
must  presume  all  mountain-chains,  with  their  inclined  strata,  to  have 
originated.  It  seems,  however,  that  the  Andes  have  been  rising  cen- 
tury after  century,  at  the  rate  of  several  feet,  while  the  Pampas  on  the 
east  have  been  raised  only  a  few  inches  in  the  same  time.  Crossing 
from  the  Atlantic  to  the  Pacific,  in  a  line  passing  through  Mendoza, 
Mr.  Darwin  traversed  a  plain  800  miles  broad,  the  eastern  part  of 
which  has  emerged  from  beneath  the  sea  at  a  very  modern  period. 
The  slope  from  the  Atlantic  is  at  first  very  gentle,  then  greater,  until 
the  traveller  finds,  on  reaching  Mendoza,  that  he  has  gained,  almost  in- 
sensibly, a  height  of  4000  feet.  The  mountainous  district  then  begins 
suddenly,  and  its  breadth  from  Mendoza  to  the  shores  of  the  Pacific  is 
120  miles,  the  average  height  of  the  principal  chain  being  from  15,000 
to  16,000  feet,  without  including  some  prominent  peaks,  which  ascend 
much  higher.  Now  all  we  require,  to  explain  the  origin  of  the  princi- 
pal inequalities  of  level  here  described,  is  to  imagine,  first,  a  zone  of  more 
violent  movement  to  the  west  of  Mendoza,  and,  secondly,  to  the  east  of 
that  place,  an  upheaving  force,  which  died  away  gradually  as  it  ap- 
proached the  Atlantic.  In  short,  we  are  only  called  upon  to  conceive, 
that  the  region  of  the  Andes  was  pushed  up  four  feet  in  the  same  pe- 
riod in  which  the  Pampas  near  Mendoza  rose  one  foot,  and  the  plains 
near  the  shores  of  the  Atlantic  one  inch.  In  Europe  we  have  learnt 
that  the  land  at  the  North  Cape  ascends  about  five  feet  in  a  century, 
while  farther  to  the  south  the  movements  diminish  in  quantity  first  to  a 
foot,  and  then,  at  Stockholm,  to  'three  inches  in  a  century,  while  at  cer- 
tain points  still  farther  south  there  is  no  movement. 

But  in  what  manner,  it  is  asked,  can  we  account  for  the  great  lateral 
pressure  which  has  been  exerted  not  only  in  the  Andes,  Alps,  and  other 
chains,  but  also  on  the  strata  of  many  low  and  nearly  level  countries  ? 
Do  not  the  folding  and  fracture  of  the  beds,  the  anticlinal  and  synclinal 
ridges  and  troughs,  as  they  are  called,  and  the  vertical,  and  even  some- 
times the  inverted  position  of  the  beds,  imply  an  abruptness  and  inten- 
sity in  the  disturbing  force  wholly  different  in  kind  and  energy  to  that 
which  now  rends  the  rocks  during  ordinary  earthquakes  ?  I  shall  treat 
more  fully  in  the  sequel  (end  of  chap.  32)  of  the  probable  subterranean 
sources,  whether  of  upward  or  downward  movement,  and  of  great  lateral 
pressure  ;  but  it  may  be  well  briefly  to  state  in  this  place  that  in  our 
own  times,  as,  for  example,  in  Chili,  in  1822,  the  volcanic  force  has 
overcome  the  resistance,  and  permanently  uplifted  a  country  of  such 
yast  extent  that  the  weight  and  volume  of  the  Andes  must  be  insignifi- 
cant in  comparison,  even  if  we  indulge  the  most  moderate  conjectures  as 
to  the  thickness  of  the  earth's  crust  above  the  volcanic  foci. 

To  assume  that  any  set  of  strata  with  which  we  are  acquainted  are 
made  up  of  such  cohesive  and  unyielding  materials,  as  to  be  able  to 


172  UPHEAVAL   AND   SUBSIDENCE  [Ce.  XL 

resist  a  power  of  such  stupendous  energy,  if  its  direction,  instead  of 
being  vertical,  happened  to  be  oblique  or  horizontal,  would  be  extremely 
rash.  But  if  they  could  yield  to  a  sideway  thrust,  even  in  a  slight  de- 
gree, they  would  become  squeezed  and  folded  to  any  amount  if  sub- 
jected for  a  sufficient  number  of  times  to  the  repeated  action  of  the 
same  force.  We  can  scarcely  doubt  that  a  mass  of  rock  several  miles 
thick  was  uplifted  in  Chili  in  1822  and  1835,  and  that  a  much  greater 
volume  of  solid  matter  is  upheaved  wherever  the  rise  of  the  land  is  very 
gradual,  as  in  Scandinavia,  the  development  of  heat  being  probably,  in 
that  region,  at  a  greater  distance  from  the  surface.  If  continents, 
rocked,  shaken,  and  fissured,  like  the  western  region  of  South  America, 
or  very  gently  elevated,  like  Norway  and  Sweden,  do  not  acquire  in  a 
few  days  or  hours  an  additional  height  of  several  thousand  feet,  this 
can  arise  from  no  lack  of  mechanical  force  in  the  subterranean  moving 
cause,  but  simply  because  the  antagonist  power,  or  the  strength,  tough- 
ness, and  density  of  the  earth's  crust  is  insufficient  to  resist,  so  long,  as 
to  allow  the  volcanic  energy  an  indefinite  time  to  accumulate.  Instead 
of  the  explosive  charge  augmenting  in  quantity  for  countless  ages,  it 
finds  relief  continuously,  or  by  a  succession  of  shocks  of  moderate  vio- 
lence, so  as  never  to  burst  or  blow  up  the  covering  of  incumbent  rock 
in  one  grand  paroxysmal  convulsion.  Even  in  its  most  energetic  efforts 
it  displays  an  intermittent  and  mitigated  intensity,  being  never  permit- 
ted to  lay  a  whole  continent  in  ruins.  Hence  the  numerous  eruptions 
of  lava  from  the  same  vent,  or  chain  of  vents,  and  the  recurrence  of 
similar  earthquakes  for  thousands  of  years  along  certain  areas  or  zones 
of  country.  Hence  the  numerous  monuments  of  the  successive  ejection 
and  injection  of  melted  matter  in  ancient  geological  epochs,  and  the  fis- 
sures formed  in  distinct  ages,  and  often  widened  and  filled  at  differ- 
ent eras. 

Among  the  causes  of  lateral  pressure,  the  expansion  by  heat  of  large 
masses  of  solid  stone  intervening  between  others  which  have  a  different 
degree  of  expansibility,  or  which  happen  not  to  have  their  temperature 
raised  at  the  same  time,  may  play  an  important  part.  But  as  we  know 
that  rocks  have  so  often  sunk  down  thousands  of  feet  below  their  origi- 
nal level,  we  can  hardly  doubt  that  much  of  the  bending  of  pliant 
strata,  and  the  packing  of  the  same  into  smaller  spaces,  has  frequently 
been  occasioned  by  subsidence.  Whether  the  failure  of  support  be 
produced  by  the  melting  of  porous  rocks,  which,  when  fluid,  and  sub- 
jected to  great  pressure,  may  occupy  less  room  than  before,  or  which, 
by  passing  from  a  pasty  to  a  crystalline  condition,  may,  as  in  the  case 
of  granite,  according  to  the  experiments  of  Deville,  suffer  a  contraction 
of  10  per  cent.,  or  whether  the  sinking  be  due  to  the  subtraction  of 
lava  driven  elsewhere  to  some  volcanic  orifice,  and  there  forced  out- 
wards, or  whether  it  be  brought  on  by  the  shrinking  of  solid  and  stony 
masses  during  refrigeration,  or  by  the  condensation  of  gases,  or  any 
other  imaginable  cause,  we  have  no  reason  to  incline  to  the  idea  that 
the  consequent  geological  changes  are  brought  about  so  suddenly,  aa 


CH.  XL]  OF   MOUNTAIN-CHAINS.  173 

that  large  parts  of  continents  are  swallowed  up  at  once  in  unfathomable 
subterranean  abysses.  If  cavities  be  formed,  they  will  be  enlarged 
gradually,  and  as  gradually  filled.  We  read,  indeed,  accounts  of  en- 
gulphed  cities  and  areas  of  limited  extent  which  have  sunk  down  many 
yards  at  once  ;  but  we  have  as  yet  no  authentic  records  of  the  sudden 
disappearance  of  mountains,  or  the  submergence  or  emergence  of  great 
islands.  On  the  other  hand,  the  creeps  in  coal  mines*  demonstrate 
that  gravitation  begins  to  act  as  soon  as  a  moderate  quantity  of  matter 
is  removed  even  at  a  great  depth.  The  roof  sinks  in,  or  the  floor  of  the 
mine  rises,  and  the  bent  strata  often  assume  as  regularly  a  curved  and 
crumpled  arrangement  as  that  observed  on  a  grander  scale  in  moun- 
tain-chains. The  absence,  indeed,  of  chaotic  disorder,  and  the  regu- 
larity of  the  plications  in  geological  formations  of  high  antiquity,  al- 
though not  unfrequently  adduced  to  prove  the  unity  and  instantaneous- 
ness  of  the  disturbing  force,  might  with  far  greater  propriety  be  brought 
forward  as  an  argument  in  favor  of  the  successive  application  of  some 
irresistible  but  moderated  force,  such  as  that  which  can  elevate  or  de- 
press a  continent. 

In  conclusion,  I  may  observe  that  one  of  the  soundest  objections  to 
the  theory  of  the  sudden  upthrow  or  downthrow  of  mountain-chains  is 
this,  that  it  provides  us  with  too  much  force  of  one  kind,  namely,  that 
of  subterranean  movement,  while  it  deprives  us  of  another  kind  of  me- 
chanical force,  namely,  that  exerted  by  the  waves  and  currents  of  the 
ocean,  which  the  geologist  requires  for  the  denudation  of  land  during  its 
slow  upheaval  or  depression.  It  may  be  safely  affirmed  that  the  quan- 
tity of  igneous  and  aqueous  action, — of  volcanic  eruption  and  denuda- 
tion,— of  subterranean  movement  and  sedimentary  deposition, — not 
only  of  past  ages,  but  of  one  geological  epoch,  or  even  the  fraction  of 
an  epoch,  has  exceeded  immeasurably  all  the  fluctuations  of  the  inor- 
ganic world  which  have  been  witnessed  by  man.  But  we  have  still  to 
inquire  whether  the  time  to  which  each  chapter  or  page  or  paragraph 
of  the  earth's  autobiography  relates,  was  not  equally  immense  when 
contrasted  with  a  brief  era  of  3000  or  5000  years.  The  real  point  on 
which  the  whole  controversy  turns,  is  the  relative  amount  of  work  done 
by  mechanical  force  in  given  quantities  of  time,  past  and  present.  Be- 
fore we  can  determine  the  relative  intensity  of  the  force  employed,  we 
must  have  some  fixed  standard  by  which  to  measure  the  time  expended 
in  its  development  at  two  distinct  periods.  It  is  not  the  magnitude  of 
the  effects,  however  gigantic  their  proportions,  which  can  inform  us  in 
the  slightest  degree  whether  the  operation  was  sudden  or  gradual,  in- 
sensible or  paroxysmal.  It  must  be  shown  that  a  slow  process  could 
never  in  any  series  of  ages  give  rise  to  the  same  results. 

The  advocate  of  paroxysmal  energy  might  assume  a  uniform  and 
fixed  rate  of  variation  in  times  past  and  present  for  the  animate  world, 
that  is  to  say,  for  the  dying-out  and  coming-in  of  species,  and  then  en- 

*  See  Lyell's  Manual  of  Elementary  Geology,  ch.  5. 


174  UPHEAVAL   AND   SUBSIDENCE    OF   MOUNTAINS.  [Cfl.  XI. 

deavor  to  prove  that  the  changes  of  the  inanimate  world  have  not  gone 
on  in  a  corresponding  ratio.  But  the  adoption  of  such  a  standard  of 
comparison  would  lead,  I  suspect,  to  a  theory  by  no  means  favorable  to 
the  pristine  intensity  of  natural  causes.  That  the  present  state  of  the 
organic  world  is  not  stationary,  can  be  fairly  inferred  from  the  fact,  that 
some  species  are  known  to  have  become  extinct  in  the  course  even  of 
the  last  three  centuries,  and  that  the  exterminating  causes  always  in 
activity,  both  on  the  land  and  in  the  waters,  are  very  numerous  ;  also, 
because  man  himself  is  an  extremely  modern  creation ;  and  we  may 
therefore  reasonably  suppose  that  some  of  the  mammalia  now  contem- 
porary with  man,  as  well  as  a  variety  of  species  of  inferior  classes,  may 
have  been  recently  introduced  into  the  earth,  to  supply  the  places  of 
plants  and  animals  which  have  from  time  to  time  disappeared.  But 
granting  that  some  such  secular  variation  in  the  zoological  and  botani- 
cal worlds  is  going  on,  and  is  by  no  means  wholly  inappreciable  to  the 
naturalist,  still  it  is  certainly  far  less  manifest  than  the  revolution  always 
in  progress  in  the  inorganic  world.  Every  year  some  volcanic  eruptions 
take  place,  and  a  rude  estimate  might  be  made  of  the  number  of  cubic 
feet  of  lava  and  scoriae  poured  or  cast  out  of  various  craters.  The 
amount  of  mud  and  sand  deposited  in  deltas,  and  the  advance  of  new 
land  upon  the  sea,  or  the  annual  retreat  of  wasting  sea-cliffs,  are  changes 
the  minimum  amount  of  which  might  be  roughly  estimated.  The  quan- 
tity of  land  raised  above  or  depressed  below  the  level  of  the  sea  might 
also  be  computed,  and  the  change  arising  from  such  movements  in  a 
century  might  be  conjectured.  Suppose  the  average  rise  of  the  land  in 
some  parts  of  Scandinavia  to  be  as  much  as  five  feet  in  a  hundred  years, 
the  present  sea-coast  might  be  uplifted  700  feet  in  fourteen  thousand 
years ;  but  we  should  have  no  reason  to  anticipate,  from  any  zoological 
data  hitherto  acquired,  that  the  molluscous  fauna  of  the  northern  seas 
would  in  that  lapse  of  years  undergo  any  sensible  amount  of  variation. 
We  discover  sea-beaches  in  Norway  700  feet  high,  in  which  the  shells 
are  identical  with  those  now  inhabiting  the  German  Ocean  ;  for  the  rise 
of  land  in  Scandinavia,  however  insensible  to  the  inhabitants,  has  evi- 
dently been  rapid  when  compared  to  the  rate  of  contemporaneous  change 
in  the  testaceous  fauna  of  the  German  Ocean.  Were  we  to  wait  there- 
fore until  the  mollusca  shall  have  undergone  as  much  fluctuation  as 
they  underwent  between  the  period  of  the  Lias  and  the  Upper  Oolite 
formations,  or  between  the  Oolite  and  Chalk,  nay,  even  between  any 
two  of  eight  subdivisions  of  the  Eocene  series,  what  stupendous  revolu- 
tions in  physical  geography  ought  we  not  to  expect,  and  how  many 
mountain-chains  might  not  be  produced  by  the  repetition  of  shocks  of 
moderate  violence,  or  by  movements  not  even  perceptible  by  man  ! 

Or,  if  we  turn  from  the  mollusca  to  the  vegetable  kingdom,  and  ask 
the  botanist  how  many  earthquakes  and  volcanic  eruptions  might  be 
expected,  and  how  much  the  relative  level  of  land  and  sea  might  be 
altered,  or  how  far  the  principal  deltas  will  encroach  upon  the  ocean, 
or  the  sea-cliffs  recede  from  the  present  shores,  before  the  species  of 


CH.  XII]      TEXTURE  OF  OLDER  AND  NEWER  ROCKS.        175 

European  forest-trees  will  die  out,  he  would  reply  that  such  alterations 
in  the  inanimate  world  might  be  multiplied  indefinitely  before  he  should 
have  reason  to  anticipate,  by  reference  to  any  known  data,  that  the  ex- 
isting species  of  trees  in  our  forests  would  disappear  and  give  place  to 
others.  In  a  word,  the  movement  of  the  inorganic  world  is  obvious  and 
palpable,  and  might  be  likened  to  the  minute-hand  of  a  clock,  the  pro- 
gress of  which  can  be  seen  and  heard,  whereas  the  fluctuations  of  the 
living  creation  are  nearly  invisible,  and  resemble  the  motion  of  the  hour- 
hand  of  a  timepiece.  It  is  only  by  watching  it  attentively  for  some 
time,  and  comparing  its  relative  position  after  an  interval,  that  we  can 
prove  the  reality  of  its  motion.* 


CHAPTER  XII. 


DIFFERENCE    IN   TEXTURE    OF   THE    OLDER    AND    NEWER    ROCKS. 

Consolidation  of  fossiliferous  strata — Some  deposits  originally  solid — Transition 
and  slaty  texture — Crystalline  character  of  Plutonic  and  Metamorphic  rocks — 
Theory  of  their  origin — Essentially  subterranean — No  proofs  that  they  were 
produced  more  abundantly  at  remote  periods. 

ANOTHER  argument  in  favor  of  the  dissimilarity  of  the  causes  opera- 
ting at  remote  and  recent  eras  has  been  derived  by  many  geologists  from 
the  more  compact,  stony,  and  crystalline  texture  of  the  older  as  com- 
pared with  the  newer  rocks. 

Consolidation  of  strata. — This  subject  may  be  considered,  first  in 
reference  to  the  fossiliferous  strata ;  and,  secondly,  in  reference  to 
those  crystalline  and  stratified  rocks  which  contain  no  organic  remains, 
such  as  gneiss  and  mica-schist.  There  can  be  no  doubt  that  the  former 
of  these  classes,  or  the  fossiliferous,  are  generally  more  compact  and 
stony  in  proportion  as  they  are  more  ancient.  It  is  also  certain  that  a 
great  part  of  them  were  originally  in  a  soft  and  incoherent  state,  and 
that  they  have  been  since  consolidated.  Thus  we  find  occasionally 
that  shingle  and  sand  have  been  agglutinated  firmly  together  by  a  fer- 
ruginous or  siliceous  cement,  or  that  lime  in  solution  has  been  intro- 
duced, so  as  to  bind  together  materials  previously  incoherent.  Organic 
remains  have  sometimes  suffered  a  singular  transformation,  as  for  ex- 

*  See  the  Author's  Anniversary  Address,  Quart.  Journ.  Geol.  Soc.  1850,  vol. 
vi  p.  46,  from  which  some  of  the  above  passages  are  extracted. 


176  DIFFERENCE   IN   TEXTUKE   OF  [On.  XIT 

pie,  where  shells,  corals,  and  wood  are  silicified,  their  calcareous  01 
ligneous  matter  having  been  replaced  by  nearly  pure  silica.  The  con- 
stituents of  some  beds  have  probably  set  and  become  hard  for  the  first 
time  Avhen  they  emerged  from  beneath  the  water. 

But,  on  the  other  hand,  we  observe  in  certain  formations  now  in  pro- 
gress, particularly  in  coral  reefs,  and  in  deposits  from  the  waters  of 
mineral  springs,  both  calcareous  and  siliceous,  that  the  texture  of  rocks 
may  sometimes  be  stony  from  the  first.  This  circumstance  may  ac- 
count for  exceptions  to  the  general  rule,  not  unfrequently  met  with, 
where  solid  strata  are  superimposed  on  others  of  a  plastic  and  incohe- 
rent nature,  as  in  the  neighborhood  of  Paris,  where  the  tertiary  forma- 
tions, consisting  often  of  compact  limestone  and  siliceous  grit,  are  moro 
stony  than  the  subjacent  chalk. 

It  will  readily  be  understood,  that  the  various  solidifying  causes,  in- 
cluding those  above  enumerated,  together  with  the  pressure  of  incum- 
bent rocks  and  the  influence  of  subterranean  heat,  must  all  of  them 
require  time  in  order  to  exert  their  full  power.  If  in  the  course  of  ages 
they  modify  the  aspect  and  internal  structure  of  stratified  deposits,  they 
will  give  rise  to  a  general  distinctness  of  character  in  the  older  as  con- 
trasted with  the  newer  formations.  But  this  distinctness  will  not  be 
the  consequence  of  any  original  diversity ;  they  will  be  unlike,  just  as 
the  wood  in  the  older  trees  of  a  forest  usually  differs  in  texture  and 
hardness  from  that  of  younger  individuals  of  the  same  species. 

Transition  texture. — In  the  original  classification  of  Werner,  the 
highly  crystalline  rocks,  such  as  granite  and  gneiss,  which  contain  no 
organic  remains,  were  called  primary,  and  the  fossiliferous  strata  sec- 
ondary, while  to  another  class  of  an  age  intermediate  between  the 
primary  and  secondary  he  gave  the  name  of  transition.  They  were 
termed  transition  because  they  partook  in  some  degree  in  their  mineral 
composition  of  the  nature  of  the  most  crystalline  rocks,  such  as  gneiss 
and  mica-schist,  while  they  resembled  the  fossiliferous  series  in  contain- 
ing occasionally  organic  remains,  and  exhibiting  evident  signs  of  a  me- 
chanical origin.  It  was  at  first  imagined,  that  the  rocks  having  this  in- 
termediate texture  had  been  all  deposited  subsequently  to  the  series 
called  primary,  and  before  all  the  more  earthy  and  fossiliferous  forma- 
tions. But  when  the  relative  position  and  organic  remains  of  these 
transition  rocks  were  better  understood,  it  was  perceived  that  they  did 
not  all  belong  to  one  period.  On  the  contrary,  the  same  mineral  char- 
acters were  found  in  strata  of  very  different  ages,  and  some  formations 
occurring  in  the  Alps,  which  several  of  the  ablest  scholars  of  Werner 
had  determined  to  be  transition,  were  ultimately  ascertained,  by  means 
of  their  fossil  contents  and  position,  to  be  members  of  the  Cretnceous, 
and  even  of  the  nummulitic  or  Eocene  period.  These  strata  had,  in 
fact,  acquired  the  transition  texture  from  the  influence  of  causes  which, 
since  their  deposition,  had  modified  their  internal  arrangement. 

Texture  and  origin  of  Plutonic  and  metamorphic  rocks. — Among  the 
most  singular  of  the  changes  superinduced  on  rocks,  we  have  occasion- 


CH.  XII]  THE   OLDER   AND   NEWER   ROCKS.  177 

ally  to  include  the  slaty  texture,  the  divisional  planes  of  which  some- 
times intersect  the  true  planes  of  stratification,  and  even  pass  directly 
through  imbedded  fossils.  If,  then,  the  crystalline,  the  slaty,  and  other 
modes  of  arrangement,  once  deemed  characteristic  of  certain  periods  in 
the  history  of  the  earth,  have  in  reality  been  assumed  by  fossiliferous 
rocks  of  different  ages  and  at  different  times,  we  are  prepared  to  inquire 
whether  the  same  may  not  be  true  of  the  most  highly  crystalline  state, 
such  as  that  of  gneiss,  mica-schist,  and  statuary  marble.  That  the 
peculiar  characteristics  of  such  rocks  are  really  due  to  a  variety  of  modi- 
fying causes  has  long  been  suspected  by  many  geologists,  and  the 
doctrine  has  gained  ground  of  late,  although  a  considerable  difference 
of  opinion  still  prevails.  According  to  the  original  Neptunian  theory, 
all  the  crystalline  formations  were  precipitated  from  a  universal  men- 
struum or  chaotic  fluid  antecedently  to  the  creation  of  animals  and 
plants,  the  unstratified  granite  having  been  first  thrown  down  so  as  to 
serve  as  a  floor  or  foundation  on  which  gneiss  and  other  stratified 
rocks  might  repose.  Afterwards,  when  the  igneous  origin  of  granite 
was  no  longer  disputed,  many  conceived  that  a  thermal  ocean  envel- 
oped the  globe,  at  a  time  when  the  first-formed  crust  of  granite  was 
cooling,  but  when  it  still  retained  much  of  its  heat.  The  hot  waters 
of  this  ocean  held  in  solution  the  ingredients  of  gneiss,  mica-schist, 
hornblende-schist,  clay-slate,  and  marble,  rocks  which  were  precipi- 
tated, one  after  the  other,  in  a  crystalline  form.  No  fossils  could  be 
inclosed  in  them,  the  high  temperature  of  the  fluid  and  the  quantity  of 
mineral  matter  which  it  held  in  solution,  rendering  it  unfit  for  the  sup- 
port of  organic  beings. 

It  would  be  inconsistent  with  the  plan  of  this  work  to  enter  here  into 
a  detailed  account  of  what  I  have  elsewhere  termed  the  metamorphic 
theory  ;*  but  I  may  state  that  it  is  now  demonstrable  in  some  countries 
that  fossiliferous  formations,  some  of  them  of  the  age  of  the  Silurian 
strata,  as  near  Christiana  in  Norway,  others  belonging  to  the  Oolitic 
period,  as  around  Carrara  in  Italy,  have  been  converted  partially  into 
gneiss,  mica-schist,  and  statuary  marble.  The  transmutation  has  been 
effected  apparently  by  the  influence  of  subterranean  heat,  acting  under 
great  pressure,  or  by  chemical  and  electrical  causes  operating  in  a  man- 
ner not  yet  understood,  and  which  have  been  termed  Plutonic  action, 
as  expressing,  in  one  word,  all  the  modifying  causes  which  may  be 
brought  into  play  at  great  depths,  and  under  conditions  never  exempli- 
fied at  the  surface.  To  this  Plutonic  action  the  fusion  of  granite  itself 
in  the  bowels  of  the  earth,  as  well  as  the  superinducement  of  the  meta- 
morphic texture  into  sedimentary  strata,  must  be  attributed ;  and  in 
accordance  with  these  views  the  age  of  each  metamorphic  formation 
may  be  said  to  be  twofold,  for  we  have  first  to  consider  the  period 
when  it  originated,  as  an  aqueous  deposit,  in  the  form  of  mud,  sand, 
marl,  or  limestone ;  secondly,  the  date  at  which  it  acquired  a  crystalline 

*  See  Lyell's  Manual  of  Elementary  Geology. 
12 


178  HYPOGENE   TEXTUKE.  [Cn.  XII 

texture.  The  same  strata,  therefore,  may,  according  to  this  view, 
be  very  ancient  in  reference  to  the  time  of  their  deposition,  and  very 
modern  in  regard  to  the  period  of  their  assuming  the  metamorphic 
character. 

No  proofs  that  these  crystalline  rocks  were  produced  more  abundantly 
at  remote  periods. — Several  modern  writers,  without  denying  the  truth 
of  the  Plutonic  or  metamorphic  theory,  still  contend  that  the  crystalline 
and  non-fossiliferous  formations,  whether  stratified  or  unstratified,  such 
as  gneiss  and  granite,  are  essentially  ancient  as  a  class  of  rocks.  They 
were  generated,  say  they,  most  abundantly  in  the  primeval  state  of 
the  globe,  since  which  time  the  quantity  produced  has  been  always  on 
the  decrease,  until  it  became  very  inconsiderable  in  the  Oolitic  and  Cre- 
taceous periods,  and  quite  evanescent  before  the  commencement  of  the 
tertiary  epoch. 

Now  the  justness  of  these  views  depends  almost  entirely  on  the  ques- 
tion whether  granite,  gneiss,  and  other  rocks  of  the  same  order  ever 
originated  at  the  surface,  or  whether,  according  to  the  opinions  above 
adopted,  they  are  essentially  subterranean  in  their  origin,  and  therefore 
entitled  to  the  appellation  of  hypogene.  If  they  were  formed  super- 
ficially in  their  present  state,  and  as  copiously  in  the  modern  as  in  the 
more  ancient  periods,  we  ought  to  see  a  greater  abundance  of  tertiary 
and  secondary  than  of  primary  granite  and  gneiss  ;  but  if  we  adopt  the 
hypogene  theory  before  explained,  their  rapid  diminution  in  volume 
among  the  visible  rocks  in  the  earth's  crust  in  proportion  as  we  investi- 
gate the  formations  of  newer  date,  is  quite  intelligible.  If  a  melted 
mass  of  matter  be  now  cooling  very  slowly  at  the  depth  of  several 
miles  beneath  the  crater  of  an  active  volcano,  it  must  remain  invisible 
until  great  revolutions  in  the  earth's  crust  have  been  brought  about. 
So  also  if  stratified  rocks  have  been  subjected  to  Plutonic  action,  and 
after  having  been  baked  or  reduced  to  semi-fusion,  are  now  cooling  and 
crystallizing  far  under  ground,  it  will  probably  require  the  lapse  of 
many  periods  before  they  will  be  forced  up  to  the  surface  and  exposed 
to  view,  even  at  a  single  point.  To  effect  this  purpose  there  may  be 
need  of  as  great  a  development  of  subterranean  movement  as  that  which 
in  the  Alps,  Andes,  and  Himalaya  has  raised  marine  strata  containing 
ammonites  to  the  height  of  8000,  14,000,  and  16,000  feet.  By  parity 
of  reasoning  we  can  hardly  expect  that  any  hypogene  rocks  of  the 
tertiary  periods  will  have  been  brought  within  the  reach  of  human 
observation,  seeing  that  the  emergence  of  such  rocks  must  always  be  so 
long  posterior  to  the  date  of  their  origin,  and  still  less  can  formations 
of  this  class  become  generally  visible  until  so  much  time  has  elapsed  as 
to  confer  on  them  a  high  relative  antiquity.  Extensive  denudation  must 
also  combine  with  upheaval  before  they  can  be  displayed  at  the  surface 
throughout  wide  areas. 

All  geologists  who  reflect  on  subterranean  movements  now  going  on, 
and  the  eruptions  of  active  volcanoes,  are  convinced  that  great  changes 
are  now  continually  in  progress  in  the  interior  of  the  earth's  crust  far  out 


CH.  XII.]  HYPOGENE  'TEXTURE.  179 

of  sight.  They  must  be  conscious,  therefore,  that  the  inaccessibility  of 
the  regions  in  which  these  alterations  are  taking  place,  compels  them  to 
remain  in  ignorance  of  a  great  part  of  the  working  of  existing  causes,  so 
that  they  can  only  form  vague  conjectures  in  regard. to  the  nature  of  the 
products  which  volcanic  heat  may  elaborate  under  great  pressure. 

But  when  they  find  in  mountain-chains  of  high  antiquity,  that  what 
was  once  the  interior  of  the  earth's  crust  has  since  been  forced  outwards 
and  exposed  to  view,  they  will  naturally  expect  in  the  examination  of 
those  mountainous  regions,  to  have  an  opportunity  of  gratifying  their 
curiosity  by  obtaining  a  sight  not  only  of  the  superficial  strata  of  remote 
eras,  but  also  of  the  contemporaneous  nether-formed  rocks.  Having 
recognized,  therefore,  in  such  mountain- chains  some  ancient  rocks  of 
aqueous  and  volcanic  origin,  corresponding  in  character  to  superficial 
formations  of  modern  date,  they  will  regard  any  other  class  of  ancient 
rocks,  such  as  granite  and  gneiss,  as  the  residual  phenomena  of  which 
they  are  in  search.  These  latter  rocks  will  not  answer  the  expectations 
previously  formed  of  their  probable  nature  and  texture,  unless  they  wear 
a  foreign  and  mysterious  aspect,  and  have  in  some  places  been  fused  or 
altered  by  subterranean  heat ;  in  a  word,  unless  they  differ  wholly  from 
the  fossiliferous  strata  deposited  at  the  surface,  or  from  the  lava  and 
scoriae  thrown  out  by  volcanoes  in  the  open  air.  It  is  the  total  distinct- 
ness, therefore,  of  crystalline  formations,  such  as  granite,  hornblende- 
schist,  and  the  rest,  from  every  substance  of  which  the  origin  is  familiar 
to  us,  that  constitutes  their  claim  to  be  regarded  as  the  effects  of  causes 
now  in  action  in  the  subterranean  regions.  They  belong  not  to  an  order 
of  things  which  has  passed  away ;  they  are  not  the  monuments  of  a 
primeval  period,  bearing  inscribed  upon  them  in  obsolete  characters  the 
words  and  phrases  of  a  dead  language ;  but  they  teach  us  that  part  of 
the  living  language  of  nature,  which  we  cannot  learn  by  our  daily  inter- 
course with  what  passes  on  the  habitable  surface. 


CHAPTER  XIII. 

UNIFORMITY  IN    THE    SERIES    OP    PAST    CHANGES    IN    THE    ANIMATE  AND 
INANIMATE    WORLD. 

Supposed  alternate  periods  of  repose  and  disorder — Observed  facts  in  which  this 
doctrine  has  originated — These  may  be  explained  by  supposing  a  uniform  and 
uninterrupted  series  of  changes — Threefold  consideration  of  this  subject ;  first,  in 
reference  to  the  living  creation,  extinction  of  species,  and  origin  of  new  animals 
and  plants ;  secondly,  in  reference  to  the  changes  produced  in  the  earth's  crust  by 
the  continuance  of  subterranean  movements  in  certain  areas,  and  their  transference 
after  long  periods  to  new  areas  ;  thirdly,  in  reference  to  the  laws  which  govern 
the  formation  of  fossiliferous  strata,  and  the  shifting  of  the  areas  of  sedimentary 
deposition — On  the  combined  influence  of  all  these  modes  and  causes  of  change 
in  producing  breaks  and  chasms  in  the  chain  of  records — Concluding  remarks 
on  the  identity  of  the  ancient  and  present  system  of  terrestrial  changes. 

Origin  of  the  doctrine  of  alternate  periods  of  repose  and  disorder. — IT 
has  been  truly  observed,  that  when  we  arrange  the  fossiliferous  forma- 
tions in  chronological  order,  they  constitute  a  broken  and  defective  series 
of  monuments :  we  pass  without  any  intermediate  gradations,  from  sys- 
tems of  strata  which  are  horizontal  to  other  systems  which  are  highly 
inclined,  from  rocks  of  peculiar  mineral  composition  to  others  which  have 
a  character  wholly  distinct, — from  one  assemblage  of  organic  remains  to 
another,  in  which  frequently  all  the  species,  and  most  of  the  genera,  are 
different.  These  violations  of  continuity  are  so  common,  as  to  constitute 
the  rule  rather  than  the  exception,  and  they  have  been  considered  by 
many  geologists  as  conclusive  in  favor  of  sudden  revolutions  in  the  inani- 
mate and  animate  world.  According  to  the  speculations  of  some  writers, 
there  have  been  in  the  past  history  of  the  planet  alternate  periods  of 
tranquillity  and  convulsion,  the  former  enduring  for  ages,  and  resembling 
that  state  of  things  now  experienced  by  man :  the  other  brief,  transient, 
and  paroxysmal,  giving  rise  to  new  mountains,  seas,  and  valleys,  annihi- 
lating one  set  of  organic  beings,  and  ushering  in  the  creation  of  another. 

It  will  be  the  object  of  the  present  chapter  to  demonstrate,  that  these 
theoretical  views  are  not  borne  out  by  a  fair  interpretation  of  geological 
monuments.  It  is  true  that  in  the  solid  framework  of  the  globe,  we 
have  a  chronological  chain  of  natural  records,  and  that  many  links  in  this 
chain  are  wanting;  but  a  careful  consideration  of  all  the  phenomena 
will  lead  to  the  opinion  that  the  series  was  originally  defective, — that  it 
has  been  rendered  still  more  so  by  time — that  a  great  part  of  what  re- 
mains is  inaccessible  to  man,  and  even  of  that  fraction  which  is  accessible, 
nine-tenths  are  to  this  day  unexplored. 

How  the  facts  may  be  explained  by  assuming  a  uniform  series  of 
changes. — The  readiest  way,  perhaps,  of  persuading  the  reader  that  we 


CH.  XIII]  CHANGES   IN   THE   ANIMATE   WORLD.  181 

may  dispense  with  great  and  sudden  revolutions  in  the  geological  order 
of  events,  is  by  showing  him  how  a  regular  and  uninterrupted  series  of 
changes  in  the  animate  and  inanimate  world  may  give  rise  to  such  breaks 
in  the  sequence,  and  such  unconformability  of  stratified  rocks,  as  are 
usually  thought  to  imply  convulsions  and  catastrophes.  It  is  scarcely 
necessary  to  state,  that  the  order  of  events  thus  assumed  to  occur,  for 
the  sake  of  illustration,  must  be  in  harmony  with  all  the  conclusions 
legitimately  drawn  by  geologists  from  the  structure  of  the  earth,  and 
must  be  equally  in  accordance  with  the  changes  observed  by  man  to  be 
now  going  on  in  the  living  as  well  as  in  the  inorganic  creation.  It  may 
be  necessary  in  the  present  state  of  science  to  supply  some  part  of  the 
assumed  course  of  nature  hypothetically ;  but  if  so,  this  must  be  done 
without  any  violation  of  probability,  and  always  consistently  with  the 
analogy  of  what  is  known  both  of  the  past  and  present  economy  of  our 
system.  Although  the  discussion  of  so  comprehensive  a  subject  must 
carry  the  beginner  far  beyond  his  depth,  it  will  also,  it  is  hoped,  stimu- 
late his  curiosity,  and  prepare  him  to  read  some  elementary  treatises  on 
geology  with  advantage,  and  teach  him  the  bearing  on  that  science  of 
the  changes  now  in  progress  on  the  earth.  At  the  same  time  it  may 
enable  him  the  better  to  understand  the  intimate  connection  between 
the  second  and  third  books  of  this  work,  the  former  of  which  is  occupied 
with  the  changes  in  the  inorganic,  the  latter  with  those  of  the  organic 
creation. 

In  pursuance,  then,  of  the  plan  above  proposed,  I  shall  consider  in 
this  chapter,  first,  what  may  be  the  course  of  fluctuation  in  the  animate 
world ;  secondly,  the  mode  in  which  contemporaneous  subterranean 
movements  affect  the  earth's  crust ;  and,  thirdly,  the  laws  which  regu- 
late the  deposition  of  sediment. 


UNIFORMITY    OF    CHANGE    CONSIDERED    FIRST    IN    REFERENCE    TO   THE 
LIVING    CREATION. 

First,  in  regard  to  the  vicissitudes  of  the  living  creation,  all  are  agreed 
that  the  sedimentary  strata  found  iu  the  earth's  crust  are  divisible  into 
a  variety  of  groups,  more  or  less  dissimilar  in  their  organic  remains  and 
mineral  composition.  The  conclusion  universally  drawn  from  the  study 
and  comparison  of  these  fossiliferous  groups  is  this,  that  at  successive 
periods  distinct  tribes  of  animals  and  plants  have  inhabited  the  land  and 
waters,  and  that  the  organic  types  of  the  newer  formations  are  more 
analogous  to  species  now  existing,  than  those  of  more  ancient  rocks.  If 
we  then  turn  to  the  present  state  of  the  animate  creation,  and  inquire 
whether  it  has  now  become  fixed  and  stationary,  we  discover  that,  on 
the  contrary,  it  is  in  a  state  of  continual  flux — that  there  are  many 
causes  in  action  which  tend  to  the  extinction  of  species,  and  which  are 
conclusive  against  the  doctrine  of  their  unlimited  durability.  But  natu- 
ral history  has  been  successfully  cultivated  for  so  short  a  period,  that  a 
few  examples  only  of  local,  and  perhaps  but  one  or  two  of  absolute,  extir- 


182  UNIFORM   SERIES   OF   CHANGES  [On.  XIIL 

pation  can  as  yet  be  proved,  and  these  only  where  the  interference  of  man 
has  been  conspicuous.  It  will  nevertheless  appear  evident,  from  the 
facts  and  arguments  detailed  in  the  third  book  (from  the  thirty- seventh 
to  the  forty-second  chapters,  inclusive)  that  man  is  not  the  only  exter- 
minating agent ;  and  that,  independently  of  his  intervention,  the  annihi- 
lation of  species  is  promoted  by  the  multiplication  and  gradual  diffu- 
sion of  every  animal  or  plant.  It  will  also  appear,  that  every  alteration 
in  the  physical  geography  and  climate  of  the  globe  cannot  fail  to  have 
the  same  tendency.  If  we  proceed  still  farther,  and  inquire  whether 
new  species  are  substituted  from  time  to  time  for  those  which  die  out, 
and  whether  there  are  certain  laws  appointed  by  the  Author  of  Nature 
to  regulate  such  new  creations,  we  find  that  the  period  of  human  obser- 
vation is  as  yet  too  short  to  afford  data  for  determining  so  weighty  a 
question.  All  that  can  be  done  is  to  show  that  the  successive  introduc- 
tion of  new  species  may  be  a  constant  part  of  the  economy  of  the  ter- 
restrial system,  without  our  having  any  right  to  expect  that  we  should 
be  in  possession  of  direct  proof  of  the  fact.  The  appearance  again  and 
again  of  new  species  may  easily  have  escaped  detection,  since  the  num- 
bers of  known  animals  and  plants  have  augmented  so  rapidly  within  the 
memory  of  persons  now  living,  as  to  have  doubled  in  some  classes,  and 
quadrupled  in  others.  It  will  also  be  remarked  in  the  sequel  (book  iii. 
chap.  43),  that  it  must  always  be  more  easy  if  species  proceeded  origi- 
nally from  single  stocks,  to  prove  that  one  which  formerly  abounded  in 
a  given  district  has  ceased  to  be,  than  that  another  has  been  called  into 
being  for  the  first  time.  If,  therefore,  there  be  as  yet  only  one  or  two 
unequivocal  instances  of  extinction,  namely,  those  of  the  dodo  and  soli- 
taire (see  ch.  41),  it  is  scarcely  reasonable  as  yet  to  hope  that  we  should 
be  cognizant  of  a  single  instance  of  the  first  appearance  of  a  new  species. 

Recent  origin  of  man,  and  gradual  approach  in  the  tertiary  fossils  of 
successive  periods  from  an  extinct  to  the  recent  fauna. — The  geologist, 
however,  if  required  to  advance  some  fact  which  may  lend  countenance 
to  the  opinion  that  in  the  most  modern  times,  that  is  to  say,  after  the 
greater  part  of  the  existing  fauna  and  flora  were  established  on  the 
earth,  there  has  still  been  a  new  species  superadded,  may  point  to  man 
himself  as  furnishing  the  required  illustration — for  man  must  be  regarded 
by  the  geologist  as  a  creature  of  yesterday,  not  merely  in  reference  to 
the  past  history  of  the  organic  world,  but  also  in  relation  to  that  par- 
ticular state  of  the  animate  creation  of  which  he  forms  a  part.  The 
comparatively  modern  introduction  of  the  human  race  is  proved  by  the 
absence  of  the  remains  of  man  and  his  works,  not  only  from  all  strata 
containing. a  certain  proportion  of  fossil  shells  of  extinct  species,  but  even 
from  a  large  part  of  the  newest  strata,  in  which  all  the  fossil  individuals 
are  referable  to  species  still  living. 

To  enable  the  reader  to  appreciate  the  full  force  of  this  evidence,  I 
shall  give  a  slight  sketch  of  the  information  obtained  from  the  newer 
strata,  respecting  fluctuations  in  the  animate  world,  in  times  immediately 
antecedent  to  the  appearance  of  man. 


CH.  XIIL]  IN    THE    ANIMATE    WOKLD.  183 

In  tracing  the  series  of  fossiliferous  formations  from  the  more  ancient 
to  the  more  modern,  the  first  deposits  in  which  we  meet  with  assem- 
blages of  organic  remains,  having  a  near  analogy  to  the  fauna  of  cer- 
tain parts  of  the  globe  in  our  own  time,  are  those  commonly  called  ter- 
tiary. Even  in  the  Eocene,  or  oldest  subdivision  of  these  tertiary 
formations,  some  few  of  the  testacea  belong  to  existing  species,  although 
almost  all  of  them,  and  apparently  all  the  associated  vertebrata,  are  now 
extinct.  These  Eocene  strata  are  succeeded  by  a  great  number  of 
more  modern  deposits,  which  depart  gradually  in  the  character  of  their 
fossils  from  the  Eocene  type,  and  approach  more  and  more  to  that  of 
the  living  creation.  In  the  present  state  of  science,  it  is  chiefly  by  the 
aid  of  shells  that  we  are  enabled  to  arrive  at  these  results,  for  of  all 
classes  the  testacea  are  the  most  generally  diffused  in  a  fossil  state,  and 
may  be  called  the  medals  principally  employed  by  nature,  in  recording 
the  chronology  of  past  events.  In  the  Miocene  deposits,  which  are 
next  in  succession  to  the  Eocene,  we  begin  to  find  a  considerable  num- 
ber, although  still  a  minority,  of  recent  species,  intermixed  with  some 
fossils  common  to  the  preceding  epoch.  Wfe  then  arrive  at  the  Plio- 
cene strata,  in  which  species  now  contemporary  with  man  begin  to  pre- 
ponderate, and  in  the  newest  of  which  nine-tenths  of  the  fossils  agree 
with  species  still  inhabiting  the  neighboring  sea. 

In  this  passing  from  the  older  to  the  newer  members  of  the  tertiary 
system  we  meet  with  many  chasms,  but  none  which  separate  entirely, 
by  a  broad  line  of  demarcation,  one  state  of  the  organic  world  from  an- 
other. There  are  no  signs  of  an  abrupt  termination  of  one  fauna  and 
flora,  and  the  starting  into  life  of  new  and  wholly  distinct  forms.  Al- 
though we  are  far  from  being  able  to  demonstrate  geologically  an  insen- 
sible transition  from  the  Eocene  to  the  Miocene,,  or  even  from  the  latter 
to  the  recent  fauna,  yet  the  more  we  enlarge  and  perfect  our  general 
survey,  the  more  nearly  do  we  approximate  to  such  a  continuous  series, 
and  the  more  gradually  are  we  conducted  from  times  when  many  of  the 
genera  and  nearly  all  the  species  were  extinct,  to  those  in  which  scarcely 
a  single  species  flourished  which  we  do  not  know  to  exist  at  present. 
Dr.  A.  Philippi,  indeed,  after  an  elaborate  comparison  of  the  fossil  ter- 
tiary shells  of  Sicily  with  those  now  living  in  the  Mediterranean,  an- 
nounces as  the  result  of  his  examination  that  there  are  strata  in  that 
island,  which  attest  a  very  gradual  passage  from  a  period,  when  only 
thirteen  in  a  hundred  of  the  shells  were  like  the  species  now  living  in 
the  sea,  to  an  era  when  the  recent  species  had  attained  a  proportion  of 
ninety-five  in  a  hundred.  There  is  therefore  evidence,  he  says,  in  Sicily 
of  this  revolution  in  the  animate  world  having  been  effected  "  without 
the  intervention  of  any  convulsion  or  abrupt  changes,  certain  species 
having  from  time  to  time  died  out,  and  others  having  been  introduced, 
until  at  length  the  existing  fauna  was  elaborated." 

It  had  often  been  objected  that  the  evidence  of  fossil  species  occur- 
ring in  two  consecutive  formations,  was  confined  to  the  testacea  or  zoo- 
phytes, the  characters  of  which  are  less  marked  and  decisive  than  those 


184:  UNIFORM    SERIES    OF    CHANGES  [Cn.  XIII 

afforded  by  the  vertebrate  animals.  But  Mr.  Owen  has  lately  insisted 
on  the  important  fact,  that  not  a  few  of  the  quadrupeds  which  now  in- 
habit our  island,  and  among  others  the  horse,  the  ass,  the  hog,  the 
smaller  wild  ox,  the  goat,  the  red  deer,  the  roe,  the  beaver,  and  many 
of  the  diminutive  rodents,  are  the  same  as  those  which  once  coexisted 
with  the  mammoth,  the  great  northern  hippopotamus,  two  kinds  of  rhi- 
noceros, and  other  mammalia  long  since  extinct.  "  A  part,"  he  ob- 
serves, "  and  not  the  whole  of  the  modern  tertiary  fauna  has  perished, 
and  hence  we  may  conclude  that  the  cause  of  their  destruction  has  not 
been  a  violent  and  universal  catastrophe  from  which  none  could 
escape."* 

Had  we  discovered  evidence  that  man  had  come  into  the  earth  at  a 
period  as  early  as  that  when  a  large  number  of  the  fossil  quadrupeds 
now  living,  and  almost  all  the  recent  species  of  land,  freshwater,  and 
marine  shells  were  in  existence,  we  should  have  been  compelled  to 
ascribe  a  much  higher  antiquity  to  our  species,  than  even  the  boldest 
speculations  of  the  ethnologist  require,  for  no  small  part  of  the  great 
physical  revolution  depicted  on  the  map  of  Europe  (PI.  3),  before  de- 
scribed, took  place  very  gradually  after  the  recent  testacea  abounded 
almost  to  the  exclusion  of  the  extinct.  Thus,  for  example,  in  the  de- 
posits called  the  "northern  drift,"  or  the  glacial  formation  of  Europe 
and  North  America,  the  fossil  marine  shells  can  easily  be  identified  with 
species  either  now  inhabiting  the  neighboring  sea,  or  living  in  the  seas 
of  higher  latitudes.  Yet  they  exhibit  no  memorials  of  the  human  race, 
or  of  articles  fabricated  by  the  hand  of  man.  Some  of  the  newest  of 
these  strata  passing  by  the  name  of  "  raised  beaches,"  occur  at  moder- 
ate elevations  on  the  coast  of  England,  Scotland,  and  Ireland.  Other 
examples  are  met  with  on  a  more  extended  scale  in  Scandinavia,  as  at 
the  height  of  200  feet  at  Uddevalla  in  Sweden,  and  at  twice  that  eleva- 
tion, near  Christiana,  in  Norway,  also  at  an  altitude  of  600  or  700  feet 
in  places  farther  north.  They  consist  of  beds  of  sand  and  clay,  filling 
hollows  in  a  district  of  granite  and  gneiss,  and  they  must  closely  resem- 
ble the  accumulations  of  shelly  matter  now  in  progress  at  the  bottom  of 
the  Norwegian  fiords.  The  rate  at  which  the  land  is  now  rising  in 
Scandinavia,  is  far  too  irregular  in  different  places  to  afford  a  safe 
standard  for  estimating  the  minimum  of  time  required  for  the  upheaval 

*  Reports  to  Brit.  Assoc.  1842,  1843,  and  Introd.  to  Brit.  Foss.  Maram.  p.  31. 
The  conchological  evidence  respecting  the  British  Miocene,  Pliocene,  and  Pleisto- 
cene fossils,  examined  by  Mr.  Forbes,  in  the  paper  before  cited,  p.  88,  note,  bear 
out  some  of  the  most  important  conclusions  of  M.  Deshayes,  quoted  by  me  in  the 
first  edition  of  the  Principles,  1831,  and  the  recent  observations  of  Philippi  in  re- 
gard to  the  passage  of  species  from  one  formation  to  another.  I  refer  to  these 
authorities  more  especially  because  this  doctrine  of  a  gradual  transition  has  been 
opposed  by  some  living  naturalists  of  high  distinction,  among  whom  I  may  men- 
tion M.  A.  d'Orbigny  and  M.  Agassiz.  I  have  long  been  convinced  that  we  must 
abandon  many  of  the  identifications  formerly  made  of  Eocene  with  recent  shells; 
but  some  errors  of  this  kind  do  not  affect  the  general  reasoning  on  the  subject 
See  a  discussion  on  this  question,  Quarterly  Journ.  of  Geog.  Soc.,  No.  5,  p.  47 
Feb.  1846. 


CH.  XIII.]  IN    THE   ANIMATE    WORLD.  185 

of  the  fundamental  granite,  and  its  marine  shelly  covering,  to  the  height 
of  so  many  hundred  feet ;  but  according  to  the  greatest  average,  of  five 
or  six  feet  in  a  century,  the  period  required  would  be  very  considerable, 
and  nearly  the  whole  of  it,  as  well  as  the  antecedent  epoch  of  submer- 
gence, seems  to  have  preceded  the  introduction  of  man  into  these  parts 
of  the  earth. 

There  are  other  post-tertiary  formations  of  fluviatile  origin,  in  the 
centre  of  Europe,  in  which  the  absence  of  human  remains  is  perhaps 
still  more  striking,  because,  when  formed,  they  must  have  been  sur- 
rounded by  dry  land.  I  allude  to  the  silt  or  loess  of  the  basin  of  the 
Rhine,  which  must  have  gradually  filled  up  the  great  valley  of  that 
river  since  the  time  when  its  waters,  and  the  contiguous  lands,  were  in- 
habited by  the  existing  species  of  freshwater  and  terrestrial  mollusks. 
Showers  of  ashes,  thrown  out  by  some  of  the  last  eruptions  of  the  Eifel 
volcanoes,  fell  during  the  deposition  of  this  fluviatile  silt,  and  were  inter- 
stratified  with  it.  But  these  volcanoes  became  exhausted,  the  valley 
was  re-excavated  through  the  silt,  and  again  reduced  to  its  present  form 
before  the  period  of  human  history.  The  study,  therefore,  of  this  shelly 
silt  reveals  to  us  the  history  of  a  long  series  of  events,  which  occurred 
after  the  testacea  now  living  inhabited  the  land  and  rivers  of  Europe, 
and  the  whole  terminated  without  any  signs  of  the  coming  of  man  into 
that  part  of  the  globe. 

To  cite  a  still  more  remarkable  example,  we  observe  in  Sicily  a  lofty 
table-land  and  hills,  sometimes  rising  to  the  height  of  3000  feet,  capped 
with  a  limestone,  in  which  from  70  to  85  per  cent,  of  the  fossil  testacea 
are  specifically  identical  with  those  now  inhabiting  the  Mediterranean. 
These  calcareous  and  other  argillaceous  strata  of  the  same  age  are  inter- 
sected by  deep  valleys  which  have  been  gradually  formed  by  denuda- 
tion, but  have  not  varied  materially  in  width  or  depth  since  Sicily  was 
first  colonized  by  the  Greeks.  The  limestone,  moreover,  which  is  of  so 
late  a  date  in  geological  chronology,  was  quarried  for  building  those 
ancient  temples  of  Girgenti  and  Syracuse,  of  which  the  ruins  carry  us 
back  to  a  remote  era  in  human  history.  If  we  are  lost  in  conjectures 
when  speculating  on  the  ages  required  to  lift  up  these  formations  to  the 
height  of  several  thousand  feet  above  the  sea,  how  much  more  remote 
must  be  the  era  when  the  same  rocks  were  gradually  formed  beneath 
the  waters  ! 

To  conclude,  it  appears  that,  in  going  back  from  the  recent  to  the 
Eocene  period,  we  are  carried  by  many  successive  steps  from  the  fauna 
now  contemporary  with  man  to  an  assemblage  of  fossil  species  wholly 
different  from  those  now  living.  In  this  retrospect  we  have  not  yet  suc- 
ceeded in  tracing  back  a  perfect  transition  from  the  recent  to  an  extinct 
fauna ;  buji  there  are  usually  so  many  species  in  common  to  the  groups 
which  stand  next  in  succession  as  to  show  that  there  is  no  great  chasm, 
no  signs  of  a  crisis  when^one  class  of  organic  beings  was  annihilated  to 
give  place  suddenly  to  another.  This  analogy,  therefore,  derived  from 
a  period  of  the  earth's  history  which  can  best  be  compared  with  the 


186  UNIFORMITY   OF    CHANGE.  [Cn.  XIU 

present  state  of  things,  and  more  thoroughly  investigated  than  any 
other,  leads  to  the  conclusion  that  the  extinction  and  creation  of  species, 
has  been  and  is  the  result  of  a  slow  and  gradual  change  in  the  organic 
world. 

UNIFORMITY  OF  CHANGE    CONSIDERED,  SECONDLY,  IN    REFERENCE    TO  SUB 
TERRANEAN    MOVEMENTS. 

To  pass  on  to  another  of  the  three  topics  before  proposed  for  discus 
sion,  the  reader  will  find,  in  the  account  given  in  the  second  book  of  the 
earthquakes  recorded  in  history,  that  certain  countries  have,  from  time 
immemorial,  been  rudely  shaken  again  and  again,  while  others,  com- 
prising by  far  the  largest  part  of  the  globe,  have  remained  to  all  ap- 
pearance motionless.  In  the  regions  of  convulsion  rocks  have  been  rent 
asunder,  the  surface  has  been  forced  up  into  ridges,  chasms  have  opened, 
or  the  ground  throughout  large  spaces  has  been  permanently  lifted  up 
above  or  let  down  below  its  former  level.  In  the  regions  of  tranquillity 
some  areas  have  remained  at  rest,  but  others  have  been  ascertained  by 
a  comparison  of  measurements,  made  at  different  periods,  to  have  risen 
by  an  insensible  motion,  as  in  Sweden,  or  to  have  subsided  very  slowly, 
as  in  Greenland.  That  these  same  movements,  whether  ascending  or 
descending,  have  continued  for .  ages  in  the  same  direction  has  been 
established  by  geological  evidence.  Thus,  we  find  both  on  the  east  and 
west  coast  of  Sweden,  that  ground  which  formerly  constituted  the  bot- 
tom of  the  Baltic  and  of  the  ocean  has  been  lifted  up  to  an  elevation  of 
sereral  hundred  feet  above  high-water  mark.  The  rise  within  the  his- 
torical period  has  not  amounted  to  many  yards,  but  the  greater  extent 
of  antecedent  upheaval  is  proved  by  the  occurrence  in  inland  spots, 
several  hundred  feet  high,  of  deposits  filled  with  fossil  shells  of  species 
now  living  either  in  the  ocean  or  the  Baltic. 

To  detect  proofs  of  slow  and  gradual  subsidence  must  in  general  be 
more  difficult ;  but  the  theory  which  accounts  for  the  form  of  circular 
coral  reefs  and  lagoon  islands,  and  which  will  be  explained  in  the  last 
chapter  of  the  third  book,  will  satisfy  the  reader  that  there  are  spaces 
on  the  globe,  several  thousand  miles  in  circumference,  throughout  which 
the  downward  movement  has  predominated  for  ages,  and  yet  the  land 
has  never,  in  a  single  instance,  gone  down  suddenly  for  several  hundred 
feet  at  once.  Yet  geology  demonstrates  that  the  persistency  of  sub- 
terranean movements  in  one  direction  has  not  been  perpetual  through- 
out all  past  time.  There  have  been  great  oscillations  of  level  by  which 
a  surface  of  dry  land  has  been  submerged  to  a  depth  of  several  thou- 
sand feet,  and  then  at  a  period  long  subsequent  raised  again  and  made, 
to  emerge.  Nor  have  the  regions  now  motionless  been  always  at  rest ; 
and  some  of  those  which  are  at  present  the  theatres  of  reiterated  earth- 
quakes have  formerly  enjoyed  a  long  continuance  of  tranquillity.  But 
although  disturbances  have  ceased  after  having  long  prevailed,  or  have 
recommenced  after  a  suspension  for  ages,  there  has  been  no  universal 
disruption  of  the  earth's  crust  or  desolation  of  the  surface  since  times 


CH.  XIII.]  SUBTERRANEAN   MOVEMENTS.  187 

the  most  remote.  The  non-occurrence  of  such  a  general  convulsion  is 
proved  by  the  perfect  horizontal! ty  now  retained  by  some  of  the  most 
ancient  fossiliferous  strata  throughout  wide  areas. 

Inferences  derived  from  unconformable  strata. — That  the  subterranean 
forces  have  visited  different  parts  of  the  globe  at  successive  periods,  is 
inferred  chiefly  from  the  unconformability  of  strata  belonging  to  groups 
of  different  ages.  Thus,  for  example,  on  the  borders  of  Wales  and 
Shropshire  we  find  the  slaty  beds  of  the  ancient  Silurian  system  curved 
and  vertical,  while  the  beds  of  the  overlying  carboniferous  shale  and 
sandstone  are  horizontal.  All  are  agreed,  that  in  such  a  case  the  older 
set  of  strata  had  suffered  great  dislocation  before  the  deposition  of  the 
newer  or  carboniferous  beds,  and  that  these  last  have  never  since  been 
convulsed  by  any  movements  of  excessive  violence.  But  the  strata  of 
the  inferior  group  suffered  only  a  local  derangement,  and  rocks  of  the 
same  age  are  by  no  means  found  everywhere  in  a  curved  or  vertical 
position.  In  various  parts  of  Europe,  and  particularly  near  Lake  Wener 
in  the  south  of  Sweden,  and  in  many  parts  of  Russia,  beds  of  the  same 
Silurian  system  maintain  the  most  perfect  horizontality  ;  and  a  similar 
observation  may  be  made  respecting  limestones  and  shales  of  the  like 
antiquity  in  the  great  lake  district  of  Canada  and  the  United  States. 
They  are  still  as  flat  and  horizontal  as  when  first  formed ;  yet  since 
their  origin  not  only  have  most  of  the  actual  mountain-chains  been  up- 
lifted, but  the  very  rocks  of  which  those  mountains  are  composed  have 
been  formed. 

It  would  be  easy  to  multiply  instances  of  similar  unconformability  in 
formations  of  other  ages  ;  but  a  few  more  will  suffice.  The  coal  meas- 
ures before  alluded  to  as  horizontal  on  the  borders  of  Wales  are  verti- 
cal in  the  Mendip  Hills  in  Somersetshire,  where  the  overlying  beds  of 
the  New  Red  Sandstone  are  horizontal.  Again,  in  the  Wolds  of  York- 
shire the  last  mentioned  sandstone  supports  on  its  curved  and  inclined 
beds  the  horizontal  Chalk.  The  Chalk  again  is  vertical  on  the  flanks 
of  the  Pyrenees,  and  the  tertiary  strata  repose  unconformably  upon  it. 

Consistency  of  local  disturbances  with  general  uniformity. — As  al- 
most every  country  supplies  illustrations  of  the  same  phenomena,  they 
who  advocate  the  doctrine  of  alternate  periods  of  disorder  and  repose 
may  appeal  to  the  facts  above  described,  as  proving  that  every  dis- 
trict has  been  by  turns  convulsed  by  earthquakes  and  then  respited 
for  ages  from  convulsions.  But  so  it  might  with  equal  truth  be 
affirmed  that  every  part  of  Europe  has  been  visited  alternately  by  win- 
ter and  summer,  although  it  has  always  been  winter  and  always  sum- 
mer in  some  part  of  the  planet,  and  neither  of  these  seasons  has  ever 
reigned  simultaneously  over  the  entire  globe.  They  have  been  always 
shifting  about  from  place  to  place ;  but  the  vicissitudes  which  recur 
thus  annually  in  a  single  spot  are  never  allowed  to  interfere  with  the 
invariable  uniformity  of  seasons  throughout  the  whole  planet. 

So,  in  regard  to  subterranean  movements,  the  theory  of  the  perpet- 
ual uniformity  of  the  force  which  they  exert  on  the  earth's  crust  is 


188  UNIFORMITY   OF   CHANGE.  [Cn.  XIII. 

quite  consistent  with  the  admission  of  their  alternate  development  and 
suspension  for  indefinite  periods  within  limited  geographical  areas. 


UNIFORMITY    OF    CHANGE    CONSIDERED,    THIRDLY,    IN    REFERENCE    TO 
SEDIMENTARY    DEPOSITION. 

It  now  remains  to  speak  of  the  laws  governing  the  deposition  of 
new  strata.  If  we  survey  the  surface  of  the  globe  we  immediately 
perceive  that  it  is  divisible  into  areas  of  deposition  and  non-deposition, 
or,  in  other  words,  at  any  given  time  there  are  spaces  which  are  the 
recipients,  others  which  are  not  the  recipients  of  sedimentary  matter. 
No  new  strata,  for  example,  are  thrown  down  on  dry  land,  which 
remains  the  same  from  year  to  year ;  whereas,  in  many  parts  of  the 
bottom  of  seas  and  lakes,  mud,  sand,  and  pebbles  are  annually  spread 
out  by  rivers  and  currents.  There  are  also  great  masses  of  limestone 
growing  in  some  seas,  or  in  mid-ocean,  chiefly  composed  of  corals  and 
shells. 

No  sediment  deposited  on  dry  land. — As  to  the  dry  land,  so  far 
from  being  the  receptacle  of  fresh  accessions  of  matter,  it  is  exposed 
almost  everywhere  to  waste  away.  Forests  may  be  as  dense  and 
lofty  as  those  of  Brazil,  and  may  swarm  with  quadrupeds,  birds,  and 
insects,  yet  at  the  end  of  ten  thousand  years  one  layer  of  black 
mould,  a  few  inches  thick,  may  be  the  sole  representative  of  those 
myriads  of  trees,  leaves,  flowers,  and  fruits,  those  innumerable  bones 
and  skeletons  of  birds,  quadrupeds,  and  reptiles,  which  tenanted  the 
fertile  region.  Should  this  land  be  at  length  submerged,  the  waves 
of  the  sea  may  wash  away  in  a  few  hours  the  scanty  covering  of 
mould,  and  it  may  merely  impart  a  darker  shade  of  color  to  the  next 
stratum  of  marl,  sand,  or  other  matter  newly  thrown  down.  So  also 
at  the  bottom  of  the  ocean  where  no  sediment  is  accumulating,  sea- 
weed, zoophytes,  fish,  and  even  shells,  may  multiply  for  ages  and  de- 
compose, leaving  no  vestige  of  their  form  or  substance  behind.  Their 
decay,  in  water,  although  more  slow,  is  as  certain  and  eventually  as 
complete  as  in  the  open  air.  Nor  can  they  be  perpetuated  for  indefi- 
nite periods  in  a  fossil  state,  unless  imbedded  in  some  matrix  which  is 
impervious  to  water,  or  which  at  least  does  not  allow  a  free  percolation 
of  that  fluid,  impregnated  as  it  usually  is,  with  a  slight  quantity  of  car- 
bonic or  other  acid.  Such  a  free  percolation  may  be  prevented  either 
by  the  mineral  nature  of  the  matrix  itself,  or  by  the  superposition  of  an 
impermeable  stratum  :  but  if  unimpeded,  the  fossil  shell  or  bone  will  be 
dissolved  and  removed,  particle  after  particle,  and  thus  entirely  effaced, 
unless  petrifaction  or  the  substitution  of  mineral  for  organic  matter  hap- 
pen to  take  place. 

That  there  has  been  land  as  well  as  sea  at  all  former  geological  pe- 
riods, we  know  from  the  fact,  that  fossil  trees  and  terrestrial  plants  are 
imbedded  in  rocks  of  every  age.  Occasionally  lacustrine  and  fluviatile 
shells,  insects,  or  the  bones  of  amphibious  or  land  reptiles,  point  to  the 


CH.  XIII. ]  SEDIMENTARY    DEPOSITION.  189 

same  conclusion.  The  existence  of  dry  land  at  all  periods  of  the  past 
implies,  as  before  mentioned,  the  partial  deposition  of  sediment,  or  its 
limitation  to  certain  areas  ;  and  the  next  point  to  which  I  shall  call 
the  reader's  attention,  is  the  shifting  of  these  areas  from  one  region  to 
another. 

First,  then,  variations  in  the  site  of  sedimentary  deposition  are 
brought  about  independently  of  subterranean  movements.  There  is 
always  a  slight  change  from  year  to  year,  or  from  century  to  century. 
The  sediment  of  the  Rhone,  for  example,  thrown  into  the  Lake  of 
Geneva,  is  now  conveyed  to  a  spot  a  mile  and  a  half  distant  from  that 
where  it  accumulated  in  the  tenth  century,  and  six  miles  from  the  point 
where  the  delta  began  originally  to  form.  We  may  look  forward  to 
the  period  when  this  lake  will  be  filled  up,  and  then  the  distribution  of 
the  transported  matter  will  be  suddenly  altered,  for  the  mud  and  sand 
brought  down  from  the  Alps  will  thenceforth,  instead  of  being  deposited 
near  Geneva,  be  carried  nearly  200  miles  southwards,  where  the  Rhone 
enters  the  Mediterranean. 

In  the  deltas  of  large  rivers,  such  as  those  of  the  Ganges  and  Indus, 
the  mud  is  first  carried  down  for  many  centuries  through  one  arm,  and 
on  this  being  stopped  up  it  is  discharged  by  another,  and  may  then 
enter  the  sea  at  a  point  50  or  100  miles  distant  from  its  first  receptacle. 
The  direction  of  marine  currents  is  also  liable  to  be  changed  by  various 
accidents,  as  by  the  heaping  up  of  new  sand-banks,  or  the  wearing 
away  of  cliffs  and  promontories. 

But,  secondly,  all  these  causes  of  fluctuation  in  the  sedimentary  areas 
are  entirely  subordinate  to  those  great  upward  or  downward  movements 
of  land  which  have  been  already  described  as  prevailing  over  large 
tracts  of  the  globe.  By  such  elevation  or  subsidence  certain  spaces  are 
gradually  submerged,  or  made  gradually  to  emerge : — in  the  one  case 
sedimentary  deposition  may  be  suddenly  renewed  after  having  been  sus- 
pended for  ages,  in  the  other  as  suddenly  made  to  cease  after  having 
continued  for  an  indefinite  period. 

Causes  of  variation  in  mineral  character  of  successive  sedimentary 
groups. — If  deposition  be  renewed  after  a  long  interval,  the  new  strata 
will  usually  differ  greatly  from  the  sedimentary  rocks  previously  formed 
in  the  same  place,  and  especially  if  the  older  rocks  have  suffered  de- 
rangement, which  implies  a  change  in  the  physical  geography  of  the 
district  since  the  previous  conveyance  of  sediment  to  the  same  spot.  It 
may  happen,  however,  that,  even  when  the  inferior  group  is  horizontal 
and  conformable  to  the  upper  strata,  these  last  may  still  differ  entirely 
in  mineral  character,  because  since  the  origin  of  the  older  formation  the 
geography  of  some  distant  country  has  been  altered.  In  that  country 
rocks  before  concealed  may  have  become  exposed  by  denudation  ;  vol- 
canoes may  have  burst  out  and  covered  the  surface  with  scoriae  and 
lava,  or  new  lakes  may  have  been  formed  by  subsidence  ;  and  other  fluc- 
tuations may  have  occurred,  by  which  the  materials  brought  down  from 
thence  by  rivers  to  the  sea  have  acquired  a  distinct  mineral  character. 


190  CHANGES    IN    MINERAL  [Cn.  XIII. 

It  is  well  known  that  the  stream  of  the  Mississippi  is  charged  with 
sediment  of  a  different  color  from  that  of  the  Arkansas  and  Red  Rivers, 
which  are  tinged  with  red  mud,  derived  from  rocks  of  porphyry  in 
"  the  far  west."  The  waters  of  the  Uruguay,  says  Darwin,  draining  a 
granitic  country,  are  clear  and  black,  those  of  the  Parana,  red.*  The 
mud  with  which  the  Indus  is  loaded,  says  Burnes,  is  of  a  clayey  hue, 
that  of  the  Chenab,  on  the  other  hand,  is  reddish,  that  of  the  Sutlej  is 
more  pale.f  The  same  causes  which  make  these  several  rivers,  some- 
times situated  at  no  great  distance  the  one  from  the  other,  to  differ 
greatly  in  the  character  of  their  sediment,  will  make  the  waters  draining 
the  same  country  at  different  epochs,  especially  before  and  after  great 
revolutions  in  physical  geography,  to  be  entirely  dissimilar.  It  is 
scarcely  necessary  to  add,  that  marine  currents  will  be  affected  in  an 
analogous  manner  in  consequence  of  the  formation  of  new  shoals,  the 
emergence  of  new  islands,  the  subsidence  of  others,  the  gradual  waste 
of  neighboring  coasts,  the  growth  of  new  deltas,  the  increase  of  coral 
reefs,  and  other  changes. 

Why  successive  sedimentary  groups  contain  distinct  fossils. — If,  in 
the  next  place,  we  assume,  for  reasons  before  stated,  a  continual  ex- 
tinction of  species  and  introduction  of  others  into  the  globe,  it  will  then 
follow  that  the  fossils  of  strata  formed  at  two  distant  periods  on  the 
same  spot,  will  differ  even  more  certainly  than  the  mineral  composition 
of  the  same.  For  rocks  of  the  same  kind  have  sometimes  been  repro- 
duced in  the  same  district  after  a  long  interval  of  time,  whereas  there 
are  no  facts  leading  to  the  opinion  that  species  which  have  once  died 
out  have  ever  been  reproduced.  The  submergence  then  of  land  must 
be  often  attended  by  the  commencement  of  a  new  class  of  sedimentary 
deposits,  characterized  by  a  new  set  of  fossil  animals  and  plants,  while 
the  reconversion  of  the  bed  of  the  sea  into  land  may  arrest  at  once 
and  for  an  indefinite  time  the  formation  of  geological  monuments. 
Should  the  land  again  sink,  strata  will  again  be  formed ;  but  one  or 
many  entire  revolutions  in  animal  or  vegetable  life  may  have  been  com- 
pleted in  the  interval. 

Conditions  requisite  for  the  original  completeness  of  a  fossiliferous 
series. — If  we  infer,  for  reasons  before  explained,  that  fluctuations  in 
the  animate  world  are  brought  about  by  the  slow  and  successive 
removal  and  creation  of  species,  we  shall  be  convinced  that  a  rare  com- 
bination of  circumstances  alone  can  give  rise  to  such  a  series  of  strata 
as  will  bear  testimony  to  a  gradual  passage  from  one  state  of  organic 
life  to  another.  To  produce  such  strata  nothing  less  will  be  requisite 
than  the  fortunate  coincidence  of  the  following  conditions :  first,  a 
never-failing  supply  of  sediment  in  the  same  region  throughout  a  period 
of  vast  duration ;  secondly,  the  fitness  of  the  deposit  in  every  part  for 
the  permanent  preservation  of  imbedded  fossils  ;  and,  thirdly,  a  gradual 

*  Darwin's  Journal,  p.  163.     2d.  ed.  p.  139. 
t  Journ.  Roy.  Geograph.  Soc.  vol.  iii.  p.  142. 


CH.  XIIL]  COMPOSITION   AND   FOSSILS.  .      191 

subsidence  to  prevent  the  sea  or  lake  from  being  filled  up  and  converted 
into  land. 

It  will  appear  in  the  chapter  on  coral  reefs,*  that,  in  certain  parts  of 
the  Pacific  and  Indian  Oceans,  most  of  these  conditions,  if  not  all,  are 
complied  with,  and  the  constant  growth  of  coral,  keeping  pace  with  the 
sinking  of  the  bottom  of  the  sea,  seems  to  have  gone  on  so  slowly,  for 
such  indefinite  periods,  that  the  sighs  of  a  gradual  change  in  organic 
life  might  probably  be  detected  in  that  quarter  of  the  globe,  if  we 
could  explore  its  submarine  geology.  Instead  of  the  growth  of  coral- 
line limestone,  let  us  suppose,  in  some  other  place,  the  continuous  -de- 
position of  fluviatile  mud  and  sand,  such  as  the  Ganges  and  Brahma- 
pootra have  poured  for  thousands  of  years  into  the  Bay  of  Bengal. 
Part  of  this  bay,  although  of  considerable  depth,  might  at  length  be 
filled  up  before  an  appreciable  amount  of  change  was  effected  in  the 
fish,  mollusca,  and  other  inhabitants  of  the  sea  and  neighboring  land. 
But,  if  the  bottom  be  lowered  by  sinking  at  the  same  rate  that  it  is 
raised  by  fluviatile  mud,  the  bay  can  never  be  turned  into  dry  land. 
In  that  case  one  new  layer  of  matter  may  be  superimposed  upon 
another  for  a  thickness  of  many  thousand  feet,  and  the  fossils  of  the 
inferior  beds  may  differ  greatly  from  those  entombed  in  the  uppermost, 
yet  every  intermediate  gradation  may  be  indicated  in  the  passage  from 
an  older  to  a  newer  assemblage  of  species.  Granting,  however,  that 
such  an  unbroken  sequence  of  monuments  may  thus  be  elaborated  in 
certain  parts  of  the  sea,  and  that  the  strata  happen  to  be  all  of  them 
well  adapted  to  preserve  the  included  fossils  from  decomposition,  how- 
many  accidents  must  still  concur  before  these  submarine  formations  will 
be  laid  open  to  our  investigation  !  The  whole  deposit  must  first  be 
raised  several  thousand  feet,  in  order  to  bring  into  view  the  very  foun- 
dation ;  and  during  the  process  of  exposure  the  superior  beds  must  not 
be  entirely  swept  away  by  denudation. 

In  the  first  place,  the  chances  are  as  three  to  one  against  the  mere 
emergence  of  the  mass  above  the  waters,  because  three-fourths  of  the 
globe  are  covered  by  the  ocean.  But  if  it  be  upheaved  and  made  to 
constitute  part  of  the  dry  land,  it  must  also,  before  it  can  be  available 
for  our  instruction,  become  part  of  that  area  already  surveyed  by  geol- 
ogists ;  and  this  area  comprehends  perhaps  less  than  a  tenth  of  the 
whole  earth.  In  this  small  fraction  of  land  already  explored,  and  still 
very  imperfectly  known,  we  are  required  to  find  a  set  of  strata,  ori- 
ginally of  limited  extent,  and  probably  much  lessened  by  subsequent 
denudation. 

Yet  it  is  precisely  because  we  do  not  encounter  at  every  step  the 
evidence  of  such  gradations  from  one  state  of  the  organic  world  to 
another,  that  so  many  geologists  embrace  the  doctrine  of  great  and 
sudden  revolutions  in  the  history  of  the  animate  world.  Not  content 
with  simply  availing  themselves,  for  the  convenience  of  classification,  of 

*  Book  iii.  ch.  60. 


192     .  CAUSES    OF   BEEAKS   IN  [On.  XIIL 

those  gaps  and  chasms  which  here  and  there  interrupt  the  continuity  oi 
the  chronological  series,  as  at  present  known,  they  deduce,  from  the 
frequency  of  these  breaks  in  the  chain  of  records,  an  irregular  mode  of 
succession  in  the  events  themselves  both  in  the  organic  and  inorganic 
world.  But,  besides  that  some  links  of  the  chain  which  once  existed 
are  now  clearly  lost  and  others  concealed  from  view,  we  have  good  rea- 
son to  suspect  that  it  was  never  complete  originally.  It  may  undoubt- 
edly be  said,  that  strata  have  been  always  forming  somewhere,  and 
therefore  at  every  moment  of  past  time  nature  has  added  a  page  to  her 
archives ;  but,  in  reference  to  this  subject,  it  should  be  remembered 
that  we  can  never  hope  to  compile  a  consecutive  history  by  gathering 
together  monuments  which  were  originally  detached  and  scattered  over 
the  globe.  For  as  the  species  of  organic  beings  contemporaneously 
inhabiting  remote  regions  are  distinct,  the  fossils  of  the  first  of  several 
periods  which  may  be  preserved  in  any  one  country,  as  in  America, 
for  example,  will  have  no  connection  with  those  of  a  second  period 
found  in  India,  and  will  therefore  no  more  enable  us  to  trace  the  signs 
of  a  gradual  change  in  the  living  creation,  than  a  fragment  of  Chinese 
history  will  fill  up  a  blank  in  the  political  annals  of  Europe. 

The  absence  of  any  deposits  of  importance  containing  recent  shells  in 
Chili,  or  anywhere  on  the  western  coast  of  South  America,  naturally 
led  Mr.  Darwin  to  the  conclusion  that  "  where  the  bed  of  the  sea  is 
either  stationary  or  rising,  circumstances  are  far  less  favorable  than 
where  the  level  is  sinking  to  the  accumulation  of  conchiferous  strata  of 
sufficient  thickness  and  extension  to  resist  the  average  vast  amount  of 
denudation/'*  An  examination  of  the  superficial  clay,  sand,  and  gravel 
of  the  most  modern  date  in  Norway  and  Sweden,  where  the  land  is  also 
rising,  would  incline  us  to  admit  a  similar  proposition.  Yet  in  these 
cases  there  has  been  a  supply  of  sediment  from  the  waste  of  the  coast 
and  the  interior,  especially  in  Patagonia  and  Chili.  Nevertheless  wher- 
ever the  bottom  of  the  sea  has  been  continually  elevated,  the  total 
thickness  of  sedimentary  matter  accumulating  at  depths  suited  to  the 
habitation  of  most  of  the  species  of  shells  can  never  be  great,  nor  can 
the  deposits  be  thickly  covered  by  superincumbent  matter,  so  as  to  be 
consolidated  by  pressure.  When  they  are  upheaved,  therefore,  the 
waves  on  the  beach  will  bear  down  and  disperse  the  loose  materials ; 
whereas  if  the  bed  of  the  sea  subsides  slowly,  a  mass  of  strata  contain- 
ing abundance  of  such  species  as  live  at  moderate  depths  may  increase 
in  thickness  to  any  amount,  and  may  extend  over  a  broad  area,  as  the 
water  gradually  encroaches  on  the  land.  If,  then,  at  particular  periods, 
as  in  the  Miocene  epoch,  fer  example,  both  in  Europe  and  North  Amer- 
ica, contemporaneous  shelly  deposits  have  originated,  and  have  been 
preserved  at  very  distant  points,  it  may  arise  from  the  prevalence  at 
that  period  of  simultaneous  subsidence  throughout  very  wide  areas. 
The  absence  in  the  same  quarters  of  the  globe  of  strata  marking  the 

*  Darwin's  S.  America,  pp.  136,  139. 


CH.  XIII.]  THE   SEQUENCE   OF    FORMATIONS.  193 

ages  which  immediately  succeeded,  may  be  accounted  for  by  supposing 
that  the  level  of  the  bed  of  the  sea  and  the  adjoining  land  was  stationary 
or  was  undergoing  slow  upheaval. 

How  far  some  of  the  great  violations  of  continuity  which  now  exist  in 
the  chronological  table  of  fossiliferous  rocks,  will  hereafter  be  removed 
or  lessened,  must  at  present  be  mere  matter  of  conjecture.  The  hiatus 
which  exists  in  Great  Britain  between  the  fossils  of  the  Lias  and  those 
of  the  Magnesian  Limestone,  is  supplied  in  Germany  by  the  rich  fauna 
and  flora  of  the  Muschelkalk,  Keuper,  and  Bunter  Sandstein,  which  we 
know  to  be  of  a  date  precisely  intermediate ;  those  three  formations 
being  interposed  in  Germany  between  others  which  agree  perfectly  in 
their  organic  remains  with  our  Lias  and  Magnesian  Limestone.  Until 
lately  the  fossils  of  the  Coal-measures  were  separated  from  those  of  the 
antecedent  Silurian  group  by  a  very  abrupt  and  decided  line  of  demar- 
cation ;  but  recent  discoveries  have  brought  to  light  in  Devonshire,  Bel- 
gium, the  Eifel,  and  Westphalia,  the  remains  of  a  fauna  of  an  intervening 
period.  This  connecting  link  is  furnished  by  the  fossil  shells,  fish,  and 
corals  of  the  Devonian  or  Old  Red  Sandstone  group,  and  some  species 
of  this  newly  intercalated  fauna  are  found  to  be  common  to  it  and  the 
subjacent  Silurian  rocks,  while  other  species  belong  to  it  in  common 
with  the  Coal-measures.  We  have  also  in  like  manner  had  some  suc- 
cess of  late  years  in  diminishing  the  hiatus  which  still  separates  the  Cre- 
taceous and  Eocene  periods  in  Europe.  Still  we  must  expect,  for  rea- 
sons before  stated,  that  some  such  chasms  will  forever  continue  to  occur 
in  some  parts  of  our  sedimentary  series. 

Consistency  of  the  theory  of  gradual  change  with  the  existence  of  great 
breaks  in  the  series. — To  return  to  the  general  argument  pursued  in  this 
chapter,  it  is  assumed,  for  reasons  above  explained,  that  a  slow  change 
of  species  is  in  simultaneous  operation  everywhere  throughout  the  habit- 
able surface  of  sea  and  land ;  whereas  the  fossilization  of  plants  and 
animals  is  confined  to  those  areas  where  new  strata  are  produced. 
These  areas,  as  we  have  seen,  are  always  shifting  their  position ;  so  that 
the  fossilizing  process,  by  means  of  which  the  commemoration  of  the 
particular  state  of  the  organic  world,  at  any  given  time,  is  affected,  may 
be  said  to  move  about,  visiting  and  revisiting  different  tracts  in  succession. 

To  make  still  more  clear  the  supposed  working  of  this  machinery,  I 
shall  compare  it  to  a  somewhat  analogous  case  that  might  be  imagined 
to  occur  in  the  history  of  human  affairs.  Let  the  mortality  of  the  pop- 
ulation of  a  large  country  represent  the  successive  extinction  of  species, 
and  the  births  of  new  individuals  the  introduction  of  new  species. 
While  these  fluctuations  are  gradually  taking  place  everywhere,  sup- 
pose commissioners  to  be  appointed  to  visit  each  province  of  the  country 
in  succession,  taking  an  exact  account  of  the  number,  names,  and  indi- 
vidual peculiarities  of  all  the  inhabitants,  and  leaving  in  each  district  a 
register  containing  a  record  of  this  information.  If,  after  the  completion 
of  one  census,  another  is  immediately  made  on  the  same  plan,  and  then 
another,  there  will,  at  last,  be  a  series  of  statistical  documents  in  each 

13 


194  CAUSES   OF  BREAKS  IN  [Cn.  XIII. 

province.  When  those  belonging  to  any  one  province  are  arranged  in 
chronological  order,  the  contents  of  such  as  stand  next  to  each  other 
will  differ  according  to  the  length  of  the  intervals  of  time  between  the 
taking  of  each  census.  If,  for  example,  there  are  sixty  provinces,  and 
all  the  registers  are  made  in  a  single  year,  and  renewed  annually,  the 
number  of  births  and  deaths  will  be  so  small,  in  proportion  to  the  whole 
of  the  inhabitants,  during  the  interval  between  the  compiling  of  the  two 
consecutive  documents,  that  the  individuals  described  in  such  documents 
will  be  nearly  identical ;  whereas,  if  the  survey  of  each  of  the  sixty 
provinces  occupies  all  the  commissioners  for  a  whole  year,  so  that  they 
are  unable  to  revisit  the  same  place  until  the  expiration  of  sixty  years, 
there  will  then  be  an  almost  entire  discordance  between  the  persons 
enumerated  in  two  consecutive  registers  in  the  same  province.  There 
are,  undoubtedly,  other  causes  besides  the  mere  quantity  of  time,  which 
may  augment  or  diminish  the  amount  of  discrepancy.  Thus,  at  some 
periods  a  pestilential  disease  may  have  lessened  the  average  duration  of 
human  life,  or  a  variety  of  circumstances  may  have  caused  the  births  to 
be  unusually  numerous,  and  the  population  to  multiply ;  or,  a  province 
may  be  suddenly  colonized  by  persons  migrating  from  surrounding  dis- 
tricts. 

These  exceptions  may  be  compared  to  the  accelerated  rate  of  fluctu- 
ation in  the  fauna  and  flora  of  a  particular  region,  in  which  the  climate 
and  physical  geography  may  be  undergoing  an  extraordinary  degree  of 
alteration. 

But  I  must  remind  the  reader,  that  the  case  above  proposed  has  no 
pretensions  to  be  regarded  as  an  exact  parallel  to  the  geological  phe- 
nomena which  I  desire  to  illustrate  ;  for  the  commissioners  are  supposed 
to  visit  the  different  provinces  in  rotation ;  whereas  the  commemorating 
processes  by  which  organic  remains  become  fossilized,  although  they 
are  always  shifting  from  one  area  to  the  other,  are  yet  very  irregular  in 
their  movements.  They  may  abandon  and  revisit  many  spaces  again 
and  again  before  they  once  approach  another  district ;  and,  besides  this 
source  of  irregularity,  it  may  often  happen  that,  while  the  depositing 
process  is  suspended,  denudation  may  take  place,  which  may  be  com- 
pared to  the  occasional  destruction  by  fire  or  other  causes  of  some  of 
the  statistical  documents  before  mentioned.  It  is  evident  that,  where 
such  accidents  occur,  the  want  of  continuity  in  the  series  may  become 
indefinitely  great,  and  that  the  monuments  which  follow  next  in  succes- 
sion will  by  no  means  be  equidistant  from  each  other  in  point  of  time. 

If  this  train  of  reasoning  be  admitted,  the  occasional  distinctness  of 
the  fossil  remains,  in  formations  immediately  in  contact,  would  be  a 
necessary  consequence  of  the  existing  laws  of  sedimentary  deposition 
and  subterranean  movement,  accompanied  by  a  constant  mortality  and 
renovation  of  species. 

As  all  the  conclusions  above  insisted  on  are  directly  opposed  to  opin- 
ions still  popular,  I  shall  add  another  comparison,  in  the  hope  of  pre- 
venting any  possible  misapprehension  of  the  argument.  Suppose  we 


CH.  XIIL]  THE   SEQUENCE   OF  FORMATIONS.  195 

had  discovered  two  buried  cities  at  the  foot  of  Vesuvius,  immediately 
superimposed  upon  each  other,  with  a  great  mass  of  tuff  and  lava  inter- 
vening, just  as  Portici  and  Resina,  if  now  covered  with  ashes,  would 
overlie  Herculaneum.  An  antiquary  might  possibly  be  entitled  to' infer, 
from  the  inscriptions  on  public  edifices,  that  the  inhabitants  of  the  infe- 
rior and  older  city  were  Greeks,  and  those  of  the  modern  towns  Italians. 
But  he  would  reason  very  hastily  if  he  also  concluded  from  these  data 
that  there  had  been  a  sudden  change  from  the  Greek  to  the  Italian  lan- 
guage in  Campania.  But  if  he  afterwards  found  three  buried  cities,  one 
above  the  other,  the  intermediate  one  being  Roman,  while,  as  in  the 
former  example,  the  lowest  was  Greek  and  the  uppermost  Italian,  he 
would  then  perceive  the  fallacy  of  his  former  opinion,  and  would  begin 
to  suspect  that  the  catastrophes  by  which  the  cities  were  inhumed 
might  have  no  relation  whatever  to  the  fluctuations  in  the  language  of 
the  inhabitants ;  and  that,  as  the  Roman  tongue  had  evidently  intervened 
between  the  Greek  and  Italian,  so  many  other  dialects  may  have  been 
spoken  in  succession,  and  the  passage  from  the  Greek  to  the  Italian  may 
have  been  very  gradual ;  some  terms  growing  obsolete,  while  others 
were  introduced  from  time  to  time. 

If  this  antiquary  could  have  shown  that  the  volcanic  paroxysms  of 
Vesuvius  were  so  governed  as  that  cities  should  be  buried  one  above  the 
other,  just  as  often  as  any  variation  occurred  in  the  language  of  the 
inhabitants,  then,  indeed,  the  abrupt  passage  from  a  Greek  to  a  Roman, 
and  from  a  Roman  to  an  Italian  city,  would  afford  proof  of  fluctuations 
no  less  sudden  in  the  language  of  the  people. 

So,  in  Geology,  if  we  could  assume  that  it  is  part  of  the  plan  of 
Nature  to  preserve,  in  every  region  of  the  globe,  an  unbroken  series  of 
monuments  to  commemorate  the  vicissitudes  of  the  organic  creation,  we 
might  infer  the  sudden  extirpation  of  species,  and  the  simultaneous 
introduction  of  others,  as  often  as  two  formations  in  contact  are  found  to 
include  dissimilar  organic  fossils.  But  we  must  shut  our  eyes  to  the 
whole  economy  of  the  existing  causes,  aqueous,  igneous,  and  organic,  if 
we  fail  to  perceive  that  such  is  not  the  plan  of  Nature. 

Concluding  remarks  on  the  identity  of  the  ancient  and  present  system 
of  terrestrial  changes. — I  shall  now  conclude  the  discussion  of  a  .ques- 
tion with  which  we  have  been  occupied  since  the  beginning  of  the  fifth 
chapter  ;  namely,  whether  there  has  been  any  interruption,  from  the 
remotest  periods,  of  one  uniform  system  of  change  in  the  animate  and 
inanimate  world.  We  were  induced  to  enter  into  that  inquiry  by  reflect- 
ing how  much  the  progress  of  opinion  in  Geology  had  been  influenced 
by  the  assumption  that  the  analogy  was  slight  in  kind,  and  still  more 
slight  in  degree,  between  the  causes  which  produced  the  former  revolu- 
tions of  the  globe,  and  those  now  in  every-day  operation.  It  appeared 
clear  that  the  earlier  geologists  had  not  only  a  scanty  acquaintance  with 
existing  changes,  but  were  singularly  unconscious  of  the  amount  of  their 
ignorance.  With  the  presumption  naturally  inspired  by  this  uncon- 
sciousness, they  had  no  hesitation  in  deciding  at  once  that  time  could  never 


196  UNIFORMITY    OF   THE   SYSTEM  [Ctt  XIII. 

enable  the  existing  powers  of  nature  to  work  out  changes  of  great  magni- 
tude, still  less  such  important  revolutions  as  those  which  are  brought  to 
light  by  Geology.  They,  therefore,  felt  themselves  at  liberty  to  indulge 
their  imaginations  in  guessing  at  what  might  be,  rather  than  inquiring 
what  is ;  in  other  words,  they  employed  themselves  in  conjecturing 
what  might  have  been  the  course  of  nature  at  a  remote  period,  rather 
than  in  the  investigation  of  what  was  the  course  of  nature  in  their  own 
times. 

It  appeared  to  them  more  philosophical  to  speculate  on  the  possibil- 
ities of  the  past,  than  patiently  to  explore  the  realities  of  the  present ; 
and  having  invented  theories  under  the  influence  of  such  maxims,  they 
were  consistently  unwilling  to  test  their  validity  by  the  criterion  of  their 
accordance  with  the  ordinary  operations  of  nature.  On  the  contrary, 
the  claims  of  each  new  hypothesis  to  credibility  appeared  enhanced  by 
the  great,  contrast,  in  kind  or  intensity,  of  the  causes  referred  to,  and 
those  now  in  operation. 

Never  was  there  a  dogma  more  calculated  to  foster  indolence,  and 
to  blunt  the  keen  edge  of  curiosity,  than  this  assumption  of  the  discord- 
ance between  the  ancient  and  existing  causes  of  change.  It  produced  a 
state  of  mind  unfavorable  in  the  highest  degree  to  the  candid  reception 
of  the  evidence  of  those  minute  but  incessant  alterations  which  every 
part  of  the  earth's  surface  is  undergoing,  and  by  which  the  condition  of 
its  living  inhabitants  is  continually  made  to  vary.  The  student,  instead 
of  being  encouraged  with  the  hope  of  interpreting  the  enigmas  presented 
to  him  in  the  earth's  structure, — instead  of  being  prompted  to  under- 
take laborious  inquiries  into  the  natural  history  of  the  organic  world,  and 
the  complicated  effects  of  the  igneous  and  aqueous  causes  now  in  oper- 
ation, was  taught  to  despond  from  the  first.  Geology,  it  was  affirmed, 
could  never  rise  to  the  rank  of  an  exact  science, — the  greater  number  of 
phenomena  must  forever  remain  inexplicable,  or  only  be  partially  eluci- 
dated by  ingenious  conjectures.  Even  the  mystery  which  invested  the 
subject  was  said  to  constitute  one  of  its  principal  charms,  affording,  as  it 
did,  full  scope  to  the  fancy  to  indulge  in  a  boundless  field  of  speculation. 

The  course  directly  opposed  to  this  method  of  philosophizing  consists 
in  an  earnest  and  patient  inquiry,  how  far  geological  appearances  are 
reconcilable  with  the  effect  of  changes  now  in  progress,  or  which  may 
be  in  progress  in  regions  inaccessible  to  us,  and  of  which  the  reality  is 
attested  by  volcanoes  and  subterranean  movements.  It  also  endeavors 
to  estimate  the  aggregate  result  of  ordinary  operations  multiplied  by 
time,  and  cherishes  a  sanguine  hope  that  the  resources  to  be  derived 
from  observation  and  experiment,  or  from  the  study  of  nature  such  as 
she  now  is,  are  very  far  from-  being  exhausted.  For  this  reason  all 
theories  are  rejected  which  involve  the  assumption  of  sudden  and  violent 
catastrophes  and  revolutions  of  the  whole  earth,  and  its  inhabitants, — 
theories  which  are  restrained  by  no  reference  to  existing  analogies,  and 
in  which  a  desire  is  manifested  to  cut,  rather  than  patiently  to  untie,  the 
Gordian  knot. 


Cn.  XIIL]  OF  TERRESTRIAL   CHANGES.  197 

We  have  now,  at  least,  the  advantage  of  knowing,  from  experience, 
that  an  opposite  method  has  always  put  geologists  on  the  road  that 
leads  to  truth, — suggesting  views  which,  although  imperfect  at  first, 
have  been  found  capable  of  improvement,  until  at  last  adopted  by  uni- 
versal consent ;  while  the  method  of  speculating  on  a  former  distinct 
state  of  things  and  causes,  has  led  invariably  to  a  multitude  of  contra- 
dictory systems,  which  have  been  overthrown  one  after  the  other, — have 
been  found  incapable  of  modification, — and  which  have  often  required 
to  be  precisely  reversed. 

The  remainder  of  this  work  will  be  devoted  to  an  investigation  of  the 
changes  now  going  on  in  the  crust  of  the  earth  and  its  inhabitants. 
The  importance  which  the  student  will  attach  to  such  researches  will 
mainly  depend  in  the  degree  of  confidence  which  he  feels  in  the  prin- 
ciples above  expounded.  If  he  firmly  believes  in  the  resemblance 
or  identity  of  the  ancient  and  present  system  of  terrestrial  changes,  he 
will  regard  every  fact  collected  respecting  the  causes  in  diurnal  action 
as  affording  him  a  key  to  the  interpretation  of  some  mystery  in  the 
past.  Events  which  have  occurred  at  the  most  distant  periods  in 
the  animate  and  inanimate  world,  will  be  acknowledged  to  throw  light 
on  each  other,  and  the  deficiency  of  our  information  respecting  some 
of  the  most  obscure  parts  of  the  present  creation  will  be  removed.  For 
as,  by  studying  the  external  configuration  of  the  existing  land  and  its 
inhabitants,  we  may  restore  in  imagination  the  appearance  of  the  an- 
cient continents  which  have  passed  away,  so  may  we  obtain  from  the 
deposits  of  ancient  seas  and  lakes  an  insight  into  the  nature  of  the  sub- 
aqueous processes  now  in  operation,  and  of  many  forms  of  organic  life, 
which,  though  now  existing,  are  veiled  from  sight.  Rocks,  also,  pro- 
duced by  subterranean  fire  in  former  ages,  at  great  depths  in  the  bowels 
of  the  earth,  present  us,  when  upraised  by  gradual  movements,  and 
exposed  to  the  light  of  heaven,  with  an  image  of  those  changes  which 
the  deep-seated  volcano  may  now  occasion  in  the  nether  regions. 
Thus,  although  we  are  mere  sojourners  on  the  surface  of  the  planet, 
chained  to  a  mere  point  in  space,  enduring  but  for  a  moment  of  time, 
the  human  mind  is  not  only  enabled  to  number  worlds  beyond  the 
unassisted  ken  of  mortal  eye,  but  to  trace  the  events  of  indefinite 
ages  before  the  creation  of  our  race,  and  is  not  even  withheld  from 
penetrating  into  the  dark  secrets  of  the  ocean,  or  the  interior  of  the 
solid  globe  ;  free,  like  the  spirit  which  the  poet  described  as  animating 
the  universe, 

ire  per  omnes 

Terrasque,  tractusque  maris,  coelumque  profundum. 


BOOK  II. 


CHANGES    IN   THE    INORGANIC    WORLD. 


AQUEOUS    CAUSES. 


CHAPTER  XIV. 

Division  of  the  subject  into  changes  of  the  organic  and  inorganic  world — Inor- 
ganic causes  of  change  divided  into  aqueous  and  igneous — Aqueous  causes  first 
considered — Fall  of  rain — Recent  rain-prints  in  mud — Destroying  and  trans- 
porting power  of  running  water — Newly  formed  valleys  in  Georgia — Sinuosi- 
ties of  rivers — Two  streams  when  united  do  not  occupy  a  bed  of  double  surface 
— Inundations  in  Scotland — Floods  caused  by  landslips  in  the  White  Moun- 
tains— Bursting  of  a  lake  in  Switzerland — Devastations  caused  by  the  Anio  at 
Tivoli — Excavations  in  the  lav?.3  of  Etna  by  Sicilian  rivers — Gorge  of  the 
Simeto — Gradual  recession  of  the  cataract  of  Niagara. 

Division  of  the  subject. — GEOLOGY  was  defined  to  be  the  science 
which  investigates  the  former  changes  that  have  taken  place  in  the 
organic  as  well  as  in  the  inorganic  kingdoms  of  nature.  As  vicissitudes 
in  the  inorganic  world  are  most  apparent,  and  as  on  them  all  fluctua- 
tions in  the  animate  creation  must  in  a  great  measure  depend,  they 
may  claim  our  first  consideration.  The  great  agents  of  change  in  the 
inorganic  world  may  be  divided  into  two  principal  classes,  the  aqueous 
and  the  igneous.  To  the  aqueous  belong  Rain,  Rivers,  Torrents, 
Springs,  Currents,  and  Tides  ;  to  the  igneous,  Volcanoes,  and  Earth- 
quakes. Both  these  classes  are  instruments  of  decay  as  well  as  of 
reproduction;  but  they  may  also  be  regarded  as  antagonist  forces. 
For  the  aqueous  agents  are  incessantly  laboring  to  reduce  the  inequal- 
ities of  the  earth's  surface  to  a  level  ;  while  the  igneous  are  equally 
active  in  restoring  the  unevenness  of  the  external  crust,  partly  by  heap- 
ing up  new  matter  in  certain  localities,  and  partly  by  depressing  one 
portion,  and  forcing  out  another,  of  the  earth's  envelope. 

It  is  difficult,  in  a  scientific  arrangement,  to  give  an  accurate  view 
of  the  combined  effects  of  so  many  forces  in  simultaneous  operation  ; 
because,  when  we  consider  them  separately,  we  cannot  easily  estimate 
either  the  extent  of  their  efficacy,  or  the  kind  of  results  which  they 
produce.  We  are  in  danger,  therefore,  when  we  attempt  to  examine 
the  influence  exerted  singly  by  each,  of  overlooking  the  modifications 
which  they  produce  on  one  another ;  and  these  are  so  complicated, 
that  sometimes  the  igneous  and  aqueous  forces  co-operate  to  produce 
a  joint  effect,  to  which  neither  of  them  unaided  by  the  other  could 


CH.  XIV.]  FALL  OF  RAIN.  199 

give  rise, — as  when  repeated  earthquakes  unite  with  running  water 
to  widen  a  valley ;  or  when  a  thermal  spring  rises  up  from  a  great 
depth,  and  conveys  the  mineral  ingredients  with  which  it  is  impreg- 
nated from  the  interior  of  the  earth  to  the  surface.  Sometimes  the 
organic  combine  with  the  inorganic  causes  ;  as  when  a  reef,  composed 
of  shells  and  corals,  protects  one  line  of  coast  from  the  destroying 
power  of  tides  or  currents,  and  turns  them  against  some  other  point ; 
or  when  drift  timber,  floated  into  a  lake,  fills  a  hollow  to  which  the 
stream  would  not  have  had .  sufficient  velocity  to  convey  earthy  sedi- 
ment. 

It  is  necessary,  however,  to  divide  our  observations  on  these  various 
causes,  and  to  classify  them  systematically,  endeavoring  as  much  as 
possible  to  keep  in  view  that  the  effects  in  nature  are  mixed  and  not 
simple,  as  they  may  appear  in  an  artificial  arrangement. 

In  treating,  in  the  first  place,  of  the  aqueous  causes,  we  may  con- 
sider them  under  two  divisions  ;  first,  those  which  are  connected  with 
the  circulation  of  water  from  the  land  to  the  sea,  under  which  are  in- 
cluded all  the  phenomena  of  rain,  rivers,  glaciers,  and  springs ;  second- 
ly, those  which  arise  from  the  movements  of  water  in  lakes,  seas,  and 
the  ocean,  wherein  are  comprised  the  phenomena  of  waves,  tides,  and 
currents.  In  turning  our  attention  to  the  former  division,  we  find  that 
the  effects  of  rivers  may  be  subdivided  into,  first,  those  of  a  destroying 
and  transporting,  and,  secondly,  those  of  a  renovating  nature ;  in  the 
former  are  included  the  erosion  of  rocks  and  the  transportation  of  mat- 
ter to  lower  levels  ;  in  the  renovating  class,  the  formation  of  deltas  by 
the  influx  of  sediment,  and  the  shallowing  of  seas ;  but  these  processes 
are  so  intimately  related  to  each  other,  that  it  will  not  always  be  possi- 
ble to  consider  them  under  their  separate  heads. 

Fall  of  Rain. — It  is  well  known  that  the  capacity  of  the  atmosphere 
to  absorb  aqueous  vapor,  and  hold  it  in  suspension,  increases  with  every 
increment  of  temperature.  This  capacity  is  also  found  to  augment  in  a 
higher  ratio  than  the  augmentation  of  the  heat.  Hence,  as  was  first 
suggested  by  the  geologist,  Dr.  Hutton,  when,  two  volumes  of  air,  of 
different  temperatures,  both  saturated  with  moisture,  mingle  together, 
clouds  and  rain  are  produced,  for  a  mean  degree  of  heat  having  resulted 
from  the  union  of  the  two  moist  airs,  the  excess  of  vapor  previously 
held  in  suspension  by  the  warmer  of  the  two  is  given  out,  and  if  it  be  in 
sufficient  abundance  is  precipitated  in  the  form  of  rain. 

As  the  temperature  of  the  atmosphere  diminishes  gradually  from  the 
equator  towards  the  pole,  the  evaporation  of  water  and  the  quantity  of 
rain  diminish  also.  According  to  Humboldt's  computation,  the  aver- 
age annual  depth  of  rain  at  the  equator  is  96  inches,  while  in  lat.  45° 
it  is  only  29  inches,  and  in  lat.  60°  not  more  than  17  inches.  But 
there  are  so  many  disturbing  causes,  that  the  actual  discharge,  in  any 
given  locality,  may  deviate  very  widely  from  this  rule.  In  England,  for 
example,  where  the  average  fall  at  London  is  24  J  inches,  as  ascertained 
at  the  Greenwich  Observatory,  there  is  such  irregularity  in  some  dis- 


200  FALL  OF  EAIN.  [On.  XIV 

tricts,  that  while  at  Whitehaven,  in  Cumberland,  there  fell  in  1849,  32 
inches,  the  quantity  of  rain  in  Borrowdale,  near  Keswick  (only  15  miles 
to  the  westward),  was  no  less  than  142  inches!*  In  like  manner,  in 
India,  Colonel  Sykes  found  by  observations  made  in  1847  and  1848, 
that  at  places  situated  between  17°  and  18°  north  lat.,  on  a  line  drawn 
across  the  Western  Ghauts  in  the  Deccan,  the  fall  of  rain  varied  from 
21  to  219  inches. f  The  annual  average  in  Bengal  is  probably  below 
80  inches,  yet  Dr.  G.  Hooker  witnessed  at  Churrapoonjee,  in  the  year 
1850,  a  fall  of  30  inches  in  24  hours,  and  in  the  same  place  during  a 
residence  of  six  months  (from  June  to  November)  530  inches !  This 
occurred  on  the  south  face  of  the  Khasia  (or  Garrow)  mountains  in 
Eastern  Bengal  (see  map,  Chap.  XVIII.),  where  the  depth  during  the 
whole  of  the  same  year  probably  exceeded  600  inches.  So  extraordi- 
nary a  discharge  of  water,  which,  as  we  shall  presently  see,  is  very  lo- 
cal, may  be  thus  accounted  for.  Warm,  southerly  winds,  blowing  over 
the  Bay  of  Bengal,  and  becoming  laden  with  vapor  during  their  pas- 
sage, reach  the  low  level  delta  of  the  Ganges  and  Brahmapootra,  where 
the  ordinary  heat  exceeds  that  of  the  sea,  and  where  evaporation  is  con- 
stantly going  on  from  countless  marshes  and  the  arms  of  the  great 
rivers.  A  mingling  of  two  masses  of  damp  air  of  different  temperatures 
probably  causes  the  fall  of  70  or  80  inches  of  rain,  which  takes  place 
on  the  plains.  The  monsoon  having  crossed  the  delta,  impinges  on  the 
Khasia  mountains,  which  rise  abruptly  from  the  plain  to  a  mean  eleva- 
tion of  between  4000  and  5000  feet.  Here  the  wind  not  only  encoun- 
ters the  cold  air  of  the  mountains,  but,  what  is  far  more  effective  as  a 
refrigerating  cause,  the  aerial  current  is  made  to  flow  upwards,  and  to 
ascend  to  a  height  of  several  thousand  feet  above  the  sea.  Both  the 
air  and  the  vapor  contained  in  it,  being  thus  relieved  of  much  atmo- 
spheric pressure,  expand  suddenly,  and  are  cooled  by  rarefaction.  The 
vapor  is  condensed,  and  about  500  inches  of  rain  are  thrown  down  an- 
nually, nearly  twenty  times  as  much  as  falls  in  Great  Britain  in  a  year, 
and  almost  all  of  it  poured  down  in  six  months.  The  channel  of  every 
torrent  and  river  is  swollen  at  this  season,  and  much  sandstone  horizon- 
tally stratified,  and  other  rocks  are  reduced  to  sand  and  gravel  by  the 
flooded  streams.  So  great  is  the  superficial  waste  (or  denudation],  that 
what  would  otherwise  be  a  rich  and  luxuriantly  wooded  region,  is  con- 
verted into  a  wild  and  barren  moorland. 

After  the  current  of  warm  air  has  been  thus  drained  of  a  large  por- 
tion of  its  moisture,  it  still  continues  its  northerly  course  to  the  opposite 
flank  of  the  Khasia  range,  only  20  miles  farther  north,  and  here  the 
fall  of  rain  is  reduced  to  70  inches  in  the  year.  The  same  wind  then 
blows  northwards  across  the  valley  of  the  Brahmapootra,  and  at  length 
arrives  so  dry  and  exhausted  at  the  Bhootan  Himalaya  (lat.  28°  N.),  that 
those  mountains,  up  to  the  height  of  5000  feet,  are  naked  and  sterile, 
and  all  their  outer  valleys  arid  and  dusty.  The  aerial  current  still  con- 

*  Miller,  Phil.  Trans.  1851,  p.  155.  f  Phil.  Trans.  1850,  p.  354. 


CH.  XIV.]  RECENT   RAIN-PKINTS.  201 

tinuing  its  northerly  course  and  ascending  to  a  higher  region,  becomes 
further  cooled,  condensation  again  ensues,  and  Bhootan,  above  5000 
feet,  is  densely  clothed  with  vegetation.* 

In  another  part  of  India,  immediately  to  the  westward,  similar  phe- 
nomena are  repeated.  The  same  warm  and  humid  winds,  copiously 
charged  with  aqueous  vapor  from  the  Bay  of  Bengal,  hold  their  course 
due  north  for  300  miles  across  the  flat  and  hot  plains  of  the  Ganges, 
till  they  encounter  the  lofty  Sikkim  mountains.  (See  map,  Chap. 
XVIII.)  On  the  southern  flank  of  these  they  discharge  such  a  deluge 
of  rain  that  the  rivers  in  the  rainy  season  rise  twelve  feet  in  as  many 
hours.  Numerous  landslips,  some  of  them  extending  three  or  four 
thousand  feet  along  the  face  of  the  mountains,  composed  of  granite, 
gneiss,  and  slate,  descend  into  the  beds  of  streams,  and  dam  them  up 
for  a  time,  causing  temporary  lakes,  which  soon  burst  their  barriers. 
"  Day  and  night,"  says  Dr.  Hooker,  "  we  heard  the  crashing  of  falling 
trees,  and  the  sound  of  boulders  thrown  violently  against  each  other  in 
the  beds  of  torrents.  By  such  wear  and  tear  rocky  fragments  swept 
down  from  the  hills  are  in  part  converted  into  sand  and  fine  mud ;  and 
the  turbid  Ganges,  during  its  annual  inundation,  derives  more  of  its 
sediment  from  this  source  than  from  the  waste  of  the  fine  clay  of  the 
alluvial  plains  below. f 

On  the  verge  of  the  tropics  a  greater  quantity  of  rain  falls  annually 
than  at  the  equator.  Yet  parts  even  of  the  tropical  latitudes  are  en- 
tirely destitute  of  rain  :  Peru,  for  example,  which  owes  its  vegetation 
solely  to  rivers  and  nightly  dews.  In  that  country  easterly  winds  pre- 
vail, blowing  from  the  Pacific,  and  these  being  intercepted  by  the  Andes, 
and  cooled  as  they  rise,  are  made  to  part  with  all  their  moisture  before 
reaching  the  low  region  to  the  leeward.  The  desert  zone  of  North 
Africa,  between  lat.  15°  and  30°  N.,  is  another  instance  of  a  rainless 
region.  Five  or  six  consecutive  years  may  pass  in  Upper  Egypt,  Nubia, 
and  Dongola,  or  in  the  Desert  of  Sahara,  without  rain. 

From  the  facts  above  mentioned,  the  reader  will  infer  that  in  the 
course  of  successive  geological  periods  there  will  be  great  variations  in 
the  quantity  of  rain  falling  in  one  and  the  same  region.  At  one  time 
there  may  be  none  whatever  during  the  whole  year ;  at  another  a  fall 
of  100  or  500  inches;  and  these  two  last  averages  may  occur  on  the 
two  opposite  flanks  of  a  mountain-chain,  not  more  than  20  miles  wide. 
While,  therefore,  the  valleys  in  one  district  are  widened  and  deepened 
annually,  they  may  remain  stationary  in  another,  the  superficial  soil 
being  protected  from  waste  by  a  dense  covering  of  vegetation.  This 
diversity  depends  on  many  geographical  circumstances,  but  principally 
on  the  height  of  the  land  above  the  sea,  the  direction  of  the  prevailing 
winds,  and  the  relative  position,  at  the  time  being,  of  the  plains,  hills, 
and  the  ocean,  conditions  all  of  which  are  liable  in  the  course  of  ages  to 
undergo  a  complete  revolution. 

*  Hooker's  Himalayan  Journal,  ined.  f  Ibid. 


202  RECENT   KAIN-PKINTS.  [CH.  XIV. 

Recent  rain-prints. — When  examining,  in  1842,  the  extensive  mud- 
flats of  Nova  Scotia,  which  are  exposed  at  low  tide  on  the  borders  of 
the  Bay  of  Fundy,  I  observed  not  only  the  foot-prints  of  birds  which 
had  recently  passed  over  the  mud,  but  also  very  distinct  impressions  of 
rain-drops.  A  peculiar  combination  of  circumstances  renders  these 
mud-flats  admirably  fitted  to  receive  and  retain  any  markings  which 
may  happen  to  be  made  on  their  surface.  The  sediment  with  which 
the  waters  are  charged  is  extremely  fine,  being  derived  from  the  destruc- 
tion of  cliffs  of  red  sandstone  and  shale,  and  as  the  tides  rise  fifty  feet 
and  upwards,  large  areas  are  laid  dry  for  nearly  a  fortnight  between  the 
spring  and  neap  tides.  In  this  interval  the  mud  is  baked  in  summer 
by  a  hot  sun,  so  that  it  solidifies  and  becomes  traversed  by  cracks, 
caused  by  shrinkage.  Portions  of  the  hardened  mud  between  these 
cracks  may  then  be  taken  up  and  removed  without  injury.  On  examin- 
ing the  edges  of  each  slab,  we  observe  numerous  layers,  formed  by 
successive  tides,  each  layer  being  usually  very  thin,  sometimes  only 
one-tenth  of  an  inch  thick.  When  a  shower  of  rain  falls,  the  highest 
portion  of  the  mud-covered  flat  is  usually  too  hard  to  receive  any  im- 
pressions ;  while  that  recently  uncovered  by  the  tide  near  the  water's 
edge  is  too  soft.  Between  these  areas  a  zone  occurs,  almost  as  smooth 
and  even  as  a  looking-glass,  on  which  every  drop  forms  a  cavity  of  cir- 
cular or  oval  form,  and,  if  the  shower  be  transient,  these  pits  retain 
their  shape  permanently,  being  dried  by  the  sun,  and  being  then  too 
firm  to  be  effaced  by  the  action  of  the  succeeding  tide,  which  deposits 
upon  them  a  new  layer  of  mud.  Hence  we  often  find,  in  splitting  open 
a  slab  an  inch  or  more  thick,  on  the  upper  surface  of  which  the  marks 
of  recent  rain  occur,  that  an  inferior  layer,  deposited  during  some  pre- 
vious rise  of  the  tide,  exhibits  on  its  under  side  perfect  casts  of  rain- 
prints,  which  stand  out  in  relief,  the  moulds  of  the  same  being  seen  on 
the  layer  below.  But  in  some  cases,  especially  in  the  more  sandy 
layers,  the  markings  have  been  somewhat  blunted  by  the  tide,  and  by 
several  rain-prints  having  been  joined  into  one  by  a  repetition  of  drops 
falling  on  the  same  spot ;  in  which  case  the  casts  present  a  very  irregu- 
lar and  blistered  appearance. 

The  finest  examples  which  I  have  seen  of  these  rain-prints  were  sent 
to  me  by  Dr.  Webster,  from  Kentville,  on  the  borders  of  the  Bay  of 
Mines,  in  Nova  Scotia.  They  were  made  by  a  heavy  shower  which 
fell  on  the  21st  of  July,  1849,  when  the  rise  and  fall  of  the  tides  were 
at  their  maximum.  The  impressions  (see  fig.  13)  consist  of  cup-shaped 
or  hemispherical  cavities,  the  average  size  of  which  is  from  one-eighth 
to  one-tenth  of  an  inch  across,  but  the  largest  are  fully  half  an  inch  in 
diameter,  and  one-tenth  of  an-  inch  deep.  The  depth  is  chiefly  below 
the  general  surface  or  plane  of  stratification,  but  the  walls  of  the  cavity 
consist  partly  of  a  prominent  rim  of  sandy  mud,  formed  of  the  matter 
which  has  been  forcibly  expelled  from  the  pit.  All  the  cavities  having 
an  oval  form  are  deeper  at  one  end,  where  they  have  also  a  higher  rim, 
and  all  the  deep  ends  have  the  same  direction,  showing  towards  which 


CH.  XIV.]  KECENT   KAIN-PKINTS.  203 

quarter  the  wind  was  blowing.  Two  or  more  drops  are  sometimes  seen 
to  have  interfered  with  each  other  ;  in  which  case  it  is  usually  possible 
to  determine  which  drop  fell  last,  its  rim  being  unbroken. 


Fig.  IS. 


Kecent  raiu-priiits,  formed  July  21,  1849,  at  Kentville,  Bay  of  Fundy,  Nova  Scotia. 
The  arrow  represents  the  direction  of  the  shower. 

On  some  of  the  specimens  the  winding  tubular  tracks  of  worms  are 
seen,  which  have  been  bored  just  beneath  the  surface  (see  fig.  13,  left 
side).  They  occasionally  pass  under  the  middle  of  a  rain-mark,  having 
been  formed  subsequently.  Sometimes  the  worms  have  dived  beneath 
the  surface,  and  then  reappeared.  All  these  appearances,  both  of  rain- 
prints  and  worm-tracks,  are  of  great  geological  interest,  as  their  exact 
counterparts  are  seen  in  rocks  of  various  ages,  even  in  formations  of 
very  high  antiquity.*  Small  cavities,  often  corresponding  in  size  to 
those  produced  by  rain,  are  also  caused  by  air-bubbles  rising  up  through 
sand  or  mud  ;  but  these  differ  in  character  from  rain- prints,  being  usually 
deeper  than  they  are  wide,  and  having  their  sides  steeper.  These, 
indeed,  are  occasionally  vertical,  or  overarching,  the  opening  at  the 
top  being  narrower  than  the  pit  below.  In  their  mode,  also,  of  mutual 
interference  they  are  unlike  rain-prints. f 

In  consequence  of  the  effects  of  mountains  in  cooling  currents  of  moist 
air,  and  causing  the  condensation  of  aqueous  vapor  in  the  manner  above 
described,  it  follows  that  in  every  country,  as  a  general  rule,  the  more 
elevated  regions  become  perpetual  reservoirs  of  water,  which  descends 
and  irrigates  the  lower  valleys  and  plains.  The  largest  quantity  of 
water  is  first  carried  to  the  highest  region,  and  then  made  to  descend 
by  steep  declivities  towards  the  sea ;  so  that  it  acquires  superior  velocity, 
and  removes  more  soil,  than  it  would  do  if  the  rain  had  been  distributed 
over  the  plains  and  mountains  equally  in  proportion  to  their  relative 

*  See  Manual  of  Geology,  Index,  Rain-prints. 

\  See  Lyell  on  recent  and  fossil  rains.  Quart.  Journ.  Geol.  Soc.  1851,  voL  vii. 
p.  239. 


204:  NEWLY  FORMED   VALLEYS.  [Cn.  XIV. 

areas.  The  water  is  also  made  by  these  means  to  pass  over  the  greatest 
distances  before  it  can  regain  the  sea. 

It  has  already  been  observed  that  in  higher  latitudes,  where  the  at- 
mosphere being  colder  is  capable  of  holding  less  water  in  suspension, 
a  diminished  fall  of  rain  takes  place.  Thus  at  St.  Petersburg,  the 
amount  is  only  16  inches,  and  at  Uleaborg  in  the  Gulf  of  Bothnia  (N. 
lat.  65°),  only  13  J  inches,  or  less  than  half  the  average  of  England,  and 
even  this  small  quantity  descends  more  slowly  in  the  temperate  zone, 
and  is  spread  more  equally  over  the  year  than  in  tropical  climates.  But 
in  reference  to  geological  changes,  frost  in  the  colder  latitude  acts  as  a 
compensating  power  in  the  disintegration  of  rocks,  and  the  transportation 
of  stones  to  lower  levels. 

Water  when  converted  into  ice  augments  in  bulk  more  than  one- 
twentieth  of  its  volume,  and  owing  to  this  property  it  widens  the  minute 
crevices  (or  joints)  of  rocks  into  which  it  penetrates.  Ice  also  in  various 
ways,  as  will  be  shown  in  the  next  chapter,  gives  buoyancy  to  mud  and 
sand,  even  to  huge  blocks  of  stone,  enabling  rivers  of  moderate  size  and 
velocity  to  carry  them  to  a  great  distance. 

The  mechanical  force  exerted  by  running  water  in  undermining  cliffs, 
and  rounding  off  the  angles  of  hard  rock,  is  mainly  due  to  the  intermix- 
ture of  foreign  ingredients.  Sand  and  pebbles,  when  hurried  along  by 
the  violence  of  the  stream,  are  thrown  against  every  obstacle  lying  in 
their  way,  and  thus  a  power  of  attrition  is  acquired,  capable  of  wearing 
through  the  hardest  siliceous  stones,  on  which  water  alone  could  make 
no  impression. 

Newly  formed  valleys. — When  travelling  in  Georgia  and  Alabama,  in 
1846,  I  saw  in  both  those  States  the  commencement  of  hundreds  of 
valleys  in  places  where  the  native  forest  had  recently  been  removed. 
One  of  these  newly  formed  gulleys  or  ravines  is  represented  in  the  an- 
nexed woodcut  (fig.  14),  from  a  drawing  which  I  made  on  the  spot, 
It  occurs  three  miles  and  a  half  due  west  of  Milledgeville,  the  capital 
of  Georgia,  and  is  situated  on  the  farm  of  Pomona,  on  the  direct  road 
to  Macon.* 

Twenty  years  ago,  before  the  land  was  cleared,  it  had  no  existence ; 
but  when  the  trees  of  the  forest  were  cut  down,  cracks  three  feet  deep 
were  caused  by  the  sun's  heat  in  the  clay  ;  and,  during  the  rains,  a  sud- 
den rush  of  water  through  the  principal  crack  deepened  it  at  its  lower 
extremity,  from  whence  the  excavating  power  worked  backwards,  till, 
in  the  course  of  twenty  years,  a  chasm,  measuring  no  less  than  55  feet 
in  depth,  300  yards  in  length,  and  varying  in  width  from  20  to  180 
feet,  was  the  result.  The  high  road  has  been  several  times  turned  to 
avoid  this  cavity,  the  enlargement  of  which  is  still  proceeding,  and  the 
old  line  of  road  may  be  seen  to  have  held  its  course  directly  over  what 
is  now  the  wildest  part  of  the  ravine.  In  the  perpendicular  walls  of  this 
great  chasm  appear  beds  of  clay  and  sand,  red,  white,  yellow,  and 

*  Lyell's  Second  Visit  to  the  United  States,  1846,  vol.  ii.  p.  25. 


CH.XIV 


SINUOSITIES    OF    RIVERS. 

Fit'.   14. 


205 


Eavine  on  the  farm  of  Pomona,  near  Milledgeville,  Georgia,  as  it  appeared  January,  1846, 
Excavated  in  twenty  years,  55  feet  deep,  and  ISO  feet  broad. 


green,  produced  by  the  decomposition  in  situ  of  hornblendic  gneiss,  with 
layers  and  veins  of  quartz,  which  remain  entire,  to  prove  that  the  whole 
mass  was  once  solid  and  crystalline. 

I  infer,  from  the  rapidity  of  the  denudation  which  only  began  here 
after  the  removal  of  the  native  wood,  that  this  spot,  elevated  about 
600  feet  above  the  sea,  has  been  always  covered  with  a  dense  forest, 
from  the  remote  time  when  it  first  emerged  from  the  sea.  The  termi- 
nation of  the  cavity  on  the  right  hand  in  the  foreground  is  the  head 
or  upper  end  of  the  ravine,  and  in  almost  every  case,  such  gulleys  are 
lengthened  by  the  streams  cutting  their  way  backwards.  The  depth 
at  the  upper  end  is  often,  as  in  this  case,  considerable,  and  there  is 
usually  at  this  point,  during  floods,  a  small  cascade. 

Sinuosities  of  rivers. — In  proportion  as  such  valleys  are  widened, 
sinuosities  are  caused  by  the  deflection  of  the  stream  first  to  one  side 


206  TRANSPORTING   POWER  OF   WATER.  [On.  XIV 

and  then  to  the  other.  The  unequal  hardness  of  the  materials  through 
which  the  channel  is  eroded  tends  partly  to  give  new  directions  to  the 
lateral  force  of  excavation.  When  by  these,  or  by  accidental  shiftings 
of  the  alluvial  matter  in  the  channel,  the  current  is  made  to  cross  its 
general  line  of  descent,  it  eats  out  a  curve  in  the  opposite  bank,  or  in 
the  side  of  the  hills  bounding  the  valley,  from  which  curve  it  is  turned 
back  again  at  an  equal  angle,  so  that  it  recrosses  the  line  of  descent, 
and  gradually  hollows  out  another  curve  lower  down  in  the  opposite 
bank,  till  the  whole  sides  of  the  valley,  or  river  bed,  present  a  succes- 
sion of  salient  and  retiring  angles.  Among  the  causes  of  deviation 
from  a  straight  course,  by  which  torrents  and  rivers  tend  in  mountain- 
ous regions  to  widen  the  valleys  through  which  they  flow,  may  be  men- 
tioned the  confluence  of  lateral  torrents,  swollen  irregularly  at  different 
seasons  by  partial  storms,  and  discharging  at  different  times  unequal 
quantities  of  sand,  mud,  and  pebbles,  into  the  main  channel. 

When  the  tortuous  flexures  of  a  river  are  extremely  great,  as  often 
happens  in  alluvial  plains,  the  aberration  from  the  direct  line  of  descent 
may  be  restored  by  the  river  cutting  through  the  isthmus  which  sepa- 
rates two  neighboring  curves.  Thus  in  the  annexed  diagram,  the 
extreme  sinuosity  of  the  river  has  caused  it  to  return  for  a  brief  space 

Fig.  15. 


in  a  contrary  direction  to  its  main  course,  so  that  a  peninsula  is  formed, 
and  the  isthmus  (at  a)  is  consumed  on  both  sides  by  currents  flowing  in 
opposite  directions.  In  this  case  an  island  is  soon  formed, — on  either 
side  of  which  a  portion  of  the  stream  usually  remains. 

Transporting  power  of  water. — In  regard  to  the  transporting  power 
of  water,  we  may  often  be  surprised  at  the  facility  with  which 
streams  of  a  small  size,  and  descending  a  slight  declivity,  bear  along 
coarse  sand  and  gravel ;  for  we  usually  estimate  the  weight  of  rocks 
in  air,  and  do  not  reflect  on  their  comparative  buoyancy  when  sub- 
merged in  a  denser  fluid.  The  specific  gravity  of  many  rocks  is  not 
more  than  twice  that  of  water,  and  very  rarely  more  than  thrice,  so 
that  almost  all  the  fragments  propelled  by  a  stream  have  lost  a  third, 
and  many  of  them  a  half,  of  what  we  usually  term  their  weight. 

It  has  been  proved  by  experiment,  in  contradiction  to  the  theories 
of  the  earlier  writers  on  hydrostatics,  to  be  a  universal  law,  regulating 
the  motion  of  running  water,  that  the  velocity  at  the  bottom  of  the 
stream  is  everywhere  less  than  in  any  part  above  it,  and  is  greatest  at 
the  surface.  Also  that  the  superficial  particles  in  the  middle  of  the 
stream  move  swifter  than  those  at  the  sides.  This  retardation  of  the 
lowest  and  lateral  currents  is  produced  by  friction ;  and  when  the 
velocity  is  sufficiently  great,  the  soil  composing  the  sides  and  bottom 


Cfl.  XIV.]  RIVER-FLOODS   IN   SCOTLAND.  207 

gives  way.  A  velocity  of  three  inches  per  second  at  the  bottom  is 
ascertained  to  be  sufficient  to  tear  up  fine  clay, — six  inches  per  second, 
fine  sand, — twelve  inches  per  second,  fine  gravel, — and  three  feet  per 
second,  stones  of  the  size  of  an  egg.* 

When  this  mechanical  power  of  running  water  is  considered,  we  are 
prepared  for  the  transportation  before  alluded  to  of  large  quantities  of 
gravel,  sand,  and  mud,  by  torrents  which  descend  from  mountainous 
regions.  But  a  question  naturally  arises,  How  the  more  tranquil  rivers 
of  the  valleys  and  plains,  flowing  on  comparatively  level  ground,  can 
remove  the  prodigious  burden  which  is  discharged  into  them  by  their 
numerous  tributaries,  and  by  what  means  they  are  enabl  ed  to  convey 
the  whole  mass  to  the  sea  ?  If  they  had  not  this  removing  power, 
their  channels  would  be  annually  choked  up,  and  the  valleys  of  the 
lower  country,  and  plains  at  the  base  of  mountain-chains,  would  be 
continually  strewed  over  with  fragments  of  rock  and  sterile  sand.  But 
this  evil  is  prevented  by  a  general  law  regulating  the  conduct  of  run- 
ning water, — that  two  equal  streams  do  not,  when  united,  occupy  a 
bed  of  double  surface.  Nay,  the  width  of  the  principal  river,  after  the 
junction  of  a  tributary,  sometimes  remains  the  same  as  before,  or  is 
even  lessened.  The  cause  of  this  apparent  paradox  was  long  ago 
explained  by  the  Italian  writers,  who  had  studied  the  confluence  of  the 
Po  and  its  feeders  in  the  plains  of  Lombardy. 

The  addition  of  a  smaller  river  augments  the  velocity  of  the  main 
stream,  often  in  the  same  proportion  as  it  does  the  quantity  of  water. 
Thus  the  Venetian  branch  of  the  Po  swallowed  up  the  Ferranese 
branch  and  that  of  Panaro  without  any  enlargement  of  its  own  dimen- 
sions. The  cause  of  the  greater  velocity  is,  first,  that  after  the  union 
of  two  rivers  the  water,  in  place  of  the  friction  of  four  shores,  has 
only  that  of  two  to  surmount ;  2dly,  because  the  main  body  of  the 
stream  being  farther  distant  from  the  banks,  flows  on  with  less  inter- 
ruption ;  and  lastly,  because  a  greater  quantity  of  water  moving  more 
swiftly,  digs  deeper  into  the  river's  bed.  By  this  beautiful  adjustment, 
the  water  which  drains  the  interior  country  is  made  continually  to 
occupy  less  room  as  it  approaches  the  sea ;  and  thus  the  most  valuable 
part  of  our  continents,  the  rich  deltas  and  great  alluvial  plains,  are  pre- 
vented from  being  constantly  under  water. 

River  floods  in  Scotland,  1829. — Many  remarkable  illustrations  of 
the  power  of  running  water  in  moving  stones  and  heavy  materials  were 
afforded  by  the  storm  and  floods  which  occurred  on  the  3d  and  4th 
of  August,  1829,  in  Aberdeenshire  and  other  counties  in  Scotland. 
The  elements  during  this  storm  assumed  all  the  characters  which  mark 
the  tropical  hurricanes  ;  the  wind  blowing  in  sudden  gusts  and  whirl- 
winds, the  lightning  and  thunder  being  such  as  is  rarely  witnessed  in 
our  climate,  and  heavy  rain  falling  without  intermission.  The  floods 
extended  almost  simultaneously,  and  with  equal  violence  over  that  part 

*  Ericyc.  Brit.  art.  Rivers. 


208  FLOODS    CAUSED   BY   LANDSLIPS.  [Cfl.  XIV 

of  the  northeast  of  Scotland  which  would  be  cut  off  by  two  lines 
drawn  from  the  head  of  Lochrannoch,  one  towards  Inverness  and  the 
other  to  Stonehaven.  The  united  line  of  the  different  rivers  which 
were  flooded,  could  not  be  less  than  from  five  to  six  hundred  miles  in 
length ;  and  the  whole  of  their  courses  were  marked  by  the  destruc- 
tion of  bridges,  roads,  crops,  and  buildings.  Sir  T.  D.  Lauder  has 
recorded  the  destruction  of  thirty-eight  bridges,  and  the  entire  obliter- 
ation of  a  great  number  of  farms  and  hamlets.  On  the  Nairn,  a  frag- 
ment of  sandstone,  fourteen  feet  long  by  three  feet  wide  and  one  foot 
thick,  was  carried  above  200  yards  down  the  river.  Some  new  ravines 
were  formed  on  the  sides  of  mountains  where  no  streams  had  previous- 
ly flowed,  and  ancient  river-channels,  which  had  never  been  filled  from 
time  immemorial,  gave  passage  to  a  copious  flood.* 

The  bridge  over  the  Dee  at  Ballater  consisted  of  five  arches,  having 
upon  the  whole  a  water-way  of  260  feet.  The  bed  of  the  river,  on  which 
the  piers  rested,  was  composed  of  rolled  pieces  of  granite  and  gneiss. 
The  bridge  was  built  of  granite,  and  had  stood  uninjured  for  twenty 
years ;  but  the  different  par,ts  were  swept  away  in  succession  by  the 
flood,  and  the  whole  mass  of  masonry  disappeared  in  the  bed  of  the 
river.  "  The  river  Don,"  observes  Mr.  Farquharson,  in  his  account  ol 
the  inundations,  "  has  upon  my  own  premises  forced  a  mass  of  four  or 
five  hundred  tons  of  stones,  many  of  them  two  or  three  hundred  pounds' 
weight,  up  an  inclined  plane,  rising  six  feet  in  eight  or  ten  yards,  and 
left  them  in  a  rectangular  heap,  about  three  feet  deep  on  a  flat  ground : 
— the  heap  ends  abruptly  at  its  lower  extremity. "f 

The  power  even  of  a  small  rivulet,  when  swollen  by  rain,  in  remov- 
ing heavy  bodies,  was  exemplified  in  August,  1827,  in  the  College,  a 
small  stream  which  flows  at  a  slight  declivity  from  the  eastern  water- 
shed of  the  Cheviot  Hills.  Several  thousand  tons'  weight  of  gravel  and 
sand  were  transported  to  the  plain  of  the  Till,  and  a  bridge,  then  in 
progress  of  building,  was  carried  away,  some  of  the  arch-stones  oi 
which,  weighing  from  half  to  three  quarters  of  a  ton  each,  were  pro- 
pelled two  miles  down  the  rivulet.  On  the  same  occasion,  the  current 
tore  away  from  the  abutment  of  a  mill-dam  a  large  block  of  greenstone- 
porphyry,  weighing  nearly  two  tons,  and  transported  it  to  the  distance 
of  a  quarter  of  a  mile.  Instances  are  related  as  occurring  repeatedly, 
in  which  from  one  to  three  thousand  tons  of  gravel  are,  in  like  manner, 
removed  by  this  streamlet  to  still  greater  distances  in  one  day.J; 

Floods  caused  by  landslips,  1826. — The  power  which  running  water 
may  exert  in  the  lapse  of  ages,  in  widening  and  deepening  a  valley, 
does  not  so  much  depend  on  the  volume  and  velocity  of  the  stream 
usually  flowing  in  it,  as  on  the  number  and  magnitude  of  the  obstruc- 
tions which  have,  at  different  periods,  opposed  its  free  passage.  If  a 
torrent,  however  small,  be  effectually  dammed  up,  the  size  of  the  valley 

*  Sir  T.  D.  Lauder's  Account  of  the  Great  Floods  in  Morayshire,  August,  1829. 
f  Quarterly  Jour,  of  Sci.  tfcc.  No.  xii.  New  Series,  p.  331. 
t  Galley,  Proceed.  Geol.  Soc.  1829. 


CH.  XIV.]  FLOODS    IN    NORTH    AMERICA.  209 

above  the  barrier,  and  its  declivity  below,  and  not  the  dimensions  of 
the  torrent,  will  determine  the  violence  of  the  debacle.  The  most  uni- 
versal source  of  local  deluges,  are  landslips,  slides,  or  avalanches,  as 
they  are  sometimes  called,  when  great  masses  of  rock  and  soil,  or  some- 
times ice  and  snow,  are  precipitated  into  the  bed  of  a  river,  the  bound- 
ary cliffs  of  which  have  been  thrown  down  by  the  shock  of  an  earth- 
quake, or  undermined  by  springs  or  other  causes.  Volumes  might  be 
filled  with  the  enumeration  of  instances  on  record  of  these  terrific  catas- 
trophes ;  I  shall  therefore  select  a  few  examples  of  recent  occurrence, 
the  facts  of  which  are  well  authenticated. 

Two  dry  seasons  in  the  White  Mountains,  in  New  Hampshire  (United 
States),  were  followed  by  heavy  rains  on  the  28th  August,  1826,  when 
from  the  steep  and  lofty  declivities  which  rise  abruptly  on  both  sides  of 
the  river  Saco,  innumerable  rocks  and  stones,  many  of  sufficient  size  to 
fill  a  common  apartment,  were  detached,  and  in  their  descent  swept 
down  before  them,  in  one  promiscuous  and  frightful  ruin,  forests,  shrubs, 
and  the  earth  which  sustained  them.  Although  there  are  numerous 
indications  on  the  steep  sides  of  these  hills  of  former  slides  of  the  same 
kind,  yet  no  tradition  had  been  handed  down  of  any  similar  catastrophe 
within  the  memory  of  man,  and  the  growth  of  the  forest  on  the  very 
spots  now  devastated,  clearly  showed  that  for  a  long  interval  nothing 
similar  had  occurred.  One  of  these  moving  masses  was  afterwards 
found  to  have  slid  three  miles,  with  an  average  breadth  of  a  quarter  of 
a  mile.  The  natural  excavations  commenced  generally  in  a  trench  a  few 
yards  in  depth  and  a  few  rods  in  width,  and  descended  the  mountains, 
widening  and  deepening  till  they  became  vast  chasms.  At  the  base  of 
these  hollow  ravines  was  seen  a  confused  mass  of  ruins,  consisting  of 
transported  earth,  gravel,  rocks,  and  trees.  Forests  of  spruce-fir  and 
hemlock,  a  kind  of  fir  somewhat  resembling  our  yew  in  foliage,  were 
prostrated  with  as  much  ease  as  if  they  had  been  fields  of  grain ;  for, 
where  they  disputed  the  ground,  the  torrent  of  mud  and  rock  accumu- 
lated behind,  till  it  gathered  sufficient  force  to  burst  the  temporary  barrier. 

The  valleys  of  the  Amonoosuck  and  Saco  presented,  for  many  miles, 
an  uninterrupted  scene  of  desolation  ;  all  the  bridges  being  carried  away, 
as  well  as  those  over  their  tributary  streams.  In  some  places,  the  road 
was  excavated  to  the  depth  of  from  fifteen  to  twenty  feet ;  in  others,  it 
was  covered  with  earth,  rocks,  and  trees,  to  as  great  a  height.  The 
water  flowed  for  many  weeks  after  the  flood,  as  densely  charged  with 
earth  as  it  could  be  without  being  changed  into  mud,  and  marks  were 
seen  in  various  localities  of  its  having  risen  on  either  side  of  the  valley  to 
more  than  twenty-five  feet  above  its  ordinary  level.  Many  sheep  and 
cattle  were  swept  away,  and  the  Willey  family,  nine  in  number,  who  in 
alarm  had  deserted  their  house,  were  destroyed  on  the  banks  of  the 
Saco ;  seven  of  their  mangled  bodies  were  afterwards  found  near  the 
river,  buried  beneath  drift-wood  and  mountain  ruins.*  Eleven  years 

*  Silliman's  Journal,  vol.  xv.  No.  2,  p.  216.     Jan.  1829. 
14 


210  FLOOD    IN    THE    VALLEY    OF   BAGNES.  [CiL  XIV. 

after  the  event,  the  deep  channels  worn  by  the  avalanches  of  mud  and 
stone,  and  the  immense  heaps  of  boulders  and  blocks  of  granite  in  the 
river  channel,  still  formed,  says  Professor  Hubbard,  a  picturesque  feature 
in  the  scenery.* 

When  I  visited  the  country  in  1845,  eight  years  after  Professor 
Hubbard,  I  found  the  signs  of  devastation  still  very  striking ;  I  also  par- 
ticularly remarked  that  although  the  surface  of  the  bare  granitic  rocks 
had  been  smoothed  by  the  passage  over  them  of  so  much  mud  and  stone, 
there  were  no  continuous  parallel  and  rectilinear  furrows,  nor  any  of  the 
fine  scratches  or  striae  which  characterize  glacial  action.  The  absence 
of  these  is  nowhere  more  clearly  exemplified  than  in  the  bare  rocks  over 
which  passed  the  great  "  Willey  slide"  of  1826.f 

But  the  catastrophes  in  the  White  Mountains  are  insignificant,  when 
compared  to  those  which  are  occasioned  by  earthquakes,  when  the 
boundary  hills,  for  miles  in  length,  are  thrown  down  into  the  hollow  of 
a  valley.  I  shall  have  opportunities  of  alluding  to  inundations  of  this 
kind,  when  treating  expressly  of  earthquakes,  and  shall  content  myself 
at  present  with  selecting  an  example  of  a  flood  due  to  a  different  cause. 

Flood  in  the  valley  of  Bagnes,  1818. — The  valley  of  Bagnes  is  one  of 
the  largest  of  the  lateral  embranchments  of  the  main  valley  of  the  Rhone, 
above  the  Lake  of  Geneva.  Its  upper  portion  was,  in  1818,  converted 
into  a  lake  by  the  damming  up  of  a  narrow  pass,  by  avalanc-hes  of  sndw 
and  ice,  precipitated  from  an  elevated  glacier  into  the  bed  of  the  river 
Dranse.  In  the  winter  season,  during  continued  frost,  scarcely  any 
water  flows  in  the  bed  of  this  river  to  preserve  an  open  channel,  so  that 
the  ice  barrier  remained  entire  until  the  melting  of  the  snows  in  spring, 
when  a  lake  was  formed  above,  about  half  a  league  in  length,  which 
finally  attained  in  some  parts  a  depth  of  about  two  hundred  feet,  and  a 
width  of  about  seven  hundred  feet.  To  prevent  or  lessen  the  mischief 
apprehended  from  the  sudden  bursting  of  the  barrier,  an  artificial  gallery, 
seven  hundred  feet  in  length,  was  cut  through  the  ice,  before  the  waters 
had  risen  to  a  great  height.  When  at  length  they  accumulated  and 
flowed  through  this  tunnel,  they  dissolved  the  ice,  and  thus  deepened 
their  channel,  until  nearly  half  of  the  whole  contents  of  the  lake  were 
slowly  drained  off.  But  at  length,  on  the  approach  of  the  hot  season, 
the  central  portion  of  the  remaining  mass  of  ice  gave  way  with  a  tremen- 
dous crash,  and  the  residue  of  the  lake  was  emptied  in  half  an  hour. 
In  the  course  of  its  descent,  the  waters  encountered  several  narrow 
gorges,  and  at  each  of  these  they  rose  to  a  great  height,  and  then  burst 
with  new  violence  into  the  next  basin,  sweeping  along  rocks,  forests, 
houses,  bridges,  and  cultivated  land.  For  the  greater  part  of  its  course 
the  flood  resembled  a  moving-  mass  of  rock  and  mud,  rather  than  of 
water.  Some  fragments  of  granitic  rocks,  of  enormous  magnitude,  and 
which  from  their  dimensions,  might  be  compared  without  exaggeration 

*  Silliman's  Journal,  vol.  xxxiv.  p.  115. 

f  See  Lyell's  Second  Visit  to  the  U.  S.  vol.  i.  p.  69. 


CH.  XIV.]  FLOOD   AT    TTVOLI,  211 

to  houses,  were  torn  out  of  a  more  ancient  alluvion,  and  borne  down 
for  a  quarter  of  a  mile.  One  of  the  fragments  moved  was  sixty  paces 
in  circumference.*  The  velocity  of  the  water,  in  the  first -part  of  its 
course,  was  thirty-three  feet  p^r  second,  which  diminished  to  six  feet 
before  it  reached  the  Lake  of  Geneva,  where  it  arrived  in  six  hours  and 
a  half,  the  distance  being  forty-five  miles.f 

This  flood  left  behind  it,  on  the  plains  of  Martigny,  thousands  of  trees 
torn  up  by  the  roots,  together  with  the  ruins  of  buildings.  Some  of  the 
houses  in  that  town  were  filled  with  mud  up  to  the  second  story.  After 
expanding  in  the  plain  of  Martigny,  it  entered  the  Rhone,  and  did  no 
farther  damage ;  but  some  bodies  of  men,  who  had  been  drowned  above 
Martigny,  were  afterwards  found,  at  the  distance  of  about  thirty  miles, 
floating  on  the  farther  side  of  the  Lake  of  Geneva,  near  Vevay. 

The  waters,  on  escaping  from  the  temporary  lake,  intermixed  with 
mud  and  rock,  swept  along,  for  the  first  four  miles,  at  the  rate  of  above 
twenty  miles  an  hour ;  and  M.  Escher,  the  engineer,  calculated  that  the 
flood  furnished  300,000  cubic  feet  of  water  every  second — an  efflux 
which  is  five  times  greater  than  that  of  the  Rhine  below  Basle.  Now, 
if  part  of  the  lake  had  not  been  gradually  drained  off,  the  flood  would 
have  been  nearly  double,  approaching  in  volume  to  some  of  the  largest 
rivers  in  Europe.  It  is  evident,  therefore,  that  when  we  are  speculating 
on  the  excavating  force  which  a  river  may  have  exerted  in  any  particu- 
lar valley,  the  most  important  question  is,  not  the  volume  of  the  existing 
stream,  nor  the  present  levels  of  its  channel,  nor  even  the  nature  of  the 
rocks,  but  the  probability  of  a  succession  of  floods  at  some  period  since 
the  time  when  the  valley  may  have  been  first  elevated  above  the  sea. 

For  several  months  after  the  debacle  of  1818,  the  Dranse,  having  no 
settled  channel,  shifted  its  position  continually  from  one  side  to  the 
other  of  the  valley,  carrying  away  newly-erected  bridges,  undermining 
houses,  and  continuing  to  be  charged  with  as  large  a  quantity  of  earthy 
matter  as  the  fluid  could  hold  in  suspension.  I  visited  this  valley  four 
months  after  the  flood,  and  was  witness  to  the  sweeping  away  of  a 
bridge,  and  the  undermining  of  part  of  a  house.  The  greater  part  of 
the  ice-barrier  was  then  standing,  presenting  vertical  cliffs  150  feet  high, 
like  ravines  in  the  lava-currents  of  Etna  or  Auvergne,  where  they  are 
intersected  by  rivers. 

Inundations,  precisely  similar,  are  recorded  to  have  occurred  at  for- 
mer periods  in  this  district,  and  from  the  same  cause.  In  1595,  for  ex- 
ample, a  lake  burst,  and  the  waters,  descending  with  irresistible  fury, 
destroyed  the  town  of  Martigny,  where  from  sixty  to  eighty  persons 
perished.  In  a  similar  flood,  fifty  years  before,  140  persons  were 
drowned. 

Flood  at  Tivoli,  1826. — I  shall  conclude  with  one  more  example 
derived  from  a  land  of  classic  recollections,  the  ancient  Tibur,  and  which, 

*  This  block  was  measured  by  Capt.  B.  Hall,  R.  N. 

f  Inundation  of  the  Val  de  Bagnes,  in  1818,  Ed.  Phil.  Journ.,  voL  i.  p.  187,  from 
memoir  of  M.  Escher. 


212  EXCAVATION    OF   ROCKS   BY   RUNNING   WATER.      [Oil.  XIV. 

like  all  the  other  inundations  above  alluded  to,  occurred  within  the 
present  century.  The  younger  Pliny,  it  will  be  remembered,  describes 
a  flood  on  the  Anio,  which  destroyed  woods,  rocks,  and  houses,  with 
the  most  sumptuous  villas  and  works  of  arts.*  For  four  or  five  centu- 
ries consecutively,  this  "headlong  stre*am,"  as  Horace  truly  called  it, 
has  often  remained  within  its  bounds,  and  then,  after  so  long  an  interval 
of  rest,  has  at  different  periods  inundated  its  banks  again,  and  widened 
its  channel.  The  last  of  these  catastrophes  happened  15th  Nov.  1826, 
after  heavy  rains,  such  as  produced  the  floods  before  alluded  to  in  Scot- 
land. The  waters  appear  also  to  have  been  impeded  by  an  artificial 
dike,  by  which  they  were  separated  into  two  parts,  a  short  distance 
above  Tivoli.  They  broke  through  this  dike ;  and  leaving  the  left  trench 
dry,  precipitated  themselves,  with  their  whole  weight,  on  the  right  side. 
Here  they  undermined,  in  the  course  of  a  few  hours,  a  high  cliff,  and 
widened  the  river's  channel  about  fifteen  paces.  On  this  height  stood 
the  church  of  St.  Lucia,  and  about  thirty-six  houses  of  the  town  of 
Tivoli,  which  were  all  carried  away,  presenting  as  they  sank  into  the 
roaring  flood,  a  terrific  scene  of  destruction  to  the  spectators  on  the  op- 
posite bank.  As  the  foundations  were  gradually  removed,  each  build- 
ing, some  of  them  edifices  of  considerable  height,  was  first  traversed 
with  numerous  rents,  which  soon  widened  into  large  fissures,  until  at 
length  the  roofs  fell  in  with  a  crash,  and  then  the  walls  sunk  into  the 
river,  and  were  hurled  down  the  cataract  below.f 

The  destroying  agency  of  the  flood  came  within  two  hundred  yards 
of  the  precipice  on  which  the  beautiful  temple  of  Vesta  stands ;  but 
fortunately  this  precious  relic  of  antiquity  was  spared,  while  the  wreck 
of  modern  structures  was  hurled  down  the  abyss.  Vesta,  it  will  be 
remembered,  in  the  heathen  mythology,  personified  the  stability  of  the 
earth ;  and  when  the  Samian  astronomer,  Aristarchus,  first  taught  that 
the  earth  revolved  on  its  axis,  and  round  the  sun,  he  was  publicly  ac- 
cused of  impiety,  "for  removing  the  everlasting  Vesta  from  her  place." 
Playfair  observed,  that  when  Hutton  ascribed  instability  to  the  earth's 
surface,  and  represented  the  continents  which  we  inhabit  as  the  theatre 
of  incessant  change  and  movement,  his  antagonists,  who  regarded  them 
as  unalterable,  assailed  him  in  a  similar  manner  with  accusations  founded 
on  religious  prejudices.^  We  might  appeal  to  the  excavating  power  of 
the  Anio  as  corroborative  of  one  of  the  most  controverted  parts  of  the 
Huttonian  theory ;  and  if  the  days  of  omens  had  not  gone  by,  the  geol- 
ogists who  now  worship  Vesta  might  regard  the  late  catastrophe  as 
portentous.  We  may,  at  least,  recommend  the  modern  votaries  of  the 
goddess  to  lose  no  time  in  making  a  pilgrimage  to  her  shrine,  for  the 
next  flood  may  not  respect  the  temple. 

Excavation  of  rocks  by  running  water. — The  rapidity  with  which 

*  Lib.  viii.  Epist.  1 7. 

f  When  at  Tivoli,  in  1829, 1  received  this  account  from  eye-witnesses  of  the 
event. 

J  Illustr.  of  Hutt.  Theory,  §  3,  p.  147. 


CH.  XIV.] 


LAVA    EXCAVATED   BY   THE   SIMETO. 


213 


even  the  smallest  streams  hollow  out  deep  channels  in  soft  and  destruc- 
tible soils  is  remarkably  exemplified  in  volcanic  countries,  where  the  sand 
and  half-consolidated  tuffs  opposed  but  a  slight  resistance  to  the  torrents 
which  descend  the  mountain -side.  After  the  heavy  rains  which  followed 
the  eruption  of  Vesuvius  in  1824,  the  water  flowing  from  the  Atrio  del 
Cavallo  cut,  in  three  days,  a  new  chasm  through  strata  of  tuff  and 
ejected  volcanic  matter,  to  the  depth  of  twenty-five  feet.  I  found  the 
old  mule-road,  in  1828,  intersected  by  this  new  ravine. 

The  gradual  erosion  of  deep  chasms  through  some  of  the  hardest  rocks, 
by  the  constant  passage  of  running  water,  charged  with  foreign  matter, 
is  another  phenomenon  of  which  striking  examples  may  be  adduced. 
Illustrations  of  this  excavating  power  are  presented  by  many  valleys  in 
central  France  where  the  channels  of  rivers  have  been  barred  up  by 
solid  currents  of  lava,  through  which  the  streams  have  re-excavated  a 
passage,  to  the  depth  of  from  twenty  to  seventy  feet  and  upwards,  and 
often  of  great  width.  In  these  cases  there  are  decisive  proofs  that 
neither  the  sea,  nor  any  denuding  wave  or  extraordinary  body  of  water, 
has  passed  over  the  spot  since  the  melted  lava  was  consolidated.  Every 
hypothesis  of  the  intervention  of  sudden  and  violent  agency  is  entirely 
excluded,  because  the  cones  of  loose  scoriae,  out  of  which  the  lavas 
flowed,  are  oftentimes  at  no  great  elevation  above  the  rivers,  and  have 
remained  undisturbed  during  the  whole  period  which  has  been  sufficient 
for  the  hollowing  out  of  such  enormous  ravines. 

Recent  excavation  ly  the  Simeto. — But  I  shall  at  present  confine  my- 
self to  examples  derived  from  events  which  have  happened  since  the 
time  of  history. 

At  the  western  base  of  Etna,  a  current  of  lava  (A  A,  fig.  16),  de- 
scending from  near  the  summit  of  the  great  volcano,  has  flowed  to  the 
distance  of  five  or  six  miles,  and  then  reached  the  alluvial  plain  of  the 


Fig.  16. 


Recent  excavation  of  lava  at  the  foot  of  Etna  by  the  river  Simeto. 

Simeto,  the  largest  of  the  Sicilian  rivers,  which  skirts  the  base  of  Etna, 
and  falls  into  the  sea  a  few  miles  south  of  Catania.  The  lava  entered 
the  river  about  three  miles  above  the  town  of  Aderno,  and  not  only  oc- 
cupied its  channel  for  some  distance,  but,  crossing  to  the  opposite  side 
of  the  valley,  accumulated  there  in  a  rocky  mass.  Gemmellaro  gives 
the  year  1603  as  the  date  of  the  eruption.*  The  appearance  of  the 

*  Quadro  Istorico  dell'  Etna,  1824. 


214:  FALLS   OF  NIAGARA.  [On.  XIT, 

current  clearly  proves,  that  it  is  one  of  the  most  modern  of  those  of 
Etna ;  for  it  has  not  been  covered  or  crossed  by  subsequent  streams  or 
ejections,  and  the  olives  which  had  been  planted  on  its  surface  were  all 
of  small  size,  when  I  examined  the  spot  in  1828,  yet  they  were  older 
than  the  natural  wood  on  the  same  lava.  In  the  course,  therefore,  of 
about  two  centuries,  the  Simeto  has  eroded  a  passage  from  fifty  to  seve> 
ral  hundred  feet  wide,  and  in  some  parts  from  forty  to  fifty  feet  deep. 

The  portion  of  lava  cut  through  is  in  no  part  porous  or  scoriaceous, 
but  consists  of  a  compact  homogeneous  mass  of  hard  blue  rock,  some- 
what inferior  in  weight  to  ordinary  basalt,  and  containing  crystals  of 
olivine  and  glassy  felspar.  The  general  declivity  of  this  part  of  the  bed 
of  the  Simeto  is  not  considerable  ;  but,  in  consequence  of  the  unequal 
waste  of  the  lava,  two  water-falls  occur  at  Passo  Manzanelli,  each  about 
six  feet  in  height.  Here  the  chasm  (B,  fig.  16)  is  about  forty  feet  deep, 
and  only  fifty  broad. 

The  sand  and  pebbles  in  the  river-bed  consist  chiefly  of  a  brown 
quartzose  sandstone,  derived  from  the  upper  country  ;  but  the  materials 
of  the  volcanic  rock  itself  must  have  greatly  assisted  the  attrition.  This 
river,  like  the  Caltabiano  on  the  eastern  side  of  Etna,  has  not  yet  cut 
down  to  •the  ancient  bed  of  which  it  was  dispossessed,  and  of  which 
the  probable  position  is  indicated  in  the  annexed  diagram  (c,  fig.  16). 

On  entering  the  narrow  ravine  where  the  water  foams  down  the  two 
cataracts,  we  are  entirely  shut  out  from  all  view  of  the  surrounding 
country  ;  and  a  geologist  who  is  accustomed  to  associate  the  character- 
istic features  of  the  landscape  with  the  relative  age  of  certain  rocks,  can 
scarcely  dissuade  himself  from  the  belief  that  he  is  contemplating  a 
scene  in  some  rocky  gorge  of  a  primary  district.  The  external  forms  of 
the  hard  blue  lava  are  as  massive  as  any  of  the  most  ancient  trap-rocks 
of  Scotland.  The  solid  surface  is  in  some  parts  smoothed  and  almost 
polished  by  attrition,  and  covered  in  others  with  a  white  lichen,  which 
imparts  to  it  an  air  of  extreme  antiquity,  so  as  greatly  to  heighten  the 
delusion.  But  the  moment  we  reascend  the  cliff  the  spell  is  broken ; 
for  we  scarcely  recede  a  few  paces,  before  the  ravine  and  river  disap- 
pear, and  we  stand  on  the  black  and  rugged  surface  of  a  vast  current  of 
lava,  which  seems  unbroken,  and  which  we  can  trace  up  nearly  to  the 
distant  summit  of  that  majestic  cone  which  Pindar  called  "  the  pillar  of 
heaven,"  and  which  still  continues  to  send  forth  a  fleecy  wreath  of  va- 
por, reminding  us  that  its  fires  are  not  extinct,  and  that  it  may  again 
give  out  a  rocky  stream,  wherein  other  scenes  like  that  now  described 
may  present  themselves  to  future  observers. 

Falls  of  Niagara. — The  falls  of  Niagara  afford  a  magnificent  exam- 
ple of  the  progressive  excavation  of  a  deep  valley  in  solid  rock.  That 
river  flows  over  a  flat  table-land,  in  a  depression  of  which  Lake  Erie 
is  situated.  Where  it  issues  from  the  lake,  it  is  nearly  a  mile  in  width, 
and  330  feet  above  Lake  Ontario,  which  is  about  30  miles  distant.  For 
the  first  fifteen  miles  below  Lake  Erie  the  surrounding  country,  com- 
prising Upper  Canada  on  the  west,  and  the  state  of  New  York  on  the 


216  FALLS    OF   NIAGARA.  [Cn.  XIV 

east,  is  almost  on  a  level  with  its  banks,  and  nowhere  more  than  thirty 
or  forty  feet  above  them.*  (See  fig.  17.)  The  river  being  occasionally 
interspersed  with  low  wooded  islands,  and  having  sometimes  a  width  of 
three  miles,  glides  along  at  first  with  a  clear,  smooth,  and  tranquil  cur- 
rent, falling  only  fifteen  feet  in  as  many  miles,  and  in  this  part  of  its 
course  resembling  an  arm  of  Lake  Erie.  But  its  character  is  afterwards 
entirely  changed,  on  approaching  the  Rapids,  where  it  begins  to  rush 
and  foam  over  a  rocky  and  uneven  limestone  bottom,  for  the  space  of 
nearly  a  mile,  till  at  length  it  is  thrown  down  perpendicularly  165  feet 
at  the  Falls.  Here  the  river  is  divided,  into  two  sheets  of  water  by  an 
island,  the  largest  cataract  being  more  than  a  third  of  a  mile  broad,  the 
smaller  one  having  a  breadth  of  six  hundred  feet.  When  the  water  has 
precipitated  itself  into  an  unfathomable  pool,  it  rushes  with  great  ve- 
locity down  the  sloping  bottom  of  a  narrow  chasm,  for  a  distance  of 
seven  miles.  This  ravine  varies  from  200  to  400  yards  in  width  from 
cliff  to  cliff ;  contrasting,  therefore,  strongly  in  its  breadth  with  that  of 
the  river  above.  Its  depth  is  from  200  to  300  feet,  and  it  intersects 
for  about  seven  miles  the  table-land  before  described,  which  terminates 
suddenly  at  Queenstown  in  an  escarpment  or  long  line  of  inland  cliff 
facing  northwards,  towards  Lake  Ontario.  The  Niagara,  on  reaching 
the  escarpment  and  issuing  from  the  gorge,  enters  the  flat  country, 
which  is  so  nearly  on  a  level  with  Lake  Ontario,  that  there  is  only  a  fall 
of  about  four  feet  in  the  seven  additional  miles  which  intervene  between 
Queenstown  and  the  shores  of  that  lake. 

It  has  long  been  the  popular  belief  that  the  Niagara  once  flowed  in  a 
shallow  valley  across  the  whole  platform,  from  the  present  site  of  the 
Falls  to  the  escarpment  (called  the  Queenstown  heights),  where  it  is 
supposed  that  the  cataract  was  first  situated,  and  that  the  river  has 
been  slowly  eating  its  way  backwards  through  the  rocks  for  the  distance 
of  seven  miles.  This  hypothesis  naturally  suggests  itself  to  every 
observer,  who  sees  the  narrowness  of  the  gorge  at  its  termination,  and 
throughout  its  whole  course,  as  far  up  as  the  Falls,  above  which 
point  the  river  expands  as  before  stated.  The  boundary  cliffs  of  the 
ravine  are  usually  perpendicular,  and  in  many  places  undermined  on 
one  side  by  the  impetuous  stream.  The  uppermost  rock  of  the  table- 
land at  the  Falls  consists  of  hard  limestone  (a  member  of  the  Si- 
lurian series),  about  ninety  feet  thick,  beneath  which  lie  soft  shales  of 
equal  thickness,  continually  undermined  by  the  action  of  the  spray, 
which  rises  from  the  pool  into  which  so  large  a  body  of  water  is  pro- 
jected, and  is  driven  violently  by  gusts  of  wind  against  the  base  of  the 

*  The  reader  will  find  in  my  Travels  in  North  America,  vol.  i.  ch.  2,  a  colored 
geological  map  and  section  of  the  Niagara  district,  also  a  bird's-eye  view  of  the 
Falls  and  adjacent  country,  colored  geologically,  of  which  the  first  idea  was  sug- 
gested by  the  excellent  original  sketch  given  by  Mr.  Bakewell.  I  have  referred 
more  fully  to  these  and  to  Mr.  Hall's  Report  on  the  Geology  of  New  York,  as 
well  as  to  the  earlier  writings  of  Hennepin  and  Kalm  in  the  same  work,  and  have 
speculated  on  the  origin  of  the  escarpment  over  which  the  Falls  may  have  been 
originally  precipitated.  Vol.  i.  p.  32,  and  vol.  ii.  p.  93. 


CH.  XIV.]  FALLS    OF   NIAGARA.  217 

precipice.  In  consequence  of  this  action,  and  that  of  frost,  the  shale 
disintegrates  and  crumbles  away,  and  portions  of  the  incumbent  rock 
overhang  40  feet,  and  often  when  unsupported  tumble  down,  so  that 
the  Falls  do  not  remain  absolutely  stationary  at  the  same  spot,  even  for 
half  a  century.  Accounts  have  come  down  to  us,  from  the  earliest  pe- 
riod of  observation,  of  the  frequent  destruction  of  these  rocks,  and  the 
sudden  descent  of  huge  fragments  in  1818  and  1828,  are  said  to  have 
shaken  the  adjacent  country  like  an  earthquake.  The  earliest  travel- 
lers, Hennepin  and  Kalm,  who  in  1678  and  1751  visited  the  Falls,  and 
published  views  of  them,  attest  the  fact,  that  the  rocks  have  been  suf- 
fering from  dilapidation  for  more  than  a  century  and  a  half,  and  that 
some  slight  changes,  even  in  the  scenery  of  the  cataract  have  been 
brought  about  within  that  time.  The  idea,  therefore,  of  perpetual  and 
progressive  waste  is  constantly  present  to  the  mind  of  every  beholder ; 
and  as  that  part  of  the  chasm,  which  has  been  the  work  of  the  last 
hundred  and  fifty  years  resembles  precisely,  in  depth,  width,  and  char- 
acter, the  rest  of  the  gorge  which  extends  seven  miles  below,  it  is  most 
natural  to  infer,  that  the  entire  ravine  has  been  hollowed  out  in  the  same 
manner,  by  the  recession  of  the  cataract. 

It  must  at  least  be  conceded,  that  the  river  supplies  an  adequate 
cause  for  executing  the  whole  task  thus  assigned  to  it,  provided  we 
grant  sufficient  time  for  its  completion.  As  this  part  of  the  country 
was  a  wilderness  till  near  the  end  of  the  last  century,  we  can  obtain 
no  accurate  data  for  estimating  the  exact  rate  at  which  the  cataract  has 
been  receding.  Mr.  Bakewell,  son  of  the  eminent  geologist  of  that 
name,  who  visited  the  Niagara  in  1829,  made  the  first  attempt  to  cal- 
culate from  the  observations  of  one  who  had  lived  forty  years  at  the 
Falls,  and  who  had  been  the  first  settler  there,  that  the  cataract  had 
during  that  period  gone  back  about  a  yard  annually.  But  after  the 
most  careful  inquiries  which  I  was  able  to  make,  during  my  visit  to 
the  spot  in  1841-2,  I  came  to  the  conclusion  that  the  average  of  one 
foot  a  year  would  be  a  much  more  probable  conjecture.  In  that  case, 
it  would  have  required  thirty-five  thousand  years  for  the  retreat  of  the 
Falls,  from  the  escarpment  of  Queenstown  to  their  present  site.  It 
seems  "by  no  means  improbable  that  such  a  result  would  be  no  exagger- 
ation of  the  truth,  although  we  cannot  assume  that  the  retrograde 
movement  has  been  uniform.  An  examination  of  the  geological  struc- 
ture of  the  district,  as  laid  open  in  the  ravine,  shows  that  at  every  step 
in  the  process  of  excavation,  the  height  of  the  precipice,  the  hardness 
of  the  materials  at  its  base,  and  the  quantity  of  fallen  matter  to  be 
removed,  must  have  varied.  At  some  points  it  may  have  receded  much 
faster  than  at  present,  but  in  general  its  pi  ogress  was  probably  slower, 
because  the  cataract,  when  it  began  to  recede,  must  have  had  nearly 
twice  its  present  height. 

From  observations  made  by  me  in  1841,  when  I  had  the  advantage 
of  being  accompanied  by  Mr.  Hall,  state  geologist  of  New  York,  and 
in  1842,  when  I  re-examined  the  Niagara  district,  I  obtained  geologi- 


218  FALLS   OF  NIAGARA.  [Cn.  XIV 

cal  evidence  of  the  former  existence  of  an  old  river-bed,  which,  I  have 
no  doubt,  indicates  the  original  channel  through  which  the  waters  once 
flowed  from  the  Falls  to  Queenstown,  at  the  height  of  nearly  three 
hundred  feet  above  the  bottom  of  the  present  gorge.  The  geological 
monuments  alluded  to,  consist  of  patches  of  sand  and  gravel,  forty  feet 
thick,  containing  fluviatile  shells  of  the  genera  Unio,  Uyclas,  Melania, 
&c.,  such  as  now  inhabit  the  waters  of  the  Niagara  above  the  Falls. 
The  identity  of  the  fossil  species  with  the  recent  is  unquestionable,  and 
these  freshwater  deposits  occur  at  the  edge  of  the  cliffs  bounding  the 
ravine,  so  that  they  prove  the  former  extension  of  an  elevated  shallow 
valley,  four  miles  below  the  falls,  a  distinct  prolongation  of  that  now 
occupied  by  the  Niagara,  in  the  elevated  region  intervening  between 
Lake  Erie  and  the  Falls.  Whatever  theory  be  framed  for  the  hollow- 
ing out  of  the  ravine  further  down,  or  for  the  three  miles  which  inter- 
vene between  the  whirlpool  and  Queenstown,  it  will  always  be  necessary 
to  suppose  the  former  existence  of  a  barrier  of  rock,  not  of  loose  and 
destructible  materials,  such  as  those  composing  the  drift  in  this  district, 
somewhere  immediately  below  the  whirlpool.  By  that  barrier  the 
waters  were  held  back  for  ages,  when  the  fluviatile  deposit,  40  feet  in 
thickness,  and  250  feet  above  the  present  channel  of  the  river,  origi- 
nated. If  we  are  led  by  this  evidence  to  admit  that  the  cataract  has 
cut  back  its  way  for  four  miles,  we  can  have  little  hesitation  in  referring 
the  excavation  of  the  remaining  three  miles  below  to  a  like  agency,  the 
shape  of  the  chasm  being  precisely  similar. 

There  have  been  many  speculations  respecting  the  future  recession 
of  the  Falls,  and  the  deluge  that  might  be  occasioned  by  the  sudden 
escape  of  the  waters  of  Lake  Erie,  if  the  ravine  should  ever  be  pro- 
longed 16  miles  backwards.  But  a  more  accurate  knowledge  of  the 
geological  succession  of  the  rocks,  brought  to  light  by  the  State  Sur- 
vey, has  satisfied  every  geologist  that  the  Falls  would  diminish  gradu- 
ally in  height  before  they  travelled  back  two  miles,  and  in  consequence 
of  a  gentle  dip  of  the  strata  to  the  south,  the  massive  limestone  now  at 
the  top  would  then  be  at  their  base,  and  would  retard,  and  perhaps  put 
an  effectual  stop  to,  the  excavating  process. 


CHAPTER  XV. 

TRANSPORTATION    OF    SOLID    MATTER   BY    ICE. 

Carrying  power  of  river-ice — Rocks  annually  conveyed  into  the  St.  Lawrence  by 
its  tributaries — Ground-ice  ;  its  origin  and  transporting  power — Glaciers — 
Theory  of  their  downward  movement — Smoothed  and  grooved  rocks — The 
moraine  unstnitified — Icebergs  covered  with  mud  and  stones — Limits  of  glaciers 
and  icebergs — Their  effects  on  the  bottom  when  they  run  aground — Packing 
of  coast-ice — Boulders  drifted  by  ice  on  coast  of  Labrador — Blocks  moved  by 
ice  in  the  Baltic. 

THE  power  of  running  water  to  carry  sand,  gravel,  and  fragments 
of  rock  to  considerable  distances  is  greatly  augmented  in  those  regions 
where,  during  some  part  of  the  year,  the  frost  is  of  sufficient  intensity 
to  convert  the  water,  either  at  the  surface  or  bottom  of  rivers,  into  ice. 

This  subject  may  be  considered  under  three  different  heads : — first, 
the  effect  of  surface-ice  and  ground-ice  in  enabling  streams  to  remove 
gravel  and  stones  to  a  distance  ;  secondly,  the  action  of  glaciers  in  the 
transport  of  boulders,  and  in  the  polishing  and  scratching  of  rocks ; 
thirdly,  the  floating  off  of  glaciers  charged  with  solid  matter  into  the 
sea,  and  the  drifting  of  icebergs  and  coast-ice. 

River-ice. — Pebbles  and  small  pieces  of  rock  may  be  seen  entangled 
in  ice,  and  floating  annually  down  the  Tay  in  Scotland,  as  far  as  the 
mouth  of  that  river.  Similar  observations  might  doubtless  be  made 
respecting  almost  all  the  larger  rivers  of  England  and  Scotland ;  but 
there  seems  reason  to  suspect  that  the  principal  transfer  from  place 
to  place  of  pebbles  and  stones  adhering  to  ice  goes  on  unseen  by  us 
under  water.  For  although  the  specific  gravity  of  the  compound 
mass  may  cause  it  to  sink,  it  may  still  be  very  buoyant,  and  easily  borne 
along  by  a  feeble  current.  The  ice,  moreover,  melts  very  slowly  at  the 
bottom  of  running  streams  in  winter,  as  the  water  there  is  often  nearly 
at  the  freezing  point,  as  will  be  seen  from  what  will  be  said  in  the 
sequel  of  ground-ice. 

As  we  traverse  Europe  in  the  latitudes  of  Great  Britain,  we  find  the 
winters  more  severe,  and  the  rivers  more  regularly  frozen  over.  M. 
Lariviere  relates  that,  being  at  Memel  on  the  Baltic  in  1821,  when  the 
ice  of  the  river  Niemen  broke  up,  he  saw  a  mass  of  ice  thirty  feet  long 
which  had  descended  the  stream,  and  had  been  thrown  ashore.  In  the 
middle  of  it  was  a  triangular  piece  of  granite,  about  a  yard  in  diameter, 
resembling  in  composition  the  red  granite  of  Finland.* 

*  Consid.  sur  les  Blocs  Errat.  1829. 


220  TRANSPORTATION   OF  SOLID   MATTER  [Cn.  XV. 

When  rivers  in  the  northern  hemisphere  flow  from  south  to  north, 
the  ice  first  breaks  up  in  the  higher  part  of  their  course,  and  the  flooded 
waters,  bearing  along  large  icy  fragments,  often  arrive  at  parts  of  the 
stream  which  are  still  firmly  frozen  over.  Great  inundations  are  thus 
frequently  occasioned  by  the  obstructions  thrown  in  the  way  of  the  de- 
scending waters,  as  in  the  case  of  the  Mackenzie  in  North  America,  and 
the  Irtish,  Obi,  Yenesei,  Lena,  and  other  rivers  of  Siberia.  (See  map, 
fig.  1,  p.  79.)  A  partial  stoppage  of  this  kind  lately  occurred  (Jan.  31, 
1840)  in  the  Vistula,  about  a  mile  and  a  half  above  the  city  of  Dantzic, 
where  the  river,  choked  up  by  packed  ice,  was  made  to  take  a  new 
course  over  its  right  bank,  so  that  it  hollowed  out  in  a  few  days  a 
deep  and  broad  channel,  many  leagues  in  length,  through  a  tract  of 
sand-hills  which  were  from  40  to  60  feet  high. 

In  Canada,  where  the  winter's  cold  is  intense,  in  a  latitude  corre- 
sponding to  that  of  central  France,  several  tributaries  of  the  St.  Law- 
rence begin  to  thaw  in  their  upper  course,  while  they  remain  frozen 
over  lower  down,  and  thus  large  slabs  of  ice  are  set  free  and  thrown 
upon  the  unbroken  sheet  of  ice  below.  Then  begins  what  is  called  the 
packing  of  the  drifted  fragments  ;  that  is  to  say,  one  slab  is  made  to 
slide  over  another,  until  a  vast  pile  is  built  up,  and  the  whole  being 
frozen  together,  is  urged  onwards  by  the  force  of  the  dammed  up 
waters  and  drift-ice.  Thus  propelled,  it  not  only  forces  along  boulders, 
but  breaks  off  from  cliffs,  which  border  the  rivers,  huge  pieces  of 
projecting  rock.  By  this  means  several  buttresses  of  solid  masonry, 
which,  up  to  the  year  1836,  supported  a  wooden  bridge  on  the  St. 
Maurice,  which  falls  into  the  St.  Lawrence,  near  the  town  of  Trois 
Rivieres,  lat.  46°  20',  were  thrown  down,  and  conveyed  by  the  ice 
into  the  main  river ;  and  instances  have  occurred  at  Montreal  of  wharfs 
and  stone-buildings,  from  30  to  50  feet  square,  having  been  removed  in 
a  similar  manner.  We  learn  from  Captain  Bayfield  that  anchors  laid 
down  within  high-water  mark,  to  secure  vessels  hauled  on  shore  for  the 
winter,  must  be  cut  out  of  the  ice  on  the  approach  of  spring,  or  they 
would  be  carried  away.  In  1834,  the  Gulnare's  bower-anchor,  weigh- 
ing half  a  ton,  was  transported  some  yards  by  the  ice,  and  so  firmly 
was  it  fixed,  that  the  force  of  the  moving  ice  broke  a  chain-cable  suited 
for  a  10-gun  brig,  and  which  had  rode  the  Gulnare  during  the  heaviest 
gales  in  the  gulf.  Had  not  this  anchor  been  cut  out  of  the  ice,  it  would 
have  been  carried  into  deep  water  and  lost.* 

The  scene  represented  in  the  annexed  plate  (pi.  2),  from  a  drawing 
by  Lieutenant  Bowen,  R.  N.,  will  enable  the  reader  to  comprehend  the 
incessant  changes  which  the  transport  of  boulders  produces  annually 
on  the  low  islands,  shores,  and  bed  of  the  St.  Lawrence  above  Quebec. 
The  fundamental  rocks  at  Richelieu  Rapid,  situated  in  lat.  46°  K,  are 
limestone  and  slate,  which  are  seen  at  low- water  to  be  covered  with 
boulders  of  granite.  These  boulders  owe  their  spheroidal  form  chiefly  tc 

*  Capt.  Bayfield,  Geol.  Soc.  Proceedings,  vol.  ii.  p.  223. 


CH.   XV.]  BY    EIVEE   ICE.  221 

weathering,  or  action  of  frost,  which  causes  the  surface  to  exfoliate  in 
concentric  plates,  so  that  all  the  more  prominent  angles  are  removed. 
At  the  point  a  is  a  cavity  in  the  mud  or  sand  of  the  beach,  now  filled 
with  water,  which  was  occupied  during  the  preceding  winter  (1835)  by 
the  huge  erratic  b,  a  mass  of  granite,  70  tons'  weight,  found  in  the 
spring  following  (1836)  at  a  distance  of  several  feet  from  its  former 
position.  Many  small  islands  are  seen  on  the  river,  such  as  c  d,  which 
afford  still  more  striking  proofs  of  the  carrying  and  propelling  power  of 
ice.  These  islets  are  never  under  water,  yet  every  winter  ice  is  thrown 
upon  them  in  such  abundance,  that  it  packs  to  the  height  of  20,  and 
even  30  feet,  bringing  with  it  a  continual  supply  of  large  stones  or 
boulders,  and  carrying  away  others  ;  the  greatest  number  being  depos- 
ited, according  to  Lieutenant  Bo  wen,  on  the  edge  of  deep  water.  On 
the  island  d,  on  the  left  of  the  accompanying  view,  a  lighthouse  is  repre- 
sented, consisting  of  a  square  wooden  building,  which  having  no  other 
foundation  than  the  boulders,  requires  to  be  taken  down  every  winter, 
and  rebuilt  on  the  reopening  of  the  river. 

These  effects  of  frost,  which  are  so  striking  on  the  St.  Lawrence 
above  Quebec,  are  by  no  means  displayed  on  a  smaller  scale  below  that 
city,  where  the  gulf  rises  and  falls  with  the  tide.  On  the  contrary ;  it 
is  in  the  estuary,  between  the  latitudes  47°  and  49°,  that  the  greatest 
quantity  of  gravel  and  boulders  of  large  dimensions  are  carried  down 
annually  towards  the  sea.  Here  the  frost  is  so  intense,  that  a  dense 
sheet  of  ice  is  formed  at  low  water,  which,  on  the  rise  of  the  tide,  is 
lifted  up,  broken,  and  thrown  in  heaps  on  the  extensive  shoals  which 
border  the  estuary.  When  the  tide  recedes,  this  packed  ice  is  exposed 
to  a  temperature  sometimes  30°  below  zero,  which  freezes  together  all 
the  loose  pieces  of  ice,  as  well  as  the  granitic  and  other  boulders.  The 
whole  of  these  are  often  swept  away  by  a  high  tide,  or  when  the  river 
is  swollen  by  the  melting  of  the  snow  in  Spring.  One  huge  block  of 
granite,  15  feet  long  by  10  feet  both  in  width  and  height,  and  estimated 
to  contain  1500  cubic  feet,  was  conveyed  in  this  manner  to  some  disr 
tance  in  the  year  1837,  its  previous  position  being  well  known,  as  up 
to  that  time  it  had  been  used  by  Captain  Bayfield  as  a  mark  for  the 
surveying  station. 

Ground-ice. — When  a  current  of  cold  air  passes  over  the  surface  of 
a  lake  or  stream  it  abstracts  from  it  a  quantity  of  heat,  and  the  specific 
gravity  of  the  water  being  thereby  increased,  the  cooled  portion  sinks. 
This  circulation  may  continue  i>ntil  the  whole  body  of  fluid  has  been 
cooled  down  to  the  temperature  of  40°  F.,  after  which,  if  the  cold  in- 
crease, the  vertical  movement  ceases,  the  water  which  is  uppermost 
expands  and  floats  over  the  heavier  fluid  below,  and  when  it  has  attained 
a  temperature  of  32°  Fahr.  it  sets  into  a  sheet  of  ice.  It  should  seem 
therefore  impossible,  according  to  this  law  of  congelation,  that  ice 
should  ever  form  at  the  bottom  of  a  river ;  and  yet  such  is  the  fact,  and 
many  speculations  have  been  hazarded  to  account  for  so  singular  a  phe- 
nomenon. M.  Arago  is  of  opinion  that  the  mechanical  action  of  a  run- 


222  GROUND-ICE   AND   GLACIERS.  [On.  XV. 

ning  stream  produces  a  circulation  by  which  the  entire  body  of  water  is 
mixed  up  together,  and  cooled  alike,  and  the  whole  being  thus  reduced 
to  the  freezing  point,  ice  begins  to  form  at  the  bottom  for  two  reasons, 
first,  because  there  is  less  motion  there,  and  secondly,  because  the 
water  is  in  contact  with. solid  rock  or  pebbles  which  have  a  cold  sur- 
face.* Whatever  explanation  we  adopt,  there  is  no  doubt  of  the  fact, 
that  in  countries  where  the  intensity  and  duration  of  the  cold  is  great, 
rivers  and  torrents  acquire  an  increase  of  carrying  power  by  the  forma- 
tion of  what  is  called  ground-ice.  Even  in  the  Thames  we  learn  from 
Dr.  Plott  that  pieces  of  this  kind  of  ice,  having  gravel  frozen  on  to  their 
under  side,  rise  up  from  the  bottom  in  winter,  and  float  on  the  surface. 
In  the  Siberian  rivers,  Weitz  describes  large  stones  as  having  been 
brought  up  from  the  river's  bed  in  the  same  manner,  and  made  to 
float.f 

Glaciers. — In  the  temperate  zone,  the  snow  lies  for  months  in  winter 
on  the  summit  of  every  high  mountain,  while  in  the  arctic  regions,  a 
long  summer's  day  of  half  a  year's  duration  is  insufficient  to  melt  the 
snow,  even  on  land  just  raised  above  the  level  of  the  sea.  It  is  there- 
fore not  surprising,  since  the  atmosphere  becomes  colder  in  proportion 
as  we  ascend  in  it,  that  there  should  be  heights,  even  in  tropical  coun- 
tries, where  the  snow  never  melts.  The  lowest  limit  to  which  the  per- 
petual snow  extends  downwards,  from  the  tops  of  mountains  at  the 
equator,  is  an  elevation  of  not  less  than  16,000  feet  above  the  sea; 
while  in  the  Swiss  Alps,  in  lat.  46°  N.  it  reaches  as  low  as  8,500  feet 
above  the  same  level,  the  loftier  peaks  of  the  Alpine  chain  being  from 
12,000  to  15,000  feet  high.  The  frozen  mass  augmenting  from  year  to 
year  would  add  indefinitely  to  the  altitude  of  alpine  summits,  were  it 
not  relieved  by  its  descent  through  the  larger  and  deeper  valleys  to 
regions  far  below  the  general  snow-line.  To  these  it  slowly  finds  its 
way  in  the  form  of  rivers  of  ice,  called  glaciers,  the  consolidation  of 
which  is  produced  by  pressure,  and  by  the  congelation  of  water  infil- 
tered  into  the  porous  mass,  which  is  always  undergoing  partial  liquefac- 
tion, and  receiving  in  summer  occasional  showers  of  rain  on  its  surface. 
In  a  day  of  hot  sunshine,  or  mild  rain,  innumerable  rills  of  pure  and 
sparkling  water  run  in  icy  channels  along  the  surface  of  the  glaciers, 
which  in  the  night  shrink,  and  come  to  nothing.  They  are  often  pre- 
cipitated in  bold  cascades  into  deep  fissures  in  the  ice,  and  contribute  to- 
gether with  springs  to  form  torrents,  which  flow  in  tunnels  at  the  bot- 
tom of  the  glaciers  for  many  a  league,  and  at  length  issue  at  their 
extremities,  from  beneath  beautiful  caverns  or  arches.  The  waters  of 
these  streams  are  always  densely  charged  with  the  finest  mud,  pro- 
duced by  the  grinding  of  rock  and  sand  under  the  weight  of  the  mov- 
ing mass.  (See  fig.  18.) 


*  M.  Arago,  Annuaire,  <fec.  1833;  and  Rev.  J.  Farquharson,  Phil.  Trans.  1835, 
p.  329. 

f  Journ.  of  Roy.  Geograph.  Soc.  vol.  vi.  p.  416. 


CH.  XV.] 


CAUSE  OF   GLACIEE    MOTION. 

Fis  18. 


223 


Glacier  with  medial  and  lateral  moraines  and  with  terminal  cave. 

The  length  of  tiie  a  \viss  g'lacieis  is  sometimes  twenty  miles,  their 
width  in  the  middle  portion,  where  they  are  broadest,  occasionally  two 
or  three  miles  ;  their  depth  or  thickness  sometimes  more  than  600  feet. 
When  they  descend  steep  slopes,  and  precipices,  or  are  forced  through 
narrow  gorges,  the  ice  is  broken  up,  and  assumes  the  most  fantastic  and 
picturesque  forms,  with  lofty  peaks  and  pinnacles,  projecting  above  the 
general  level.  These  snow-white  masses  are  often  relieved  by  a  dark 
background  of  pines,  as  in  the  valley  of  Chamouni ;  and  are  not  only 
surrounded  with  abundance  of  the  wild  rhododendron  in  full  flower, 
but  encroach  still  lower  into  the  region  of  cultivation,  and  trespass  on 
fields  where  the  tobacco-plant  is  nourishing  by  the  side  of  the  peasant's 
hut. 

The  cause  of  glacier  motion  has  of  late  been  a  subject  of  careful 
investigation  and  much  keen  controversy.  Although  a  question  of 
physics,  rather  than  of  geology,  it  is  too  interesting  to  allow  me  to  pass 
it  by  without  some  brief  mention.  De  Saussure,  whose  travels  in  the 
Alps  are  full  of  original  observations,  as  well  as  sound  and  comprehen- 
sive general  views,  conceived  that  the  weight  of  'the  ice  might  be  suffi- 
cient to  urge  it  down  the  slope  of  the  valley,  if  the  sliding  motion  were 
aided  by  the  water  flowing  at  the  bottom.  For  this  "  gravitation 
theory"  Charpentier,  followed  by  Agassiz,  substituted  the  hypothesis  of 
dilatation.  The  most  solid  ice  is  always  permeable  to  water,  and  pen- 


224:  MOTIONS   OF   GLACIEES.  [On.  XV. 

etrated  by  innumerable  fissures  and  capillary  tubes,  often  extremely 
minute.  These  tubes  imbibe  the  aqueous  fluid  during  the  day,  which 
freezes,  it  is  said,  in  the  cold  of  the  night,  and  expands  while  in  the  act 
of  congelation.  The  distension  of  the  whole  mass  exerts  an  immense 
force,  tending  to  propel  the  glacier  in  the  direction  of  least  resistance 
— "  in  other  words,  down  the  valley."  This  theory  was  opposed  by 
Mr.  Hopkins  on  mathematical  and  mechanical  grounds,  in  several  able 
papers.  Among  other  objections,  he  pointed  out  that  the  friction  of 
so  enormous  a  body  as  a  glacier  on  its  bed  is  so  great,  that  the  vertical 
direction  would  always  be  that  of  least  resistance,  and  if  a  considerable 
distension  of  the  mass  should  take  place,  by  the  action  of  freezing,  it 
would  tend  to  increase  its  thickness,  rather  than  accelerate  its  down- 
ward progress.  He  also  contended  (and  his  arguments  were  illustrated 
by  many  ingenious  experiments),  that  a  glacier  can  move  along  an 
extremely  slight  slope,  solely  by  the  influence  of  gravitation,  owing  to 
the  constant  dissolution  of  ice  in  contact  with  the  rocky  bottom,  and 
the  number  of  separate  fragments  into  which  the  glacier  is  divided  by 
fissures,  so  that  freedom  of  motion  is  imparted  to  its  several  parts 
somewhat  resembling  that  of  an  imperfect  fluid.  To  this  view  Profes- 
sor James  Forbes  objected,  that  gravitation  would  not  supply  an  ade- 
quate cause  for  the  sliding  of  solid  ice  down  slopes  having  an  inclina- 
tion of  no  more  than  four  or  five  degrees,  still  less  would  it  explain 
how  the  glacier  advances  where  the  channel  expands  and  contracts. 
The  Mer  de  Glace  in  Chamouni,  for  example,  after  being  2000  yards 
wide,  passes  through  a  strait  only  900  yards  in  width.  Such  a  gorge, 
it  is  contended,  would  be  choked  up  by  the  advance  of  any  solid 
mass,  even  if  it  be  broken  up  into  numerous  fragments.  The  same 
acute  observer  remarked,  that  water  in  the  fissures  and  pores  of  gla- 
ciers cannot,  and  does  not  part  with  its  latent  heat,  so  as  to  freeze 
every  night  to  a  great  depth,  or  far  in  the  interior  of  the  mass.  Had 
the  dilatation  theory  been  true,  the  chief  motion  of  the  glacier  would 
have  occurred  about  sunset,  when  the  freezing  of  the  water  must  be 
greatest,  and  it  had,  in  fact,  been  at  first  assumed  by  those  who  favored 
that  hypothesis,  that  the  mass  moved  faster  at  the  sides,  where  the 
melting  of  ice  was  promoted  by  the  sun's  heat,  reflected  from  boundary 
precipices. 

Agassiz  appears  to  have  been  the  first  to  commence,  in  1841,  aided 
by  a  skilful  engineer,  M.  Escher  de  la  Linth,  a  series  of  exact  measure- 
ments to  ascertain  the  laws  of  glacier  motion,  and  he  soon  discovered, 
contrary  to  his  preconceived  notions,  that  the  stream  of  ice  moved  more 
slowly  at  the  sides  than  at  the  centre,  and  faster  in  the  middle  region 
of  the  glacier  than  at  its  extremity.*  Professor  James  Forbes,  who 
had  joined  Mr.  Agassiz  during  his  earlier  investigations  in  the  Alps, 

*  See  Systeme  GlaHaire,  by  Agassiz,  Guyot,  and  Desor,  pp.  436,  437,  445.  Mr. 
Agassiz,  at  p.  462,  states  that  he  published  in  the  Deutsche  Vierteljahrschrift  for 
1841,  this  result  as  to  the  central  motion  being  greater  than  that  of  the  sides,  and 
was,  therefore,  the  first  to  correct  his  own  previous  mistake. 


CH.  XV.]  MOTIONS   OF   GLACIERS.  225 

undertook  himself  an  independent  series  of  experiments,  which  he  fol- 
lowed up  with  great  perseverance,  to  determine  the  laws  of  glacier 
motion.  These  he  found  to  agree  very  closely  with  the  laws  govern- 
ing the  course  of  rivers,  their  progress  being  greater  in  the  centre  than 
at  the  sides,  and  more  rapid  at  the  surface  than  at  the  bottom.  This 
fact  was  verified  by  carefully  fixing  a  great  number  of  marks  in  the 
ice,  arranged  in  a  straight  line,  which  gradually  assumed  a  beautiful 
curve,  the  middle  part  pointing  down  the  glacier,  and  showing  a  veloci- 
ty there,  double  or  treble  that  of  the  lateral  parts.*  He  ascertained 
that  the  rate  of  advance  by  night  was  nearly  the  same  as  by  day,  and 
that  even  the  hourly  march  of  the  icy  stream  could  be  detected,  al- 
though the  progress  might  not  amount  to  more  than  six  or  seven  inches 
in  twelve  hours.  By  the  incessant  though  invisible  advance  of  the 
marks  placed  on  the  ice,  "  time,"  says  Mr.  Forbes,  "was  marked  out 
as  by  a  shadow  on  a  dial,  and  the  unequivocal  evidence  which  I  ob- 
tained, that  even  while  walking  on  a  glacier  we  are,  day  by  day,  and 
hour  by  hour,  imperceptibly  carried  on  by  the  resistless  flow  of  the  icy 
stream,  filled  me  with  admiration."  (Travels  in  the  Alps,  p.  133.)  In 
order  to  explain  this  remarkable  regularity  of  motion,  and  its  obedience 
to  laws  so  strictly  analogous  to  those  of  fluids,  the  same  writer  pro- 
posed the  theory  that  the  ice,  instead  of  being  solid  and  compact,  is  a 
viscous  or  plastic  body,  capable  of  yielding  to  great  pressure,  and  the 
more  so  in  proportion  as  its  temperature  is  higher,  and  as  it  approaches 
more  nearly  to  the  melting  point.  He  endeavors  to  show  that  this 
hypothesis  will  account  for  many  complicated  phenomena,  especially 
for  a  ribboned  or  veined  structure  which  is  everywhere  observable 
in  the  ice,  and  might  be  produced  by  lines  of  discontinuity,  arising 
from  the  different  rates  at  which  the  various  portions  of  the  semi-rigid 
glacier  advance  and  pass  each  other.  Many  examples  are  adduced  to 
prove  that  a  glacier  can  model  itself  to  the  form  of  the  ground  over 
which  it  is  forced,  exactly  as  would  happen  if  it  possessed  a  certain 
ductility,  and  this  power  of  yielding  under  intense  pressure,  is  shown 
not  to  be  irreconcilable  with  the  idea  of  the  ice  being  sufficiently  com- 
pact to  break  into  fragments,  when  the  strain  upon  its  parts  is  exces- 
sive ;  as  where  the  glacier  turns  a  sharp  angle,  or  descends  upon  a 
rapid  or  convex  slope.  The  increased  velocity  in  summer  is  attributed 
partly  to  the  greater  plasticity  of  the  ice,  when  not  exposed  to  in- 
tense cold,  and  partly  to  the  hydrostatic  pressure  of  the  water  in  the 
capillary  tubes,  which  imbibe  more  of  this  liquid  in  the  hot  season. 

On  the  assumption  of  the  ice  being  a  rigid  mass,  Mr.  Hopkins  attribu- 
ted the  more  rapid  motions  in  the  centre  to  the  unequal  rate  at  which 
the  broad  stripes  of  ice,  intervening  between  longitudinal  fissures,  ad- 
vance ;  but  besides  that  there  are  parts  of  the  glacier  where  no  such 
fissures  exist,  such  a  mode  of  progression,  says  Mr.  Forbes,  would  cause 
the  borders  of  large  transverse  rents  or  "  crevasses,"  to  be  jagged  like  a 

*  J.  Forbes.     8th  Letter  on  Glaciers,  Aug.  1844. 
15 


226  TRANSPORTATION    OF    ROCKS    BY    GLACIERS.  [On.  XV. 

saw,  instead  of  being  perfectly  even  and  straight- edged.*  An  experiment 
recently  made  by  Mr.  Christie,  secretary  to  the  Royal  Society,  appears 
to  demonstrate  that  ice,  under  great  pressure,  possesses  a  sufficient  de- 
gree of  moulding  and  self-adapting  power  to  allow  it  to  be  acted  upon, 
as  if  it  were  a  pasty  substance.  A  hollow  shell  of  iron  an  inch  and  a 
half  thick,  the  interior  being  ten  inches  in  diameter,  was  filled  with  water, 
in  the  course  of  a  severe  winter,  and  exposed  to  the  frost,  with  the  fuze- 
hole  uppermost.  A  portion  of  the  water  expanded  in  freezing,  so  as  to 
protrude  a  cylinder  of  ice  from  the  fuze-hole  ;  and  this  cylinder  contin- 
ued to  grow  inch  by  inch  in  proportion  as  the  central  nucleus  of  water 
froze.  As  we  cannot  doubt  that  an  outer  shell  of  ice  is  first  formed, 
and  then  another  within,  the  continued  rise  of  the  column  through  the 
fuze-hole  must  proceed  from  the  squeezing  of  successive  shells  of  ice 
concentrically  formed,  through  the  narrow  orifice  ;  and  yet  the  pro- 
truded cylinder  consisted  of  entire,  and  not  fragmentary  ice.f 

The  agency  of  glaciers  in  producing  permanent  geological  changes  con- 
sists partly  in  their  power  of  transporting  gravel,  sand,  and  huge  stones 
to  great  distances,  and  partly  in  the  smoothing,  polishing,  and  scoring 
of  their  rocky  channels,  and  the  boundary  walls  of  the  valleys  through 
which  they  pass.  At  the  foot  of  every  steep  cliff  or  precipice  in  high 
Alpine  regions,  a  talus  is  seen  of  rocky  fragments  detached  by  the  al- 
ternate action  of  frost  and  thaw.  If  these  loose  masses,  instead  of  ac- 
cumulating on  a  stationary  base,  happen  to  fall  upon  a  glacier,  they  will 
move  along  with  it,  and,  in  place  of  a  single  heap,  they  will  form  in  the 
course  of  years  a  long  stream  of  blocks.  If  a  glacier  be  20  miles  long, 
and  its  annual  progression  about  500  feet,  it  will  require  about  two  cen- 
turies for  a  block  thus  lodged  upon  its  surface  to  travel  down  from  the 
higher  to  the  lower  regions,  or  to  the  extremity  of  the  icy  mass.  This 
terminal  point  remains  usually  unchanged  from  year  to  year,  although 
every  part  of  the  ice  is  in  motion,  because  the  liquefaction  by  heat  is  just 
sufficient  to  balance  the  onward  movement  of  the  glacier,  which  may  be 
compared  to  an  endless  file  of  soldiers,  pouring  into  a  breach,  and  shot 
down  as  fast  as  they  advance. 

The  stones  carried  along  on  the  ice  are  called  in  Switzerland  the 
"  moraines"  of  the  glacier.  There  is  always  one  line  of  blocks  on  each 
side  or  edge  of  the  icy  stream,  and  often  several  in  the  middle,  where  they 
are  arranged  in  long  ridges  or  mounds,  often  several  yards  high.  (See 
fig.  18,  p.  223.)  The  cause  of  these  "medial  moraines"  was  first  ex- 
plained by  Agassiz,  who  referred  them  to  the  confluence  of  tributary 
glaciers. |  Upon  the  union  of  two  streams  of  ice,  the  right  lateral  moraine 

*  See  Mr.  Hopkins  on  Motion 'of  Glaciers,  Cambridge  Phil.  Trans.  1844,  and 
Phil.  Mag.  1845.  Some  of  the  late  concessions  of  this  author  as  to  a  certain  plas^ 
ticity  in  the  mass,  appear  to  me  to  make  the  difference  between  him  and  Profes- 
sor Forbes  little  more  than  one  of  degree.  (For  the  latest  summary  of  Prof. 
Forbes'  views,  see  Phil.  Trans.  1846,  pt.  2.) 

f  This  experiment  is  cited  by  Mr.  Forbes,  Phil.  Trans.  1846,  p.  206  ;  and  I  have 
conversed  with  Mr.  Christie  on  the  subject. 

\  Etudes  sur  les  Glaciers,  1840. 


CH.  XV.]        KOCKS   AND   MUD   TRANSPORTED   BY   GLACIERS.  227 

of  one  of  the  streams  comes  in  contact  with  the  left  lateral  moraine  of 
the  other,  and  they  afterwards  move  on  together,  in  the  centre,  if  the 
confluent  glaciers  are  equal  in  size,  or  nearer  to  one  side  if  unequal. 

All  sand  and  fragments  of  soft  stone  which  fall  through  fissures  and 
reach  the  bottom  of  the  glaciers,  or  which  are  interposed  between  the 
glacier  and  the  steep  sides  of  the  valley,  are  pushed  along,  and  ground 
down  into  mud,  while  the  larger  and  harder  fragments  have  their  angles 
worn  off.  At  the  same  time  the  fundamental  and  boundary  rocks  are 
smoothed  and  polished,  and  often  scored  with  parallel  furrows,  or  with 
lines  and  scratches  produced  by  hard  minerals,  such  as  crystals  of  quartz, 
which  act  like  the  diamond  upon  glass.*  This  effect  is  perfectly  differ- 
ent from  that  caused  by  the  action  of  water,  or  a  muddy  torrent  forcing 
along  heavy  fragments  ;  for  when  stones  are  fixed  firmly  in  the  ice,  and 
pushed  along  by  it  under  great  pressure,  in  straight  lines,  they  scoop  out 
long  rectilinear  furrows  or  grooves  parallel  to  each  other.f  The  dis- 
covery of  such  markings  at  various  heights  far  above  the  surface  of  the 
existing  glaciers  and  for  miles  beyond  their  present  terminations,  affords 
geological  evidence  of  the  former  extension  of  the  ice  beyond  its  present 
limits  in  Switzerland  and  other  countries. 

The  moraine  of  the  glacier,  observes  Charpentier,  is  entirely  devoid  of 
stratification,  for  there  has  been  no  sorting  of  the  materials,  as  in  the  case 
of  sand,  mud,  and  pebbles,  when  deposited  by  running  water.  The  ice 
transports  indifferently,  and  to  the  same  spots,  the  heaviest  blocks  and 
the  finest  particles,  mingling  all  together,  and  leaving  them  in  one  con- 
fused and  promiscuous  heap  wherever  it  melts.J 

Icebergs. — In  countries  situated  in  high  northern  latitudes,  like  Spitz- 
bergen,  between  70°  and  80°  N.,  glaciers,  loaded  with  mud  and  rock, 
descend  to  the  sea,  and  there  huge  fragments  of  them  float  off  and  be- 
come icebergs.  Scoresby  counted  500  of  these  bergs  drifting  along 
in  latitudes  69°  and  70°  N.,  which  rose  above  the  surface  from  the 
height  of  100  to  200  feet,  and  measured  from  a  few  yards  to  a  mile  m 
circumference.^  Many  of  them  were  loaded  with  beds  of  earth  and  rock 
of  such  thickness,  that  the  weight  was  conjectured  to  be  from  50,000  to 
100,000  tons.  Specimens  of  the  rocks  were  obtained,  and  among  them 
were  granite,  gneiss,  mica-schist,  clay-slate,  granular  felspar,  and  green- 
stone. Such  bergs  must  be  of  great  magnitude ;  because  the  mass  of 
ice  below  the  level*  of  the  water  is  about  eight  times  greater  than  that 
above.  Wherever  they  are  dissolved,  it  is  evident  that  the  "  moraine" 
will  fall  to  the  bottom  of  the  sea.  In  this  manner  may  submarine  val- 
leys, mountains,  and  platforms  become  strewed  over  with  gravel,  sand, 
mud,  and  scattered  blocks  of  foreign  rock,  of  a  nature  perfectly  dissimi- 
lar from  all  in  the  vicinity,  and  which  may  have  been  transported  across 
unfathomable  abysses.  If  the  bergs  happen  to  melt  in  still  water,  so 
that  the  earthy  and  stony  materials  may  fall  tranquilly  to  the  bottom, 

*  See  Manual  of  Geol.  ch.  xi. 

f   Aga-siz,  Jam.  Ed.  New  Phil.  Journ.  No.  54,  p.  388. 

\  Charpentier,  Ann.  des  Mines,  torn.  viii. ;  pee  also  Papers  by  MM.  Venetz  and 
Aga^siz.  §  Voyage  in  1822,  p.  233. 


228  BOOKS    AND   MUD   TRANSPORTED   BY   GLACIERS.      [On.  XV 

the  deposit  will  probably  be  unstratified,  like  the  terminal  moraine  of  a 
glacier ;  but  whenever  the  materials  are  under  the  influence  of  a  current 
of  water  as  they  fall,  they  will  be  sorted  and  arranged  according  to  theii 
relative  weight  and  size,  and  therefore  more  or  less  perfectly  stratified. 

In  a  former  chapter  it  was  stated  that  some  ice  islands  have  been 
known  to  drift  from  Baffin's  Bay  to  the  Azores,  and  from  the  South  Pole 
to  the  immediate  neighborhood  of  the  Cape  of  Good  Hope,  so  that  the 
area  over  which  the  effects  of  moving  ice  may  be  experienced,  compre- 
hends a  large  portion  of  the  globe. 

We  learn  from  Von  Buch  that  the  most  southern  point  on  the  conti- 
nent of  Europe  at  which  a  glacier  comes  down  to  the  sea  is  in  Norway, 
in  lat.  67°  N.*  But  Mr.  Darwin  has  shown,  that  they  extend  to  the 
sea,  in  South  America,  in  latitudes  more  than  20°  nearer  the  equator 
than  in  Europe ;  as,  for  example,  in  Chili,  where,  in  the  Gulf  of  Penas, 
lat.  46°  40'  S.,  or  the  latitude  of  central  France ;  and  in  Sir  George 
Eyre's  Sound,  in  the  latitude  of  Paris,  they  give  origin  to  iceb'ergs,  which 
were  seen  in  1834  carrying  angular  pieces  of  granite,  and  stranding  them 
in  fiords,  where  the  shores  were  composed  of  clay-slate.f  A  large  pro- 
portion, however,  of  the  ice-islands  seen  floating  both  in  the  northern 
and  southern  hemispheres,  are  probably  not  generated  by  glaciers,  but 
rather  by  the  accumulation  of  coast  ice.  When  the  sea  freezes  at  the 
base  of  a  lofty  precipice,  the  sheet  of  ice  is  prevented  from  adhering  to 
the  land  by  the  rise  and  fall  of  the  tide.  Nevertheless,  it  often  con- 
tinues on  the  shore  at  the  foot  of  the  cliff,  and  receives  accessions  of 
drift  snow  blown  from  the  land.  Under  the  weight  of  this  snow  the  ice 
sinks  slowly  if  the  water  be  deep,  and  the  snow  is  gradually  converted 
into  ice  by  partial  liquefaction  and  re-congelation.  In  this  manner,  islands 
of  ice  of  great  thickness  and  many  leagues  in  length,  originate,  and  are 
eventually  blown  out  to  sea  by  off-shore  winds.  In  their  interior  are  in- 
closed many  fragments  of  stone  which  had  fallen  upon  them  from  over- 
hanging cliffs  during  their  formation.  Such  floating  icebergs  are  com- 
monly flat-topped,  but  their  lower  portions  are  liable  to  melt  in  latitudes 
where  the  ocean  at  a  moderate  depth  is  usually  warmer  than  the  surface 
water  and  the  air.  Hence  their  centre  of  gravity  changes  continually, 
and  they  turn  over  and  assume  very  irregular  shapes. 

In  a  voyage  of  discovery  made  in  the  antarctic  regions  in  1839,  a  dark- 
colored  angular  mass  of  rock  was  seen  imbedded  in  an  iceberg,  drifting 
along  in  mid-ocean  in  lat.  6 1  °  S.  That  part  of  the  rock  which  was  visi- 
ble was  about  12  feet  in  height,  and  from  5  to  6  in  width,  but  the  dark 
color  of  the  surrounding  ice  indicated  that  much  more  of  the  stone  was 
concealed.  A  sketch  made  by  Mr.  Macnab,  when  the  vessel  was  within 
a  quarter  of  a  mile  of  it,  is  now. published. J  This  iceberg,  one  of  many 
observed  at  sea  on  the  same  day,  was  between  250  and  300  feet  high, 
and  was  no  less  than  1400  miles  from  any  certainly  known  land.  It  is 
exceedingly  improbable,  says  Mr.  Darwin,  in  his  notice  of  this  phenom- 

*  Travels  in  Norway.  f  Darwin's  Journal,  p.  283. 

\  Journ.  of  Roy.  Geograph.  Soc.  vol.  ix.  p.  526. 


CH.  XV.]         KOCKS    AND    MUD    TRANSPORTED   BY    GLACIERS.  229 

enon,  that  any  land  will  hereafter  be  discovered  within  100  miles,  of  the 
spot,  and  it  must  be  remembered  that  the  erratic  was  still  firmly  fixed 
in  the  ice,  and  may  have  sailed  for  many  a  league  farther  before  it 
dropped  to  the  bottom.* 

Captain  Sir  James  Ross,  in  his  antarctic  voyage  in  1841,  42,  and  43, 
saw  multitudes  of  icebergs  transporting  stones  and  rocks  of  various 
sizes,  with  frozen  mud,  in  high  southern  latitudes.  His  companion, 
Dr.  J.  Hooker,  informs  me  that  he  came  to  the  conclusion  that  most 
of  the  southern  icebergs  have  stones  in  them,  although  they  are  usually 
concealed  from  view  by  the  quantity  of  snow  which  falls  upon  them. 

In  the  account  given  by  Messrs.  Dease  and  Simpson,  of  their  recent 
arctic  discoveries,  we  learn  that  in  lat.  71°  N.,  long.  156°  W.,  they 
found  "  a  long  low  spit,  named  Point  Barrow,  composed  of  gravel  and 
coarse  sand,  in  some  parts  more  than  a  quarter  of  a  mile  broad,  which 
the  pressure  of  the  ice  had  forced  up  into  numerous  mounds,  that, 
viewed  from  a  distance,  assumed  the  appearance  of  huge  boulder 
rocks."f 

This  fact  is  important,  as  showing  how  masses  of  drift  ice,  when 
stranding  on  submarine  banks,  may  exert  a  lateral  pressure  capable  of 
bending  and  dislocating  any  yielding  strata  of  gravel,  sand,  or  mud. 
The  banks  on  which  icebergs  occasionally  run  aground  between  Baffin's 
Bay  and  Newfoundland,  are  many  hundred  feet  under  water,  and  the 
force  with  which  they  are  struck  will  depend  not  so  much  on  the  ve- 
locity as  the  momentum  of  the  floating  ice-islands.  The  same  berg  is 
often  carried  away  by  a  change  of  wind,  and  then  driven  back  again 
upon  the  same  bank,  or  it  is  made  to  rise  and  fall  by  the  waves  of  the 
ocean,  so  that  it  may  alternately  strike  the  bottom  with  its  whole 
weight,  and  then  be  lifted  up  again  until  it  has  deranged  the  superficial 
beds  over  a  wide  area.  In  this  manner  the  geologist  may  account,  per- 
haps, for  the  circumstance  that  in  Scandinavia,  Scotland,  and  other 
countries  where  erratics  are  met  with,  the  beds  of  sand,  loam,  and 
gravel  are  often  vertical,  bent,  and  contorted  into  the  most  complicated 
folds,  while  the  underlying  strata,  although  composed  of  equally  pliant 
materials,  are  horizontal.  But  some  of  these  curvatures  of  loose  strata 
may  also  have  been  due  to  repeated  alternations  of  layers  of  gravel  and 
sand,  ice  and  snow,  the  melting  of  the  latter  having  caused  the  interca- 
lated beds  of  indestructible  matter  to  assume  their  present  anomalous 
position. 

There  can  be  little  doubt  that  icebergs  must  often  break  off  the  peaks 
and  projecting  points  of  submarine  mountains,  and  must  grate  upon  and 
polish  their  surface,  furrowing  or  scratching  them  in  precisely  the  same 
way  as  we  have  seen  that  glaciers  act  on  the  solid  rocks  over  which 
they  are  propelled.]; 

*  Journ.  of  Roy.  Geograph.  Soc.  vol.  ix.  p.  529. 

f  Ibid.  vol.  viii.  p.  221. 

\  In  my  Travels  in  N.  America,  pp.  19,  23,  <fec.,  and  Second  Visit  to  the  U.  S., 
vol.  i.  ch.  2,  also  in  my  Manual  of  Geology,  a  more  full  account  of  the  action  of 
floating  ice  and  coast-ice,  and  its  bearing  on  geology,  will  be  found. 


230 


ICE-DRIFTED   ROCKS   OF   LABRADOR. 


[Cn.  XV. 


To  conclude :  it  appears  that  large  stones,  mud,  and  gravel  are  car- 
ried down  by  the  ice  of  rivers,  estuaries,  and  glaciers,  into  the  sea, 
where  the  tides  and  currents  of  the  ocean,  aided  by  the  wind,  cause 
them  to  drift  for  hundreds  of  miles  from  the  place  of  their  origin.  Al- 
though it  will  belong  more  properly  to  the  seventh  and  eighth  chapters 
to  treat  of  the  transportation  of  solid  matter  by  the  movements  of  the 
ocean,  I  shall  add  here  what  I  have  farther  to  say  on  this  subject  in 
connection  with  ice. 

The  saline  matter  which  sea-water  holds  in  solution,  prevents  its  con- 
gelation, except  where  the  most  intense  cold  prevails.  But  the  drifting 
of  the  snow  from  the  land  often  renders  the  surface-water  brackish  near 
the  coast,  so  that  a  sheet  of  ice  is  readily  formed  there,  and  by  this 
means  a  large  quantity  of  gravel  is  frequently  conveyed  from  place  to 
place,  and  heavy  boulders  also,  when  the  coast-ice  is  packed  into  dense 
masses.  Both  the  large  and  small  stones  thus  conveyed  usually  travel 
in  one  direction  like  shingle-beaches,  and  this  was  observed  to  take 
place  on  the  coast  of  Labrador  and  Gulf  of  St.  Lawrence,  between  the 
latitudes  50°  and  60°  N.,  by  Capt.  Bayfield,  during  his  late  survey. 
The  line  of  coast  alluded tto  is  strewed  over  for  a  distance  of  700  miles 
with  ice-borne  boulders,  often  6  feet  in  diameter,  which  are  for  the  most 
part  on  their  way  from  north  to  south,  or  in  the  direction  of  the  prevail- 
ing current.  Some  points  on  this  coast  have  been  observed  to  be  occa- 
sionally deserted,  and  then  again  at  another  season  thickly  bestrewed 
with  erratics. 

The  accompanying  drawing  (fig.  19),  for  which  I  am  indebted  to 

Fig.  19. 


Boulders,  chiefly  of  granite,  stranded  by  ice  on  the  coast  of  Labrador,  between  lat.  50°  and  60°  N. 
(Lieut.  Bowen,  E.  N.) 

Lieut.  Bowen,  R.  N.,  represents  the  ordinary  appearance  of  the  Labrador 
coast,  between  the  latitudes  of  50°  and  60°  N.  Countless  blocks,  chiefly 
granitic,  and  of  various  sizes,  are  seen  lying  between  high  and  low-watei 


CH.  XV.]  ICE-DRIFTED    ROCKS    OF    THE    BALTIC.  231 

mark.  Capt.  Bayfield  saw  similar  masses  carried  by  ice  through  the 
Straits  of  Belle  Isle,  between  Newfoundland  and  the  American  conti- 
nent, which  he  conceives  may  have  travelled  in  the  course  of  'years 
from  Baffin's  Bay,  a  distance  which  may  be  compared  in  our  hemisphere 
to  the  drifting  of  erratics  from  Lapland  and  Iceland  as  far  south  as  Ger- 
many, France,  and  England. 

It  may  be  asked  in  what  manner  have  these  blocks  been  originally 
detached  ?  We  may  answer  that  some  have  fallen  from  precipitous 
cliffs,  others  have  been  lifted  up  from  the  bottom  of  the  sea,  adhering 
by  their  tops  to  the  ice,  while  others  have  been  brought  down  by  rivers 
and  glaciers. 

The  erratics  of  North  America  are  sometimes  angular,  but  most  of 
them  have  been  rounded  either  by  friction  or  decomposition.  The 
granite  of  Canada,  as  before  remarked  (p.  221),  has  a  tendency  to  con- 
centric exfoliation,  and  scales  off  in  spheroidal  coats  when  exposed  to 
the  spray  of  the  sea  during  severe  frosts.  The  range  of  the  thermome- 
ter in  that  country  usually  exceeds,  in  the  course  of  the  year,  100°,  and 
sometimes  120°  F. ;  and,  to  prevent  the  granite  used  in  the  buildings 
of  Quebec  from  peeling  off  in  winter,  it  is  necessary  to  oil  and  paint  the 
squared  stones. 

In  parts  of  the  Baltic,  such  as  the  Gulf  of  Bothnia,  where  the  quan- 
tity of  salt  in  the  water  amounts  in  general  to  one  fourth  only  of  that  in 
the  ocean,  the  entire  surface  freezes  over  in  winter  to  the  depth  of  5  or 
6  feet.  Stones  are  thus  frozen  in,  and  afterwards  lifted  up  about  3  feet 
perpendicularly  on  the  melting  of  the  snow  in  summer,  and  then  carried 
by  floating  ice-islands  to  great  distances.  Professor  Von  Baer  states,  in 
a  communication  on  this  subject  to  the  Academy  of  St.  Petersburg,  that 
a  block  of  granite,  weighing  a  million  of  pounds,  was  carried  by  ice  dur- 
ing the  winter  of  1837-8  from  Finland  to  the  island  of  Hockland,  and 
two  other  huge  blocks  were  transported  about  the  years  1806  and  1814 
by  packed  ice  on  the  south  coast  of  Finland,  according  to  the  testimony 
of  the  pilots  and  inhabitants,  one  block  having  travelled  about  a  quarter 
of  a  mile,  and  lying  about  18  feet  above  the  level  of  the  sea.* 

More  recently  Dr.  Forchhammer  has  shown  that  in  the  Sound,  the 
Great  Belt,  and  other  places  near  the  entrance  of  the  Baltic,  ground-ice 
forms  plentifully  at  the  bottom  and  then  rises  to  the  surface,  charged 
with  sand  and  gravel,  stones  and  sea-weed.  Sheets  of  ice,  also,  with 
included  boulders,  are  driven  up  on  the  coast  during  storms,  and  "  pack- 
ed" to  a  height  of  50  feet.  To  the  motion  of  such  masses,  but  still 
more  to  that  of  the  ground-ice,  the  Danish  professor  attributes  the  stria- 
tion  of  rocky  surfaces,  forming  the  shores  and  bed  of  the  sea,  and  he  re- 
lates a  striking  fact  to  prove  that  large  quantities  of  rocky  fragments 
are  annually  carried  by  ice  out  of  the  Baltic.  "  In  the  year  1807,"  he 
says, •"  at  the  time  of  the  bombardment  of  the  Danish  fleet,  an  English 
sloop-of-war,  riding  at  anchor  in  the  roads  at  Copenhagen,  blew  up.  In 

*  Jam.  Ed.  New  Phil.  Journ.  No.  xlviii.  p.  439. 


232  ORIGIN   OF   SPRINGS.  [On.  XVI. 

1844,  or  thirty-seven  years  afterwards,  one  of  our  divers,  known  to  be  a 
trustworthy  man,  went  down  to  save  whatever  might  yet  remain  in  the 
shipwrecked  vessel.  He  found  the  space  between  decks  entire,  but 
covered  with  blocks  from  6  to  8  cubic  feet  in  size,  and  some  of  them 
heaped  one  upon  the  other.  He  also  affirmed,  that  all  the  sunk  ships 
which  he  had  visited  in  the  Sound,  were  in  like  manner  strewed  over 
with  blocks." 

Dr.  Forchhammer  also  informs  us,  that  during  an  intense  frost  in 
February,  1844,  the  Sound  was  suddenly  frozen  over,  and  sheets  of  ice, 
driven  by  a  storm,  were  heaped  up  at  the  bottom  of  the  Bay  of  Taar- 
beijk,  threatening  to  destroy  a  fishing-village  on  the  shore.  The  whole 
was  soon  frozen  together  into  one  mass,  and  forced  up  on  the  beach, 
forming  a  mound  more  than  16  feet  high,  which  threw  down  the  walls 
of  several  buildings.  "  When  I  visited  the  spot  next  day,  I  saw  ridges 
of  ice,  sand,  and  pebbles,  not  only  on  the  shore,  but  extending'  far  out 
into  the  bottom  of  the  sea,  showing  how  greatly  its  bed  had  been  changed, 
and  how  easily,  where  it  is  composed  of  rock,  it  may  be  furrowed  and 
streaked  by  stones  firmly  fixed  in  the  moving  ice."* 


CHAPTER  XVI. 

PHENOMENA    OF    SPRINGS. 

Origin  of  Springs — Artesian  wells — Borings  at  Paris — Distinct  causes  by  which 
mineral  and  thermal  waters  may  be  raised  to  the  surface — Their  connection  with 
volcanic  agency — Calcareous  springs — Travertin  of  the  Elsa — Baths  of  San 
Vignone  and  of  San  Filippo,  near  Radicofani — Spheroidal  structure  in  travertin 
— Lake  of  the  Solfatara,  near  Rome — Travertin  at  Cascade  of  Tivoli — Gypseous, 
siliceous,  and  ferruginous  springs — Brine  springs — Carbonated  springs — Disin- 
tegration of  granite  in  Auvergne — Petroleum  springs — Pitch  lake  of  Trinidad. 

Origin  of  springs. — THE  action  of  running  water  on  the  surface  of  the 
land  having  been  considered,  we  may  next  turn  our  attention  to  what 
may  be  termed  "  the  subterranean  drainage,"  or  the  phenomena  of 
springs.  Every  one  is  familiar  with  the  fact,  that  certain  porous  soils, 
such  as  loose  sand  and  gravel,  absorb  water  with  rapidity,  and  that  the 
ground  composed  of  them  soon  dries  up  after  heavy  showers.  If  a  well 
be  sunk  in  such  soils,  we  often  penetrate  to  considerable  depths  before 
we  meet  with  water  ;  but  this  is  usually  found  on  our  approaching  the 
lower  parts  of  the  formation,  where  it  rests  on  some  impervious  bed  ;  for 
here  the  water,  unable  to  make  its  way  downwards  in  a  direct  line, 
accumulates  as  in  a  reservoir,  and  is  ready  to  ooze  out  into  any  opening 
which  may  be  made,  in  the  same  manner  as  we  see  the  salt  water  flow 
into,  and  fill,  any  hollow  which  we  dig  in  the  sands  of  the  shore  at  low  tide. 

*  Bulletin  de  la  Soc.  Geol.  de  France,  1847,  torn.  iv.  pp.  1182,  1183. 


CH.  XVL]  ORIGIN   OF   SPRINGS.  233 

The  facility  with  which  .water  can  percolate  loose  and  gravelly  soils 
is  clearly  illustrated  by  the  effect  of  the  tides  in  the  Thames  between 
Richmond  and  London.  The  river,  in  this  part  of  its  course,  flows 
through  a  bed  of  gravel  overlying  clay,  and  the  porous  superstratum 
is  alternately  saturated  by  the  water  of  the  Thames  as  the  tide  rises, 
and  then  drained  again  to  the  distance  of  several  hundred  feet  from  the 
banks  when  the  tide  falls,  so  that  the  wells  in  this  tract  regularly  ebb 
and  flow. 

If  the  transmission  of  water  through  a  porous  medium  be  so  rapid, 
we  cannot  be  surprised  that  springs  should  be  thrown  out  on  the  side 
of  a  hill,  where  the  upper  set  of  strata  consist  of  chalk,  sand,  or  other 
permeable  substances,  while  the  subjacent  are  composed  of  clay  or 
other  retentive  soils.  The  only  difficulty,  indeed,  is  to  explain  why  the 
water  does  not  ooze  out  everywhere  along  the  line  of  junction  of  the 
two  formations,  so  as  to  form  one  continuous  land-soak,  instead  of  a 
few  springs  only,  and  these  far  distant  from  each  other.  The  principal 
cause  of  this  concentration  of  the  waters  at  a  few  points  is,  first,  the 
frequency  of  rents  and  fissures,  which  act  as  natural  drains ;  secondly, 
the  existence  of  inequalities  in  the  upper  surface  of  the  impermeable 
stratum,  which  lead  the  water,  as  valleys  do  on  the  external  surface  of 
a  country,  into  certain  low  levels  and  channels. 

That  the  generality  of  springs  owe  their  supply  to  the  atmosphere  is 
evident  from  this,  that  they  become  languid,  or  entirely  cease  to  flow, 
after  long  droughts,  and  are  again  replenished  after  a  continuance  of 
rain.  Many  of  them  are  probably  indebted  for  the  constancy  and  uni- 
formity of  their  volume  to  the  great  extent  of  the  subterranean  reser- 
voirs with  which  they  communicate,  and  the  time  required  for  these  to 
empty  themselves  by  percolation.  Such  a  gradual  and  regulated  dis- 
charge is  exhibited,  though  in  a  less  perfect  degree,  in  every  great  lake 
which  is  not  sensibly  -affected  in  its  level  by  sudden  showers,  but  only 
slightly  raised  ;  so  that  its  channel  of  efflux,  instead  of  being  swollen 
suddenly  like  the  bed  of  a  torrent,  is  enabled  to  carry  off  the  surplus 
water  gradually. 

Much  light  has  been  thrown,  of  late  years,  on  the  theory  of  springs, 
by  the  boring  of  what  are  called  by  the  French  "  Artesian  wells,"  be- 
cause the  method  has  long  been  known  and  practised  in  Artois  ;  and  it 
is  now  demonstrated  that  there  are  sheets,  and  in  some  places  currents 
of  fresh  water,  at  various  depths  in  the  earth.  The  instrument  em- 
ployed in  excavating  these  wells  is  a  large  augur,  and  the  cavity  bored 
is  usually  from  three  to  four  inches  in  diameter.  If  a  hard  rock  is  met 
with,  it  is  first  triturated  by  an  iron  rod,  and  the  materials  being  thus 
reduced  to  small  fragments  or  powder,  are  readily  extracted.  To  hinder 
the  sides  of  the  well  from  falling  in,  as  also"  to  prevent  the  spreading  of 
the  ascending  water  in  the  surrounding  soil,  a  jointed  pipe  is  introduced, 
formed  of  wood  in  Artois,  but  in  other  countries  more  commonly  of 
metal.  It  frequently  happens  that,  after  passing  through  hundreds  of 
feet  of  retentive  soils,  a  water-bearing  stratum  is  at  length  pierced, 


234:  ORIGIN   OF   SPRINGS.  [Cu.  XVI. 

when  the  fluid  immediately  ascends  to  the  surface,  and  flows  over. 
The  first  rush  of  the  water  up  the  tube  is  often  violent,  so  that  for  a  time 
the  water  plays  like  a  fountain,  and  then,  sinking,  continues  to  flow  over 
tranquilly,  or  sometimes  remains  stationary  at  a  certain  depth  below  the 
orifice  of  the  well'.  This  spouting  of  the  water  in  the  first  instance  is 
probably  owing  to  the  disengagement  of  air  and  carbonic  acid  gas,  for 
both  of  these  have  been  seen  to  bubble  up  with  the  water.* 

At  Sheerness,  at  the  mouth  of  the  Thames,  a  well  was  bored  on  a 
low  tongue  of  land  near  the  sea,  through  300  feet  of  the  blue  clay  of 
London,  below  which  a  bed  of  sand  and  pebbles  was  entered,  belonging, 
doubtless,  to  the  plastic  clay  formation  ;  when  this  stratum  was  pierced, 
the  water  burst  up  with  impetuosity,  and  filled  the  well.  By  another 
perforation  at  the  same  place,  the  water  was  found  at  the  depth  of  328 
feet  below  the  surface  clay  ;  it  first  rose  rapidly  to  the  height  of  189  feet, 
and  then,  in  the  course  of  a  few  hours,  ascended  to  an  elevation  of 
eight  feet  above  the  level  of  the  ground.  In  1824  a  well  was  dug  at 
Fulham,  near  the  Thames,  at  the  Bishop  of  London's,  to  the  depth  of 
317  feet,  which,  after  traversing  the  tertiary  strata,  was  continued 
through  67  feet  of  chalk.  The  water  immediately  rose  to  the  surface, 
and  the  discharge  was  about  50  gallons  per  minute.  In  the  garden  of 
the  Horticultural  Society  at  Chiswick,  the  borings  passed  through  19 
feet  of  gravel,  242^  feet  of  clay  and  loam,  and  67^  feet  of  chalk,  and 
the  water  then  rose  to  the  surface  from  a  depth  of  329  feet.f  At  the 
Duke  of  Northumberland's,  above  Chiswick,  the  borings  were  carried  to 
the  extraordinary  depth  of  620  feet,  so  as  to  enter  the  chalk,  when  a 
considerable  volume  of  water  was  obtained,  which  rose  four  feet  above 
the  surface  of  the  ground.  In  a  well  of  Mr.  Brooks,  at  Hammersmith, 
the  rush  of  water  from  a  depth  of  360  feet  was  so  great,  as  to  inundate 
several  buildings  and  do  considerable  damage  ;  and  at  Tooting,  a  suffi- 
cient stream  was  obtained  to  turn  a  wheel,  and  raise  the  water  to  the 
upper  stories  of  the  houses. J  In  1838,  the  total  supply  obtained  from 
the  chalk  near  London  was  estimated  at  six  million  gallons  a  day,  and, 
in  1851,  at  nearly  double  that  amount,  the  increase  being  accompanied 
by  an  average  fall  of  no  less  than  two  feet  a  year  in  the  level  to  which 
the  water  rose.  The  water  stood  commonly,  in  1822,  at  high- water 
mark,  and  had  sunk  in  1851  to  45,  and  in  some  wells  to  65  feet  below 
high-water  mark.§  This  fact  shows  the  limited  capacity  of  the  subter- 
ranean reservoir.  In  the  last  of  three  wells  bored  through  the  chalk 
at  Tours,  to  the  depth  of  several  hundred  feet,  the  water  rose  32  feet 
above  the  level  of  the  soil,  and  the  discharge  amounted  to  300  cubic 
yards  of  water  every  twenty-four  hours.  || 

By  way  of  experiment,  the  sinking  of  a  well  was  commenced  at  Paris 

*  Consult  J.  Prestwich,  Water-bearing  Strata  around  London.  1851.  (Van 
Voorst.) 

f  Sabine,  Journ.  of  Sci.  No.  xxxiii.  p.  72.     1824. 

\  Hericart  de  Thury,  "  Puits  Fores,"  p.  49.  §  Prestwich,  p.  69. 

|  Bull,  de  la  Soc.  GeoL  de  France,  torn  iii.  p.  194. 


CH.  XVI] 


ARTESIAN   WELLS. 


235 


in  1834,  which  had  reached,  in  November,  1839,  a  depth  of  more  than 
1600  English  feet,  and  yet  no  water  ascended  to  the  surface.  The 
government  were  persuaded  by  M.  Arago  to  persevere,  if  necessary,  to 
the  depth  of  more  than  2000  feet ;  but  when  they  had  descended 
above  1800  English  feet  below  the  surface,  the  water  rose  through 
the  tube  (which  was  about  ten  inches  in  diameter),  so  as  to  discharge 
half  a  million  of  gallons  of  limpid  water  every  twenty-four  hours.  The 
temperature  of  the  water  increased  at  the  rate  of  1°  8'  F.  for  every  101 
English  feet,  as  they  went  down,  the  result  agreeing  very  closely  with 
the  anticipations  of  the  scientific  advisers  of  this  most  spirited  under- 
taking. 

Mr.  Briggs,  the  British  consul  in  Egypt,  obtained  water  between 
Cairo  and  Suez,  in  a  calcareous  sand,  at  the  depth  of  thirty  feet ;  but 
it  did  not  rise  in  the  well.*  But  other  borings  in  the  same  desert,  of 
variable  depth,  between  50  and  300  feet,  and  which  passed  through 
alternations  of  sand,  clay,  and  siliceous  rock,  yielded  water  at  the 
surface. | 

The  rise  and  overflow  of  the  water  in  Artesian  wells  is  generally 
referred,  and  apparently  with  reason,  to  the  same  principle  as  the  play 
of  an  artificial  fountain.  Let  the  porous  stratum  or  set  of  strata,  a  a, 
rest  on  the  impermeable  rock  d,  and  be  covered  by  another  mass  of  an 
impermeable  nature.  The  whole  mass  a  a  may  easily,  in  such  a  posi- 
tion, become  saturated  with  water,  which  may  descend  from  its  higher 
and  exposed  parts — a  hilly  region  to  which  clouds  are  attracted,  and 

Fig.  20. 


where  rain  falls  in  abundance.  Suppose  that  at  some  point,  as  at  ft, 
an  opening  be  made,  which  gives  a  free  passage  upwards  to  the  waters 
confined  in  a  a,  at  so  low  a  level  that  they  are  subjected  to  the  pres- 
sure of  a  considerable  column  of  water  collected  in  the  more  elevated 
portion  of  the  same  stratum.  The  water  will  then  rush  out,  just  as  the 
liquid  from  a  large  barrel  which  is  tapped,  and  it  will  rise  to  a  height 
corresponding  to  the  level  of  its  point  of  departure,  or,  rather,  to  a 
height  which  balances  the  pressure  previously  exerted  by  the  confined 
waters  against  the  roof  and  sides  of  the  stratum  or  reservoir  a  a.  In 
like  manner,  if  there  happen  to  be  a  natural  fissure  c,  a  spring  will  be 
produced  at  the  surface  on  precisely  the  same  principle. 

Among  the  causes  of  the  failure  of  Artesian  wells,  we  may  mention 
those  numerous  rents  and  faults  which  abound  in  some  rocks,  and  the 

*  Boue  Resume  des  Prog,  de  la  Geol.  en  1832,  p.  184. 
f  Seventh  Rep.  Brit.  Ass.  1837,  p.  66. 


236  ARTESIAN   WELLS.  [Cfl.  XVI. 

deep  ravines  and  valleys  by  which  many  countries  are  traversed  ;  for, 
when  these  natural  lines  of  drainage  exist,  there  remains  a  small  quan- 
tity only  of  water  to  escape  by  artificial  issues.  We  are  also  liable  to 
be  baffled  by  the  great  thickness  either  of  porous  or  impervious  strata, 
or  by  the  dip  of  the  beds,  which  may  carry  off  the  waters  from  the  ad- 
joining high  lands  to  some  trough  in  an  opposite  direction,  as  when  the 
borings  are  made  at  the  foot  of  an  escarpment  where  the  strata  incline 
inwards,  or  in  a  direction  opposite  to  the  face  of  the  cliffs. 

The  mere  distance  of  hills  or  mountains  need  not  discourage  us  from 

O 

making  trials ;  for  the  waters  which  fall  on  these  higher  lands  readily 
penetrate  to  great  depths  through  highly  inclined  or  vertical  strata,  or 
through  the  fissures  of  shattered  rocks,  and  after  flowing  for  a  great 
distance,  must  often  reascend  and  be  brought  up  again  by  other  fissures, 
so  as  to  approach  the  surface  in  the  lower  country.  Here  they  may 
be  concealed  beneath  the  covering  of  undisturbed  horizontal  beds,  which 
it  may  be  necessary  to  pierce  in  order  to  reach  them.  It  should  be 
remembered,  that  the  course  of  waters  flowing  under  ground  bears 
but  a  remote  resemblance  to  that  of  rivers  on  the  surface,  there  being, 
in  the  one  case,  a  constant  descent  from  a  higher  to  a  lower  level  from 
the  source  of  the  stream  to  the  sea ;  whereas,  in  the  other,  the  water 
may  at  one  time  sink  far  below  the  level  of  the  ocean,  and  afterwards 
rise  again  high  above  it. 

Among  other  curious  facts  ascertained  by  aid  of  the  borer,  it  is 
proved  that  in  strata  of  different  ages  and  compositions,  there  are  often 
open  passages  by  which  the  subterranean  waters  circulate.  Thus,  at 
St.  Ouen,  in  France,  five  distinct  sheets  of  water  were  intersected  in  a 
well,  and  from  each  of  these  a  supply  obtained.  In  the  third  water- 
bearing stratum,  at  the  depth  of  150  feet,  a  cavity  was  found  in  which 
the  borer  fell  suddenly  about  a  foot,  and  thence  the  water  ascended  in 
great  volume.*  The  same  falling  of  the  instrument,  as  in  a  hollow 
space,  has  been  remarked  in  England  and  other  countries.  At  Tours, 
in  1830,  a  well  was  perforated  quite  through  the  chalk,  when  the 
water  suddenly  brought  up,  from  a  depth  of  364  feet,  a  great  quantity 
of  fine  sand,  with  much  vegetable  matter  and  shells.  Branches  of  a 
thorn  several  inches  long,  much  blackened  by  their  stay  in  the  water, 
were  recognized,  as  also  the  stems  of  marsh  plants,  and  some  of  their 
roots,  which  were  still  white,  together  with  the  seeds  of  the  same  in  a 
state  of  preservation,  which  showed  that  they  had  not  remained  more 
than  three  or  four  months  in  the  water.  Among  the  seeds  were  those 
of  the  marsh  plant  Galium  uliginosum  y  and  among  the  shells,  a  fresh- 
water species  (Planorbis  marginatus),  and  some  land  species,  as  Helix 
rotundata  and  H.  striata.  M.  Dujardin,  who,  with  others,  observed 
this  phenomenon,  supposes  that  the  waters  had  flowed  from  some  val- 
leys of  Auvergne  or  the  Vivarais  since  the  preceding  autumn. f 

An  analogous  phenomenon  is  recorded  at  Reimke,  near  Bochum  in 

*  H.  de  Thury,  p.  295.  f  Bull,  de  la  Soc.  G6ol  de  France,  torn.  i.  p.  93. 


CH.  XVI]  MINERAL    AND   THERMAL    SPRINGS.  237 

Westphalia,  where  the  water  of  an  Artesian  well  brought  up,  from  a 
depth  of  156  feet,  several  small  fish,  three  or  four  inches  long,  the 
nearest  streams  in  the  country  being  at  a  distance  of  some  leagues.* 

In  both  cases  it  is  evident  that  water  had  penetrated  to  great 
depths,  not  simply  by  filtering  through  a  porous  mass,  for  then  it 
would  have  left  behind  the  shells,  fish,  and  fragments  of  plants,  but  by 
flowing  through  some  open  channels  in  the  earth.  Such  examples 
may  suggest  the  idea  that  the  leaky  beds  of  rivers  are  often  the  feeders 
of  springs. 

MINERAL    AND    THERMAL    SPRINGS. 

Almost  all  springs,  even  those  which  we  consider  the  purest,  are 
impregnated  with  some  foreign  ingredients,  which,  being  in  a  state  of 
chemical  solution,  are  so  intimately  blended  with  the  water  as  not  to 
affect  its  clearness,  while  they  render  it,  in  general,  more  agreeable  to 
our  taste,  and  more  nutritious  than  simple  rain-water.  But  the  springs 
called  mineral  contain  an  unusual  abundance  of  earthy  matter  in  solution, 
'and  the  substances  with  which  they  are  impregnated  correspond  remark- 
ably with  those  evolved  in  a  gaseous  form  by  volcanoes.  Many  of  these 
springs  are  thermal,  i.  e.,  their  temperature  is  above  the  mean  tempera- 
ture of  the  place,  and  they  rise  up  through  all  kinds  of  rock ;  as,  for 
example,  through  granite,  gneiss,  limestone,  or  lava,  but  are  most  fre- 
quent in  volcanic  regions,  or  where  violent  earthquakes  have  occurred 
at  eras  comparatively  modern. 

The  water  given  out  by  hot  springs  is  generally  more  voluminous  and 
less  variable  in  quantity  at  different  seasons  than  that  proceeding  from 
any  others.  In  many  volcanic  regions,  jets  of  steam,  called  by  the 
Italians  "  stufas/'  issue  from  fissures,  at  a  temperature  high  above  the 
boiling  point,  as  in  the  neighborhood  of  Naples,  and  in  the  Lipari  Isles, 
and  are  disengaged  unceasingly  for  ages.  Now,  if  such  columns  of 
steam,  which  are  often  mixed  with  other  gases,  should  be  condensed 
before  reaching  the  surface  by  coming  in  contact  with  strata  filled  with 
cold  water,  they  may  give  rise  to  thermal  and  mineral  springs  of  every 
degree  of  temperature.  It  is,  indeed,  by  this  means  only,  and  not  by 
hydrostatic  pressure,  that  we  can  account  for  the  rise  of  such  bodies  of 
water  from  great  depths ;  nor  can  we  hesitate  to  admit  the  adequacy  of 
the  cause,  if  we  suppose  the  expansion  of  the  same  elastic  fluids  to  be 
sufficient  to  raise  columns  of  lava  to  the  lofty  summits  of  volcanic  moun- 
tains. Several  gases,  the  carbonic  acid  in  particular,  are  disengaged  in 
a  free  state  from  the  soil  in  many  districts,  especially  in  the  regions  of 
active  or  extinct  volcanoes ;  and  the  same  are  found  more  or  less  inti- 
mately combined  with  the  waters  of  all  mineral  springs,  both  cold  and 
thermal.  Dr.  Daubeny  and  other  writers  have  remarked,  not  only  that 
these  springs  are  most  abundant  in  volcanic  regions,  but  that  when 
remote  from  them,  their  site  usually  coincides  with  the  position  of  some 

*  Bull,  do  la  Soc.  Geol.  de  France,  torn.  ii.  p.  248. 


238  MINERAL   SPRINGS.  [Ce.  XVI. 

great  derangement  in  the  strata ;  a  fault,  for  example,  or  great  fissure, 
•  indicating  that  a  channel  of  communication  has  been  opened  with  the 
interior  of  the  earth  at  some  former  period  of  local  convulsion.  It  is 
also  ascertained  that  at  great  heights  in  the  Pyrenees  and  Himalaya 
mountains  hot  springs  burst  out  from  granitic  rocks,  and  they  are  abun- 
dant in  the  Alps  also,  these  chains  having  all  been  disturbed  and  dislo- 
cated at  times  comparatively  modern,  as  can  be  shown  by  independent 
geological  evidence. 

The  small  area  of  volcanic  regions  may  appear,  at  first  view,  to  pre- 
sent an  objection  to  these  views,  but  not  so  when  we  include  earth- 
quakes among  the  effects  of  igneous  agency.  A  large  proportion  of 
the  land  hitherto  explored  by  geologists  can  be  shown  to  have  been 
rent  or  shaken  by  subterranean  movements  since  the  oldest  tertiary 
strata  were  formed.  It  will  also  be  seen,  in  the  sequel,  that  new 
springs  have  burst  out,  and  others  have  had  the  volume  of  their  waters 
augmented,  and  their  temperature  suddenly  raised  after  earthquakes,  so 
that  the  description  of  these  springs  might  almost  with  equal  propriety 
have  been  given  under  the  head  of  "  igneous  causes,"  as  they  are  agents 
of  a  mixed  nature,  being  at  once  igneous  and  aqueous. 

But  how,  it  will  be  asked,  can  the  regions  of  volcanic  heat  send  forth 
such  inexhaustible  supplies  of  water?  The  difficulty  of  solving  this 
problem  would,  in  truth,  be  insurmountable,  if  we  believed  that  all  the 
atmospheric  waters  found  their  way  into  the  basin  of  the  ocean  ;  but  in 
boring  near  the  shore  we  often  meet  with  streams  of  fresh  water  at  the 
depth  of  several  hundred  feet  below  the  sea  level ;  and  these  probably 
descend,  in  many  cases,  far  beneath  the  bottom  of  the  sea,  when  not 
artificially  intercepted  in  their  course.  Yet,  how  much  greater  may  be 
the  quantity  of  salt  water  which  sinks  beneath  the  floor  of  the  ocean, 
through  the  porous  strata  of  which  it  is  often  composed,  or  through 
fissures  rent  in  it  by  earthquakes.  After  penetrating  to  a  considerable 
depth,  this  water  may  encounter  a  heat  of  sufficient  intensity  to  convert 
it  into  vapor,  even  under  the  high  pressure  to  which  it  would  then  be 
subjected.  This  heat  would  probably  be  nearest  the  surface  in  volcanic 
countries,  and  farthest  from  it  in  those  districts  which  have  been  longest 
free  from  eruptions  or  earthquakes. 

It  would  follow  from  the  views  above  explained,  that  there  must  be 
a  twofold  circulation  of  terrestrial  waters ;  one  caused  by  solar  heat, 
and  the  other  by  heat  generated  in  the  interior  of  our  planet.  We 
know  that  the  land  would  be  unfit  for  vegetation,  if  deprived  of  the 
waters  raised  into  the  atmosphere  by  the  sun ;  but^it  is  also  true  that 
mineral  springs  are  powerful  instruments  in  rendering  the  surface  sub- 
servient to  the  support  of  animal  and  vegetable  life.  Their  heat  is  said 
to  promote  the  development  of  the  aquatic  tribes  in  many  parts  of  the 
ocean,  and  the  substances  which  they  carry  up  from  the  bowels  of  the 
earth  to  the  habitable  surface,  are  of  a  nature  and  in  a  form  which 
adapts  them  peculiarly  for  the  nutrition  of  animals  and  plants. 

As  these  springs  derive  their  chief  importance  to  the  geologist  from 


CH.  XVI.]  CALCAREOUS  SPRINGS.  239 

the  quantity  and  quality  of  the  earthy  materials  which,  like  volcanoes, 
they  convey  from  below  upwards,  they  may  properly  be  considered  in 
reference  to  the  ingredients  which  they  hold  in  solution.  These  consist 
of  a  great  variety  of  substances ;  but  chiefly  salts  with  bases  of  lime, 
magnesia,  alumine,  and  iron,  combined  with  carbonic,  sulphuric,  and  mu- 
riatic acids.  Muriate  of  soda,  silica,  and  free  carbonic  acid  are  frequently 
present ;  also  springs  of  petroleum,  or  liquid  bitumen,  and  of  naphtha. 

Calcareous  springs. — Our  first  attention  is  naturally  directed  to  springs 
which  are  highly  charged  with  calcareous  matter,  for  these  produce  a 
variety  of  phenomena  of  much  interest  in  geology.  It  is  known  that 
rain-water  collecting  carbonic  acid  from  the  atmosphere  has  the  property 
of  dissolving  the  calcareous  rocks  over  which  it  flows,  and  thus,  in  the 
smallest  ponds  and  rivulets,  matter  is  often  supplied  for  the  earthy  se- 
cretions of  testacea,  and  for  the  growth  of  certain  plants  on  which  they 
feed.  But  many  springs  hold  so  much  carbonic  acid  in  solution,  that 
they  are  enabled  to  dissolve  a  much  larger  quantity  of  calcareous  matter 
than  rain-water  ;  and  when  the  acid  is  dissipated  in  the  atmosphere,  the 
mineral  ingredients  are  thrown  down,  in  the  form  of  porous  tufa  or  of 
more  compact  travertin.* 

Auvergne. — Calcareous  springs,  although  most  abundant  in  limestone 
districts,  are  by  no  means  confined  to  thera,  but  flow  out  indiscriminately 
from  all  rock  formations.  In  central  France,  a  district  where  the  pri- 
mary rocks  are  unusually  destitute  of  limestone,  springs  copiously 
charged  with  carbonate  of  lime  rise  up  through  the  granite  and  gneiss. 
Some  of  these  are  thermal,  and  probably  deiive  their  origin  from  the 
deep  source  of  volcanic  heat,  once  so  active  in  that  region.  One  of  these 
springs,  at  the  northern  base  of  the  hill  upon  which  Claremont  is  built, 
issues  from  volcanic  peperino,  which  rests  on  granite.  It  has  formed, 
by  its  incrustations,  an  elevated  mound  of  travertin,  or  white  concretion- 
ary limestone,  240  feet  in  length,  and,  at  its  termination,  sixteen  feet 
high  and  twelve  wide.  Another  encrusting  spring  in  the  same  depart- 
ment, situated  at  Chaluzet,  near  Pont  Gibaud,  rises  in  a  gneiss  country, 
at  the  foot  of  a  regular  volcanic  cone,  at  least  twenty  miles  from  any 
calcareous  rock.  Some  masses  of  tufaceous  deposit,  produced  by  this 
spring,  have  an  oolitic  texture. 

Valley  of  the  Elsa. — If  we  pass  from  the  volcanic  district  of  France 
to  that  which  skirts  the  Apennines  in  the  Italian  peninsula,  we.  meet 
with  innumerable  springs  which  have  precipitated  so  much  calcareous 
matter,  that  the  whole  ground  in  some  parts  of  Tuscany  is  coated  over 
with  tufa  and  travertin,  and  sounds  hollow  beneath  the  foot. 

In  other  places  in  the  same  country,  compact  rocks  are  seen  descend- 
ing the  slanting  sides  of  hills,  very  much  in  the  manner  of  lava  currents, 
except  that  they  are  of  a  white  color  and  terminate  abruptly  when  they 
reach  the  course  of  a  river.  These  consist  of  a  calcareous  precipitate 
from  springs,  some  of  which  are  still  flowing,  while  others  have  disap- 

*  See  Glossary,  "  Tufa,"  "  Travertin." 


240 


TBAVEKTIN   OF   SAN   VIGNONF 


[OH.  XVI. 


peared  or  changed  their  position.  Such  masses  are  frequent  on  the 
slope  of  the  hills  which  bound  the  valley  of  the  Elsa,  one  of  the  tribu- 
taries of  the  Arno,  which  flows  near  Colle,  through  a  valley  several  hun- 
dred feet  deep,  shaped  out  of  a  lacustrine  formation,  containing  fossil 
shells  of  existing  species.  I  observed  here  that  the  travertin  was  un- 
conformable  to  the  lacustrine  beds,  its  inclination  according  with  the 
slope  of  the  sides  of  the  valley.  One  of  the  finest  examples  which  I 
saw  was  at  the  Molino  delle  Caldane,  near  Colle.  The  Sena,  and  several 
other  small  rivulets  which  feed  the  Elsa,  have  the  property  of  encrusting 
wood  and  herbs  with  calcareous  stone.  In  the  bed  of  the  Elsa  itself, 
aquatic  plants,  such  as  Charee,  which  absorb  large  quantities  of  carbon- 
ate of  lime,  are  very  abundant. 

Baths  of  San  Vignone. — Those  persons  who  have  merely  seen  the 
action  of  petrifying  waters  in  England,  will  not  easily  form  an  adequate 
conception  of  the  scale  on  which  the  same  process  is  exhibited  in  those 
regions  which  lie  nearer  to  the  active  centres  of  volcanic  disturbance. 
One  of  the  most  striking  examples  of  the  rapid  precipitation  of  carbonate 
of  lime  from  thermal  waters,  occurs  in  the  hill  of  San  Vignone  in  Tus- 
cany, at  a  short  distance  from  Radicofani,  and  only  a  few  hundred  yards 
from  the  high  road  between  Sienna  and  Rome.  The  spring  issues  from 
near  the  summit  of  a  rocky  hill,  about  100  feet  in  height.  The  top  of 


Fig.  21. 


Baths  of  San  Vignone. 


Section  of  travertin,  San  Vignone. 

the  hill  stretches  in  a  gently  inclined  platform  to  the  foot  of  Mount 
Amiata,  a  lofty  eminence,  which  consists  in  great  part  of  volcanic  prod- 
ucts. The  fundamental  rock,  from  which  the  spring  issues,  is  a  black 
slate,  with  serpentine  (6  b,  fig.  21),  belonging  to  the  older  Apennine  for- 
mation. The  water  is  hot,  has  a  strong  taste,  and,  when  not  in  very 
small  quantity,  is  of  a  bright  green  color.  So  rapid  is  the  deposition 
near  the  source,  that  in  the  bottom  of  a  conduit-pipe  for  carrying  off 
the  water  to  the  baths,  and  which  is  inclined  at  an  angle  of  30°,  half  a 
foot  of  solid  travertin  is  formed  every  year.  A  more  compact  rock  is 
produced  where  the  water  flows  slowly ;  and  the  precipitation  in  winter, 
when  there  is  lea«t  evaporation,  is  said  to  be  more  solid,  but  less  in 
quantity  by  one-fourth,  than  in  summer.  The  rock  is  generally  white  ; 
some  parts  of  it  are  compact,  and  ring  to  the  hammer ;  others  are  eel- 


CH.  XVI]  TRAVERTIN   OF   SAN   FILTPPO.  241 

lular,  and  with  such  cavities  as  are  seen  in  the  carious  part  of  bone  or 
the  siliceous  millstone  of  the  Paris  basin.  A  portion  of  it  also  below 
the  village  of  San  Vignone  consists  of  incrustations  of  long  vegetable 
tubes,  and  may  be  called  tufa.  Sometimes  the  travertin  assumes  pre- 
cisely the  botryoidal  and  mammillary  forms,  common  to  similar  deposits 
in  Auvergne,  of  a  much  older  date ;  and,  like  them,  it  often  scales  off 
in  thin,  slightly  undulating  layers. 

A  large  mass  of  travertin  (c,  fig.  21)  descends  the  hill  from  the 
point  where  the  spring  issues,  and  reaches  to  the  distance  of  about  half 
a  mile  east  of  San  Vignone.  The  beds  take  the  slope  of  the  hill  at 
about  an  angle  of  6°,  and  the  planes  of  stratification  are  perfectly  par- 
allel. One  stratum,  composed  of  many  layers,  is  of  a  compact  nature, 
and  fifteen  feet  thick ;  it  serves  as  an  excellent  building  stone,  and  a 
mass  of  fifteen  feet  in  length  was,  in  1828,  cut  out  for  the  new  bridge 
over  the  Orcia.  Another  branch  of  it  (a,  fig.  21)  descends  to  the  west, 
for  250  feet  in  length,  of  varying  thickness,  but  sometimes  200  feet 
deep  ;  it  is  then  cut  off  by  the  small  river  Orcia,  as  some  glaciers  in 
Switzerland  descend  into  a  valley  till  their  progress  is  suddenly  arrested 
by  a  transverse  stream  of  water. 

The  abrupt  termination  of  the  mass  of  rock  at  the  river,  where  its 
thickness  is  undiminished,  clearly  shows  that  it  would  proceed  much 
farther  if  not  arrested  by  the  stream,  over  which  it  impends  slightly. 
But  it  cannot  encroach  upon  the  channel  of  the  Orcia,  being  constantly 
undermined,  so  that  its  solid  fragments  are  seen  strewed  amongst  the 
alluvial  gravel.  However  enormous,  therefore,  the  mass  of  solid  rock 
may  appear  which  has  been  given  out  by  this  single  spring,  we  may 
feel  assured  that  it  is  insignificant  in  volume  when  compared  to  that 
which  has  been  carried  to  the  sea  since  the  time  when  it  began  to  flow. 
What  may  have  been  the  length  of  that  period  of  time  we  have  no 
data  for  conjecturing.  In  quarrying  the  travertin,  Roman  tiles  have 
been  sometimes  found  at  the  depth  of  five  or  six  feet. 

Baths  of  San  Filippo. — On  another  hill,  not  many  miles  from  that 
last  mentioned,  and  also  connected  with  Mount  Amiata,  the  summit  of 
which  is  about  three  miles  distant,  are  the  celebrated  baths  of  San 
Filippo.  The  subjacent  rocks  consist  of  alternations  of  black  slate,  lime- 
stone, and  serpentine.  There  are  three  warm  springs  containing  car- 
bonate and  sulphate  of  lime,  and  sulphate  of  magnesia.  The  water 
which  supplies  the  baths  falls  into  a  pond,  where  it  has  been  known  to 
deposit  a  solid  mass  thirty  feet  thick  in  about  twenty  years.*  A  manu- 
factory of  medallions  in  basso-relievo  is  carried  on  at  these  baths.  The 
water  is  conducted  by  canals  into  several  pits,  in  which  it  deposits  trav- 
ertin and  crystals  of  sulphate  of  lime.  After  being  thus  freed  from  its 
grosser  parts,  it  is  conveyed  by  a  tube  to  the  summit  of  a  small  cham- 
ber, and  made  to  fall  through  a  space  of  ten  or  twelve  feet.  The  cur- 
rent is  broken  in  its  descent  by  numerous  crossed  sticks,  by  which  the 

*  Dr.  Grosse  on  the  Baths  of  San  Filippo,  Ed.  Phil.  Journ.  vol.  iL  p.  292, 

Id 


242  SPHEROIDAL  TRAVERTIN.  [Cfl.  XVL 

spray  is  dispersed  around  upon  certain  moulds,  which  are  rubbed 
lightly  over  with  a  solution  of  soap,  and  a  deposition  of  solid  matter 
like  marble  is  the  result,  yielding  a  beautiful  cast  of  the  figures  formed 
in  the  mould.  The  geologist  may  derive  from  these  experiments  con- 
siderable light,  in  regard  to  the  high  slope  of  the  strata  at  which  some 
semi-crystalline  precipitations  can  be  formed ;  for  some  of  the  moulds 
are  disposed  almost  perpendicularly,  yet  the  deposition  is  nearly  equal 
in  all  parts. 

A  hard  stratum  of  stone,  about  a  foot  in  thickness,  is  obtained  from 
the  waters  of  San  Filippo  in  four  months ;  and,  as  the  springs  are 
powerful,  and  almost  uniform  in  the  quantity  given  out,  we  are  at  no 
loss  to  comprehend  the  magnitude  of  the  mass  which  descends  the 
hill,  which  is  a  mile  and  a  quarter  in  length  and  the  third  of  a  mile  in 
breadth,  in  some  places  attaining  a  thickness  of  250  feet  at  least.  To 
what  length  it  might  have  reached  it  is  impossible  to  conjecture,  as  it  is 
cut  off,  like  the  travertin  of  San  Vignone,  by  a  small  stream,  where  it 
terminates  abruptly.  The  remainder  of  the  matter  held  in  solution  is 
carried  on  probably  to  the  sea. 

Spheroidal  structure  in  travertin. — But  what  renders  this  recent 
limestone  of  peculiar  interest  to  the  geologist,  is  the  spheroidal  form 
which  it  assumes,  analogous  to  that  of  the  cascade  of  Tivoli,  afterwards 
to  be  described.  (See  fig.  22,  p.  244.)  The  lamination  of  some  of  the 
concentric  masses  is  so  minute  that  sixty  may  be  counted  in  the  thick- 
ness of  an  inch,  yet,  notwithstanding  these  marks  of  gradual  and  suc- 
cessive deposition,  sections  are  sometimes  exhibited  of  what  might  seem 
to  be  perfect  spheres.  This  tendency  to  a  mammillary  and  globular 
structure  arises  from  the  facility  with  which  the  calcareous  matter  is 
precipitated  in  nearly  equal  quantities  on  all  sides  of  any  fragment  of 
shell  or  wood  or  any  inequality  of  the  surface  over  which  the  mineral 
water  flows,  the  form  of  the  nucleus  being  readily  transmitted  through 
any  number  of  successive  envelopes.  But  these  masses  can  never  be 
perfect  spheres,  although  they  often  appear  such  when  a  transverse 
section  is  made  in  any  line  not  in  the  direction  of  the  point  of  attach- 
ment. There  are,  indeed,  occasionally  seen  small  oolitic  and  pisolitic 
grains,  of  which  the  form  is  globular ;  for  the  nucleus,  having  been  for 
a  time  in  motion  in  the  water,  has  received  fresh  accessions  of  matter  on 
all  sides. 

In  the  same  manner  I  have  seen,  on  the  vertical  walls  of  large  steam- 
boilers,  the  heads  of  nails  or  rivets  covered  by  a  series  of  enveloping 
crusts  of  calcareous  matter,  usually  sulphate  of  lime  ;  so  that  a  concre- 
tionary nodule  is  formed,  preserving  a  nearly  globular  shape,  when  in- 
creased to  a  mass  several  inches-  in  diameter.  In  these,  as  in  many  traver- 
tins, there  is  often  a  combination  of  the  concentric  and  radiated  structure. 

Campagna  di  Roma.— The,  country  around  Rome,  like  many  parts  of 
the  Tuscan  States  already  referred  to,  has  been  at  some  former  period 
the  site  of  numerous  volcanic  eruptions;  and  the  springs  are  still 
copiously  impregnated  with  lime,  carbonic  acid,  and  sulphuretted  hydro- 


CH.  XVI.]  CALCAREOUS   PRECIPITATES.  243 

gen.  A  hot  spring  was  discovered  about  1827,  near  Civita  Vecchia, 
by  Signer  Riccioli,  which  deposits  alternate  beds  of  a  yellowish  trav- 
ertin, and  a  white  granular  rock,  not  distinguishable,  in  hand  speci- 
mens, either  in  grain,  color,  or  composition,  from  statuary  marble.  There 
is  a  passage  between  this  and  ordinary  travertin.  The  mass  accumu- 
lated near  the  spring  is  in  some  places  about  six  feet  thick. 

Lake  of  the  Solfatara. — In  the  Campagna,  between  Rome  and  Tiv- 
oli,  is  the  Lake  of  the  Solfatara,  called  also  Lago  di  Zolfo  (lacus  albula), 
into  which  flows  continually  a  stream  of  tepid  water  from  a  smaller 
lake,  situated  a  few  yards  above  it.  The  water  is  a  saturated  solution 
of  carbonic  acid  gas,  which  escapes  from  it  in  such  quantities  in  some 
parts  of  its  surface,  that  it  has  the  appearance  of  being  actually  in  ebul- 
lition. "  I  have  found  by  experiment,"  says  Sir  Humphry  Davy,  "  that 
the  water  taken  from  the  most  tranquil  part  of  the  lake,  even  after  be- 
ing agitated  and  exposed  to  the  air,  contained  in  solution  more  than  its 
o\Vn  volume  of  carbonic  acid  gas,  with  a  very  small  quantity  of  sulphu- 
retted hydrogen.  Its  high  temperature,  which  is  pretty  constant  at  80° 
of  Fahr.,  and  the  quantity  of  carbonic  acid  that  it  contains,  render  it 
peculiarly  fitted  to  afford  nourishment  to  vegetable  life.  The  banks  of 
travertin  are  everywhere  covered  with  reeds,  lichen,  confervae,  and 
various  kinds  of  aquatic  vegetables ;  and  at  the  same  time  that  the  pro- 
cess of  vegetable  life  is  going  on,  the  crystallizations  of  the  calcareous 
matter,  which  is  everywhere  deposited,  in  consequence  of  the  escape 
of  carbonic  acid,  likewise  proceed.  There  is,  I  believe,  no  place  in  the 
world  where  there  is  a  more  striking  example  of  the  opposition  or  con- 
trast of  the  laws  of  animate  and  inanimate  nature,  of  the  forces  of  inor- 
ganic chemical  affinity,  and  those  of  the  powers  of  life."  * 

The  same  observer  informs  us  that  he  fixed  a  stick  in  a  mass  of 
travertin  covered  by  the  water  in  the  month  of  May,  and  in  April  fol- 
lowing he  had  some  difficulty  in  breaking,  with  a  sharp -pointed  hammer, 
the  mass  which  adhered  to  the  stick,  and  which  was  several  inches  in 
thickness.  The  upper  part  was  a  mixture  of  light  tufa  and  the  leaves 
of  confervae  ;  below  this  was  a  darker  and  more  solid  travertin,  contain- 
ing black  and  decomposed  masses  of  confervas  ;  in  the  inferior  part  the 
travertin  was  more  solid,  and  of  a  gray  color,  but  with  cavities  probably 
produced  by  the  decomposition  of  vegetable  matter.f 

The  stream  which  flows  out  of  this  lake  fills  a  canal  about  nine  feet 
broad  and  four  deep,  and  is  conspicuous  in  the  landscape  by  a  line  of 
vapor  which  rises  from  it.  It  deposits  calcareous  tufa  in  this  channel, 
and  the  Tiber  probably  receives  from  it,  as  well  as  from  numerous  other 
streams,  much  carbonate  of  lime  in  solution,  which  may  contribute  to 
the  rapid  growth  of  its  delta.  A  large  proportion  of  the  most  splendid 
edifices  of  ancient  and  modern  Rome  are  built  of  travertin,  derived  from 
the  quarries  of  Ponte  Lucano,  where  there  has  evidently  been  a  lake  at 
a  remote  period,  on  the  same  plain  as  that  already  described. 

*  Consolations  in  Travel,  pp.  123-125.  f  Ibid.  p.  127. 


244 


TRAVERTIN    IN    TIVOLI. 


[On.  XVL 


Travertin  of  Tivoli. — In  the  same  neighborhood  the  calcareous 
waters  of  the  Anio  incrust  the  reeds  which  grow  on  its  banks,  and  the 
foam  of  the  cataract  of  Tivoli  forms  beautiful  pendant  stalactites.  On 
the  sides  of  the  deep  chasm  into  which  the  cascade  throws  itself,  there 

Fig.  22. 


Section  of  spheroidal  concretionary  Travertin  under  the  Cascade  of  Tivoli. 

is  seen  an  extraordinary  accumulation  of  horizontal  beds  of  tufa  and 
travertin,  from  four  to  five  hundred  feet  in  thickness.  The  section 
immediately  under  the  temples  of  Vesta  and  the  Sibyl,  displays,  in  a 
precipice  about  four  hundred  feet  high,  some  spheroids  which  are  from 
six  to  eight  feet  in  diameter,  each  concentric  layer  being  about  the  eighth 
of  an  inch  in  thickness.  The  preceding  diagram  exhibits  about  fourteen 
feet  of  this  immense  mass,  as  seen  in  the  path  cut  out  of  the  rock  in  de- 
scending from  the  temple  of  Vesta  to  the  Grotto  di  Nettuno.  I  have 
not  attempted  to  express  in  this  drawing  the  innumerable  thin  layers  of 
which  these  magnificent  spheroids  are  composed,  but  the  lines  given 
mark  some  of  the  natural  divisions  into  which  they  are  separated  by 
minute  variations  in  the  size  or  color  of  the  laminae.  The  undulations 


CH.  XVI]  SULPHUREOUS    AND    GYPSEOUS   SPRINGS.  24:5 

also  are  much  smaller  in  proportion  to  the  whole  circumference  than  in 
the  drawing.  The  beds  (a  a)  are  of  hard  travertin  and  soft  tufa ;  be-  * 
low  them  is  a  pisolite  (6),  the  globules  being  of  different  sizes :  under- 
neath this  appears  a  mass  of  concretionary  travertin  (c  c),  some  of  the 
spheroids  being  of  the  above-mentioned  extraordinary  size.  In  some 
places  (as  at  d)  there  is  a  mass  of  amorphous  limestone,  or  tufa,  sur- 
rounded by  concentric  layers.  At  the  bottom  is  another  bed  of 
pisolite  (6),  in  which  the  small  nodules  are  about  the  size  and  shape 
of  beans,  and  some  of  them  of  filberts,  intermixed  with  some  smaller 
oolitic  grains.  In  the  tufaceous  strata,  wood  is  seen  converted  into  a 
light  tufa. 

There  can  be  little  doubt  that  the  whole  of  this  deposit  was  formed 
in  an  extensive  lake  which  existed  when  the  external  configuration  of 
this  country  varied  greatly  from  that  now  observed.  The  Anio  throws 
itself  into  a  ravine  excavated  in  the  ancient  travertin,  and  its  waters 
give  rise  to  masses  of  calcareous  stone,  scarcely  if  at  all  distinguishable 
from  the  older  rock.  I  was  shown,  in  1828,  in  the  upper  part  of  the 
travertin,  the  hollow  left  by  a  cart-wheel,  in  which  the  outer  circle  and 
the  spokes  had  been  decomposed,  and  the  spaces  which  they  filled  left 
void.  It  seemed  to  me  at  the  time  impossible  to  explain  the  position 
of  this  mould  without  supposing  that  the  wheel  was  imbedded  before 
the  lake  was  drained  ;  but  Sir  R.  Murchison  suggests  that  it  may  have 
been  washed  down  by  a  flood  into  the  gorge  in  modern  times,  and  then 
incrusted  with  calcareous  tufa  in  the  same  manner  as  the  wooden  beam 
of  the  church  of  St.  Lucia  was  swept  down  in  1826,  and  stuck  fast  in 
the  Grotto  of  the  Syren,  where  it  still  remains,  and  will  eventually  be 
quite  imbedded  in  travertin. 

I  have  already  endeavored  to  explain  (p.  241),  when  speaking  of 
the  travertin  of  San  Filippo,  how  the  spheroidal  masses  represented  in 
figure  22  may  have  been  formed. 

Sulphureous  and  gypseus  springs. — The  quantity  of  other  mineral 
ingredients  wherewith  springs  in  general  are  impregnated,  is  insignifi- 
cant in  comparison  to  lime,  and  this  earth  is  most  frequently  combined 
with  carbonic  acid.  But  as  sulphuric  acid,  and  sulphuretted  hydrogen 
are  very  frequently  supplied  by  springs,  gypsum  may,  perhaps,  be  de- 
posited largely  in  certain  seas  and  lakes.  Among  other  gypseous 
precipitates  at  present  known  on  the  land,  I  may  mention  those  of 
Baden,  near  Vienna,  which  feed  the  public  bath.  Some  of  these  sup- 
ply singly  from  600  to  1000  cubic  feet  of  water  per  hour,  and  deposit 
a  fine  powder,  composed  of  a  mixture  of  sulphate  of  lime  with  sulphur 
and  muriate  of  lime.*  The  thermal  waters  of  Aix,  in  Savoy,  in  passing 
through  strata  of  Jurassic  limestone,  turn  them  into  gypsum  or  sulphate 
of  lime.  In  the  Andes,  at  the  Puenta  del  Inca,  Lieutenant  Brand 
found  a  thermal  spring  at  the  temperature  of  91°  Fahr.,  containing  a 
large  proportion  of  gypsum  with  carbonate  of  lime  and  other  ingredi- 

*  C.  Prevost,  Essai  sur  la  Constitution  Physique  du  Bassin  de  Vienne,  p.  10. 


246  SILICEOUS   SPRINGS.  [On.  XVI. 

ents.*  Many  of  the  mineral  springs  of  Iceland,  says  Mr.  R.  Bunsen, 
deposit  gypsum,f  and  sulphureous  acid  gas  escapes  plentifully  from 
them  as  from  the  volcanoes  of  the  same  island.  It  may,  indeed,  be  laid 
down  as  a  general  rule,  that  the  mineral  substances  dissolved  in  hot 
springs  agree  very  closely  with  those  which  are  disengaged  in  a  gaseous 
form  from  the  craters  of  active  volcanoes. 

Siliceous  springs. — Azores. — In  order  that  water  should  hold  a  very 
large  quantity  of  silica  in  solution,  it  seems  necessary  that  it  should  be 
raised  to  a  high  temperature.];  The  hot  springs  of  the  Yalle  das 
Fernas,  in  the  island  of  St.  Michael,  rising  through  volcanic  rocks,  pre- 
cipitate vast  quantities  of  siliceous  sinter.  Around  the  circular  basin  of 
the  largest  spring,  which  is  between  twenty  and  thirty  feet  in  diameter, 
alternate  layers  are  seen  of  a  coarser  variety  of  sinter  mixed  with  clay, 
including  grass,  ferns,  and  reeds,  in  different  states  of  petrifaction.  In 
some  instances,  alumina,  which  is  likewise  deposited  from  the  hot 
waters,  is  the  mineralizing  material.  Branches  of  the  same  ferns  which 
now  flourish  in  the  island  are  found  completely  petrified,  preserving  the 
same  appearance  as  when  vegetating,  except  that  they  acquire  an  ash- 
gray  color.  Fragments  of  wood,  and  one  entire  bed  from  three  to  five 
feet  in  depth,  composed  of  reeds  now  common  in  the  island,  have  be- 
come completely  mineralized. 

The  most  abundant  variety  of  siliceous  sinter  occurs  in  layers,  from  a 
quarter  to  half  an  inch  in  thickness,  accumulated  on  each  other  often 
to  the  height  of  a  foot  and  upwards,  and  constituting  parallel,  and  for 
the  most  part  horizontal,  strata  many  yards  in  extent.  This  sinter  has 
often  a  beautiful  semi-opalescent  lustre.  A  recent  breccia  is  also  in 
the  act  of  forming,  composed  of  obsidian,  pumice,  and  scoriae,  cemented 
by  siliceous  sinter.§ 

Geysers  of  Iceland. — But  the  hot  springs  in  various  parts  of  Iceland, 
particularly  the  celebrated  geysers,  afford  the  most  remarkable  example 
of  the  deposition  of  silex.||  The  circular  reservoirs  into  which  the  gey- 
sers fall,  are  lined  in  the  interior  with  a  variety  of  opal,  and  round  the 
edges  with  sinter.  The  plants  incrusted  with  the  latter  substance  have 
much  the  same  appearance  as  those  incrusted  with  calcareous  tufa  in 
our  own  country.  They  consist  of  various  grasses,  the  horse-tail 
(Equisetum),  and  leaves  of  the  birch-tree,  which  are  the  most  common 
of  all,  though  no  trees  of  this  species  now  exist  in  the  surrounding 
country.  The  petrified  stems  also  of  the  birch  occur  in  a  state  much 
resembling  agatized  wood.^f 

By  analysis  of  the  water,  Mr.  Faraday  has  ascertained  that  the  solu- 
tion of  the  silex  is  promoted  by  the  presence  of  the  alkali,  soda.  He 
suggests  that  the  deposition  of  silica  in  an  insoluble  state  takes  place 
partly  because  the  water  when  cooled  by  exposure  to  the  air  is  unable 

*  Travels  across  the  Andes,  p.  240.  f  Annalen  der  Chem.  1847. 

t  Daubeny  on  Volcanoes,  p.  222. 

£$  Dr.  Webster  on  the  Hot  Springs  of  Furnas,  Ed.  Phil.  Journ.  vol.  vi.  p.  306. 

|   See  a  cut  of  the  Icelandic  geyser,  chap.  32. 

\  M.  Robert,  Bulletin  de  la  Soc.  Ge'ol.  de  France,  torn.  vii.  p.  11. 


CH.  XVI]  FERRUGINOUS   AND   BRINE   SPRINGS.  247 

to  retain  as  much  silica  as  when  it  issues  from  the  earth  at  a  tempera- 
ture of  180°  or  190°  Fahr. ;  and  partly  because  the  evaporation  of  the 
water  decomposes  the  compound  of  silica  and  soda  which  previously 
existed.  This  last  change  is  probably  hastened  by  the  carbonic  acid 
of  the  atmosphere  uniting  with  the  soda.  The  alkali,  when  disunited 
from  the  silica,  would  readily  be  dissolved  in  and  removed  by  running 
water.* 

Mineral  waters,  even  when  charged  with  a  small  proportion  of  silica, 
as  those  of  Ischia,  may  supply  certain  species  of  corals,  sponges,  and  in- 
fusoria, with  matter  for  their  siliceous  secretions  ;  but  there  is  little  doubt 
that  rivers  obtain  silex  in  solution  from  another  and  far  more  general 
source,  namely,  the  decomposition  of  felspar.  When  this  mineral, 
which  is  so  abundant  an  ingredient  in  the  hypogene  and  trappean  rocks, 
has  disintegrated,  it  is  found  that  the  residue,  called  porcelain  clay,  con- 
tains a  small  proportion  only  of  the  silica  which  existed  in  the  original 
felspar,  the  other  part  having  been  dissolved  and  removed  by  water.f 

Ferruginous  springs. — The  waters  of  almost  all  springs  contain  some 
iron  in  solution  ;  and  it  is  a  fact  familiar  to  all,  that  many  of  them  are 
so  copiously  impregnated  with  this  metal,  as  to  stain  the  rocks  or  herb- 
age through  which  they  pass,  and  to  bind  together  sand  and  gravel  into 
solid  masses.  We  may  naturally,  then,  conclude  that  this  iron,  which 
is  constantly  conveyed  from  the  interior  of  the  earth  into  lakes  and  seas, 
and  which  does  not  escape  again  from  them  into  the  atmosphere  by 
evaporation,  must  act  as  a  coloring  and  cementing  principle  in  the  sub- 
aqueous deposits  now  in  progress.  Geologists  are  aware  that  many 
ancient  sandstones  and  conglomerates  are  bound  together  or  colored 
by  iron. 

Brine  springs. — So  great  is  the  quantity  of  muriate  of  soda  in  some 
springs,  that  they  yield  one-fourth  of  their  weight  in  salt.  They  are 
rarely,  however,  so  saturated,  and  generally  contain,  intermixed  with 
salt,  carbonate  and  sulphate  of  lime,  magnesia,  and  other  mineral  ingre- 
dients. The  brine  springs  of  Cheshire  are  the  richest  in  our  country ; 
those  of  Northwich  being  almost  saturated.  Those  of  Barton  also,  in 
Lancashire,  and  Droitwich  in  Worcestershire,  are  extremely  rich.J  They 
are  known  to  have  flowed  for  more  than  1000  years,  and  the  quantity 
of  salt  which  they  have  carried  into  the  Severn  and  Mersey  must  be 
enormous.  These  brine  springs  rise  up  through  strata  of  sandstone  and 
red  marl,  which  contain  large  beds  of  rock  salt.  The  origin  of  the  brine, 
therefore,  may  be  derived  in  this  and  many  other  instances  from  beds  of 
fossil  salt;  but  as  muriate  of  soda  is  one  of  the  products  of  volcanic 
emanations  and  of  springs  in  volcanic  regions,  the  original  source  of  salt 
may  be  as  deep  seated  as  that  of  lava. 

Many  springs  in  Sicily  contain  muriate  of  soda,  and  the  "fiume  salso," 

*  Barrow's  Iceland,  p.  209. 

f  See  Lyell's  Manual  of  Elementary  Geology  ;  and  Dr.  Turner,  Jam.  Ed.  New 
Phil.  Journ.  No.  xxx.  p.  246. 

J  L.  Horner,  Geol.  Trans,  vol.  ii.  p.  94. 


248  ATMOSPHERE   OF   CAKBONIC   ACID.  [Cn.  XVI. 

in  particular,  is  impregnated  with  so  large  a  quantity,  that  cattle  refuse 
to  drink  of  it.  A  hot  spring,  rising  through  granite,  at  Saint  Nectaire, 
in  Auvergne,  may  be  mentioned  as  one  of  many,  containing  a  large  pro- 
portion of  muriate  of  soda,  together  with  magnesia  and  other  ingre- 
dients.* 

Carbonated  springs. — Auvergne. — Carbonic  acid  gas  is  very  plentifully 
disengaged  from  springs  in  almost  all  countries,  but  particularly  near 
active  or  extinct  volcanoes.  This  elastic  fluid  has  the  property  of  decom- 
posing many  of  the  hardest  rocks  with  which  it  comes  in  contact,  partic- 
ularly that  numerous  class  in  whose  composition  felspar  is  an  ingredient. 
It  renders  the  oxide  of  iron  soluble  in  water,  and  contributes,  as  was 
before  stated,  to  the  solution  of  calcareous  matter.  In  volcanic  districts 
these  gaseous  emanations  are  not  confined  to  springs,  but  rise  up  in  the 
state  of  pure  gas  from  the  soil  in  various  places.  The  Grotto  del  Cane, 
near  Naples,  affords  an  example,  and  prodigious  quantities  are  now 
annually  disengaged  from  every  part  of  the  Limagne  d'Auvergne,  where 
it  appears  to  have  been  developed  in  equal  quantity  from  time  imme- 
morial. As  the  acid  is  invisible,  it  is  not  observed,  except  an  excavation 
be  made,  wherein  it  immediately  accumulates,  so  that  it  will  extinguish 
a  candle.  There  are  some  springs  in  this  district,  where  the  water  is 
seen  bubbling  and  boiling  up  with  much  noise,  in  consequence  of  the 
abundant  disengagement  of  this  gas.  In  the  environs  of  Pont-Gibaud, 
not  far  from  Clermont,  a  rock  belonging  to  the  gneiss  formation,  in  which 
lead-mines  are  worked,  has  been  found  to  be  quite  saturated  with  car- 
bonic acid  gas,  which  is  constantly  disengaged.  The  carbonates  of  iron, 
lime,  and  manganese  are  so  dissolved,  that  the  rock  is  rendered  soft,  and 
the  quartz  alone  remains  unattacked.f  Not  far  off  is  the  small  volcanic 
cone  of  Chaluzet,  which  once  broke  up  through  the  gneiss,  and  sent 
forth  a  lava  stream. 

Supposed  atmosphere  of  carbonic  acid. — Prof.  Bischoff  in  his  history 
of  volcanoes,];  has  shown  what  enormous  quantities  of  carbonic  acid  gas 
are  exhaled  in  the  vicinity  of  the  extinct  craters  of  the  Rhine  (in  the 
neighborhood  of  the  Laacher-see,  for  example,  and  the  Eifel),  and  also 
in  the  mineral  springs  of  Nassau  and  other  countries,  where  there  are  no 
immediate  traces  of  volcanic  action.  It  would  be  easy  to  calculate  in 
how  short  a  period  the  solid  carbon,  thus  emitted  from  the  interior  of  the 
earth  in  an  invisible  form,  would  amount  to  a  quantity  as  great  as  could 
be  obtained  from  the  trees  of  a  large  forest,  and  how  many  thousand 
years  would  be  required  to  supply  the  materials  of  a  dense  seam  of  pure 
coal  from  the  same  source.  Geologists  who  favor  the  doctrine  of  the 
former  existence  of  an  atmosphere  highly  charged  with  carbonic  acid,  at 
the  period  of  the  ancient  coal-plants,  have  not  sufficiently  reflected  on 
the  continual  disengagement  of  carbon,  which  is  taking  place  in  a  gase- 
ous form  from  springs,  as  also  in  a  free  state  from  the  ground  and  from 

*  Ann.  de  1' Auvergne,  tome  i.  p.  234. 

•f-  Ann.  Sclent,  de  1'Auvergne,  tome  ii.    June,  1829. 

%  Edinb.  New  Phil.  Journ.     Oct.  1839. 


CH.  XVI]  ATMOSPHERE   OF   CARBONIC    ACID.  249 

volcanic  craters  into  the  air.  We  know  that  all  plants  are  now  engaged 
in  secreting  carbon,  and  many  thousands  of  large  trees  are  annually 
floated  down  by  great  rivers,  and  buried  in  their  alluvial  deposits  ;  but 
before  we  can  assume  that  the  quantity  of  carbon  which  becomes  per- 
manently locked  up  in  the  earth  by  such  agency  will  bring  about  an 
essential  change  in  the  chemical  composition  of  the  atmosphere,  we  must 
be  sure  that  the  trees  annually  buried  contain  more  carbon  than  is  given 
out  from  the  interior  of  the  earth  in  the  same  lapse  of  time.  Every  large 
area  covered  by  a  dense  mass  of  peat,  bears  ample  testimony  to  the  fact, 
that  several  million  tons  of  carbon  have  been  taken  from  the  air,  by  the 
powers  of  vegetable  life,  and  stored  up  in  the  earth's  crust,  a  large 
quantity  of  oxygen  having  been  at  the  same  time  set  free ;  but  we  can- 
not infer  from  these  circumstances,  that  the  constitution  of  the  atmos- 
phere has  been  materially  deranged,  until  we  have  data  for  estimating 
the  rate  at  which  dead  animal  and  vegetable  substances  are  daily  putre- 
fying,— organic  remains  and  various  calcareous  rocks  decomposing,  and 
volcanic  regions  emitting  fresh  volumes  of  carbonic  acid  gas.  That  the 
ancient  carboniferous  period  was  one  of  vast  duration  all  geologists  are 
agreed  ;  instead,  therefore,  of  supposing  an  excess  of  carbonic  acid  in 
the  air  at  that  epoch,  for  the  support  of  a  peculiar  flora,  we  may  imagine 
Time  to  have  multiplied  the  quantity  of  carbon  given  out  annually  by 
mineral  springs,  volcanic  craters,  and  other  sources,  until  the  component 
elements  of  any  given  number  of  coal-seams  had  been  evolved  from  be- 
low, without  any  variation  taking  place  in  the  constitution  of  the  atmos- 
phere. It  has  been  too  common,  in  reasoning  on  this  question,  to  com- 
pute the  loss  of  carbon  by  ,the  volume  of  coal  stored  up  in  the  ancient 
strata,  and  to  take  no  account  of  the  annual  gain,  by  the  restoration  of 
carbonic  acid  to  the  atmosphere,  through  the  machinery  above  alluded  to.* 

Disintegrating  effects  of  carbonic  acid. — The  disintegration  of  granite 
is  a  striking  feature  of  large  districts  in  Auvergne,  especially  in  the 
neighborhood  of  Clermont.  This  decay  was  called  by  Dolomieu,  "  la 
maladie  du  granite ;"  and  the  rock  may  with  propriety  be  said  to  have 
the  rot,  for  it  crumbles  to  pieces  in  the  hand.  The  phenomenon  may, 
without  doubt,  be  ascribed  to  the  continual  disengagement  of  carbonic 
acid  gas  from  numerous  fissures. 

In  the  plains  of  the  Po,  between  Verona  and  Parma,  especially  at 
Villa  Franca,  south  of  Mantua,  I  observed  great  beds  of  alluvium,  con- 
sisting chiefly  of  primary  pebbles,  percolated  by  spring-water,  charged 
with  carbonate  of  lime  and  carbonic  acid  in  great  abundance.  They  are 
for  the  most  part  incrusted  with  calc-sinter ;  and  the  rounded  blocks  of 
gneiss,  which  have  all  the  outward  appearance  of  solidity,  have  been  so 
disintegrated  by  the  carbonic  acid  as  readily  to  fall  to  pieces. 

The  subtraction  of  many  of  the  elements  of  rocks  by  the  solvent  power 
of  carbonic  acid,  ascending  both  in  a  gaseous  state  and  mixed  with 
spring- water  in  the  crevices  of  rocks,  must  be  one  of  the  most  powerful 

*  Sco  Ly  ell's  Travels  in  N.  America,  vol.  L  p.  150. 


250  PETKOLEUM   SPRINGS.  [Cfi.  XVI. 

sources  of  those  internal  changes  and  rearrangements  of  particles  so 
often  observed  in  strata  of  every  age.  The  calcareous  matter,  for  ex- 
ample, of  shells,  is  often  entirely  removed  and  replaced  by  carbonate  of 
iron,  pyrites,  silex,  or  some  other  ingredient,  such  as  mineral  waters 
usually  contain  in  solution.  It  rarely  happens,  except  in  limestone 
rocks,  that  the  carbonic  acid  can  dissolve  all  the  constituent  parts  of  the 
mass ;  and  for  this  reason,  probably,  calcareous  rocks  are  almost  the 
only  ones  in  which  great  caverns  and  long  winding  passages  are  found. 

Petroleum  springs. — Springs  of  which  the  waters  contain  a  mixture 
of  petroleum  and  the  various  minerals  allied  to  it,  as  bitumen,  naphtha, 
asphaltum,  and  pitch,  are  very  numerous,  and  are,  in  many  cases,  un- 
doubtedly connected  with  subterranean  fires,  which  raise  or  sublime  the 
more  subtle  parts  of  the  bituminous  matters  contained  in  rocks.  Many 
springs  in  the  territory  of  Modena  and  Parma,  in  Italy,  produce  petro- 
leum in  abundance ;  but  the  most  powerful,  perhaps,  yet  known,  are 
those  on  the  Irawadi,  in  the  Burman  empire.  In  one  locality  there  are 
said  to  be  520  wells,  which  yield  annually  400,000  hogsheads  of  petro- 
leum.* 

Pitch  lake  of  Trinidad. — Fluid  bitumen  is  seen  to  ooze  from  the 
bottom  of  the  sea,  on  both  sides  of  the  island  of  Trinidad,  and  to  rise 
up  to  the  surface  of  the  water.  Near  Cape  La  Braye  there  is  a  vortex 
which,  in  stormy  weather,  according  to  Captain  Mallet,  gushes  out, 
raising  the  water  five  or.  six  feet,  and  covers  the  surface  for  a  considera- 
ble space  with  petroleum,  or  tar ;  and  the  same  author  quotes  Gumilla, 
as  stating,  in  his  "Description  of  the  Orinoco,"  that  about  seventy  years 
ago,  a  spot  of  land  on  the  western  coast  of  Trinidad,  near  half-way  be- 
tween the  capital  and  an  Indian  village,  sank  suddenly,  and  was  imme- 
diately replaced  by  a  small  lake  of  pitch,  to  the  great  terror  of  the 
inhabitants.f 

It  is  probable  that  the  great  pitch  lake  of  Trinidad  owes  its  origin  to 
a  similar  cause ;  and  Dr.  Nugent  has  justly  remarked,  that  in  that  dis- 
trict all  the  circumstances  are  now  combined  from  which  deposits  of 
pitch  may  have  originated.  The  Orinoco  has  for  ages  been  rolling 
down  great  quantities  of  woody  and  vegetable  bodies  into  the  surround- 
ing sea,  where,  by  the  influence  of  currents  and  eddies,  they  may  be 
arrested  and  accumulated  in  particular  places.  The  frequent  occurrence 
of  earthquakes  and  other  indications  of  volcanic  action  in  those  parts 
lend  countenance  to  the  opinion,  that  these  vegetable  substances  may 
have  undergone,  by  the  agency  of  subterranean  fire,  those  transforma- 
tions and  chemical  changes  which  produce  petroleum ;  and  this  may, 
by  the  same  causes,  be  forced  up  to  the  surface,  where,  by  exposure  to 
the  air,  it  becomes  inspissated,  and  forms  the  different  varieties  of  pure 
and  earthy  pitch,  or  asphaltum,  so  abundant  in  the  island. J 

*  Symes,  Embassy  to  Ava,  vol.  ii.  Geol.  Trans,  second  series,  vol.  ii.  part  iii.  p 
188. 

f  Dr.  Nugent,  Geol.  Trans,  vol.  i.  p.  69. 
%  Ibid.  p.  67. 


CH.  XVII]  DELTAS   IN    LAKKS.  251 

It  may  be  stated  generally,  that  a  large  portion  of  the  finer  particles 
and  the  more  crystalline  substances,  found  in  sedimentary  rocks  of  dif- 
ferent ages,  are  composed  of  the  same  elements  as  are  now  held  in  so- 
lution by  springs,  while  the  coarser  materials  bear  an  equally  strong 
resemblance  to  the  pebbles  and  sedimentary  matter  carried  down  by 
torrents  and  rivers.  It  should  also  be  remembered,  that  it  is  not  only 
during  inundations,  when  the  muddy  sediment  is  apparent,  that  rivers 
are  busy  in  conveying  solid  matter  to  the  sea,  but  that  even  when  their 
waters  are  perfectly  transparent,  they  are  annually  bearing  along  vast 
masses  of  carbon,  lime,  and  silica  to  the  ocean. 


CHAPTER  XVII. 

REPRODUCTIVE    EFFECTS    OF    RIVERS. 

Lake  deltas — Growth  of  the  delta  of  the  Upper  Rhine  in  the  Lake  of  Geneva — 
Computation  of  the  age  of  deltas — Recent  deposits  in  Lake  Superior — Deltas 
of  inland  seas — Course  of  the  Po — Artificial  embankments  of  the  Po  and  Adige 
— Delta  of  the  Po,  and  other  rivers  entering  the  Adriatic — Rapid  conversion  of 
that  gulf  into  land — Mineral  characters  of  the  new  deposits — Marine  delta  of 
the  Rhone — Various  proofs  of  its  increase — Stony  nature  of  its  deposits — Coast 
of  Asia  Minor — Delta  of  the  Nile. 

DELTAS    IN    LAKES. 

I  HAVE  already  spoken  in  the  14th  chapter  of  the  action  of  running 
water,  and  of  the  denuding  power  of  rivers,  but  we  can  only  form  a 
just  conception  of  the  excavating  and  removing  force  exerted  by  such 
bodies  of  water,  when  we  have  the  advantage  of  examining  the  repro- 
ductive effects  of  the  same  agents :  in  other  words,  of  beholding  in  a 
palpable  form  the  aggregate  amount  of  matter,  which  they  have  thrown 
down  at  certain  points  in  their  alluvia]  plains,  or  in  the  basins  of  lakes 
and  seas.  Yet  it  will  appear,  when  we  consider  the  action  of  currents, 
that  the  growth  of  deltas  affords  a  very  inadequate  standard  by  which 
to  measure  the  entire  carrying  power  of  running  water,  since  a  consid- 
erable portion  of  fluviatile  sediment  is  swept  far  out  to  sea. 

Deltas  may  be  divided  into,  first,  those  which  are  formed  in  lakes ; 
secondly,  those  in  island  seas,  where  the  tides  are  almost  impercepti- 
ble ;  and,  thirdly,  those  on  the  borders  of  the  ocean.  The  most  charac- 
teristic distinction  between  the  lacustrine  and  marine  deltas  consists  in 
the  nature  of  the  organic  remains  which  become  imbedded  in  their 
deposits  ;  for,  in  the  case  of  a  lake,  it  is  obvious  that  these  must 
consist  exclusively  of  such  genera  of  animals  as  inhabit  the  land  or 
the  waters  of  a  river  or  a  lake  ;  whereas,  in  the  other  case,  there  will 
be  an  admixture,  and  most  frequently  a  predominance,  of  animals  which 
inhabit  salt  water.  In  regard,  however,  to  the  distribution  of  inorganic 


252  LAKE  OF  GENEVA.  [On.  XVII. 

matter,  the  deposits  of  lakes  and  seas  are  formed  under  very  analogous 
circumstances. 

Lake  of  Geneva. — Lakes  exemplify  the  first  reproductive  operations 
in  which  rivers  are  engaged  when  they  convey  the  detritus  of  rocks 
and  the  'ingredients  of  mineral  springe  from  mountainous  regions.  The 
accession  of  new  land  at  the  mouth  of  the  Rhone,  at  the  upper  end  of 
the  Lake  of  Geneva,  or  the  Leman  Lake,  presents  us  with  an  example 
of  a  considerable  thickness  of  strata  which  have  accumulated  since  the 
historical  era.  This  sheet  of  water  is  about  thirty-seven  miles  long,  and 
its  breadth  is  from  two  to  eight  miles.  The  shape  of  the  bottom  is 
very  irregular,  the  depth  having  been  found  by  late  measurements  to 
vary  from  20  to  160  fathoms.*  The  Rhone,  where  it  enters  at  the  upper 
end,  is  turbid  and  discolored ;  but  its  waters,  where  it  issues  at  the 
town  of  Geneva,  are  beautifully  clear  and  transparent.  An  ancient 
town,  called  Port  Vallais  (Portus  Valesiae  of  the  Romans),  once  situated 
at  the  water's  edge,  at  the  upper  end,  is  now  more  than  a  mile  and  a 
half  inland — this  intervening  alluvial  tract  having  been  acquired  in 
about  eight  centuries.  The  remainder  of  the  delta  consists  of  a  flat 
alluvial  plain,  about  five  or  six  miles  in  length,  composed  of  sand  and 
mud,  a  little  raised  above  the  level  of  the  river,  and  full  of  marshes. 

Sir  Henry  De  la  Beche  found,  after  numerous  soundings  in  all  parts 
of  the  lake,  that  there  was  a  pretty  uniform  depth  of  from  120  to  160 
fathoms  throughout  the  central  region,  and  on  approaching  the  delta, 
the  shallowing  of  the  bottom  began  to  be  very  sensible  at  a  distance 
of  about  a  mile  and  three  quarters  from  the  mouth  of  the  Rhone  ; 
for  a  line  drawn  from  St.  Gingoulph  to  Vevey  gives  a  mean  depth 
of  somewhat  less  than  600  feet,  and  from  that  part  of  the  Rhone, 
the  fluviatile  mud  is  always  found  along  the  bottom.f  We  may  state, 
therefore,  that  the  new  strata  annually  produced  are  thrown  down 
upon  a  slope  about  two  miles  in  length  ;  so  that,  notwithstanding  the 
great  depth  of  the  lake,  the  new  deposits  are  inclined  at  so  slight  an 
angle,  that  the  dip  of  the  beds  would  be  termed,  in  ordinary  geological 
language,  horizontal. 

The  strata  probably  consist  of  alternations  of  finer  and  coarser  par- 
ticles ;  for,  during  the  hotter  months  from  April  to  August,  when  the 
snows  melt,  the  volume  and  velocity  of  the  river  are  greatest,  and  large 
quantities  of  sand,  mud,  vegetable  matter,  and  drift-wood  are  intro- 
duced ;  but  during  the  rest  of  the  year,  the  influx  is  comparatively 
feeble,  so  much  so,  that  the  whole  lake,  according  to  Saussure,  stands 
six  feet  lower.  If,  then,  we  could  obtain  a  section  of  the  accumulation 
formed  in  the  last  eight  centuries,  we  should  see  a  great  series  of 
strata,  probably  from  600  to"  900  feet  thick  (the  supposed  original 
depth  of  the  head  of  the  lake),  and  nearly  two  miles  in  length,  in- 
clined at  a  very  slight  angle.  In  the  mean  time,  a  great  number  of 


*  De  la  Beche,  Ed.  Phil.  Journ.  vol.  ii.  p.  107.    Jan.  1820. 
f  De  la  Beche,  MS. 


CH.  XVII.]  AGE   OF   DELTAS.  253 

smaller  deltas  are  growing  around  the  borders  of  the  lake,  at  the 
mouths  of  rapid  torrents,  which  pour  in  large  masses  of  sand  and  peb- 
bles. The  body  of  water  in  these  torrents  is  too  small  to  enable  them 
to  spread  out  the  transported  matter  over  so  extensive  an  area  as  the 
Rhone  does.  Thus,  for  example,  there  is  a  depth  of  eighty  fathoms 
within  half  a  mile  of  the  shore,  immediately  opposite  the  great  torrent 
which  enters  east  of  Ripaille,  so  that  the  dip  of  the  strata  in  that  minor 
delta  must  be  about  four  times  as  great  as  those  deposited  by  the  main 
river  at  the  upper  extremity  of  the  lake.* 

Chronological  computations  of  the  age  of  deltas. — The  capacity  of  this 
basin  being  now  ascertained,  it  would  be  an  interesting  subject  of  in- 
quiry, to  determine  in  what  number  of  years  the  Leman  Lake  will  be 
converted  into  dry  land.  It  would  not  be  very  difficult  to  obtain  the 
elements  for  such  a  calculation,  so  as  to  approximate  at  least  to  the 
quantity  of  time  required  for  the  accomplishment  of  the  result.  The 
number  of  cubic  feet  of  water  annually  discharged  by  the  river  into  the 
lake  being  estimated,  experiments  might  be  made  in  the  winter  and 
summer  months,  to  determine  the  proportion  of  matter  held  in  sus- 
pension or  in  chemical  solution  by  the  Rhone.  It  would  be  also  neces- 
sary to  allow  for  the  heavier  matter  drifted  along  at  the  bottom,  which 
might  be  estimated  on  hydrostatical  principles,  when  the  average  size  of 
the  gravel  and  the  volume  and  velocity  of  the  stream  at  different  seasons 
were  known.  Supposing  all  these  observations  to  have  been  made,  it 
would  be  more  easy  to  calculate  the  future  than  the  former  progress  of 
the  delta,  because  it  would  be  a  laborious  task  to  ascertain,  with  any 
degree  of  precision,  the  original  depth  and  extent  of  that  part  of  the 
lake  which  is  already  filled  up.  Even  if  this  information  were  actually 
obtained  by  borings,  it  would  only  enable  us  to  approximate  within  a 
certain  number  of  centuries  to  the  time  when  the  Rhone  began  to  form 
its  present  delta ;  but  this  would  not  give  us  the  date  of  tlje  origin  of 
the  Leman  Lake  in  its  present  form,  because  the  river  may  have  flowed 
into  it  for  thousands  of  years,  without  importing  any  sediment  whatever. 
Such  would  have  been  the  case,  if  the  waters  had  first  passed  through  a 
chain  of  upper  lakes  ;  and  that  this  was  actually  the  fact,  seems  indicated 
by  the  course  of  the  Rhone  between  Martigny  and  the  Lake  of  Geneva, 
and,  still  more  decidedly,  by  the  channels  of  many  of  its  principal  feeders. 

If  we  ascend,  for  example,  the  valley  through  which  the  Dranse  flows, 
we  find  that  it  consists  of  a  succession  of  basins,  one  above  the  other,  in 
each  of  which  there  is  a  wide  expanse  of  flat  alluvial  lands,  separated 
from  the  next  basin  by  a  rocky  gorge,  once  perhaps  the  barrier  of  a  lake. 
The  river  seems  to  have  filled  these  lakes,  one  after  the  other,  and  to 
have  partially  cut  through  the  barriers,  some  of  which  it  is  still  gradu- 
ally eroding  to  a  greater  depth.  Before,  therefore,  we  can  pretend  even 
to  hazard  a  conjecture  as  to  the  era  at  which  the  principal  delta  of  Lake 
Leman  or  any  other  delta  commenced,  we  must  be  thoroughly  acquaint- 

*  De  la  Beche,  MS. 


254  DELTAS   OF   LAKE   SUPERIOR.  [On.  XVII. 

ed  with  the  geographical  features  and  geological  history  of  the  whole 
system  of  higher  valleys  which  communicate  with  the  main  stream,  and 
all  the  changes  which  they  have  undergone  since  the  last  series  of  con- 
vulsions which  agitated  and  altered  the  face  of  the  country. 

Lake  Superior. — Lake  Superior  is  the  largest  body  of  freshwater  in 
the  world,  being  above  1700  geographical  miles  in  circumference  when 
we  follow  the  sinuosities  of  its  coasts,  and  its  length,  on  a  curved  line 
drawn  through  its  centre,  being  more  than  400,  and  its  extreme  breadth 
above  150  geographical  miles.  Its  surface  is  nearly  as  large  as  the 
whole  of  England.  Its  average  depth  varies  from  80  to  150  fathoms  ; 
but,  according  to  Captain  Bayfield,  there  is  reason  to  think  that  its 
greatest  depth  would  not  be  overrated  at  200  fathoms,  so  that  its  bottom 
is,  in  some  parts,  nearly  600  feet  below  the  level  of  the  Atlantic,  its  sur- 
face being  about  as  much  above  it.  There  are  appearances  in  different 
parts  of  this,  as  of  the  other  Canadian  lakes,  leading  us  to  infer  that  its 
waters  formerly  occupied  a  higher  level  than  they  reach  at  present ;  for 
at  a  considerable  distance  from  the  present  shores,  parallel  lines  of  rolled 
stones  and  shells  are  seen  rising  one  above  the  other,  like  the  seats  of 
an  amphitheatre.  These  ancient  lines  of  shingle  are  exactly  similar  to 
the  present  beaches  in  most  bays,  and  they  often  attain  an  elevation  of 
40  or  50  feet  above  the  present  level.  As  the  heaviest  gales  of  wind 
do  not  raise  the  waters  more  than  three  or  four  feet,  the  elevated  beaches 
have  by  some  been  referred  to  the  subsidence  of  the  lake  at  former  pe- 
riods, in  consequence  of  the  wearing  down  of  its  barrier ;  by  others  to 
the  upraising  of  the  shores  by  earthquakes,  like  those  which  have  pro- 
duced similar  phenomena  on  the  coast  of  Chili. 

The  streams  which  discharge  their  waters  into  Lake  Superior  are  sev- 
eral hundred  in  number,  without  reckoning  those  of  smaller  size ;  and 
the  quantity  of  water  supplied  by  them  is  many  times  greater  than  that 
discharged  at  the  Falls  of  St.  Mary,  the  only  outlet.  The  evaporation, 
therefore,  is  very  great,  and  such  as  might  be  expected  from  so  vast  an 
extent  of  surface.  On  the  northern  side,  which  is  encircled  by  primary 
mountains,  the  rivers  sweep  in  many  large  boulders  with  smaller  gravel 
and  sand,  chiefly  composed  of  granitic  and  trap  rocks.  There  are  also 
currents  in  the  lake  in  various  directions,  caused  by  the  continued  preva- 
lence of  strong  winds,  and  to  their  influence  we  may  attribute  the  dif- 
fusion of  finer  mud  far  and  wide  over  great  areas ;  for  by  numerous 
soundings  made  during  Captain  Bayfield's  survey,  it  was  ascertained 
that  the  bottom  consists  generally  of  a  very  adhesive  clay,  containing 
shells  of  the  species  at  present  existing  in  the  lake.  When  exposed  to 
the  air,  this  clay  immediately  becomes  indurated  in  so  great  a  degree,  as 
to  require  a  smart  blow  to  break  it.  It  effervesces  slightly  with  diluted 
nitric  acid,  and  is  of  different  colors  in  different  parts  of  the  lake ;  in  one 
district  blue,  in  another  red,  and  in  a  third  white,  hardening  into  a  sub- 
stance resembling  pipeclay.*  From  these  statements,  the  geologist  will 

*  Trans,  of  Lit.  and  Hist.  Soc.  of  Quebec,  vol.  i.  p.  5,  1829. 


CH.  XVIL]  DELTAS   OF   INLAND   SEAS.  255 

not  fail  to  remark  how  closely  these  recent  lacustrine  formations  in 
America  resemble  the  tertiary  argillaceous  and  calcareous  marls  of  la- 
custrine origin  in  Central  France.  In  both  cases  many  of  the  genera  of 
shells  most  abundant,  as  Limnea  and  Planorbis,  are  the  same ;  and  in 
regard  to  other  classes  of  organic  remains  there  must  be  the  closest 
analogy,  as  I  shall  endeavor  more  fully  to  explain  when  speaking  of  the 
imbedding  of  plants  and  animals  in  recent  deposits. 

DELTAS    OF    INLAND    SEAS. 

Having  thus  briefly  considered  some  of  the  lacustrine  deltas  now  in 
progress,  we  may  next  turn  our  attention  to  those  of  inland  seas. 

Course  of  the  Po. — The  Po  affords  an  instructive  example  of  the 
manner  in  which  a  great  river  bears  down  to  the  sea  the  matter  poured 
into  it  by  a  multitude  of  tributaries  descending  from  lofty  chains  of 
mountains.  The  changes  gradually  effected  in  the  great  plain  of  North- 
ern Italy,  since  the  time  of  the  Roman  republic,  are  considerable.  Ex- 
tensive lakes  and  marshes  have  been  gradually  filled  up,  as  those  near 
Placentia,  Parma,  and  Cremona,  and  many  have  been  drained  naturally 
by  the  deepening  of  the  beds  of  rivers.  Deserted  river-courses  are  not 
unfrequent,  as  that  of  the  Serio  Morto,  which  formerly  fell  into  the 
Adda,  in  Lombardy.  The  Po  also  itself  has  often  deviated  from  its 
course,  having  after  the  year  1390  deserted  part  of  the  territory  of 
Cremona,  and  invaded  that  of  Parma ;  its  old  channel  being  still  recog- 
nizable, and  bearing  the  name  of  Po  Morto.  There  is  also  an  old  chan- 
nel of  the  Po  in  the  territory  of  Parma,  called  Po  Vecchio,  which  was 
abandoned  in  the  twelfth  century,  when  a  great  number  of  towns  were 
destroyed. 

Artificial  embankments  of  Italian  rivers. — To  check  these  and  similar 
aberrations,  a  general  system  of  embankment  has  been  adopted ;  and 
the  Po,  Adige,  and  almost  all  their  tributaries,  are  now  confined  between 
high  artificial  banks.  The  increased  velocity  acquired  by  streams  thus 
closed  in,  enables  them  to  convey  a  much  larger  portion  of  foreign  mat- 
ter to  the  sea ;  and,  consequently,  the  deltas  of  the  Po  and  Adige  have 
gained  far  more  rapidly  on  the  Adriatic  since  the  practice  of  embank- 
ment became  almost  universal.  But,  although  more  sediment  is  borne 
to  the  sea,  part  of  the  sand  and  mud,  which  in  the  natural  state  of 
things  would  be  spread  out  by  annual  inundations  over  the  plain,  now 
subsides  in  the  bottom  of  the  river-channels ;  and  their  capacity  being 
thereby  diminished,  it  is  necessary,  in  order  to  prevent  inundations  in 
the  following  spring,  to  extract  matter  from  the  bed,  and  to  add  it  to 
the  banks  of  the  river.  Hence  it  happens  that  these  streams  now  tra- 
verse the  plain  on  the  top  of  high  mounds,  like  the  waters  of  aqueducts, 
and  at  Ferrara  the  surface  of  the  Po  has  become  more  elevated  than 
the  roofs  of  the  houses.*  The  magnitude  of  these  barriers  is  a  subject 

*  Prony,  see  Cuvier,  Disc.  Prelim,  p.  146. 


256  DELTAS   OF   THE   PO   AND   ADIGE.  [On.  XV1L 

of  increasing  expense  and  anxiety,  it  having  been  sometimes  found  neces- 
sary to  give  an  additional  height  of  nearly  one  foot  to  the  banks  of  the 
Adige  and  Po  in  a  single  season. 

The  practice  of  embankment  was  adopted  on  some  of  the  Italian 
rivers  as  early  as  the  thirteenth  century ;  and  Dante,  writing  in  the 
beginning  of  the  fourteenth,  describes,  in  the  seventh  circle  of  hell,  a 
rivulet  of  tears  separated  from  a  burning  sandy  desert  by  embankments 
"  like  those  which,  between  Ghent  and  Bruges,  were  raised  against  the 
ocean,  or  those  which  the  Paduans  had  erected  along  the  Brenta  to 
defend  their  villas  on  the  melting  of  the  Alpine  snows." 

Quale  i  Fiamminghi  tra  Guzzante  e  Bruggia, 
Temendo  il  fiotto  che  in  ver  lor  s'avventa, 
Fanno  lo  schermo,  perche  il  mar  si  fuggia, 
E  quale  i  Padovan  lungo  la  Brenta, 
Per  difender  lor  ville  e  lor  castelli, 
Anzi  che  Chiarentana  il  caldo  senta. — 

Inferno,  Canto  xv. 

In  the  Adriatic,  from  the  northern  part  of  the  Gulf  of  Trieste,  where 
the  Isonzo  enters,  down  to  the  south  of  Ravenna,  there  is  an  uninter- 
rupted series  of  recent  accessions  of  land,  more  than  100  miles  in  length, 
which,  within  the  last  2000  years,  have  increased  from  two  to  twenty 
miles  in  breadth.  A  line  of  sand-bars  of  great  length  has  been  formed 
nearly  all  along  the  western  coast  of  this  gulf,  inside  of  which  are 
lagunes,  such  as  those  of  Venice,  and  the  large  lagune  of  Comacchio, 
20  miles  in  diameter.  Newly  deposited  mud  brought  down  by  the 
streams  is  continually  lessening  the  depth  of  the  lagunes,  and  converting 
part  of  them  into  meadows.*  The  Isonzo,  Tagliamento,  Piave,  Brenta, 
Adige,  and  Po,  besides  many  other  inferior  rivers,  contribute  to  this 
advance  of  the  coast-line  and  to  the  shallowing  of  the  lagunes  and  the 
gulf. 

Delta  of  the  Po. — The  Po  and  the  Adige  may  now  be  considered  as 
entering  by  one  common  delta,  for  two  branches  of  the  Adige  are  con- 
nected with  arms  of  the  Po,  and  thus  the  principal  delta  has  been 
pushed  out  beyond  those  bars  which  separate  the  lagunes  from  the  sea. 
The  rate 'of  the  advance  of  this  new  land  has  been  accelerated,  as  before 
stated,  since  the  system  of  embanking  the  rivers  became  genera],  espe- 
cially at  that  point  where  the  Po  and  Adige  enter.  The  waters  are  no 
longer  permitted  to  spread  themselves  far  and  wide  over  the  plains,  and 
to  leave  behind  them  the  larger  portion  of  their  sediment.  Mountain 
torrents  also  have  become  more  turbid  since  the  clearing  away  of  for- 
ests, which  once  clothed  the  southern  flanks  of  the  Alps.  It  is  calcu- 
lated that  the  mean  rate  of  advance  of  the  delta  of  the  Po  on  the 
Adriatic  between  the  years  1200  and  1600  was  25  yards  or  metres  a 
year,  whereas  the  mean  annual  gain  from  1600  to  1804  was  70  metres.f 

*  See  De  Beaumont,  Geologic  Pratique,  vol.  i.  p.  323,  1844. 
f  Prony,  cited  by  Cuvier,  Discours  Prelimin. 


CH.  XVII.]  t   DELTA   OF    THE   PO. 

Adria  was  a  seaport  in  the  time  of  Augustus,  and  had,  in  ancient 
times,  given  its  name  to  the  gulf;  it  is  now  about  twenty  Italian  miles 
inland.  Ravenna  was  also  a  seaport,  and  is  now  about  four  miles  from 
the  main  sea.  Yet  even  before  the  practice  of  embankment  was  intro- 
duced, the  alluvium  of  the  Po  advanced  with  rapidity  on  the  Adriatic ; 
for  Spina,  a  very  ancient  city,  originally  built  in  the  district  of  Ravenna, 
at  the  mouth  of  a  great  arm  of  the  Po,  was,  so  early  as  the  commence- 
ment of  our  era,  eleven  miles  distant  from  the  sea.* 

But  although  so  many  rivers  are  rapidly  converting  the  Adriatic  into 
land,  it  appears,  by  the  observations  of  M.  Morlot,  that  since  the  time 
of  the  Romans,  there  has  been  a  general  subsidence  of  the  coast  and 
bed  of  this  sea  in  the  same  region  to  the  amount  of  five  feet,  so  that 
the  advance  of  the  new-made  land  has  not  been  so  fast  as  it  would  have 
been  had  the  level  of  the  coast  remained  unaltered.  The  signs  of  a 
much  greater  depression  anterior  to  the  historical  period  have  also  been 
brought  to  light  by  an  Artesian  well,  bored  in  1847,  to  the  depth  of 
more  than  400  feet,  which  still  failed  to  penetrate  through  the  modern 
fluviatile  deposit.  The  auger  passed  chiefly  through  beds  of  sand  and 
clay,  but  at  four  several  depths,  one  of  them  very  near  the  bottom  of 
the  excavation,  it  pierced  beds  of  turf,  or  accumulations  of  vegetable 
matter,  precisely  similar  to  those  now  formed  superficially  on  the  ex- 
treme borders  of  the  Adriatic.  Hence  we  learn  that  a  considerable 
area  of  what  was  once  land  has  sunk  down  400  feet  in  the  course  of 
ages.f 

The  greatest  depth  of  the  Adriatic,  between  Dalmatia  and  the  mouths 
of  the  Po,  is  twenty-two  fathoms  ;  but  a  large  part  of  the  Gulf  of  Trieste 
and  the  Adriatic,  opposite  Venice,  is  less  than  twelve  fathoms  deep. 
Farther  to  the  south,  where  it  is  less  affected  by  the  influx  of  great 
rivers,  the  gulf  deepens  considerably.  Donati,  after  dredging  the  bottom, 
discovered  the  new  deposits  to  consist  partly  of  mud  and  partly  of  rock, 
the  rock  being  formed  of  calcareous  matter,  incrusting  shells.  He  also 
ascertained,  that  particular  species  of  testacea  were  grouped  together  in 
certain  places,  and  were  becoming  slowly  incorporated  with  the  mud  or 
calcareous  precipitates.];  Olivi,  also,  found  some  deposits  of  sand,  and 
others  of  mud,  extending  half  way  across  the  gulf ;  and  he  states  that 
their  distribution  along  the  bottom  was  evidently  determined  by  the 
prevailing  current.§  It  is  probable,  therefore,  that  the  finer  sediment 
of  all  the  rivers  at  the  head  of  the  Adriatic  may  be  intermingled  by  the 
influence  of  the  current ;  and  all  the  central  parts  of  the  gulf  may  be 
considered  as  slowly  filling  up  with  horizontal  deposits,  similar  to  those 
of  the  Subapennine  hills,  and  containing  many  of  the  same  species  of 
shells.  The  Po  merely  introduces  at  present  fine  sand  and  mud,  for  it 
carries  no  pebbles  farther  than  the  spot  where  i,t  joins  the  Trebia,  west 
of  Piacenza.  Near  the  northern  borders  of  the  basin,  the  Isonzo, 

*  Brocchi,  Conch.  Foss.  Subap.  vol.  i.  p.  118. 

|  Archiac,  Histoire  des  Progres  de  la  Geol.  1848,  vol.  it  p.  232.  \ 

J  Brocchi,  Conch.  Foss.  Subap.  vol.  i.  p.  39.  §  Ibid.  vol.  ii.  p.  94. 

17 


258  DELTA   OF   THE   RHONE,  [Cfl.  XVII. 

Tagliamento,  and  many  other  streams,  are  forming  immense  beds  of 
sand  and  some  conglomerate  ;  for  here  some  high  mountains  of  Alpine 
limestone  approach  within  a  few  miles  of  the  sea. 

In  the  time  of  the  Romans,  the  hot-baths  of  Monfalcone  were  on  one 
of  several  islands  of  Alpine  limestone,  between  which  and  the  mainland, 
on  the  north,  was  a  channel  of  the  sea,  about  a  mile  broad.  This  chan- 
nel is  now  converted  into  a  grassy  plain,  which  surrounds  the  islands  on 
all  sides.  Among  the  numerous  changes  on  this  coast,  we  find  that  the 
present  channel  of  the  Isonzo  is  several  miles  to  the  west  of  its  ancient 
bed,  in  part  of  which,  at  Ronchi,  the  old  Roman  bridge  which  crossed 
the  Via  Appia  was  lately  found  buried  in  fluviatile  silt. 

Marine  delta  of  the  Rhone. — The  lacustrine  delta  of  the  Rhone  in 
Switzerland  has  already  been  considered  (p.  251),  its  contemporaneous 
marine  delta  may  now  be  described.  Scarcely  has  the  river  passed  out 
of  the  Lake  of  Geneva  before  its  pure  waters  are  again  filled  with  sand 
and  sediment  by  the  impetuous  Arve,  descending  from  the  highest  Alps, 
and  bearing  along  in  its  current  the  granitic  detritus  annually  brought 
down  by  the  glaciers  of  Mont  Blanc.  The  Rhone  afterwards  receives 
vast  contributions  of  transported  matter  from  the  Alps  of  Dauphiny, 
and  the  primary  and  volcanic  mountains  of  Central  France ;  and  when 
at  length  it  enters  the  Mediterranean,  it  discolors  the  blue  waters  of 
that  sea  with  a  whitish  sediment,  for  the  distance  of  between  six  and 
seven  miles,  throughout  which  space  the  current  of  fresh  water  is  per- 
ceptible. 

Strabo's  description  of  the  delta  is  so  inapplicable  to  its  present  con- 
figuration, as  to  attest  a  complete  alteration  in  the  physical  features  of 
the  country  since  the  Augustan  age.  It  appears,  however,  that  the 
head  of  the  delta,  or  the  point  at  which  it  begins  to  ramify,  has  re- 
mained unaltered  since  the  time  of  Pliny,  for  he  states  that  the  Rhone 
divided  itself  at  Aries  into  two  arms.  This  is  the  case  at  present ;  one 
of  the  branches,  the  western,  being  now  called  Le  Petit  Rhone,  which 
is  again  subdivided  before  entering  the  Mediterranean.  The  advance  of 
the  base  of  the  delta,  in  the  last  eighteen  centuries,  is  demonstrated  by 
many  curious  antiquarian  monuments.  The  most  striking  of  these  is  the 
great  and  unnatural  detour  of  the  old  Roman  road  from  Ugernum  to 
Beziers  (Boeterrce)  which  went  round  by  Nismes  (Nemausus).  It  is 
clear  that,  when  this  was  first  constructed,  it  was  impossible  to  pass  in 
a  direct  line,  as  now,  across  the  delta,  and  that  either  the  sea  or  marshes 
intervened  in  a  tract  now  consisting  of  terra  firma.*  Astruc  also 
remarks,  that  all  the  places  on  low  lands,  lying  to  the  north  of  the  old 
Roman  road  between  Nismes  and  Beziers,  have  names  of  Celtic  origin, 
evidently  given  to  them  by  the  first  inhabitants  of  the  country ;  where- 
as, the  places  lying  south  of  that  road,  towards  the  sea,  have  names  of 
Latin  derivation,  and  were  clearly  founded  after  the  Roman  language 
had  been  introduced. 

*  M6m.  d' Astruc,  cited  by  Von  Hoff,  vol.  i.  p.  288. 


CH.  XVII.]  DELTA   OF   THE   RHONE.  259 

Another  proof,  also,  of  the  great  extent  of  land  which  has  come  into 
existence  since  the  Romans  conquered  and  colonized  Gaul,  is  derived 
from  the  fact,  that  the  Roman  writers  never  mention  the  thermal 
waters  of  Balaruc  in  the  delta,  although  they  were  well  acquainted  with 
those  of  Aix,  and  others  still  more  distant,  and  attached  great  import- 
ance to  them,  as  they  invariably  did  to  all  hot  springs.  The  waters  of 
Balaruc,  therefore,  must  have  formerly  issued  under  the  sea — a  com- 
mon phenomenon  on  the  borders  of  the  Mediterranean  ;  and  on  the 
advance  of  the  delta  they  continued  to  flow  out  through  the  new 
deposits. 

Among  the  more  direct  proofs  of  the  increase  of  land,  we  find  that 
Mese,  described  under  the  appellation  of  Mesua  Collis  by  Pomponius 
Mela,*  and  stated  by  him  to  be  nearly  an  island,  is  now  far  inland. 
Notre  Dame  des  Ports,  also,  was  a  harbor  in  898,  but  is  now  a  league 
from  -the  shore.  Psalmodi  was  an  island  in  815,  and  is  now  two 
leagues  from  the  sea.  Several  old  lines  of  towers  and  sea-marks  occur 
at  different  distances  from  the  present  coast,  all  indicating  the  succes- 
sive retreat  of  the  sea,  for  each  line  has  in  its  turn  become  useless  to 
mariners  ;  which  may  well  be  conceived,  when  we  state  that  the  Tower 
of  Tignaux,  erected  on  the  shore  so  late  as  the  year  1737,  is  already  a 
mile  remote  from  it.f 

By  the  confluence  of  the  Rhone  and  the  currents  of  the  Mediterra- 
nean, driven  by  winds  from  the  south,  sand-bars  are  often  formed  across 
the  mouths  of  the  river ;  by  these  means  considerable  spaces  become 
divided  off  from  the  sea,  and  subsequently  from  the  river  also,  when  it 
shifts  its  channels  of  efflux.  As  some  of  these  lagoons  are  subject  to 
the  occasional  ingress  of  the  river  when  flooded,  and  of  the  sea  during 
storms,  they  are  alternately  salt  and  fresh.  Others,  after  being  filled 
with  salt  water,  are  often  lowered  by  evaporation  till  they  become 
more  salt  than  the  sea  ;  and  it  has  happened,  occasionally,  that  a  con- 
siderable precipitate  of  muriate  of  soda  has  taken  place  in  these  natural 
salterns.  During  the  latter  part  of  Napoleon's  career,  when  the  excise 
laws  were  enforced  with  extreme  rigor,  the  police  was  employed  to 
prevent  such  salt  from  being  used.  The  fluviatile  and  marine  shells 
inclosed  in  these  small  lakes  often  live  together  in  brackish  water ;  but 
the  uncongenial  nature  of  the  fluid  usually  produces  a  dwarfish  size, 
and  sometimes  gives  rise  to  strange  varieties  in  form  and  color. 

Captain  Smyth  in  his  survey  of  the  coast  of  the  Mediterranean, 
found  the  sea  opposite  the  mouth  of  the  Rhone,  to  deepen  gradually 
from  four  to  forty  fathoms,  within  a  distance  of  six  or  seven  miles, 
over  which  the  discolored  fresh  water  extends  ;  so  that  the  inclination 
of  the  new  deposits  must  be  too  slight  to  be  appreciable  in  such  an 
extent  of  section  as  a  geologist  usually  obtains  in  examining  ancient 
formations.  When  the  wind  blew  from  the  southwest,  the  ships  em- 

*  Lib.  ii.  c.  v. 

f  Bouche,  Chorographie  et  Hist,  de  Provence,  vol.  i  p.  23,  cited  by  Von  Hofl, 
voL  i.  p.  290. 


260  DELTAS    ON   THE   COAST   OF  ASIA   MINOR.  [Cn.  XVII. 

ployed  in  the  survey  were  obliged  to  quit  their  moorings ;  and  when 
they  returned,  the  new  sand-banks  in  the  delta  were  found  covered 
over  with  a  great  abundance  of  marine  shells.  By  this  means,  we  learn 
how  occasional  beds  of  drifted  marine  shells  may  become  interstratified 
with  freshwater  strata  at  a  river's  mouth. 

Stony  nature  of  its  deposits. — That  a  great  proportion,  at  least, 
of  the  new  deposit  in  the  delta  of  the  Rhone  consists  of  rock,  and  not 
of  loose  incoherent  matter,  is  perfectly  ascertained.  In  the  Museum  at 
Montpelier  is  a  cannon  taken  up  from  the  sea  near  the  mouth  of  the 
river,  imbedded  in  a  crystalline  calcareous  rock.  Large  masses,  also, 
are  continually  taken  up  of  an  arenaceous  rock,  cemented  by  calcareous 
matter,  including  multitudes  of  broken  shells  of  recent  species.  The 
observations  lately  made  on  this  subject  corroborate  the  former  state- 
ment of  Marsilli,  that  the  earthy  deposits  of  the  coast  of  Languedoc  form 
a  stony  substance,  for  which  reason  he  ascribes  a  certain  bituminous, 
saline,  and  glutinous  nature  to  the  substances  brought  down  with  sand 
by  the  Rhone.*  If  the  number  of  mineral  springs  charged  with  car- 
bonate of  lime  which  fall  into  the  Rhone  and  its  feeders  in  different 
parts  of  France  be  considered,  we  shall  feel  no  surprise  at  the  lapidifi- 
cation  of  the  newly  deposited  sediment  in  this  delta.  It  should  be 
remembered,  that  the  fresh  water  introduced  by  rivers  being  lighter 
than  the  water  of  the  sea,  floats  over  the  latter,  and  remains  upon  the 
surface  for  a  considerable  distance.  Consequently  it  is  exposed  to 
as  much  evaporation  as  the  waters  of  a  lake  ;  and  the  area  over  which 
the  river-water  is  spread,  at  the  junction  of  great  rivers  and  the  sea, 
may  well  be  compared,  in  point  of  extent,  to  that  of  considerable  lakes. 

Now,  it  is  well  known,  that  so  great  is  the  quantity  of  water  carried 
off  by  evaporation  in  some  lakes,  that  it  is  nearly  equal  to  the  water 
flowing  in  ;  and  in  some  inland  seas,  as  the  Caspian,  it  is  quite  equal. 
We  may,  therefore,  well  suppose  that,  in  cases  where  a  strong  current 
does  not  interfere,  the  greater  portion  not  only  of  the  matter  held  mechan- 
ically in  suspension,  but  of  that  also  which  is  in  chemical  solution,  may 
be  precipitated  at  no  great  distance  from  the  shore.  When  these  finer 
ingredients  are  extremely  small  in  quantity,  they  may  only  suffice  to 
supply  crustaceous  animals,  corals,  and  marine  plants,  with  the  earthy 
particles  necessary  for  their  secretions ;  but  whenever  it  is  in  excess 
(as  generally  happens  if  the  basin  of  a  river  lie  partly  in  a  district  of 
active  or  extinct  volcanoes),  then  will  solid  deposits  be  formed,  and  the 
shells  will  at  once  be  included  in  a  rocky  mass. 

Coast  of  Asia  Minor. — Examples  of  the  advance  of  the  land  upon 
the  sea  are  afforded  by  the  southern  coast  of  Asia  Minor.  Admiral 
Sir  F.  Beaufort  has  pointed  out  in  his  survey  the  great  alterations 
effected  since  the  time  of  Strabo,  where  havens  are  filled  up,  islands 
joined  to  the  mainland,  and  where  the  whole  continent  has  increased 
many  miles  in  extent.  Strabo  himself,  on  comparing  the  outline  of  the 
coast  in  his  time  with  its  ancient  state,  was  convinced,  like  our  country  - 

*  Hist.  Phys.  de  la  Mer. 


CH.  X  VII]  ,  DELTA   OF   THE   NILE.  261 

man,  that  it  had  gained  very  considerably  upon  the  sea.  The  new- 
formed  strata  of  Asia  Minor  consist  of  stone,  not  of  loose  incoherent 
materials.  Almost  all  the  streamlets  and  rivers,  like  many  of  those  in 
Tuscany  and  the  south  of  Italy,  hold  abundance  of  carbonate  of  lime 
in  solution,  and  precipitate  travertin,  or  sometimes  bind  together  the 
sand  and  gravel  into  solid  sandstones  and  conglomerates ;  every  delta 
and  sand-bar  thus  acquires  solidity,  which  often  prevents  streams  from 
forcing  their  way  through  them,  so  that  their  mouths  are  constantly 
changing  their  position.* 

Delta  of  the  Nile. — That  Egypt  was  "  the  gift  of  the  Nile,"  was  the 
opinion  of  her  priests  before  the  time  of  Herodotus ;  and  Rennell  ob- 
serves, that  the  "  configuration  and  composition  of  the  low  lands  leave 
no  room  for  doubt  that  the  sea  once  washed  the  base  of  the  rocks  on 
which  the  pyramids  of  Memphis  stand,  the  present  base  of  which  is 
washed  by  the  inundation  of  the  Nile,  at  an  elevation  of  70  or  80  feet 
above  the  Mediterranean.  But  when  we*  attempt  to  carry  back  our  ideas 
to  the  remote  period  when  the  foundation  of  the  delta  was  first  laid,  we 
are  lost  in  the  contemplation  of  so  vast  an  interval  of  time."f  Herodo- 
tus observes,  "  that  the  country  round  Memphis  seemed  formerly  to 
have  been  an  arm  of  the  sea  gradually  filled  by  the  Nile,  in  the  same 
manner  as  the  Meander,  Achelous,  and  other  streams,  had  formed  deltas. 
Egypt,  therefore,  he  says,  like  the  Red  Sea,  was  once  a  long  narrow  bay, 
and  both  gulfs  were  separated  by  a  small  neck  of  land.  If  the  Nile, 
he  adds,  should  by  any  means  have  an  issue  into  the  Arabian  Gulf,  it 
might  choke  it  up  with  earth  in  20,000  or  even,  perhaps,  in  10,000 
years ;  and  why  may  not  the  Nile  have  filled  a  still  greater  gulf  with 
mud  in  the  space  of  time  which  has  passed  before  our  age  ?"J 

The  distance  between  Memphis  and  the  most  prominent  part  of  the 
delta  in  a  straight  line  north  and  south,  is  about  100  geographical  miles; 
the  length  of  the  base  of  the  delta  is  more  than  200  miles  if  we  follow 
the  coast  between  the  ancient  extreme  eastern  and  western  arms  ;  but  as 
these  are  now  blocked  up,  that  part  only  of  Lower  Egypt  which  inter- 
venes between  the  Rosetta  and  Damietta  branches,  is  usually  called  the 
delta,  the  coast  line  of  which  is  about  90  miles  in  length.  The  bed  of 
the  river  itself,  says  Sir  J.  G.  Wilkinson,  undergoes  a  gradual  increase 
of  elevation  varying  in  different  places,  and  always  lessening  in  propor- 
tion as  the  river  approaches  the  sea.  "  This  increase  of  elevation  in 
perpendicular  height  is  much  smaller  in  Lower  than  in  Upper  Egypt, 
and  in  the  delta  it  diminishes  still  more  ;  so  that,  according  to  an  ap- 
proximate calculation,  the  land  about  Elephantine,  or  the  first  cataract, 
lat.  24°  5',  has  been  raised  nine  feet  in  1700  years ;  at  Thebes,  lat.  25° 
43',  about  seven  feet ;  and  at  Heliopolis  and  Cairo,  lat.  30°,  about  five 
feet  ten  inches.  At  Rosetta  and  the  mouths  of  the  Nile,  lat.  31°  30;, 
the  diminution  in  the  perpendicular  thickness  of  the  deposit  is  lessened 

*  Karamania,  or  a  brief  Description  of  the  Coast  of  Asia  Minor,  <fcc.  London, 
1817. 

f  Geog.  Syst.  of  Herod,  vol.  ii.  p.  107.  \  Euterpe,  XI. 


262  MUD   OF   THE   NILE.  [Cn.  XVII. 

in  a  much  greater  decreasing  ratio  than  in  the  straitened  valley  of  Cen- 
tral and  Upper  Egypt,  owing  to  the  great  extent,  east  and  west,  over 
which  the  inundation  spreads."* 

For  this  reason  the  alluvial  deposit  does  not  cause  the  delta  to  protrude 
rapidly  into  the  sea,  although  some  ancient  cities  are  now  a  mile  or  more 
inland,  and  the  mouths  of  the  Nile,  mentioned  by  the  earlier  geographers, 
have  been  many  of  them  silted  up,  and  the  outline  of  the  coast  entirely 
changed. 

The  bed  of  the  Nile  always  keeps  pace  with  the  general  elevation  of 
the  soil,  and  the  banks  of  this  river,  like  those  of  the  Mississippi  and  its 
tributaries  (see  p.  265),  are  much  higher  than  the  flat  land  at  a  distance, 
so  that  they  are  seldom  covered  during  the  highest  inundations.  In 
consequence  of  the  gradual  rise  of  the  river's  bed,  the  annual  flood  is 
constantly  spreading  over  a  wider  area,  and  the  alluvial  soil  encroaches 
on  the  desert,  covering,  to  the  depth  of  six  or  seven  feet,  the  base  of 
statues  and  temples  which  the  waters  never  reached  3000  years  ago. 
Although  the  sands  of  the  Libyan  deserts  have  in  some  places  been 
drifted  into  the  valley  of  the  Nile,  yet  these  aggressions,  says  Wilkinson, 
are  far  more  than  counterbalanced  by  the  fertilizing  effect  of  the  water 
which  now  reaches  farther  inland  towards  the  desert,  so  that  the  num- 
ber of  square  miles  of  arable  soil  is  greater  at  present  than  at  any  pre- 
vious period. 

Mud  of  the  Nile. — On  comparing  the  different  analyses  which  have 
been  published  of  this  mud,  it  will  be  found  that  it  contains  a  large 
quantity  of  argillaceous  matter,  with  much  peroxide  of  iron,  some  car- 
bonate of  lime,  and  a  small  proportion  of  carbonate  of  magnesia.  The 
latest  and  most  careful  analysis  by  M.  Lassaigne  shows  a  singularly  close 
resemblance  in  the  proportions  of  the  ingredients  of  silica,  alumina,  iron, 
carbon,  lime,  and  magnesia,  and  those  observed  in  ordinary  mica  ;f  but 
a  much  larger  quantity  of  calcareous  matter  is  sometimes  present. 

In  many  places,  as  at  Cairo,  where  artificial  excavations  have  been 
made,  or  where  the  river  has  undermined  its  banks,  the  mud  is  seen  to 
be  thinly  stratified,  the  upper  part  of  each  annual  layer  consisting  of 
earth  of  a  lighter  color  than  the  lower,  and  the  whole  separating  easily 
from  the  deposit  of  the  succeeding  year.  These  annual  layers  are  vari- 
able in  thickness ;  but,  according  to  the  calculations  of  Girard  and  Wil- 
kinson, the  mean  annual  thickness  of  a  layer  at  Cairo  cannot  exceed  that 
of  a  sheet  of  thin  pasteboard,  and  a  stratum  of  two  or  three  feet  must 
represent  the  accumulation  of  a  thousand  years. 

The  depth  of  the  Mediterranean  is  about  twelve  fathoms  at  a  small 
distance  from  the  shore  of  the  delta  ;  it  afterwards  increases  gradually  to 
50,  and  then  suddenly  descends  to  380  fathoms,  which  is,  perhaps,  the 
original  depth  of  the  sea  where  it  has  not  been  rendered  shallower  by 
fluviatile  matter.  We  learn  from  Lieut.  Newbold  that  nothing  but  the 

*  Journ.  of  Roy.  Geograph.  Soe.  vol.  ix.  p.  432. 

f  Quart.  Journ.  GeoL  Soc.  vol.  v. ;  Memoirs,  p.  20 ;  and  Lassaigne,  Journ.  4 
Pharm.  t.  v.  p.  468. 


CH.  XVIIL]  BASIN   OF   THE   MISSISSIPPI.  263 

finest  and  lightest  ingredients  reach  the  Mediterranean,  where  he  has 
observed  the  sea  discolored  by  them  to  the  distance  of  40  miles  from 
the  shore.*  The  small  progress  of  the  delta  in  the  last  2000  years  affords, 
perhaps,  no  measure  for  estimating  its  rate  of  growth  when  it  was  an 
inland  bay,  and  had  not  yet  protruded  itself  beyond  the  coast-liqe  of 
the  Mediterranean.  A  powerful  current  now  sweeps  along  the  shores 
of  Africa,  from  the  Straits  of  Gibraltar  to  the  prominent  convexity  of 
Egypt,  the  western  side  of  which  is  continually  the  prey  of  the  waves  ; 
so  that  not  only  are  fresh  accessions  of  land  checked,  but  ancient  parts 
of  the  delta  are  carried  away.  By  this  cause,  Canopus  and  some  other 
towns  have  been  overwhelmed  ;  but  to  this  subject  I  shall  again  refer 
when  speaking  of  tides  and  currents. 


CHAPTER  XVIII. 

REPRODUCTIVE    EFFECTS    OF    RIVERS Continued. 

Deltas  formed  under  the  influence  of  tides — Basin  and  delta  of  the  Mississippi — 
Alluvial  plain — River-banks  and  bluffs — Curves  of  the  river — Natural  rafts 
and  snags — New  lakes,  and  effects  of  earthquakes — Antiquity  of  the  delta — 
Delta  of  the  Ganges  and  Brahmapootra — Head  of  the  delta  and  Sunderbunds — 
Islands  formed  and  destroyed — Crocodiles — Amount  of  fluviatile  sediment  in 
the  water — Artesian  boring  at  Calcutta — Proofs  of  subsidence — Age  of  the 
delta — Convergence  of  deltas — Origin  of  existing  deltas  not  contemporaneous — 
Grouping  of  strata  and  stratification  in  deltas — Conglomerates — Constant  inter- 
change of  land  and  sea.  . 

IN  the  last  chapter  several  examples  were  given  of  the  deltas  of  inland 
seas,  where  the  influence  of  the  tides  is  almost  imperceptible.  We 
may  next  consider  those  marine  or  oceanic  deltas,  where  the  tides  play 
an  important  part  in  the  dispersion  of  fluviatile  sediment,  as  in  the  Gulf 
of  Mexico,  where  they  exert  a  moderate  degree  of  force,  and  then  in  the 
Bay  of  Bengal,  where  they  are  extremely  powerful.  In  regard  to 
estuaries,  which  Rennel  termed  "  negative  deltas,"  they  will  be  treated 
of  more  properly  when  our  attention  is  specially  turned  to  the  opera- 
tions of  tides  and  currents  (chapters  20,  21,  and  22).  In  this  case, 
instead  of  the  land  gaining  on  the  sea  at  the  river's  mouth,  the  tides 
penetrate  far  inland  beyond  the  general  coast-line. 

BASIN    AND    DELTA    OF    THE    MISSISSIPPI. 

Alluvial  plain. — The  hydrographical  basin  of  the  Mississippi  displays, 
on  the  grandest  scale,  the  action  of  running  water  on  the  surface  of  a 
vast  continent.  This  magnificent  river  rises  nearly  in  the  forty-ninth 

*  Quart.  Journ.  Geol.  Soc.  1848,  vol.  iv.  p.  342. 


264  BASIN   OF   THE   MISSISSIPPI.  [Ca  XVIIL 

parallel  of  north  latitude,  and  flows  to  the  Gulf  of  Mexico  in  the  twenty- 
ninth — a  course,  including  its  meanders,  of  more  than  three  thousand 
miles.  It  passes  from  a  cold  climate,  where  the  hunter  obtains  his  furs 
and  peltries,  traverses  the  temperate  latitudes,  and  discharges  its  waters 
into  the  sea  in  the  region  of  rice,  the  cotton  plant,  and  the  sugar-cane. 
From  near  its  mouth  at  the  Balize  a  steamboat  may  ascend  for  2000 
miles  with  scarcely  any  perceptible  difference  in  the  width  of  the  river. 
Several  of  its  tributaries,  the  Red  River,  the  Arkansas,  the  Missouri,  the 
Ohio,  and  others,  would  be  regarded  elsewhere  as  of  the  first  importance, 
and,  taken  together,  are  navigable  for  a  distance  many  times  exceeding 
that  of  the  main  stream.  No  river  affords  a  more  striking  illustration 
of  the  law  before  mentioned,  that  an  augmentation  of  volume  does  not 
occasion  a  proportional  increase  of  surface,  nay,  is  even  sometimes  at- 
tended with  a  narrowing  of  the  channel.  The  Mississippi  is  half  a  mile 
wide  at  its  junction  with  the  Missouri,  the  latter  being  also  of  equal 
width  ;  yet  the  united  waters  have  only,  from  their  confluence  to  the 
mouth  of  the  Ohio,  a  medial  width  of  about  half  a  mile.  The  junction 
of  the  Ohio  seems  also  to  produce  no  increase,  but  rather  a  decrease, 
of  surface.*  The  St.  Francis,  White,  Arkansas,  and  Red  rivers  are 
also  absorbed  by  the  main  stream  with  scarcely  any  apparent  increase 
of  its  width,  although  here  and  there  it  expands  to  a  breadth  of  1 J,  or 
even  to  2  miles.  On  arriving  at  New  Orleans,  it  is  somewhat  less  than 
half  a  mile  wide.  Its  depth  there  is  very  variable,  the  greatest  at  high 
water  being  168  feet.  The  mean  rate  at  which  the  whole  body  of 
water  flows  is  variously  estimated ;  according  to  Mr.  Forshey  the  mean 
velocity  of  the  current  at  the  surface,  somewhat  exceeds  2j  miles  an 
hour  when  the  water  is  at  a  mean  height.  For  300  miles  above  New 
Orleans  the  distance  measured  by  the  winding  river  is  about  twice  as 
great  as  the  distance  in  a  right  line.  For  the  first  100  miles  from  the 
mouth  the  rate  of  fall  is  T80  inch  per  mile,  for  the  second  hundred  2 
inches,  for  the  third  2'30,  for  the  fourth  2'57. 

The  alluvial  plain  of  the  Mississippi  begins  to  be  of  great  width  below 
Cape  Girardeau,  50  miles  above  the  junction  of  the  Ohio.  At  this 
junction  it  is  about  50  miles  broad,  south  of  which  it  contracts  to  about 
30  miles  at  Memphis,  expands  again  to  80  miles  at  the  mouth  of  the 
White  River,  and  then,  after  various  contractions  and  expansions,  pro- 
trudes beyond  the  general  coast-line,  in  a  large  delta,  about  90  miles  in 
width,  from  N.  E.  to  S.  W.  Mr.  Forshey  estimates  the  area  of  the 
great- plain  as  above  defined  at  31,200  square  miles,  with  a  circumfer- 
ence of  about  3000  miles,  exceeding  the  area  of  Ireland.  If  that  part 
of  this  plain  which  lies  below,  or  to  the  south  of  the  branching  off  of 
the  highest  arm,  called  the  Atchafalaya,  be  termed  the  delta,  it  consti- 
tutes less  than  half  of  the  whole,  being  14,000  square  British  miles  in 
area.  The  delta  may  be  said  to  be  bounded  on  the  east,  west,  and 

*  Flint's  Geography,  vol.  i.  p.  142.  Lyell's  Second  Visit  to  the  United  States, 
vol.  ii.  chaps.  28  to  34. 


OH.  XVIII.]  CURVES   OF   THE   MISSISSIPPI.  265 

south  by  the  sea ;  on  the  north  chiefly  by  the  broad  valley-plain  which 
entirely  resembles  it  in  character  as  in  origin.  The  east  and  west 
boundaries  of  the  alluvial  region  above  the  head  of  the  delta  consists  of 
cliffs  or  b'uffs,  which  on  the  east  side  of  the  Mississippi  are  very  abrupt, 
and  are  undermined  by  the  river  at  many  points.  They  consist, 'from 
Baton  Rouge  in  Louisiana,  where  they  commence,  as  far  north  as  the 
borders  of  Kentucky,  of  geological  formations  newer  than  the  cretaceous, 
the  lowest  being  Eocene,  and  the  uppermost  consisting  of  loam,  re- 
sembling the  loess  of  the  Rhine,  and  containing  freshwater  and  land 
shells  almost  all  of  existing  species.  (See  fig.  23.)  These  recent  shells 
are  associated  with  the  bones  of  the  mastodon,  elephant,  tapir,  mylodon, 
horec,  ox,  and  other  quadrupeds,  most  of  them  of  extinct  species. 

I  have  endeavored  to  show  in  my  Second  Visit  to  the  United  States, 
that  this  extensive  formation  of  loam  is  either  an  ancient  alluvial  plain 
or  a  delta  of  the  great  river,  formed  originally  at  a  lower  level,  and 
since  upheaved,  and  partially  denuded. 

The  Mississippi  in  that  part  of  its  course  which  is  below  the  mouth 
of  the  Ohio,  frequently  washes  the  eastern  bluffs,  but  never  once  comes 
in  contact  with  the  western.  These  are  composed  of  similar  forma- 
tions ;  but  I  learn  from  Mr.  Forshey  that  they  rise  up  more  gently 
from  the  alluvial  plain  (as  at  a,  fig.  23).  It  is  supposed  that  the 

Fig.  23. 

VALLEY  OP  THE  MISSISSIPPI. 
Louisiana. 


32  1  34 

1.  Modern  alluvium  of  Mississippi.        2.  Loam  or  Loess.        3.  /  Eocene.        4.  Cretaceous. 

waters  are  thrown  to  the  eastern  side,  because  all  the  large  tributary 
rivers  entering  from  the  west  have  filled  that  side  of  the  great  valley 
with  their  deltas,  or  with  a  sloping  mass  of  clay  and  sand  ;  so  that  the 
opposite  bluffs  are  undermined,  and  the  Mississippi  is  slowly  but  inces- 
santly advancing  eastward.* 

Curves  of  the  Mississippi. — The  river  traverses  the  plain  in  a  mean- 
dering course,  describing  immense  curves.  After  sweeping  round  the 
half  of  a  circle,  it  is  carried  in  a  rapid  current,  diagonally  across  the 
ordinary  direction  of  its  channel,  to  another  curve  of  similar  shape. 
Opposite  to  each  of  these,  there  is  always  a  sand-bar,  answering,  in  the 
convexity  of  its  form,  to  the  concavity  of  "  the  bend,"  as  it  is  called.} 
The  river,  by  continually  wearing  these  curves  deep,  returns,  like  many 
other  streams  before  described,  on  its  own  track,  so  that  a  vessel  in 
some  places,  after  sailing  for  twenty-five  or  thirty  miles,  is  brought 
round  again  to  within  a  mile  of  the  place  whence  it  started.  When  the 
waters  approach  so  near  to  each  other,  it  often  happens -at  high  floods 

*  Geograph.  Descrip.  of  Louisiana,  by  W.  Darby,  Philadelphia,  1816,  p.  102. 
f  Flint's  Geography,  vol.  i.  p.  152. 


266  WASTE   OF  THE   BANKS   OF  THE  MISSISSIPPI.     [On.  XVIIL 

that  they  burst  through  the  small  tongue  of  land,  and  insulate  a  portion, 
rushing  through  what  is  called  the  "  cut-off,"  so  that  vessels  may  pass 
from  one  point  to  another  in  half  a  mile  to  a  distance  which  it  previ- 
ously required  a  voyage  of  twenty  miles  to  reach.  As  soon  as  the  river 
has  excavated  the  new  passage,  bars  of  sand  and  mud  are  formed  at 
the  two  points  of  junction  with  the  old  bend,  which  is  soon  entirely 
separated  from  the  main  river  by  a  continuous  mud-bank  covered  with 
wood.  The  old  bend  then  becomes  a  semicircular  lake  of  clear  water, 
inhabited  by  large  gar-fish,  alligators,  and  wild  fowl,  which  the  steam- 
boats have  nearly  driven  away  from  the  main  river.  A  multitude  of 
such  crescent-shaped  lakes,  scattered  far  and  wide  over  the  alluvial 
plain,  the  greater  number  of  them  to  the  west,  but  some  of  them  also 
eastward  of  the  Mississippi,  bear  testimony  of  the  extensive  wanderings 
of  the  great  stream  in  former  ages.  For  the  last  two  hundred  miles 
above  its  mouth  the  course  of  the  river  is  much  less  winding  than 
above,  there  being  only  in  the  whole  of  that  distance  one  great  curve, 
that  called  the  "  English  Turn."  This  great  straightness  of  the  stream 
is  ascribed  by  Mr.  Forshey  to  the  superior  tenacity  of  the  banks,  which 
are  more  clayey  in  this  region. 

The  Mississippi  has  been  incorrectly  described  by  £ome  of  the  earlier 
geographers,  as  a  river  running  along  the  top  of  a  long  hill,  or  mound 
in  a  plain.  In  reality  it  runs  in  a  valley,  from  100  to  200  or  more  feet 
in  depth,  as  a,  c,  b,  fig.  24,  its  banks  forming  long  strips  of  land  par- 
allel to  the  course  of  the  main  stream,  and  to  the  swamps  g,  f,  and  d,  e, 
lying  on  each  side.  These  extensive  morasses,  which  are  commonly  well- 
wooded,  though  often  submerged  for  months  continuously,  are  rarely 
more  than  fifteen  feet  below  the  summit  level  of  the  banks.  The  banks 
themselves  are  occasionally  overflowed,  but  are  usually  above  water  for 

Fig.  24 


c 
Section  of  channel,  bank,  levees  (a  and  6),  and  swamps  of  Mississippi  river. 

a  breadth  of  about  two  miles.  They  follow  all  the  curves  of  the  great 
river,  and  near  New  Orleans  are  raised  artificially  by  embankments  (or 
levees),  a  b,  fig.  24,  through  which  the  river  when  swollen  sometimes 
cuts  a  deep  channel  (or  crevasse),  inundating  the  adjoining  low  lands 
and  swamps,  and  not  sparing  the  lower  streets  of  the  great  city. 

The  cause  of  the  uniform  upward  slope  of  the  river -bank  above  the 
adjoining  alluvial  plain  is  this  :  when  the  waters  charged  with  sediment 
pass  over  the  banks  in  the  flood  season,  their  velocity  is  checked  among 
the  herbage  and  reeds,  and  they  throw  down  at  once  the  coarser  and 
more  sandy  matter  with  which  they  are  charged.  But  the  fine  parti- 
cles of  mud  are  carried  farther  on,  so  that  at  the  distance  of  about  two 


CH.  XVIII]  KAFT   OF   THE   ATCHAFALAYA.  267 

miles,  a  thin  film  of  fine  clay  only  subsides,  forming  a  stiff  unctuous 
black  soil,  which  gradually  envelops  the  base  of  trees  growing  on  the 
borders  of  the  swamps. 

Waste  of  the  banks. — It  has  been  said  of  a  mountain  torrent,  that  "  it 
lays  down  what  it  will  remove,  and  removes  what  it  has  laid  down ;" 
and  in  like  manner  the  Mississippi,  by  the  continual  shifting  of  its  course, 
sweeps  away,  during  a  great  portion  of  the  year,  considerable  tracts  of 
alluvium,  which  were  gradually  accumulated  by  the  overflow  of  former 
years,  and  the  matter  now  left  during  the  spring-floods  will  be  at  some 
future  time  removed.  After  the  flood  season,  when  the  river  subsides 
within  its  channel,  it  acts  with  destructive  force  upon  the  alluvial  banks, 
softened  and  diluted  by  the  recent  overflow.  Several  acres  at  a  time, 
thickly  covered  with  wood,  are  precipitated  into  the  stream  ;  and  large 
portions  of  the  islands  are  frequently  swept  away. 

"  Some  years  ago,"  observes  Captain  Hall,  "  when  the  Mississippi  was 
regularly  surveyed,  all  its  islands  were  numbered,  from  the  confluence 
of  the  Missouri  to  the  sea ;  but  every  season  makes  such  revolutions, 
not  only  in  the  number,  but  in  the  magnitude  and  situation  of  these 
islands,  that  this  enumeration  is  now  almost  obsolete.  Sometimes  large 
islands  are  entirely  melted  away ;  at  other  places  they  have  attached 
themselves  to  the  main  shore,  or,  which  is  the  more  correct  statement, 
the  interval  has  been  filled  up  by  myriads  of  logs  cemented  together  by 
mud  and  rubbish."* 

Rafts. — ,0ne  of  the  most  interesting  features  in  the  great  rivers  of  this 
part  of  America  is  the  frequent  accumulation  of  what  are  termed  "  rafts," 
or  masses  of  floating  trees,  which  have  been  arrested  in  their  progress 
by  snags,  islands,  shoals,  or  other  obstructions,  and  made  to  accumulate, 
so  as  to  form  natural  bridges,  reaching  entirely  across  the  stream.  One 
of  the  largest  of  these  was  called  the  raft  of  the  Atchafalaya,  an  arm  of 
the  Mississippi,  which  was  certainly  at  some  former  time  the  channel  of 
the  Red  River,  when  the  latter  found  its  way  to  the  Gulf  of  Mexico  by 
a  separate  course.  The  Atchafalaya  being  in  a  direct  line  with  the 
general  direction  of  the  Mississippi,  catches  a  large  portion  of  the  timber 
annually  brought  down  from  the  north  ;  and  the  drift-trees  collected  in 
about  thirty-eight  years  previous  to  1816  formed  a  continuous  raft,  no 
less  than  ten  miles  in  length,  220  yards  wide,  and  eight  feet  deep.  The 
whole  rose  and  fell  with  the  water,  yet  was  covered  with  green  bushes 
and  trees,  and  its  surface  enlivened  in  the  autumn  by  a  variety  of  beau- 
tiful flowers.  It  went  on  increasing  till  about  1835,  when  some  of  the 
trees  upon  it  had  grown  to  the  height  of  about  sixty  feet.  Steps  were 
then  taken  by  the  State  of  Louisiana  to  clear  away  the  whole  raft,  and 
open  the  navigation,  which  was  effected,  not  without  great  labor,  in  the 
space  of  four  years. 

The  rafts  on  Red  River  are  equally  remarkable :  in  some  parts  of  its 
course,  cedar-trees  are  heaped  up  by  themselves,  and  in  other  places, 

*  Travels  in  North  America,  vol.  iii.  p.  861. 


268  MISSISSIPPI. — DKIFT-WOOD.  [Cn.  XVIII. 

pines.  Oft  the  rise  of  the  waters  in  summer  hundreds  of  these  are  seen, 
some  with  their  green  leaves  still  upon  them,  just  as  they  have  fallen 
from  a  ne  ghboring  bank,  others  leafless,  broken  and  worn  in  their  pas- 
sage from  a  far  distant  tributary :  wherever  they  accumulate  on  the 
edge  of  a  sand-bar  they  arrest  the  current,  and  soon  become  covered 
with  sediment.  On  this  mud  the  young  willows  and  the  poplars  called 
cotton- wood  spring  up,  their  boughs  still  farther  retarding  the  stream, 
and  as  the  inundation  rises,  accelerating  the  deposition  of  new  soil.  The 
bank  continuing  to  enlarge,  the  channel  at  length  becomes  so  narrow 
that  a  single  long  tree  may  reach  from  side  to  side,  and  the  remaining 
space  is  then  soon  choked  up  by  a  quantity  of  other  timber. 

"  Unfortunately  for  the  navigation  of  the  Mississippi,"  observes  Cap- 
tain Hall,  "  some  of  the  largest  trunks,  after  being  cast  down  from  the 
position  on  which  they  grew,  get  their  roots  entangled  with  the  bottom 
of  the  river,  where  they  remain  anchored,  as  it  were,  in  the  mud.  The 
force  of  the  current  naturally  gives  their  tops  a  tendency  downwards, 
and,  by  its  flowing  past,  soon  strips  them  of  their  leaves  and  branches. 
These  fixtures,  called  snags,  or  planters,  are  extremely  dangerous  to  the 
steam-vessels  proceeding  up  the  stream,  in  which  they  lie  like  a  lance 
in  rest,  concealed  beneath  the  water,  with  their  sharp  ends  pointed 
directly  against  the  bows  of  the  vessels  coming  up.  For  the  most  part 
these  formidable  snags  remain  so  still  that  they  can  be  detected  only  by 
a  slight  ripple  above  them,  not  perceptible  to  inexperienced  eyes.  Some- 
times, however,  they  vibrate  up  and  down,  alternately  showing  their 
heads  above  the  surface  and  bathing  them  beneath  it."*  So  imminent, 
until  lately,  was  the  danger  caused  by  these  obstructions,  that  almost 
all  the  boats  on  the  Mississippi  were  constructed  on  a  particular  plan, 
to  guard  against  fatal  accidents ;  but  in  the  last  ten  years,  by  the  aid 
of  the  power  of  steam  and  the  machinery  of  a  snag-boat,  as  it  is  called, 
the  greater  number  of  these  trunks  of  trees  have  been  drawn  out  of  the 
mud.f 

The  prodigious  quantity  of  wood  annually  drifted  down  by  the  Mis- 
sissippi and  its  tributaries,  is  a,  subject  of  geological  interest,  not  merely 
as  illustrating  the  manner  in  which  abundance  of  vegetable  matter  be- 
comes, in  the  ordinary  course  of  nature,  imbedded  in  submarine  and  es- 
tuary deposits,  but  as  attesting  the  constant  destruction  of  soil  and 
transportation  of  matter  to  lower  levels  by  the  tendency  of  rivers  to 
shift  their  courses.  Each  of  these  trees  must  have  required  many  years, 
some  of  them  centuries,  to  attain  their  full  size ;  the  soil,  therefore, 
whereon  they  grew,  after  remaining  undisturbed  for  long  periods,  is 
ultimately  torn  up  and  swept  away. 

*  Travels  in  North  America,  vol.  iii.  p.  362. 

•j-  "  The  boats  are  fitted,"  says  Captain  Hall, "  with  what  is  called  a  snag-cham- 
ber; — a  partition  formed  of  stout  planks,  which  is  calked,  and  made  so  effectually 
water-tight  that  the  foremost  end  of  the  vessel  is  cut  off  as  entirely  from  the  rest 
of  the  hold  as  if  it  belonged  to  another  boat.  If  the  steam-vessel  happen  to  run 
against  a  snag,  and  that  a  hole  is  made  in  her  bow,  under  the  surface,  this  cham- 
ber merely  fills  with  water." — Travels  in  North  America,  vol.  iii.  p.  363, 


CH.  XVIII]  NEW   LAKES   IN    LOUISIANA.  269 

It  is  also  found  in  excavating  at  New  Orleans,  even  at  the  depth  of 
several  yards  below  the  level  of  the  sea,  that  the  soil  of  the  delta  con- 
tains innumerable  trunks  of  trees,  layer  above  layer,  some  prostrate,  as 
if  drifted,  others  broken  off  near  the  bottom,  but  remaining  still  erect, 
and  with  their  roots  spreading  on  all  sides,  as  if  in  their  natural  position. 
In  such  situations  they  appeared  to  me  to  indicate  a  sinking  of  the 
ground,  as  the  trees  must  formerly  have  grown  in  marshes  above  the 
sea-level.  In  the  higher  parts  of  the  alluvial  plain,  for  many  hundred 
miles  above  the  head  of  the  delta,  similar  stools  and  roots  of  trees  are 
also  seen  buried  in  stiff  clay  at  different  levels,  one  above  the  other,  and 
exposed  to  view  in  the  banks  at  low  water.  They  point  clearly  to  the 
successive  growth  of  forests  in  the  extensive  swamps  of  the  plain,  where 
the  ground  was  slowly  raised,  year  after  year,  by  the  mud  thrown  down 
during  inundations.  These  roots  and  stools  belong  chiefly  to  the  decidu- 
ous cypress  (Taxodium  distichum),  and  other  swamp-trees,  and  they 
bear  testimony  to  the  constant  shifting  of  the  course  of  the  great  river, 
which  is  always  excavating  land  originally  formed  at  some  distance  from 
its  banks. 

Formation  of  lakes  in  Louisiana. — Another  striking  feature  in  the 
basin  of  the  Mississippi,  illustrative  of  the  changes  now  in  progress,  is 
the  formation  by  natural  causes  of  great  lakes,  and  the  drainage  of  others. 
These  are  especially  frequent  in  the  basin  of  the  Red  River  in  Louisiana, 
where  the  largest  of  them,  called  Bistineau,  is  more  than  thirty  miles 
long,  and  has  a  medium  depth  of  from  fifteen  to  twenty  feet.  In  the 
deepest  parts  are  seen  numerous  cypress-trees,  of  all  sizes,  now  dead, 
and  most  of  them  with  their  tops  broken  by  the  wind,  yet  standing 
erect  under  water.  This  tree  resists  the  action  of  air  and  water  longer 
than  any  other,  and,  if  not  submerged  throughout  the  whole  year,  will 
retain  life  for  an  extraordinary  period.  Lake  Bistineau,  as  well  as  Black 
Lake,  Cado  Lake,  Spanish  Lake,  Natchitoches  Lake,  and  many  others, 
have  been  formed,  according  to  Darby,  by  the  gradual  elevation  of  the 
bed  of  Red  River,  in  which  the  alluvial  accumulations  have  been  so  great 
as  to  raise  its  channel,  and  cause  its  waters,  during  the  flood  season,  to 
flow  up  the  mouths  of  many  tributaries,  and  to  convert  parts  of  their 
courses  into  lakes.  In  the  autumn,  when  the  level  of  Red  River  is  again 
depressed,  the  waters  rush  back,  and  some  lakes  become  grassy  meadows, 
with  streams  meandering  through  them.*  Thus,  there  is  a  periodical 
flux  and  reflux  between  Red  River  and  some  of  these  basins,  which  are 
merely  reservoirs,  alternately  emptied  and  filled,  like  our  tide  estuaries — 
with  this  difference,  that  in  the  one  case  the  land  is  submerged  for  seve- 
ral months  continuously,  and  in  the  other  twice  in  every  twenty-four 
hours.  It  has  happened,  in  several  cases,  that  a  raft  of  timber  or  a  bar 
has  been  thrown  by  Red  River  across  some  of  the  openings  of  these 
channels,  and  then  the  lakes  become,  like  Bistineau,  constant  repositories 
of  water.  But,  even  in  these  cases,  their  level  is  liable  to  annual  ele- 

*  Darby's  Louisiana,  p.  33. 


270  THE   SUNK   COUNTRY.  [On.  XVIIL 

Cation  and  depression,  because  the  flood  of  the  main  river,  when  at  its 
height,  passes  over  the  bar ;  just  as,  where  sand-hills  close  the  entrance 
of  an  estuary  on  the  Norfolk  or  Suffolk  coast,  the  sea,  during  some  high 
tide  or  storm,  has  often  breached  the  barrier  and  inundated  again  the 
interior. 

I  am  informed  by  Mr.  Featherstonhaugh  that  the  plains  of  the  Red 
River  and  the  Arkansas  are  so  low  and  flat,  that  whenever  the  Missis- 
sippi rises  thirty  feet  above  its  ordinary  level,  those  great  tributaries  are 
made  to  flow  back,  and  inundate  a  region  of  vast  extent.  Both  the 
streams  alluded  to  contain  red  sediment,  derived  from  the  decomposition 
of  red  porphyry  ;  and  since  1833,  when  there  was  a  great  inundation  in 
the  Arkansas,  an  immense  swamp  has  been  formed  near  the  Mammelle 
mountain,  comprising  30,000  acres,  with  here  and  there  large  lagoons, 
where  the  old  bed  of  the  river  was  situated  ;  in  which  innumerable  trees, 
for  the  most  part  dead,  are  seen  standing,  of  cypress,  cotton-wood,  or 
poplar,  the  triple-thorned  acacia,  and  others,  which  are  of  great  size. 
Their  trunks  appear  as  if  painted  red  for  about  fifteen  feet  from  the 
ground ;  at  which  height  a  perfectly  level  line  extends  through  the 
whole  forest,  marking  the  rise  of  the  waters  during  the  last  flood.* 

But  most  probably  the  causes  above  assigned  for  the  recent  origin  of 
these  lakes  are  not  the  only  ones.  Subterranean  movements  have  alter- 
ed, so  lately  as  the  years  1811—12,  the  relative  levels  of  various  parts  of 
the  basin  of  the  Mississippi,  situated  300  miles  northeast  of  Lake  Bisti- 
neau.  In  those  years  the  great  valley,  from  the  mouth  of  the  Ohio  to 
that  of  the  St.  Francis,  including  a  tract  300  miles  in  length,  and  exceed- 
ing in  area  the  whole  basin  of  the  Thames,  was  convulsed  to  such  a  de- 
gree, as  to  create  new  islands  in  the  river,  and  lakes  in  the  alluvial  plain. 
Some  of  these  were  on  the  left  or  east  bank  of  the  Mississippi,  and  were 
twenty  miles  in  extent ;  as,  for  example,  those  named  Reelfoot  and  Obion 
in  Tennessee,  formed  in  the  channels  or  valleys  of  small  streams  bearing 
the  same  names.f 

But  the  largest  area  affected  by  the  great  convulsion  lies  eight  or  ten 
miles  to  the  westward  of  the  Mississippi,  and  inland  from  the  town  of 
New  Madrid,  in  Missouri.  It  is  called  "  the  sunk  country,"  and  is  said 

*  Featherstonhaugh,  Geol.  Report,  Washington,  1835,  p.  84. 

f  Trees  submerged  in  an  upright  position  have  been  observed  in  other  parts  of 
N.  America.  Thus  Captains  Clark  and  Lewis  found,  about  the  year  1807,  a  forest 
of  pines  standing  erect  under  water  in  the  body  of  the  Columbia  river,  which  they 
supposed,  from  the  appearance  of  the  trees,  to  have  been  submerged  only  about 
twenty  years.  (Travels,  <fec.  vol.  ii.  p.  241.)  More  lately  (1835),  the  Rev.  Mr. 
Parker  observed  on  the  same  river  (lat.  45°  N".,  long.  121°  W.)  trees  standing  in 
their  natural  position  in  spots  where  the  water  was  more  than  twenty  feet  deep. 
The  tops  of  the  trees  had  disappeared ;  but  between  high  and  low  water-mark 
the  trunks  were  only  partially  decayed  ;  and  the  roots  were  seen  through  the 
clear  water,  spreading  as  they  had  grown  in  their  native  forest.  (Tour  beyond 
the  Rocky  Mountains,  p.  132.)  Some  have  inferred  from  these  facts  that  a  tract 
of  land,  more  than  twenty  miles  in  length,  must  have  subsided  vertically ;  but 
Capt.  Fremont,  Dec.  1845  (Rep.  of  Explor.  Exped.  p.  195),  satisfied  himself  that 
the  submerged  forests  have  been  formed  by  immense  land-slides  from  the  moun- 
tains, which  here  closely  shut  in  the  river. 


CH.  XVIIL]  MISSISSIPPI. DEPOSITS   IN   THE   DELTA.  271 

to  extend  along  the  course  of  the  White  Water  and  its  tributaries,  for  a 
distance  of  between  seventy  and  eighty  miles  north  and  south,  and  thirty 
miles  or  more  east  and  west.  Throughout  this  area,  innumerable  sub- 
merged trees,  some  standing  leafless,  others  prostrate,  are  seen  ;  and  so 
great  is  the  extent  of  lake  and  marsh,  that  an  active  trade  in  the  skins 
of  muskrats,  mink,  otters,  and  other  wild  animals,  is  now  carried  On 
there.  In  March,  1846,  I  skirted  the  borders  of  the  "sunk  country" 
nearest  to  New  Madrid,  passing  along  the  Bayou  St.  John  and  Little 
Prairie,  where  dead  trees  of  various  kinds,  some  erect  in  the  water,  others 
fallen,  and  strewed  in  dense  masses  over  the  bottom,  in  the  shallows,  and 
near  the  shore,  were  conspicuous.  I  also  beheld  countless  rents  in  the 
adjoining  dry  alluvial  plains,  caused  by  the  movements  of  the  soil  in  1811- 
12,  and  still  open,  though  the  rains,  frost,  and  river  inundations,  have 
greatly  diminished  their  original  depth.  I  observed,  moreover,  numer- 
ous circular  cavities,  called  "  sunk  holes,"  from  ten  to  thirty  yards  wide, 
and  twenty  feet  or  more  in  depth,  which  interrupt  the  general  level  of 
the  plain.  These  were  formed  by  the  spouting  out  of  large  quantities 
of  sand  and  mud  during  the  earthquakes.* 

That  the  prevailing  changes  of  level  in  the  delta  and  alluvial  plain  of 
the  Mississippi  have  been  caused  by  the  subsidence,  rather  than  the  up- 
heaval of  land,  appears  to  me  established  by  the  fact,  that  there  are  no 
protuberances  of  upraised  alluvial  soil,  projecting  above  the  level  surface 
of  the  great  plain.  It  is  true  that  the  gradual  elevation  of  that  plain, 
by  new  accessions  of  matter,  would  tend  to  efface  every  inequality  de- 
rived from  this  source,  but  we  might  certainly  have  expected  to  find 
more  broken  ground  between  the  opposite  bluffs,  had  local  upthrows  of 
alluvial  strata  been  of  repeated  occurrence. 

Antiquity  of  the  delta. — The  vast  size  of  the  alluvial  plain  both  above 
and  below  the  head  of  the  delta,  or  the  branching  off  of  the  uppermost 
arm  of  the  Atchafalaya,  has  been  already  alluded  to.  Its  superficial 
dimensions,  according  to  Mr.  Forshey,  exceed  30,000  square  miles, 
nearly  half  of  which  belong  to  the  true  delta.  The  deposits  consist 
partly  of  sand  originally  formed  upon  or  near  the  banks  of  the  river,  and 
its  tributaries,  partly  of  gravel,  swept  down  the  main  channel,  of  which 
the  position  has  continually  shifted,  and  partly  of  fine  mud  slowly  ac- 
cumulated in  the  swamps.  The  farther  we  descend  the  river  towards 
its  mouth,  the  finer  becomes  the  texture  of  .the  sediment.  The  whole 
alluvial  formation,  from  the  base  of  the  delta  upwards,  slopes  with  a 
very  gentle  inclination,  rising  about  three  inches  in  a  mile  from  the  level 
of  the  sea  at  the  Balize,  to  the  height  of  about  200  feet  in  a  distance  of 
about  800  miles. 

That  a  large  portion  of  this  fluviatile  deposit,  together  with  the  fluvio- 
mariue  strata  now  in  progress  near  the  Balize,  consists  of  mud  and  sand 
with  much  vegetable  matter  intermixed,  may  be  inferred  from  what  has 

*  For  an  account  of  the  "  sunk  country,"  shaken  by  the  earthquake  of  1811-12,' 
see  Lyell's  Second  Visit  to  the  United  States,  ch.  33. 


272  MISSISSIPPI. DEPOSITS   IN   THE   DELTA.  [Cu.  XVIIL 

been  said  of  the  abundance  of  drift  trees  floated  down  every  summer. 
These  are  seen  matted  together  into  a  net-work  around  the  extensive 
mud  banks  at  the  extreme  mouths  of  the  river.  Every  one  acquainted 
with  the  geography  of  Louisiana  is  aware  that  the  most  southern  part 
of  the  delta  forms  a  long  narrow  tongue  of  land  protruding  for  50  miles 
into  the  Gulf  of  Mexico,  at  the  end  of  which  are  numerous  channels  of 
discharge.  This  singular  promontory  consists  simply  of  the  river  and 
its  two  low,  flat  banks,  covered  with  reeds,  young  willows,  and  poplars. 
Its  appearance  answers  precisely  to  that  of  the  banks  far  in  the  interior, 
when  nothing  appears  above  water  during  inundations  but  the  higher 
part  of  the  sloping  glacis  or  bank.  In  the  one  case  we  have  the  swamps 
or  an  expanse  of  freshwater  with  the  tops  of  trees  appearing  above,  in 
the  other  the  bluish  green  surface  of  the  Gulf  of  Mexico.  An  opinion  has 
very  commonly  prevailed  that  this  narrow  promontory,  the  newest  prod- 
uct of  the  river,  has  gained  very  rapidly  upon  the  sea,  since  the  founda- 
tion of  New  Orleans  ;  but  after  visiting  the  Balize  in  1846,  in  company 
with  Dr.  Carpenter,  and  making  many  inquiries  of  the  pilots,  and  com- 
paring the  present  outline  of  the  coast  with  the  excellent  Spanish  chart, 
published  by  Chaiievoix  120  years  before,  we  came  to  a  different  conclu- 
sion. The  rate  of  permanent  advance  of  the  new  land  has  been  very 
slow,  not  exceeding  perhaps  one  mile  in  a  century.  The  gain  may  have 
been  somewhat  more  rapid  in  former  years,  when  the  new  strip  of  soil 
projected  less  far  into  the  gulf,  since  it  is  now  much  more  exposed  to 
the  action  of  a  strong  marine  current.  The  tides  also,  when  the  waters 
of  the  river  are  low,  enter  into  each  opening,  and  scour  them  out,  de- 
stroying the  banks  of  mud  and  the  sand-bars  newly  formed  during  the 
flood  season. 

An  observation  of  Darby,  in  regard  to  the  strata  composing  part  of 
this  delta,  deserves  attention.  In  the  steep  banks  of  the  Atchafalaya, 
before  alluded  to,  the  following  section,  he  says,  is  observable  at  low 
water : — first  an  upper  stratum,  consisting  invariably  of  bluish  clay, 
common  to  the  banks  of  the  Mississippi ;  below  this  a  stratum  of  red 
ochreous  earth,  peculiar  to  Red  River,  under  which  the  blue  clay  of  the 
Mississippi  again  appears  ;  and  this  arrangement  is  constant,  proving,  as 
that  geographer  remarks,  that  the  waters  of  the  Mississippi  and  the  Red 
River  occupied  alternately,  at  some  former  periods,  considerable  tracts 
below  their  present  point  of  union.*  Such  alternations  are  probably 
common  in  submarine  spaces  situated  between  two  converging  deltas  ; 
for,  before  the  two  rivers  unite,  there  must  almost  always  be  a  certain 
period  when  an  intermediate  tract  will  by  turns  be  occupied  and  aban- 
doned by  the  waters  of  each  stream ;  since  it  can  rarely  happen  that 
the  season  of  highest  flood  will  precisely  correspond  in  each.  In  the 
case  of  the  Red  River  and  Mississippi,  which  carry  off  the  waters  from 
countries  placed  under  widely  distant  latitudes,  an  exact  coincidence  in 
the  time  of  greatest  inundation  is  very  improbable. 

*  Darby's  Louisiana,  p.  103. 


OH.  XVIII.]  SEDIMENT   OF  THE   MISSISSIPPI.  273 

The  antiquity  of  the  delta,  or  length  of  the  period  which  has  been 
occupied  in  the  deposition  of  so  vast  a  mass  of  alluvial  matter,  is  a 
question  which  may  well  excite  the  curiosity  of  every  geologist.  Suf- 
ficient data  have  not  yet  been  obtained  to  -afford  a  full  and  satisfactory 
answer  to  the  inquiry,  but  some  approximation  may  already  be  made  to 
the  minimum  of  time  required. 

When  I  visited  New  Orleans,  in  February,  1846,  I  found  that  Dr. 
Riddell  had  made  numerous  experiments  to  ascertain  the  proportion  of 
sediment  contained  in  the  waters  of  the  Mississippi ;  and  he  concluded 
that  the  mean  annual  amount  of  solid  matter  was  to  the  water  as  y^T  5 
in  weight,  or  about  3-^9^  in  volume.*  From  the  observations  of  the 
same  gentleman,  and  those  of  Dr.  Carpenter  and  Mr.  Forshey,  an  emi- 
nent engineer,  to  whom  I  have  before  alluded,  the  average  width,  depth, 
and  velocity  of  the  Mississippi,  and  thence  the  mean  annual  discharge 
of  water  were  deduced.  I  assumed  528  feet,  or  the  tenth  of  a  mile, 
as  the  probable  thickness  of  the  deposit  of  mud  and  sand  in  the  delta ; 
founding  my  conjecture  chiefly  on  the  depth  of  the  Gulf  of  Mexico, 
between  the  southern  point  of  Florida  and  the  Balize,  which  equals  on 
an  average  100  fathoms,  and  partly  on  some  borings  600  feet  deep  in 
the  delta,  near  Lake  Pontchartrain,  north  of  New  Orleans,  in  which  the 
bottom  of  the  alluvial  matter  is  said  not  to  have  been  reached.  The 
area  of  the  delta  being  about  13,600  square  statute  miles,  and  the  quan- 
tity of  solid  matter  annually  brought  down  by  the  river  3,702^758,400 
cubic  feet,  it  must  have  taken  67,000  years  for  the  formation  of 
the  whole;  and  if  the  alluvial  matter  of  the  plain  above  be  264  feet 
deep,  or  half  that  of  the  delta,f  it  must  have  required  33,500  more 
years  for  its  accumulation,  even  if  its  area  be  estimated  as  only  equal 
to  that  of  the  delta,  whereas  it  is  in  fact  larger.  If  some  deduction  be 
made  from  the  time  here  stated,  in  consequence  of  the  effect  of  the 
drift-wood,  which  must  have  aided  in  filling  up  more  rapidly  the  space 
above  alluded  to,  a  far  more  important  allowance  must  be  made  on  the 
other  hand,  for  the  loss  of  matter,  owing  to  the  finer  particles  of  mud 

*  The  calculations  here  given  were  communicated  to  the  British  Association, 
in  a  lecture  which  I  delivered  at  Southampton  in  September,  1846.  (See  Athe- 
nteum  Journal,  Sept.  26,  1846,  and  Report  of  British  Association,  1846,  p.  117.) 
Dr.  Riddell  has  since  repeated  his  experiments  on  the  quantity  of  sediment  in 
the  river  at  New  Orleans  without  any  material  variation  in  the  results. 

Mr.  Forshey,  in  a  memoir  on  the  Physics  of  the  Mississippi,  published  in  1850, 
adopts  Dr.  Riddell's  estimate  for  the  quantity  of  mud,  but  takes  447,199  cubic 
feet  per  second  as  the  average  discharge  of  water  for  the  year  at  Carrolton,  nine 
miles  above  New  Orleans,  a  result  deduced  from  thirty  years  of  observations. 
This  being  one-tenth  more  than  I  had  assumed,  would  add  a  tenth  to  the  sediment, 
and  would  diminish  by  one-eleventh  the  number  of  years  required  to  accomplish 
the  task  above  alluded  to.  "  The  cubic  contents  of  sedimentary  matter,"  says 
Forshey,  "are  equal  to  4,083,333,333,  and  this  sediment  would  annually  cover 
twelve  miles  square  one  foot  deep." 

f  The  Mississippi  is  continually  shifting  its  course  in  the  great  alluvial  plain, 
cutting  frequently  to  the  depth  of  100,  and  even  sometimes  to  the  depth  of  250 
feet.  As  the  old  channels  become  afterwards  filled  up,  or  in  a  great  degree 
obliterated,  this  excavation  alone  mnst  have  given  a  considerable  depth  to  the 
basin,  which  receives  the  alluvial  deposit,  and  subsidences  like  those  accompany- 
ing the  earthquake  of  New  Madrid  in  1811-12  may  have  given  still  more  depth. 

18 


2T4:  DELTA   OF   THE   MISSISSIPPI.  [On.  XVIIL 

not  settling  at  the  mouths  of  the  river,  but  being  swept  out  far  to  sea 
during  the  predominant  action  of  the  tides,  and  the  waves  in  the  winter 
months,  when  the  current  of  fresh  water  is  feeble.  Yet  however  vast 
the  time  during  which  the  Mississippi  has  been  transporting  its  earthy 
burden  to  the  ocean,  the  whole  period,  though  far  exceeding,  perhaps, 
100,000  years,  must  be  insignificant  in  a  geological  point  of  view,  since 
the  bluffs  or  cliffs,  bounding  the  great  valley,  and  therefore  older  in 
date,  and  which  are  from  50  to  250  feet  in  perpendicular  height,  con- 
sist in  great  part  of  loam  containing  land,  fluviatile,  and  lacustrine  shells 
of  species  still  inhabiting  the  same  country.  (See  fig.  23,  p.  265.) 

Before  we  take  leave  of  the  great  delta,  we  may  derive  an  instruct- 
ive lesson  from  the  reflection  that  the  new  deposits  already  formed,  or 
now  accumulating,  whether  marine  or  freshwater,  must  greatly  resem- 
ble in  composition,  and  the  general  character  of  their  organic  remains, 
many  ancient  strata,  which  enter  largely  into  the  earth's  structure. 
Yet  there  is  no  sudden  revolution  in  progress,  whether  on  the  land  or 
in  the  waters,  whether  in  the  animate  or  the  inanimate  world.  Not- 
withstanding the  excessive  destruction  of  soil  and  uprooting  of  trees, 
the  region  which  yields  a  never-failing  supply  of  drift-wood  is  densely 
clothed  with  noble  forests,  and  is  almost  unrivalled  in  its  power  of  sup- 
porting animal  and  vegetable  life.  In  spite  of  the  undermining  of  many 
a  lofty  bluff,  and  the  encroachments  of  the  delta  on  the  sea — in  spite 
of  the  earthquake,  which  rends  and  fissures  the  soil,  or  causes  areas 
more  than  sixty  miles  in  length  to  sink  down  several  yards  in  a  few 
months,  the  general  features  of  the  district  remain  unaltered,  or  are 
merely  undergoing  a  slow  and  insensible  change.  Herds  of  wild  deer 
graze  on  the  pastures,  or  browse  upon  the  trees ;  and  if  they  diminish 
in  number,  it  is  only  where  they  give  way  to  man  and  the  domestic 
animals  which  follow  in  his  train.  The  bear,  the  wolf,  the  fox,  the 
panther,  and  the  wild-cat,  still  maintain  themselves  in  the  fastnesses  of 
the  forests  of  cypress  and  gum-tree.  The  racoon  and  the  opossum 
are  everywhere  abundant,  while  the  musk-rat,  otter,  and  mink  still 
frequent  the  rivers  and  lakes,  and  a  few  beavers  and  buffaloes  have  not 
yet  been  driven  from  their  ancient  haunts.  The  waters  teem  with  ali- 
gators,  tortoises,  and  fish,  and  their  surface  is  covered  with  millions  of 
migratory  waterfowl,  which  perform  their  annual  voyage  between  the 
Canadian  lakes  and  the  shores  of  the  Mexican  Gulf.  The  power  of 
man  begins  to  be  sensibly  felt,  and  many  parts  of  the  wilderness  to  be 
replaced  by  towns,  orchards,  and  gardens.  The  gilded  steamboats,  like 
moving  palaces,  stem  the  force  of  the  current,  or  shoot  rapidly  down 
the  descending  stream,  through  the  solitudes  of  the  forests  and  prai- 
ries. Already  does  the  flourishing  population  of  the  great  valley  far 
exceed  that  of  the  thirteen  United  States  when  first  they  declared  their 
independence.  Such  is  the  state  of  a  continent  where  trees  and  stones 
are  hurried  annually  by  a  thousand  torrents,  from  the  mountains  to  the 
plains,  and  where  sand  and  finer  matter  are  swept  down  by  a  vast  cur- 
rent to  the  sea,  together  with  the  wreck  of  countless  forests  and  the 


CH.  XVIIL]       DELTA    OF   THE    GANGES    AND    BRAHMAPOOTRA.  275 

bones  of  animals  which  perish  in  the  inundations.  When  these  mate- 
rials reach  the  gulf,  they  do  not  render  the  waters  unfit  for  aquatic  ani- 
mals ;  but  on  the  contrary,  the  ocean  here  swarms  with  life,  as  it  gen- 
erally does  where  the  influx  of  a  great  river  furnishes  a  copious  supply 
of  organic  and  mineral  matter.  Yet  many  geologists,  when  they  behold 
the  spoils  of  the  land  heaped  in  successive  strata,  and  blended  confus- 
edly with  the  remains  of  fishes,  or  interspersed  with  broken  shells  and 
corals  ;  when  they  see  portions  of  erect  trunks  of  trees  with  their  roots 
still  retaining  their  natural  position,  and  one  tier  of  these  preserved 
in  a  fossil  state  above  another,  imagine  that  they  are  viewing  the  signs 
of  a  turbulent  instead  of  a  tranquil  and  settled  state  of  the  planet. 
They  read  in  such  phenomena  the  proof  of  chaotic  disorder  and  reiter- 
ated catastrophes,  instead  of  indications  of  a  surface  as  habitable  as  the 
most  delicious  and  fertile  districts  now  tenanted  by  man. 

DELTA    OF    THE    GANGES    AND    BRAHMAPOOTRA. 

As  an  example  of  a  still  larger  delta  advancing  upon  the  sea  in  oppo- 
sition to  more  powerful  tides,  I  shall  next  describe  that  of  the  Ganges 
and  Brahmapootra  (or  Burrampooter).  These,  the  two  principal  rivers 
of  India,  descend  from  the  highest  mountains  in  the  world,  and  partial- 
ly mingle  their  waters  in  the  low  plains  of  Hindostan,  before  reaching 
the  head  of  the  Bay  of  Bengal.  The  Brahmapootra,  somewhat  the 
larger  of  the  two,  formerly  passed  to  the  east  of  Dacca,  even  so  lately 
as  the  beginning  of  the  present  century,  pouring  most  of  its  waters  into 
one  of  the  numerous  channels  in  the  delta  called  "the  Megna  "  By 

Fig.  25. 


ASIA 

oChira[Jooujci 


The  Soundings  in  the  Bay 
are  shown, 

3  Fathoms  and  under 

5  Fm.  Hue  and  undei 

20  Fm.  line  and  under 

50  Fm 

The  "S.watch,"  having 
no  bottom,  with  from 
100  to  200  Fm.,  thus.... 


MAP  of  the  DELTA  of  the  GANGES  and  BRAHMAPOOTRA. 


276  DELTA    OF   THE    GANGES.  [Cn.  XVIII. 

that  name  the  main  stream  was  always  spoken  of  by  Rennell  and  others 
in  their  memoirs  on  this  region.  But  the  main  trunk  now  unites  with 
an  arm  of  the  Ganges  considerably  higher  up,  at  a  point  about  100 
miles  distant  from  the  sea;  and  it  is  constantly,  according  to  Dr.  Hook- 
er, working  its  way  westward,  having  formerly,  as  may  be  seen  by 
ancient  maps,  moved  eastward  for  a  long  period. 

The  area  of  the  delta  of  the  combined  rivers,  for  it  is  impossible  now 
to  distinguish  what  belongs  to  each,  is  considerably  more  than  double 
that  of  the  Nile,  even  if  we  exclude  from  the  delta  a  large  extent  of 
low,  flat,  alluvial  plain,  doubtless  of  fluviatile  origin,  which  stretches 
more  than  100  miles  to  the  hills  west  of  Calcutta  (see  map,  fig.  25), 
and  much  farther  in  a  northerly  direction  beyond  the  head  of  the  great 
delta.  The  head  of  a  delta  is  that  point  where  the  first  arm  is  given  off. 
Above  that  point  a  river  receives  the  waters  of  tributaries  flowing  from 
higher  levels ;  below  it,  on  the  contrary,  it  gives  out  portions  of  its 
waters  to  lower  levels,  through  channels  which  flow  into  adjoining 
swamps,  or  which  run  directly  to  the  sea.  The  Mississippi,  as  before 
described,  has  a  single  head,  which  originated  at  an  unknown  period 
when  the  Red  River  joined  it.  In  the  great  delta  of  Bengal  there  may 
be  said  to  be  two  heads  nearly  equidistant  from  the  sea,  that  of  the 
Ganges  (G,  map,  fig.  25),  about  30  miles  below  Rajmahal,  or  216  stat- 
ute miles  in  a  direct  line  from  the  sea,  and  that  of  the  Brahmapootra 
(B),  below  Chirapoonjee,  where  the  river  issues  from  the  Khasia  moun- 
tains, a  distance  of  224  miles  from  the  Bay  of  Bengal. 

It  will  appear,  by  reference  to  the  map,  that  the  great  body  of  fresh 
water  derived  from  the  two  rivers  enters  the  bay  on  its  eastern  side ; 
and  that  a  large  part  of  the  delta  bordering  on  the  sea  is  composed  of 
a  labyrinth  of  rivers  and  creeks,  all  filled  with  salt  water,  except  those 
immediately  communicating  with  the  Hoogly,  or  principal  arm  of  the 
Ganges.  This  tract  alone,  known  by  the  name  of  the  Woods,  or  Sun- 
derbunds  (more  properly  Soonderbuns),  a  wilderness  infested  by  tigers 
and  crocodiles,  is,  according  to  Rennell,  equal  in  extent  to  the  whole 
principality  of  Wales.* 

On  the  sea-coast  there  are  eight  great  openings,  each  of  which  has 
evidently,  at  some  ancient  period,  served  in  its  turn  as  the  principal 
channel  of  discharge.  Although  the  flux  and  reflux  of  the  tide  extend 
even  to  the  heads  of  the  delta  when  the  rivers  are  low,  yet,  when  they 
are  periodically  swollen  by  tropical  rains,  their  volume  and  velocity 
counteract  the  tidal  current,  so  that,  except  very  near  the  sea,  the  ebb 
and  flow  become  insensible.  During  the  flood  season,  therefore,  the 
Ganges  and  Brahmapootra  almost  assume  in  their  delta,  the  character  of 
rivers  entering  an  inland  sea ;  the  movements  of  the  ocean  being  then 
subordinate  to  the  force  of  the  rivers,  and  only  slightly  disturbing  their 
operations.  The  great  gain  of  the  delta  in  height  and  area  takes  place 
during  the  inundations  ;  and,  during  other  seasons  of  the  year,  the 

*  Account  of  the  Ganges  and  Burrampooter  rivers,  by  Major  Rennell,  PhiL 
Trans.  1781. 


OH.  XVIII.]  DELTA.   OF   THE   GANGES.  277 

ocean  makes  reprisals,  scouring  out  the  channels,  and  sometimes  de- 
vouring rich  alluvial  plains. 

Islands  formed  and  destroyed. — Major  R.  H.  Colebrooke,  in  his 
account  of  the  course  of  the  Ganges,  relates  examples  of  the  rapid 
filling  up  of  some  of  its  branches,  and  the  excavation  of  new  channels, 
where  the  number  of  square  miles  of  soil  removed  in  a  short  time  (the 
column  of  earth  being  114  feet  high)  was  truly  astonishing.  Forty 
square  miles,  or  25,600  acres,  are  mentioned  as  having  been  carried 
away,  in  one  place,  in  the  course  of  a  few  years.*  The  immense  trans- 
portation of  earthy  matter  by  the  Ganges  and  Brahmapootra  is  proved 
by  the  great  magnitude  of  the  islands  formed  in  their  channels  during 
a  period  far  short  of  that  of  a  man's  life.  Some  of  these,  many  miles 
in  extent,  have  originated  in  large  sand-banks  thrown  up  round  the 
points  at  the  angular  turning  of  the  rivers,  and  afterwards  insulated 
by  breaches  of  the  streams.  Others,  formed  in  the  main  channel, 
are  caused  by  some  obstruction  at  the  bottom.  A  large  tree,  or  a 
sunken  boat,  is  sometimes  sufficient  to  check  the  current,  and  cause  a 
deposit  of  sand,  which  accumulates  till  it  usurps  a  considerable  portion 
of  the  channel.  The  river  then  undermines  its  banks  on  each  side,  to 
supply  the  deficiency  in  its  bed,  and  the  island  is  afterwards  raised  by 
fresh  deposits  during  every  flood.  In  the  great  gulf  below  Luckipour, 
formed  by  the  united  waters  of  the  Ganges  and  Megna,  some  of  the 
islands,  says  Rennell,  rival  in  size  and  fertility  the  Isle  of  Wight. 
While  the  river  is  forming  new  islands  in  one  part,  it  is  sweeping  away 
old  ones  in  others.  Those  newly  formed  are  soon  overrun  with  reeds, 
long  grass,  the  Tamarix  Indica,  and  other  shrubs,  forming  impenetra- 
ble thickets,  where  the  tiger,  the  rhinoceros,  the  buffalo,  deer,  and  other 
wild  animals,  take  shelter.  It  is  easy,  therefore,  to  perceive,  that  both 
animal  and  vegetable  remains  may  occasionally  be  precipitated  into  the 
flood,  and  become  imbedded  in  the  sediment  which  subsides  in  the  delta. 

Three  or  four  species  of  crocodile,  of  two  distinct  sub-genera,  abound 
in  the  Ganges,  and  its  tributary  and  contiguous  waters ;  and  Mr.  H.  T. 
Colebrooke  informed  me,  that  he  had  seen  both  forms  in  places  far 
inland,  many  hundred  miles  from  the  sea.  The  Gangetic  crocodile,  or 
Gavial  (in  correct  orthography,  Garial),  is  confined  to  the  fresh  water, 
living  exclusively  on  fish,  but  the  commoner  kinds,  called  Koomiah  and 
Muggar,  frequent  both  fresh  and  salt,  being  much  larger  and  fiercer  in 
salt  and  brackish  water.f  These  animals  swarm  in  the  brackish  water 
along  the  line  of  sand-banks,  where  the  advance  of  the  delta  is  most 
rapid.  Hundreds  of  them  are  seen  together  in  the  creeks  of  the  delta, 

*  Trans,  of  the  Asiatic  Society,  vol.  vii.  p.  14. 

f  Cuvier  referred  the  true  crocodiles  of  the  Ganges  to  a  single  species,  C.  bipor- 
catus.  But  I  learn  from  Dr.  Falconer  that  there  are  three  well-marked  species, 
C.  biporcatus,  C.  paluxtris,  and  C.  bombifrons.  C.  bombifrons  occurs  iu  the 
northern  branches  of  the  Ganges,  1000  miles  from  Calcutta;  C.  biporcatus  ap- 
pears to  be  confined  to  the  estuary ;  and  C.  palustris,  to  range  from  the  estuary 
to  the  central  parts  of  Bengal.  The  garial  is  found  along  with  C.  bombifrons  in 
the  north,  and  descends  to  the  region  of  G.  biporcatus  in  the  estuary. 


278  DELTA   OF  THE  GANGES  [Cn.  XVIII 


or  basking  in  the  sun  on  the  shoals  without.  They  will  attack  men 
and  cattle,  destroying  the  natives  when  bathing,  and  tame  and  wild 
animals  which  come  to  drink.  "I  have  not  unfrequently,"  says  Mr. 
Colebrooke,  "  been  witness  to  the  horrid  spectacle  of  a  floating  corpse 
seized  by  a  crocodile  with  such  avidity,  that  he  half  emerged  above  the 
water  with  his  prey  in  his  mouth."  The  geologist  will  not  fail  to  ob- 
serve how  peculiarly  the  habits  and  distribution  of  these  saurians  expose 
them  to  become  imbedded  in  the  horizontal  strata  of  fine  mud,  which 
are  annually  deposited  over  many  hundred  square  miles  in  the  Bay  of 
Bengal.  The  inhabitants  of  the  land,  which  happen  to  be  drowned  or 
thrown  into  the  water,  are  usually  devoured  by  these  voracious  reptiles ; 
but  we  may  suppose  the  remains  of  the  saurians  themselves  to  be  con- 
tinually entombed  in  the  new  formations.  The  number,  also,  of  bodies 
of  the  poorer  class  of  Hindoos  thrown  annually  into  the  Ganges  is  so 
great,  that  some  of  their  bones  or  skeletons  can  hardly  fail  to  be  occa- 
sionally enveloped  in  fluviatile  mud. 

It  sometimes  happens,  at  the  season  when  the  periodical  flood  is  at 
its  height,  that  a  strong  gale  of  wind,  conspiring  with  a  high  spring- 
tide, checks  the  descending  current  of  the  river,  and  gives  rise  to  most 
destructive  inundations.  From  this  cause,  in  1763,  the  waters  at  Lucki- 
pour  rose  six  feet  above  their  ordinary  level,  and  the  inhabitants  of  a  con- 
siderable district,  with  their  houses  and  cattle,  were  totally  swept  away. 

The  population  of  all  oceanic  deltas  are  particularly  exposed  to  suffer 
by  such  catastrophes,  recurring  at  considerable  intervals  of  time ;  and 
we  may  safely  assume  that 'such  tragical  events  have  happened  again 
and  again  since  the  Gangetic  delta  was  inhabited  by  man.  If  human 
experience  and  forethought  cannot  always  guard  against  these  calami- 
ties, still  less  can  the  inferior  animals  avoid  them  ;  and  the  monuments 
of  such  disastrous  inundations  must  be  looked  for  in  great  abundance  in 
strata  of  all  ages,  if  the  surface  of  our  planet  has  always  been  governed 
by  the  same  laws.  When  we  reflect  on  the  general  order  and  tranquil- 
lity that  reigns  in  the  rich  and  populous  delta  of  Bengal,  notwithstand- 
ing the  havoc  occasionally  committed  by  the  depredations  of  the  ocean, 
we  perceive  how  unnecessary  it  is  to  attribute  the  imbedding  of  succes- 
sive races  of  animals  in  older  strata  to  extraordinary  energy  in  the 
causes  of  decay  and  reproduction  in  the  infancy  of  our  planet,  or  to  those 
general  catastrophes  and  sudden  revolutions  so  often  resorted  to. 

Deposits  in  the  delta. — The  quantity  of  mud  held  in  suspension  by 
the  waters  of  the  Ganges  and  Brahmapootra  is  found,  as  might  be  ex- 
pected, to  exceed  that  of  any  of  the  rivers  alluded  to  in  this  or  the  pre- 
ceding chapters  ;  for,  in  the  first  place,  their  feeders  flow  from  moun- 
tains of  unrivalled  altitude,  and  do  not  clear  themselves  in  any  lakes, 
as  does  the  Rhine  in  the  Lake  of  Constance,  or  the  Rhone  in  that  of  Ge- 
neva. And,  secondly,  their  whole  course  is  nearer  the  equator  than  that 
of  the  Mississippi,  or  any  great  river,  respecting  which  careful  experi- 
ments have  been  made,  to  determine  the  quantity  of  its  water  and 
earthy  contents.  The  fall  of  rain,  moreover,  as  we  have  before  seen,  is 


OH.  XVIII.]  AND    BRAHMAPOOTRA.  279 

excessive  on  the  southern  flanks  of  the  first  range  of  mountains  which 
rise  from  the  plains  of  Hindostan,  and  still  more  remarkable  is  the  quan- 
tity sometimes  poured  down  in  one  day.  (See  above,  p.  200.)  The 
sea,  where  the  Ganges  and  Brahmapootra  discharge  their  main  stream  at 
the  flood  season,  only  recovers  its  transparency  at  the  distance  of  fi;om 
60  to  100  miles  from  the  delta ;  and  we  may  take  for  granted  that  the 
current  continues  to  transport  the  finer  particles  much  farther  south 
than  where  the  surface  water  first  becomes  clear.  The  general  slope, 
therefore,  of  the  new  strata  must  be  extremely  gentle.  According  to 
the  best  charts,  there  is  a  gradual  deepening  from  four  to  about  sixty 
fathoms,  as  we  proceed  from  the  base  of  the  delta  to  the  distance  of 
about  one  hundred  miles  into  the  Bay  of  Bengal.  At  some  few  points 
seventy,  or  even  one  hundred,  fathoms  are  obtained  at  that  distance. 

One  remarkable  exception,  however,  occurs  to  the  regularity  of  the 
shape  of  the  bottom.  Opposite  the  middle  of  the  delta,  at  the  distance 
of  thirty  or  forty  miles  from  the  coast,  a  deep  submarine  valley  occurs, 
called  the  "swatch  of  no  ground,"  about  fifteen  miles  in  diameter, 
where  soundings  of  180,  and  even  300,  fathoms  fail  to  reach  the 
bottom.  (See  map,  p.  275.)  This  phenomenon  is  the  more  extraordi- 
nary, since  the  depression  runs  north  to  within  five  miles  of  the  line  of 
shoals ;  and  not  only  do  the  waters  charged  with  sediment  pass  over 
it  continually,  but,  during  the  monsoons,  the  sea,  loaded  with  mud  and 
sand,  is  beaten  back  in  that  direction  towards  the  delta.  As  the  mud 
is  known  to  extend  for  eighty  miles  farther  into  the  gulf,  an  enormous 
thickness  of  matter  must  have  been  deposited  in  "  the  swatch."  We 
may  conclude,  therefore,  either  that  the  original  depth  of  this  part  of 
the  Bay  of  Bengal  was  excessive,  or  that  subsidences  have  occurred  in 
modern  times.  The  latter  conjecture  is  the  less  improbable,  as  the 
whole  area  of  the  delta  has  been  convulsed  in  the  historical  era  by 
earthquakes,  and  actual  subsidences  have  taken  place  in  the  neighboring 
coast  of  Chittagong,  while  "  the  swatch"  lies  not  far  from  the  volcanic 
band  which  connects  Sumatra,  Barren  Island,  and  Ramree.* 

Opposite  the  mouth  of  the  Hoogly  river,  and  immediately  south  of 
Saugor  Island,  four  miles  from  the  nearest  land  of  the  delta,  a  new  islet 
was  formed  about  twenty  years  ago,  called  Edmonstone  Island,  on  the 
centre  of  which  a  beacon  was  erected  as  a  landmark  in  1817.  In  1818 
the  island  had  become  two  miles  long  and  half  a  mile  broad,  and  was 
covered  with  vegetation  and  shrubs.  Some  houses  were  then  built  upon 
it,  and  in  1820  it  was  used  as  a  pilot  station.  The  severe  gale  of  1823 
divided  it  into  two  parts,  and  so  reduced  its  size  as  to  leave  the  beacon 
standing  out  in  the  sea,  where,  after  remaining  seven  years,  it  was  washed 
away.  The  islet  in  1836  had  been  converted  by  successive  storms  into 
a  sand-bank,  half  a  mile  long,  on  which  a  sea-mark  was  placed. 

Although  there  is  evidence  of  gain  at  some  points,  the  general  pro- 
gress of  the  coast  is  very  slow ;  for  the  tides,  when  the  river  water  is 
low,  are  actively  employed  in  removing  alluvial  matter.  In  the  Sun- 

*  See  below,  ch.  22  and  29. 


280  DELTA   OF   THE   GANGES.  [Cu.  XVIII 

derbunds  the  usual  rise  and  fall  of  the  tides  is  no  more  than  eight  feet, 
but,  on  the  east  side  of  the  delta,  Dr.  Hooker  observed,  in  the  winter  of 
1851,  a  rise  of  from  sixty  to  eighty  feet,  producing  among  the  islands  at 
the  mouths  of  the  Megna  and  Fenny  rivers,  a  lofty  wave  or  "  bore"  as 
they  ascend,  and  causing  the  river  water  to  be  ponded  back,  and  then 
to  sweep  down  with  great  violence  when  the  tide  ebbs.  The  bay  for 
forty  miles  south  of  Chittagong  is  so  fresh  that  neither  algae  nor  man- 
groves will  grow  in  it.  We  may,  therefore,  conceive  how  effective  may 
be  the  current  formed  by  so  great  a  volume  of  water  in  dispersing  fine 
mud  over  a  wide  area.  Its  power  is  sometimes  augmented  by  the 
agitation  of  the  bay  during  hurricanes  in  the  month  of  May.  The  new 
superficial  strata  consists  entirely  of  fine  sand  and  mud  ;  such,  at  least, 
are  the  only  materials  which  are  exposed  to  view  in  regular  beds  on  the 
banks  of  the  numerous  creeks.  Neither  here  or  higher  up  the  Ganges, 
could  Dr.  Hooker  discover  any  land  or  freshwater  shells  in  sections  of 
the  banks,  which  in  the  plains  higher  up  sometimes  form  cliffs  eighty 
feet  in  height  at  low  water.  In  like  manner  I  have  stated*  that  I  was 
unable  to  find  any  buried  shells  in  the  delta  or  modern  river  cliffs  of 
the  Mississippi. 

No  substance  so  coarse  as  gravel  occurs  in  any  part  of  the  delta  of 
the  Ganges  and  Brahmapootra,  nor  nearer  the  sea  than  400  miles.  Yet 
it  is  remarkable  that  the  boring  of  an  Artesian  well  at  Fort  William, 
near  Calcutta,  in  the  years  1835-1840,  displayed,  at  the  depth  of  120 
feet,  clay  and  sand  with  pebbles.  This  boring  was  carried  to  a  depth 
of  481  feet  below  the  level  of  Calcutta,  and  the  geological  section  ob- 
tained in  the  operation  has  been  recorded  with  great  care.  Under  the 
surface  soil,  at  a  depth  of  about  ten  feet,  they  came  to  a  stiff  blue  clay 
about  forty  feet  in  thickness  ;  below  which  was  sandy  clay,  containing 
in  its  lower  portion  abundance  of  decayed  vegetable  matter,  which  at 
the  bottom  assumed  the  character  of  a  stratum  of  black  peat  two  feet 
thick.  This  peaty  mass  was  considered  as  a  clear  indication  (like  the 
"dirt-bed"  of  Portland)  of  an  ancient  terrestrial  surface,  with  a  forest 
or  Sunderbund  vegetation.  Logs  and  branches  of  a  red-colored  wood 
occur  both  above  and  immediately  below  the  peat,  so  little  altered  that 
Dr.  Wallich  was  able  to  identify  them  with  the  Soondri  tree,  fferitiera 
littoralis,  one  of  the  most  prevalent  forms  at  the  base  of  the  delta.  Dr. 
Falconer  tells  me  that  similar  peat  has  been  met  with  at  other  points 
round  Calcutta  at  the  depth  of  nine  feet  and  twenty-five  feet.  It 
appears,  therefore,  that  there  has  been  a  sinking  down  of  what  was 
originally  land  in  this  region,  to  the  amount  of  seventy  feet  or  more  per- 
pendicular ;  for  Calcutta  is  only  a  few  feet  above  the  level  of  the  sea, 
and  the  successive  peat-beds  seem  to  imply  that  the  subsidence  of  the 
ground  was  gradual  or  interrupted  by  several  pauses.  Below  the  vege- 
table mass  they  entered  upon  a  stratum  of  yellowish  clay  about  ten  feet 
thick,  containing  horizontal  layers  of  kunkar  (or  kankar),  a  nodular,  con-  . 
cretionary,  argillaceous  limestone,  met  with  abundantly  at  greater  or 

*  Second  Visit  to  the  United  States,  vol.  ii.  p.  145. 


CH.  XVIII.]  AGE   OF   THE   DELTA   OF   THE   GANGES.  281 

less  depths  in  all  parts  of  the  valley  of  the  Ganges,  over  many  thousand 
square  miles,  and  always  presenting  the  same  characters,  even  at  a  dis- 
tance of  one  thousand  miles  north  of  Calcutta.  Some  of  this  kunkar  is 
said  to  be  of  very  recent  origin  in  deposits  formed  by  river  inundations 
near  Saharanpoor.  After  penetrating  120  feet,  they  found  loam  con- 
taining water-worn  fragments  of  mica-slate  and  other  kinds  of  rock, 
which  the  current  of  the  Ganges  can  no  longer  transport  to  this  region. 
In  the  various  beds  pierced  through  below,  consisting  of  clay,  marl, 
and  friable  sandstone,  with  kunkar  here  and  there  intermixed,  no  organic 
remains  of  decidedly  marine  origin  were  met  with.  Too  positive  a  con- 
clusion ought  not,  it  is  true,  to  be  drawn  from  such  a  fact,  when  we 
consider  the  narrow  bore  of  the  auger  and  its  effect  in  crushing  shells 
and  bones.  Nevertheless,  it  is  worthy  of  remark,  that  the  only  fossils 
obtained  in  a  recognizable  state  were  of  a  fluviatile  or  terrestrial  charac- 
ter. Thus,  at  the  depth  of  350  feet,  the  bony  shell  of  a  tortoise,  or 
trionyx,  a  freshwater  genus,  was  found  in  sand,  resembling  the  living 
species  of  Bengal.  From  the  same  stratum,  also,  they  drew  up  the  lower 
half  of  the  humerus  of  a  ruminant,  at  first  referred  to  a  hyaena.  It  was 
the  size  and  shape,  says  Dr.  Falconer,  of  the  shoulder-bone  of  the  Cervus 
porcinus,  or  common  hog-deer,  of  India.  At  the  depth  of  380  feet, 
clay  with  fragments  of  lacustrine  shells  was  incumbent  on  what  appears 
clearly  to  have  been  another  "  dirt-bed,"  or  stratum  of  decayed  wood, 
implying  a  period  of  repose  of  some  duration,  and  a  forest- covered  land, 
which  must  have  subsided  300  feet,  to  admit  of  the  subsequent  super- 
position of  the  overlying  deposits.  It  has  been  conjectured  that,  at 
the  time  when  this  area  supported  trees,  the  land  extended  much  far- 
ther out  into  the  Bay  of  Bengal  than  now,  and  that  in  later  times  the 
Ganges,  while  enlarging  its  delta,  has  been  only  recovering  lost  ground 
from  the  sea. 

At  the  depth  of  about  400  feet  below  the  surface,  an  abrupt  change 
was  observed  in  the  character  of  the  strata,  which  were  composed  in 
great  part  of  sand,  shingle,  and  boulders,  the  only  fossils  observed  being 
the  vertebrae  of  a  crocodile,  shell  of  a  trionyx,  and  fragments  of  wood 
very  little  altered,  and  similar  to  that  buried  in  beds  far  above.  These 
gravelly  beds  constituted  the  bottom  of  the  section  at  the  depth  of  481 
feet,  when  the  operations  were  discontinued,  in  consequence  of  an  acci- 
dent which  happened  to  the  auger. 

The  occurrence  of  pebbles  at  the  depths  of  120  and  400  feet  implies 
an  important  change  in  the  geographical  condition  of  the  region  around 
or  near  Calcutta.  The  fall  of  the  river,  or  the  general  slope  of  the  allu- 
vial plain  may  have  been  formerly  greater ;  or,  before  a  general  and  per- 
haps unequal  subsidence,  hills  once  nearer  the  present  base  of  the  delta 
may  have  risen  several  hundred  feet,  forming  islands  in  the  bay,  which 
may  have  sunk  gradually,  and  become  buried  under  fluviatile  sediment. 

Antiquity  of  the  delta. — It  would  be  a  matter  of  no  small  scientific  in- 
terest, if  experiments  were  made  to  enable  us  to  determine,  with  some 
degree  of  accuracy,  the  mean  quantity  of  earthy  matter  discharged  an- 


282  SEDIMENT   IN   WATERS   OF   THE   GANGES.         [Cn.  XVIII. 

nually  into  the  sea  by  the  united  waters  of  the  Ganges  and  Brahmapoo- 
tra. The  Rev.  Mr.  Everest  instituted,  in  1831-2,  a  series  of  observa- 
tions on  the  earthy  matter  brought  down  by  the  Ganges,  at  Ghazepoor, 
500  miles  from  the  sea.  He  found  that,  in  1831,  the  number  of  cubic 
feet  of  water  discharged  by  the  river  per  second  at  that  place  was, 
during  the 

Rains  (4  months) .  494,208 

Winter  (5  months) 71,200 

Hot  weather  (3  months) 36,330 

so  that  we  may  state  in  round  numbers  that  500,000  cubic  feet  per 
second  flow  down  during  the  four  months  of  the  flood  season,  from 
June  to  September,  and  less  than  60,000  per  second  during  the  remain- 
ing eight  months. 

The  average  quantity  of  solid  matter  suspended  in  the  water  during 
the  rains  was,  by  weight,  j-g-g- th  part ;  but  as  the  water  is  about  one- 
half  the  specific  gravity  of  the  dried  mud,  the  solid  matter  discharged  is 
g- Jg-th  part  in  bulk,  or  577  cubic  feet  per  second.  This  gives  a  total  of 
6,082,041,600  cubic  feet  for  the  discharge  in  the  122  days  of  the  rain. 
The  proportion  of  sediment  in  the  waters  at  other  seasons  was  compara- 
tively insignificant,  the  total  amount  during  the  five  winter  months  being 
only  247,881,600  cubic  feet,  and  during  the  three  months  of  hot  weather 
38,154,240  cubic  feet.  The  total  annual  discharge,  then,  would  be 
6,368,077,440  cubic  feet. 

This  quantity  of  mud  would  in  one  year  raise  a  surface  of  228^ 
square  miles,  or  a  square  space,  each  side  of  which  should  measure  15 
miles,  a  height  of  one  foot.  To  give  some  idea  of  the  magnitude  of  this 
result,  we  will  assume  that  the  specific  gravity  of  the  dried  mud  is  only 
one-half  that  of  granite  (it  would,  however,  be  more) ;  in  that  case,  the 
earthy  matter  discharged  in  a  year  would  equal  3,184,038,720  cubic 
feet  of  granite.  Now  about  12 J  cubic  feet  of  granite  weigh  one  ton; 
and  it  is  computed  that  the  great  Pyramid  of  Egypt,  if  it  were  a  solid 
mass  of  granite,  would  weigh  about  600,000,000  tons.  The  mass  of 
matter,  therefore,  carried  down  annually  would,  according  to  this  esti- 
mate, more  than  equal  in  weight  and  bulk  forty-two  of  the  great  pyra- 
mids of  Egypt,  and  that  borne  down  in  the  four  months  of  the  rains 
would  equal  forty  pyramids.  But  if,  without  any  conjecture  as  to  what 
may  have  been  the  specific  gravity  of  the  mud,  we  attend  merely  to  the 
weight  of  solid  matter  actually  proved  by  Mr.  Everest  to  have  been 
contained  in  the  water,  we  find  that  the  number  of  tons  weight  which 
passed  down  in  the  122  days  of  the  rainy  season  was  339,413,760, 
which  would  give  the  weight  of  fifty-six  pyramids  and  a  half ;  and  in 
the  whole  year  355,361,464  tons,  or  nearly  the  weight  of  sixty  pyramids. 

The  base  of  the  great  Pyramid  of  Egypt  covers  eleven  acres,  and  its 
perpendicular  height  is  about  five  hundred  feet.  It  is  scarcely  possible 
to  present  any  picture  to  the  mind  which  will  convey  an  adequate  con- 
ception of  the  mighty  scale  of  this  operation,  so  tranquilly  and  almost 
insensibly -carried  on  by  the  Ganges,  as  it  glides  through  its  alluvial 


CH.  XVIII.]  SEDIMENT   IN    WATERS    OF    BRAHMAPOOTRA.  283 

plain,  even  at  a  distance  of  500  miles  from  the  sea.  It  may,  nowever, 
be  stated,  that  if  a  fleet  of  more  than  eighty  Indiamen,  each  freighted 
with  about  1400  tons'  weight  of  mud,  were  to  sail  down  the  river  every 
hour  of  every  day  and  night  for  four  months  continuously,  they  would 
only  transport  from  the  higher  country  to  the  sea  a  mass  of  solid  matter 
equal  to  that  borne  down  by  the  Ganges,  even  in  this  part  of  its  course, 
in  the  four  months  of  the  flood  season.  Or  the  exertions  of  a  fleet  of 
about  2000  such  ships  going  down  daily  with  the  same  burden,  and 
discharging  it  into  the  gulf,  would  be  no  more  than  equivalent  to  the 
operations  of  the  great  river. 

The  most  voluminous  current  of  lava  which  has  flowed  from  Etna 
within  historical  times  was  that  of  1669.  Ferrara,  after  correcting 
Borelli's  estimate,  calculated  the  quantity  of  cubic  yards  of  lava  in  this 
current  at  140,000,000.  Now,  this  would  not  equal  in  bulk  one-fifth 
of  the  sedimentary  matter  which  is  carried  down  in  a  single  year  by  the 
Ganges,  past  Ghazepoor,  according  to  the  estimate  above  explained  ;  so 
that  it  would  require  five  grand  eruptions  of  Etna  to  transfer  a  mass  of 
lava  from  the  subterranean  regions  to  the  surface,  equal  in  volume  to 
the  mud  carried  down  in  one  year  to  that  place. 

Captain  R.  Strachey,  of  the  Bengal  Engineers,  has  remarked  to  me, 
not  only  that  Ghazepoor,  where  Mr.  Everest's  observations  were  made, 
is  500  miles  from  the  sea,  but  that  the  Ganges  has  not  been  joined  there 
by  its  most  important  feeders.  These  drain  upon  the  whole  750  miles 
of  the  Himalaya,  and  no  more  than  150  miles  of  that  mountain-chain 
have  sent  their  contributions  to  the  main  trunk  at  Ghazepoor.  Below 
that  place,  the  Ganges  is  joined  by  the  Gogra,  Gunduk,  Khosee,  and 
Teesta  from  the  north,  to  say  nothing  of  the  Sone  flowing  from  the 
south,  one  of  the  largest  of  the  rivers  which  rise  in  the  table-land  of 
central  India.  (See  map,  fig.  25,  p.  275.)  Moreover  the  remaining  600 
miles  of  the  Himalaya  comprise  that  eastern  portion  of  the  basin  where 
the  rains  are  heaviest.  (See  above,  p.  200.)  The  quantity  of  water 
therefore  carried  down  to  the  sea  may  probably  be  four  or  five  times  as 
much  as  that  which  passes  Ghazepoor. 

The  Brahmapootra,  according  to  Major  Wilcox,*  in  the  month  of 
January,  when  it  is  near  its  minimum,  discharges  150,000  cubic  feet  of 
water  per  second  at  Gwalpara,  not  many  miles  above  the  head  of  its 
delta.  Taking  the  proportions  observed  at  Ghazepoor  at  the  different 
seasons  as  a  guide,  the  probable  average  discharge  of  the  Brahmapootra 
for  the  whole  year  may  be  estimated  at  about  the  same  as  that  of  the 
Ganges.  Assuming  this ;  and  secondly,  in  order  to  avoid  the  risk  of 
exaggeration,  that  the  proportion  of  sediment  in  their  waters  is  about  a 
third  less  than  Mr.  Everest's  estimate,  the  mud  borne  down  to  the  Bay 
of  Bengal  in  one  year  would  equal  40,000  millions  of  cubic  feet,  or  be- 
tween six  and  seven  times  as  much  as  that  brought  down  to  Ghazepoor, 
according  to  Mr.  Everest's  calculations  in  1831,  and  ten  times  as  much 
as  that  conveyed  annually  by  the  Mississippi  to  the  Gtilf  of  Mexico. 
*  Asiatic  Researches,  vol.  xvii.  p.  466. 


284:  CONCLUDING   REMARKS   ON   DELTAS.  [On.  XVIII 

Captain  Strachey  estimates  the  annually  inundated  portion  of  the 
delta  at  250  mile's  in  length  by  80  in  breadth,  making  an  area  of  20,000 
square  miles.  The  space  south  of  this  in  the  bay,  where  sediment  is 
thrown  down,  may  be  300  miles  from  E.  to  W.  by  150  N.  and  S.,  or 
45,000  square  miles,  which,  added  to  the  former,  gives  a  surface  of 
65,000  square  miles,  over  which  the  sediment  is  spread  out  by  the  two 
rivers.  Suppose  then  the  solid  matter  to  amount  to  40,000  millions  of 
cubic  feet  per  annum,  the  deposit,  he  observes,  must  be  continued  for 
forty-five  years  and  three-tenths  to  raise  the  whole  area  a  height  of  one 
foot,  or  13,600  years  to  raise  it  300  feet :  and  this,  as  we  have  seen,  is 
much  less  than  the  thickness  of  the  fluviatile  strata  actually  penetrated, 
(and  the  bottom  not  reached)  by  the  auger  at  Calcutta. 

Nevertheless  we  can  by  no  means  deduce  from  these  data  alone,  what 
will  be  the  future  rate  of  advance  of  the  delta,  nor  even  predict  whether 
the  land  will  gain  on  the  sea,  or  remain  stationary.  At  the  end  of 
13,000  years  the  bay  may  be  less  shallow  than  now,  provided  a  moder- 
ate depression,  corresponding  to  that  experienced  in  part  of  Greenland 
for  many  centuries  shall  take  place  (see  chap.  30).  A  subsidence  quite 
insensible  to  the  inhabitants  of  Bengal,  not  exceeding  two  feet  three 
inches  in  a  century,  would  be  more  than  sufficient  to  counterbalance  all 
the  efforts  of  the  two  mighty  rivers  to  extend  the  limits  of  their  delta. 
We  have  seen  that  the  Artesian  borings  at  Calcutta  attest,  what  the  vast 
depth  of  the  "  swatch"  may  also  in  all  likelihood  indicate,  that  the  an- 
tagonist force  of  subsidence  has  predominated  for  ages  over  the  influx  of 
fluviatile  mud,  preventing  it  from  raising  the  plains  of  Bengal,  or  from 
filling  up  a  larger  portion  of  the  bay. 

CONCLUDING    REMARKS    ON    DELTAS. 

Convergence  of  deltas. — If  we  possessed  an  accurate  series  of  maps 
of  the  Adriatic  for  many  thousand  years,  our  retrospect  would,  without 
doubt,  carry  us  gradually  back  to  the  time  when  the  number  of  rivers 
descending  from  the  mountains  into  that  gulf  by  independent  deltas  was 
far  greater  in  number.  The  deltas  of  the  Po  and  the  Adige,  for  instance, 
would  separate  themselves  within  the  recent  era,  as,  in  all  probability, 
would  those  of  the  Isonzo  and  the  Torre.  If,  on  the  other  hand,  we 
speculate  on  future  changes,  we  may  anticipate  the  period  when  the 
number  of  deltas  will  greatly  diminish ;  for  the  Po  cannot  continue  to 
encroach  at  the  rate  of  a  mile  in  a  hundred  years,  and  other  rivers  to 
gain  as  much  in  six  or  seven  centuries  upon  the  shallow  gulf,  without 
new  junctions  occurring  from  time  to  time  ;  so  that  Eridanus,  "  the  king 
of  rivers,"  will  continually  boast  a  greater  number  of  tributaries.  The 
Ganges  and  the  Brahmapootra"  have  perhaps  become  partially  confluent 
in  the  same  delta  within  the  historical,  or  at  least  within  the  human  era ; 
and  the  date  of  the  junction  of  the  Red  River  and  the  Mississippi  would, 
in  all  likelihood,  have  been  known,  if  America  had  not  been  so  recently 
discovered.  The  union  of  the  Tigris  and  the  Euphrates  must  undoubt- 
edly have  been  one  of  the  modern  geographical  changes  of  our  Earth, 


CH.   XVIII]  AGE   OF    EXISTING    DELTAS.  285 

for  Col.  Rawlinson  informs  me  that  the  delta  of  those  rivers  has  advanced 
two  miles  in  the  last  sixty  years,  and  is  supposed  to  have  encroached 
about  forty  miles  upon  the  Gulf  of  Persia  in  the  course  of  the  last  twenty- 
five  centuries. 

When  the  deltas  of  rivers,  having  many  mouths,  converge,  a  partial 
union  at  first  takes  place  by  the  confluence  of  some  one  or  more  of  their 
arms  ;  but  it  is  not  until  the  main  trunks  are  connected  above  the  head 
of  the  common  delta,  that  a  complete  intermixture  of  their  joint  waters 
and  sediment  takes  place.  The  union,  therefore,  of  the  Po  and  Adige, 
and  of  the  Ganges  and  Brahmapootra,  is  still  incomplete.  If  we  reflect 
on  the  geographical  extent  of  surface  drained  by  rivers  such  as  now  en- 
ter the  Bay  of  Bengal,  and  then  consider  how  complete  the  blending 
together  of  the  greater  part  of  their  transported  matter  has  already  be- 
come, and  throughout  how  vast  a  delta  it  is  spread  by  numerous  arms, 
we  no  longer  feel  so  much  surprise  at  the  area  occupied  by  some  ancient 
formations  of  homogeneous  mineral  composition.  But  our  surprise  will 
be  still  farther  lessened,  when  we  afterwards  inquire  (ch.  21)  into  the 
action  of  tides  and  currents  in  disseminating  sediment. 

Age  of  existing  deltas. — If  we  could  take  for  granted,  that  the  rela- 
tive level  of  land  and  sea  had  remained  stationary  ever  since  all  the  ex- 
isting deltas  began  to  be  formed — could  we  assume  that  their  growth 
commenced  at  one  and  the  same  instant  when  the  present  continents 
acquired  their  actual  shape — we  might  understand  the  language  of 
geologists  who  speak  of  "  the  epoch  of  existing  continents."  They  en- 
deavor to  calculate  the  age  of  deltas  from  this  imaginary  fixed  period  ; 
and  they  calculate  the  gain  of  new  land  upon  the  sea,  at  the  mouths  of 
rivers,  as  having  begun  everywhere  simultaneously.  But  the  more  we 
study  the  history  of  deltas,  the  more  we  become  convinced  that  upward 
and  downward  movements  of  the  land  and  contiguous  bed  of  the  sea 
have  exerted,  and  continue  to  exert,  an  influence  on  the  physical  geog- 
raphy of  many  hydrographical  basins,  on  a  scale  comparable  in  mag- 
nitude or  importance  to  the  amount  of  fluviatile  deposition  effected  in  an 
equal  lapse  of  time.  In  the  basin  of  the  Mississippi,  for  example,  proofs 
both  of  descending  and  ascending  movements  to  a  vertical  amount  of 
several  hundred  feet  can  be  shown  to  have  taken  place  since  the  existing 
species  of  land  and  freshwater  shells  lived  in  that  region.* 

The  deltas  also  of  the  Po  and  Ganges  have  each,  as  we  have  seen  (p. 
257),  when  probed  by  the  Artesian  auger,  borne  testimony  to  a  gradual 
subsidence  of  land  to  the  extent  of  several  hundred  feet — old  terrestrial 
surfaces,  turf,  peat,  forest-land,  and  "  dirt-beds,"  having  been  pierced  at 
various  depths.  The  changes  of  level  at  the  mouth  of  the  Indus  in 
Cutch  (see  below,  chap.  27),  anfl  those  of  New  Madrid  in  the  valley  of 
the  Mississippi  (see  p.  270,  and  chap.  27),  are  equally  instructive,  as 
demonstrating  unceasing  fluctuations  in  the  levels  of  those  areas  into 
which  running  water  is  transporting  sediment.  If,  therefore,  the  exact 

*  Lyell's  Second  Visit  to  the  United  States,  vol.  ii.  chap.  84. 


286  GROUPING    OF 'STRATA    IN    DELTAS.  [On.  XVIIL 

age  of  all  modern  deltas  could  be  known,  it  is  scarcely  probable  that 
we  should  find  any  two  of  them  in  the  world  to  have  coincided  in  date, 
or  in  the  time  when  their  earliest  deposits  originated. 

Grouping  of  strata  in  deltas. — The  changes  which  have  taken  place 
in  deltas,  even  within  the  times  of  history,  may  suggest  many  important 
considerations  in  regard  to  the  manner  in  which  subaqueous  sediment  is 
distributed.  With  the  exception  of  some  cases  hereafter  to  be  noticed, 
there  are  some  general  laws  of  arrangement  which  must  evidently  hold 
good  in  almost  all  the  lakes  and  seas  now  filling  up.  If  a  lake,  for  ex- 
ample, be  encircled  on  two  sides  by  lofty  mountains,  'receiving  from 
them  many  rivers  and  torrents  of  different  sizes,  and  if  it  be  bounded 
on  the  other  sides,  where  the  surplus  waters  issue,  by  a  comparatively 
low  country,  it  is  not  difficult  to  define  some  of  the  leading  geological 
features  which  must  characterize  the  lacustrine  formation,  when  this 
basin  shall  have  been  gradually  converted  into  dry  land  by  the  influx  of 
sediment.  The  strata  would  be  divisible  into  two  principal  groups  :  the 
older  comprising  those  deposits  which  originated  on  the  side  adjoining 
the  mountains,  where  numerous  deltas  first  began  to  form ;  and  the 
newer  group  consisting  of  beds  deposited  in  the  more  central  parts  of 
the  basin,  and  towards  the  side  farthest  from  the  mountains.  The  fol- 
lowing characters  would  form  the  principal  marks  of  distinction  between 
the  strata  in  each  series  : — The  more  ancient  system  would  be  composed, 
for  the  most  part,  of  coarser  materials,  containing  many  beds  of  pebbles 
and  sand,  often  of  great  thickness,  and  sometimes  dipping  at  a  consider- 
able angle.  These,  with  associated  beds  of  finer  ingredients,  would,  if 
traced  round  the  borders  of  the  basin,  be  seen  to  vary  greatly  in  color 
and  mineral  composition,  and  would  also  be  very  irregular  in  thickness. 
The  beds,  on  the  contrary,  in  the  newer  group,  would  consist  of  finer 
particles,  and  would  be  horizontal,  or  very  slightly  inclined.  Their 
color  and  mineral  composition  would  be  very  homogeneous  throughout 
large  areas,  and  would  differ  from  almost  all  the  separate  beds  in  the 
older  series. 

The  following  causes  would  produce  the  diversity  here  alluded  to  be- 
tween the  two  great  members  of  such  lacustrine  formations  : — When 
the  rivers  and  torrents  first  reach  the  edge  of  the  lake,  the  detritus 
washed  down  by  them  from  the  adjoining  heights  sinks  at  once  into 
deep  water,  all  the  heavier  pebbles  and  sand  subsiding  near  the  shore. 
The  finer  mud  is  carried  somewhat  farther  out,  but  not  to  the  distance 
of  many  miles,  for  the  greater  part  may  be  seen,  as,  for  example,  where 
the  Rhone  enters  the  Lake  of  Geneva,  to  fall  down  in  clouds  to  the 
bottom,  not  far  from  the  river's  mouth.  Thus  alluvial  tracts  are  soon 
formed  at  the  mouths  of  every  torrent  and  river,  and  many  of  these  in 
the  course  of  ages  become  of  considerable  extent.  Pebbles  and  sand 
are  then  transported  farther  from  the  mountains  ;  but  in  their  passage 
they  decrease  in  size  by  attrition,  and  are  in  part  converted  into  mud 
and  sand.  At  length  some  of  the  numerous  deltas,  which  are  all  di- 
rected towards  a  common  centre,  approach  near  to  each  other ;  those 


CH.  XVIIL]  STRATIFICATION   IN   DELTAS.  287 

of  adjoining  torrents  become  united,  and  each  is  merged,  in  its  turn,  in 
the  delta  of  the  largest  river,  which  advances  most  rapidly  into  the  lake, 
and  renders  all  the  minor  streams,  one  after  the  other,  its  tributaries. 
The  various  mineral  ingredients  of  all  are  thus  blended  together  into 
one  homogeneous  mixture,  and  the  sediment  is  poured  out  from  a  com- 
mon channel  into  the  lake. 

As  the  average  size  of  the  transported  particles  decreases,  while  the 
force  and  volume  of  the  main  river  augments,  the  newer  deposits  are 
diffused  continually  over  a  wider  area,  and  are  consequently  more  hori- 
zontal than  the  older.  When  at  first  there  were  many  independent 
deltas  near  the  borders  of  the  basin,  their  separate  deposits  differed  en- 
tirely from  eacli  other ;  one  may  have  been  charged,  like  the  Arve 
where  it  joins  the  Rhone,  with  white  sand  and  sediment  derived  from 
granite — another  may  have  been  black,  like  many  streams  in  the  Tyrol, 
flowing  from  the  waste  of  decomposing  rocks  of  dark  slate — a  third 
may  have  been  colored  by  ochreous  sediment,  like  the  Red  River  in 
Louisiana — a  fourth,  like  the  Elsa  in  Tuscany,  may  have  held  much 
carbonate  of  lime  in  solution.  At  first  they  would  each  form  distinct 
deposits  of  sand,  gravel,  limestone,  marl,  or  other  materials ;  but,  after 
their  junction,  new  chemical  combinations  and  a  distinct  color  would  be 
the  result,  and  the  particles,  having  been  conveyed  ten,  twenty,  or  a 
greater  number  of  miles  over  alluvial  plains,  would  become  finer. 

In  those  deltas  where  the  tides  and  strong  marine  currents  interfere, 
the  above  description  would  only  be  applicable,  with  certain  modifica- 
tions. If  a  series  of  earthquakes  accompany  the  growth  of  a  delta,  and 
change  the  levels  of  the  land  from  time  to  time,  as  in  the  region  where 
the  Indus  now  enters  the  sea,  the  phenomena  will  depart  still  more 
widely  from  the  ordinary  type.  If,  after  a  protracted  period  of  rest,  a 
delta  sink  down,  pebbles  may  be  borne  along  in  shallow  water  near  the 
foot  of  the  boundary  hills,  so  as  to  form  conglomerates  overlying  the 
fine  mud  previously  thrown  into  deeper  water  in  the  same  area. 

Causes  of  stratification  in  deltas. — The  stratified  arrangement,  which 
is  observed  to  prevail  so  generally  in  aqueous  deposits,  is  most  fre- 
quently due  to  variations  in  the  velocity  of  running  water,  which  cannot 
sweep  along  particles  of  more  than  a  certain  size  and  weight  when 
moving  at  a  given  rate.  Hence,  as  the  force  of  the  stream  augments  or 
decreases,  the  materials  thrown  down  in  successive  layers  at  particular 
places  are  rudely  sorted,  according  to  their  dimensions,  form,  and  spe- 
cific gravity.  Where  this  cause  has  not  operated,  as  where  sand,  mud, 
and  fragments  of  rock  are  conveyed  by  a  glacier,  a  confused  heap  of 
rubbish  devoid  of  all  stratification  is  produced. 

Natural  divisions  are  also  occasioned  in  deltas,  by  the  interval  of  time 
which  separates  annually  the  deposition  of  matter  during  the  periodical 
rains,  or  melting  of  snow  upon  the  mountains.  The  deposit  of  each 
year  may  acquire  some  degree  of  consistency  before  that  of  the  succeed- 
ing year  is  superimposed.  A  variety  of  circumstances  also  give  rise 
annually,  or  sometimes  from  day  to  day,  to  slight  variations  in  color, 


288  CAUSES    OF   STRATIFICATION.  [Cn.  XVIII. 

fineness  of  the  particles,  and  other  characters,  by  which  alternations  of 
strata  distinct  in  texture  and  mineral  ingredients  must  be  produced. 
Thus,  for  example,  at  one  period  of  the  year,  drift-wood  may  be  carried 
down,  and,  at  another,  mud,  as  was  before  stated  to  be  the  case  in  the 
delta  of  the  Mississippi  ;  or  at  one  time,  when  the  volume  and  velocity 
of  the  stream  are  greatest,  pebbles  and  sand  may  be  spread  over  a  cer- 
tain area,  over  which,  when  the  waters  are  low,  fine  matter  or  chemical 
precipitates  are  formed.  During  inundations,  the  turbid  current  of 
fresh  water  often  repels  the  sea  for  many  miles  ;  but  when  the  river 
is  low,  salt  water  again  occupies  the  same  space.  When  two  deltas  are 
converging,  the  intermediate  space  is  often,  for  reasons  before  explained, 
alternately  the  receptacle  of  different  sediments  derived  from  the  con- 
verging streams  (see  p.  272).  The  one  is,  perhaps,  charged  with  cal- 
careous, the  other  with  argillaceous  matter;  or  one  sweeps  down  sand 
and  pebbles,  the  other  impalpable  mud.  These  differences  may  be 
repeated  with  considerable  regularity,  until  a  thickness  of  hundreds  of 
feet  of  alternating  beds  is  accumulated.  The  multiplication,  also,  of 
shells  and  corals  in  particular  spots,  and  for  limited  periods,  gives  rise 
occasionally  to  lines  of  separation,  and  divides  a  mass  which  might 
otherwise  be  homogeneous  into  distinct  strata. 

An  examination  of  the  shell  marl  now  forming  in  the  Scotch  lakes,  or 
the  sediment  termed  "  warp,"  which  subsides  from  the  muddy  water  of 
the  Humber  and  other  rivers,  shows  that  recent  deposits  are  often  com- 
posed of  a  great  number  of  extremely  thin  layers,  either  even  or  slightly 
undulating,  and  preserving  a  general  parallelism  to  the  planes  of  strati- 
fication. Sometimes,  however,  the  laminae  in  modern  strata  are  dis- 
posed diagonally  at  a  considerable  angle,  which  appears  to  take  place 
where  there  are  conflicting  movements  in  the  waters.  In  January,  1829, 
I  visited,  in  company  with  Professor  L.  A.  Necker,  of  Geneva,  the  con- 
fluence of  the  Rhone  and  Arve,  when  those  rivers  were  very  low,  and 
were  cutting  channels  through  the  vast  heaps  of  debris  thrown  down 
from  the  waters  of  the  Arve  in  the  preceding  spring.  One  of  the  sand- 
banks which  had  formed,  in  the  spring  of  1828,  where  the  opposing 
currents  of  the  two  rivers  neutralized  each  other,  and  caused  a  retarda- 
tion in  the  motion,  had  been  undermined  ;  and  the  following  is  an  exact 
representation  of  the  arrangement  of  lamina?  exposed  in  a  vertical  sec- 
tion. The  length  of  the  portion  here  seen  is  about  twelve  feet,  and  the 
height  five.  The  strata  A  A  consist  of  irregular  alternations  of  pebbles 
and  sand  in  undulating  beds :  below  these  are  seams  of  very  fine  sand 
B  B,  some  as  thin  as  paper,  others  about  a  quarter  of  an  inch  thick.  The 
strata  c  o  are  composed  of  layers  of  fine  greenish-gray  sand  as  thin  as 
paper.  Some  of  the  inclined  beds  will  be  seen  to  be  thicker  at  their 
upper,  others  at  their  lower  extremity,  the  inclination  of  some  being 
very  considerable.  These  layers  must  have  accumulated  one  on  the 
other  by  lateral  apposition,  probably  when  one  of  the  rivers  was  very 
gradually  increasing  o.-  diminishing  in  velocity,  so  that  the  point  of 
greatest  retardation  caused  by  their  conflicting  currents  shifted  slowly, 


Cn.  XVIIL] 


INTERCHANGE    OF    LAND    AND    SEA. 


289 


allowing  the  sediment  to  be  thrown  down  in  successive  layers  on  a 
sloping  bank.     The  same  phenomenon  is  exhibited  in  older  strata  of  all 


ages. 


Fig.  26. 


TnL 


Section  of  a  sand-bank  in  the  bed  of  the  Arve  at  its  confluence  with  the  Ehone,  showing  the 
stratification  of  deposits  where  currents  meet 

If  the  bed  of  a  lake  or  of  the  sea  be  sinking,  whether  at  a  uniform  or 
an  unequal  rate,  or  oscillating  in  level  during  the  deposition  of  sediment, 
these  movements  will  give  rise  to  a  different  class  of  phenomena,  as,  for 
example,  to  repeated  alternations  of  shallow-water  and  deep-water  de- 
posits, each  with  peculiar  organic  remains,  or  to  frequent  repetitions  of 
similar  beds,  formed  at  a  uniform  depth,  and  inclosing  the  same  organic 
remains,  and  to  other  results  too  complicated  and  varied  to  admit  of 
enumeration  here. 

Formation  of  conglomerates. — Along  the  base  of  the  Maritime  Alps, 
between  Toulon  and  Genoa,  the  rivers,  with  few  exceptions,  are  now 
forming  strata  of  conglomerate  and  sand.  Their  channels  are  often  sev- 
eral miles  in  breadth,  some  of  them  being  dry,  and  the  rest  easily  forded 
for  nearly  eight  months  in  the  year,  whereas  during  the  melting  of  the 
snow  they  are  swollen,  and  a  great  transportation  of  mud  and  pebbles 
takes  place.  In  order  to  keep  open  the  main  road  from  France  to  Italy, 
now  carried  along  the  sea-coast,  it  is  necessary  to  remove  annually  great 
masses  of  shingle  brought  down  during  the  flood  season.  A  portion  of 
the  pebbles  are  seen  in  some  localities,  as  near  Nice,  to  form  beds  of 
shingle  along  the  shore,  but  the  greater  part  are  swept  into  a  deep  sea. 
The  small  progress  made  by  the  deltas  of  minor  rivers  on  this  coast 
need  not  surprise  us,  when  we  recollect  that  there  is  sometimes  a  depth 
of  two  thousand  feet  at  a  few  hundred  yards  from  the  beach,  as  near 
Nice.  Similar  observations  might  be  made  respecting  a  large  propor- 
tion of  the  rivers  in  Sicily,  and  among  others,  respecting  that  which, 
immediately  north  of  the  port  of  Messina,  hurries  annually  vast  masses 
of  granitic  pebbles  into  the  sea. 

Constant  interchange  of  land  and  sea. — I  may  here  conclude  my  re- 
marks on  deltas,  observing  that,  imperfect  as  is  our  information  of  the 
changes  which  they  have  undergone  within  the  last  three  thousand 
years,  they  are  sufficient  to  show  how  constant  an  interchange  of  sea 

*  See  Manual  of  Geology  by  the  Author. 
19 


290  TIDES.  [On.  XIX, 

and  land  is  taking  place  on  the  face  of  our  globe.  In  the  Mediterranean 
alone,  many  flourishing  inland  towns,  and  a  still  greater  number  of  ports, 
now  stand  where  the  sea  rolled  its  waves  since  the  era  of  the  early  civ- 
ilization of  Europe.  If  we  could  compare  with  equal  accuracy  the  an- 
cient and  actual  state  of  all  the  islands  and  continents,  we  should  prob- 
ably discover  that  millions  of  our  race  are  now  supported  by  lands  sit- 
uated where  deep  seas  prevailed  in  earlier  ages.  In  many  district  not 
yet  occupied  by  man,  land  animals  and  forests  now  abound  where  ships 
once  sailed ;  and,  on  the  other  hand,  we  shall  find,  on  inquiry,  that  in- 
roads of  the  ocean  have  been  no  less  considerable.  When  to  these  rev- 
olutions, produced  by  aqueous  causes,  we  add  analogous  changes 
wrought  by  igneous  agency,  we  shall,  perhaps,  acknowledge  the  justice 
of  the  conclusion  of  Aristotle,  who  declared  that  the  whole  land  and 
sea  on  our  globe  periodically  changed  places.* 


CHAPTER  XIX. 

DESTROYING    AND    TRANSPORTING    EFFECTS    OF    TIDES    AND    CURRENTS. 

Difference  in  the  rise  of  tides — Lagullas  and  Gulf  currents — Velocity  of  currents 
— Causes  of  currents — Action  of  the  sea  on  the  British  coast — Shetland  Islands 
— Large  blocks  removed — Isles  reduced  to  clusters  of  rocks — Orkney  isles — 
Waste  of  East  coast  of  Scotland — and  East  coast  of  England — Waste  of  the 
cliffs  of  Holderness,  Norfolk,  and  Suffolk — Sand-dunes,  how  far  chronometers 
— Silting  up  of  estuaries — Yarmouth  estuary — Suffolk  coast — Dunwich — Essex 
coast — Estuary  of  the  Thames — Goodwin  Sands — Coast  of  Kent — Formation  of 
the  Straits  of  Dover — South  coast  of  England — Sussex — Hants — Dorset — 
Portland — Origin  of  the  Chesil  Bank — Cornwall — Coast  of  Brittany. 

ALTHOUGH  the  movements  of  great  bodies  of  water,  termed  tides  and 
currents,  are  in  general  due  to  very  distinct  causes,  their  effects  cannot 
be  studied  separately ;  for  they  produce,  by  their  joint  action,  aided  by 
that  of  the  waves,  those  changes  which  are  objects  of  geological  inter- 
est. These  forces  may  be  viewed  in  the  same  manner  as  we  before 
considered  rivers,  first,  as  employed  in  destroying  portions  of  the  solid 
crust  of  the  earth  and  removing  them  to  other  places ;  secondly,  as  re- 
productive of  new  strata. 

Tides. — It  would  be  superfluous  at  the  present  day  to  offer  any  re- 
marks on  the  cause  of  the  tides.  They  are  not  perceptible  in  lakes  or 
in  most  inland  seas ;  in  the  Mediterranean  even,  deep  and  extensive  as 
is  that  sea,  they  are  scarcely  sensible  to  ordinary  observation,  their 
effects  being  quite  subordinate  to  those  of  the  winds  and  currents.  In 
some  places,  however,  as  in  the  Straits  of  Messina,  there  is  an  ebb  and 
flow  to  the  amount  of  two  feet  and  upwards ;  at  Naples  and  at  the 

*  See  p.  13. 


CH.  XIX.]  TIDES. CURRENTS.  291 

Euripus,  of  twelve  or  thirteen  inches  ;  and  at  Venice,  according  to  Ren- 
nelJ,  of  five  feet.*  In  the  Syrtes,  also,  of  the  ancients,  two  wide  shal- 
low gulfs,  which  penetrate  very  far  within  the  northern  coast  of  Africa, 
between  Carthage  and  Gyrene,  the  rise  is  said  to  exceed  five  feet.f 

In  islands  remote  from  any  continent,  the  ebb  and  flow  of  the  ocean 
is  very  slight,  as  at  St.  Helena,  for  example,  where  it  is  rarely  above 
three  feet.|  In  any  given  line  of  coast,  the  tides  are  greatest  in  narrow 
channels,  bays,  and  estuaries,  and  least  in  the  intervening  tracts  where 
the  land  is  prominent.  Thus,  at  the  entrance  of  the  estuary  of  the 
Thames  and  Medway,  the  rise  of  the  spring  tides  is  eighteen  feet ;  but 
when  we  follow  our  eastern  coast  from  thence  northward,  towards 
Lowestoff  and  Yarmouth,  we  find  a  gradual  diminution,  until  at  the 
places  last  mentioned,  the  highest  rise  is  only  seven  or  eight  feet. 
From  this  point  there  begins  again  to  be  an  increase,  so  that  at  Comer, 
where  the  coast  again  retires  towards  the  west,  the  rise  is  sixteen  feet ; 
and  towards  the  extremity  of  the  gulf  called  "  the  Wash,"  as  at  Lynn 
and  in  Boston  Deeps,  it  is  from  twenty-two  to  twenty -four  feet,  and  in 
some  extraordinary  cases  twenty-six  feet.  From  thence  again  there  is 
a  decrease  towards  the  north,  the  elevation  at  the  Spurn  Point  being 
from  nineteen  to  twenty  feet,  and  at  Flamborough  Head  and  the  York- 
shire coast  from  fourteen  to  sixteen  feet.§ 

At  Milford  Haven  in  Pembrokeshire,  at  the  mouth  of  the  Bristol 
Channel,  the  tides  rise  thirty-six  feet ;  and  at  King-Road  near  Bristol, 
forty-two  feet.  At  Chepstow  on  the  Wye,  a  small  river  which  opens 
into  the  estuary  of  the  Severn,  they  reach  fifty  feet,  and  sometimes 
sixty-nine,  and  even  seventy-two  feet.  A  current  which  sets  in  on 
the  French  coast,  to  the  west  of  Cape  La  Hague,  becomes  pent  up  by 
Guernsey,  Jersey,  and  other  islands,  till  the  rise  of  the  tide  is  from 
twenty  to  forty-five  feet,  which  last  height  it  attains  at  Jersey,  and  at 
St.  Malo,  a  seaport  of  Brittany.  The  tides  in  the  Basin  of  Mines,  at  the 
head  of  the  Bay  of  Fundy  in  Nova  Scotia,  rise  to  the  height  of  seventy 
feet. 

There  are,  however,  some  coasts  where  the  tides  seem  to  offer  an 
exception  to  the  rule  above  mentioned ;  for  while  there  is  scarcely  any 
rise  in  the  estuary  of  the  Plata  in  S.  America,  there  is  an  extremely  high 
tide  on  the  open  coast  of  Patagonia,  farther  to  the  south.  Yet  even  in 
this  region  the  tides  reach  their  greatest  elevation  (about  fifty  feet)  in 
the  Straits  of  Magellan,  and  so  far  at  least  they  conform  to  the  general 
rule.  || 

Currents. — The  most  extensive  and  best  determined  system  of  cur- 
rents, is  that  which  has  its  source  in  the  Indian  Ocean  under  the  influ- 
ence of  the  trade  winds  ;  and  which,  after  doubling  the  Cape  of  Good 

*  Geog.  of  Herod,  vol.  ii.  p.  331. 
f  Ibid.  p.  328. 

\  Romme,  Vents  et  Courans,  vol.  ii.  p.  2.  Rev.  F.  Fallows,  Quart  Journ.  of 
Science,  March,  1829. 

§  The  heights  of  these  tides  were  given  me  by  the  late  Captain  Hewett,  R.  N. 
|[  On  the  authority  of  Admiral  Sir  F.  Beaufort,  R.  N. 


292  CURRENTS.  [CH.  XIX. 

Hope,  inclines  to  the  northward,  along  the  western  coast  of  Africa,  then 
across  the  Atlantic,  near  the  equator,  where  it  is  called  the  equatorial 
current,  and  is  lost  in  the  Caribbean  Sea,  yet  seems  to  be  again  revived 
in  the  current  which  issues  from  the  Gulf  of  Mexico.  From  thence  it 
flows  rapidly  through  the  Straits  of  Bahama,  taking  the  name  of  the 
Gulf  Stream,  and  passing  in  a  northeasterly  direction,  by  the  Banks 
of  Newfoundland,  towards  the  Azores. 

We  learn  from  the  posthumous  work  of  Rennell  on  this  subject,  that 
the  Lagullas  current,  so  called  from  the  cape  and  bank  of  that  name,  is 
formed  by  the  junction  of  two  streams,  flowing  from  the  Indian  Ocean ; 
the  one  from  the  channel  of  Mozambique,  down  the  southeast  coast  of 
Africa ;  the  other  from  the  ocean  at  large.  The  collective  stream  is 
from  ninety  to  one  hundred  miles  in  breadth,  and  runs  at  the  rate  of 
from  two  and  a  half  to  more  than  four  miles  per  hour.  It  is  at  length 
turned  westward  by  the  Lagullas  bank,  which  rises  from  a  sea  of  great 
depth  to  within  one  hundred  fathoms  of  the  surface.  It  must  therefore 
be  inferred,  says  Rennell,  that  the  current  here  is  more  than  one  hun- 
dred fathoms  deep,  otherwise  the  main  body  of  it  would  pass  across  the 
bank,  instead  of  being  deflected  westward,  so  as  to  flow  round  the  Cape 
of  Good  Hope.  From  this  cape  it  flows  northward,  as  before  stated, 
along  the  western  coast  of  Africa,  taking  the  name  of  the  South  Atlantic 
current.  It  then  enters  the  Bight,  or  Bay  of  Benin,  and  is  turned  west- 
ward, partly  by  the  form  of  the  coast  there,  and  partly,  perhaps,  by  the 
Guinea  current,  which  runs  from  the  north  into  the  same  great  bay. 
From  the  centre  of  this  bay  proceeds  the  equatorial  current  already 
mentioned,  holding  a  westerly  direction  across  the  Atlantic,  which  it 
traverses,  from  the  coast  of  Guinea  to  that  of  Brazil,  flowing  afterwards 
by  the  shores  of  Guiana  to  the  West  Indies.  The  breadth  of  this  cur- 
rent varies  from  160  to  450  geographical  miles,  and  its  velocity  is  from 
twenty-five  to  seventy-nine  miles  per  day,  the  mean  rate  being  about 
thirty  miles.  The  length  of  its  whole  course  is  about  4000  miles.  As 
it  skirts  the  coast  of  Guiana,  it  is  increased  by  the  influx  of  the  waters 
of  the  Amazon  and  Orinoco,  and  by  their  junction  acquires  accelerated 
velocity.  After  passing  the  island  of  Trinidad  it  expands,  and  is  almost 
lost  in  the  Caribbean  Sea ;  but  there  appears  to  be  a  general  movement 
of  that  sea  towards  the  Mexican  Gulf,  which  discharges  the  most  power- 
ful of  all  currents  through  the  Straits  of  Florida,  where  the  waters  run 
in  the  northern  part  with  a  velocity  of  four  or  five  miles  an  hour,  hav- 
ing a  breadth  of  from  thirty-five  to  fifty  miles.* 

The  temperature  of  the  Gulf  of  Mexico  is  86°  F.  in  summer,  or  6° 
higher  than  that  of  the  ocean,  in  the  same  parallel  (25°  N.  lat.),  and 
a  large  proportion  of  this  warmth  is  retained,  even  where  the  stream 
reaches  the  43°  N.  lat.  After  issuing  from  the  Straits  of  Florida,  the 
current  runs  in  a  northerly  direction  to  Cape  Hatteras,  in  North  Caro- 
lina, about  35°  N.  lat.,  where  it  is  more  than  seventy  miles  broad,  and 

*  Consult  the  map  of  Currents  by  Capt.  F.  Beechy,  R.  K,  Admiralty  Manual, 
1849,  London. 


CH.  XIX.]  VELOCITY   OF   CURRENTS.  293 

still  moves  at  the  rate  of  seventy-five  miles  per  day.  In  about  the  40° 
N.  lat.,  it  is  turned  more  towards  the  Atlantic  by  the  extensive  banks 
of  Naritucket  and  St.  George,  which  are  from  200  to  300  feet  beneath 
the  surface  of  the  sea ;  a  clear  proof  that  the  current  exceeds  that  depth. 
On  arriving  near  the  Azores,  the  stream  widens,  and  overflows,  as  it 
were,  forming  a  large  expanse  of  warm  water  in  the  centre  of  the  North 
Atlantic,  over  a  space  of  200  or  300  miles  from  north  to  south,  and 
having  a  temperature  of  from  8°  to  10°  Fahr.  above  the  surrounding 
ocean.  The  whole  area,  covered  by  the  Gulf  water,  is  estimated  by 
Rennell  at  2000  miles  in  length,  and,  at  a  mean,  350  miles  in  breadth ; 
an  area  more  extensive  than  that  of  the  Mediterranean.  The  warm 
water  has  been  sometimes  known  to  reach  the  Bay  of  Biscay,  still  re- 
taining five  degrees  of  temperature  above  that  of  the  adjoining  ocean ; 
and  a  branch  of  the  Gulf  current  occasionally  drifts  fruits,  plants,  and 
wood,  the  produce  of  America  and  the  West  Indies,  to  the  shores  of 
Ireland  and  the  Hebrides. 

From  the  above  statements  we  may  understand  why  Rennell  has 
characterized  some  of  the  principal  currents  as  oceanic  rivers,  which  he 
describes  as  being  from  50  to  250  miles  in  breadth,  and  having  a 
rapidity  exceeding  that  of  the  largest  navigable  rivers  of  the  continents, 
and  so  deep  as  to  be  sometimes  obstructed,  and  occasionally  turned 
aside,  by  banks,  the  tops  of  which  do  not  rise  within  forty,  fifty,  or 
even  one  hundred  fathoms  of  the  surface  of  the  sea.* 

Greatest  velocity  of  currents. — The  ordinary  velocity  of  the  principal 
currents  of  the  ocean  is  from  one  to  three  miles  per  hour ;  but  when 
the  boundary  lands  converge,  large  bodies  of  water  are  driven  gradually 
into  a  narrow  space,  and  then  wanting  lateral  room,  are  compelled  to 
raise  their  level.  Whenever  this  occurs  their  velocity  is  much  in- 
creased. The  current  which  runs  through  the  Race  of  Alderney,  be- 
tween the  island  of  that  name  and  the  main  land,  has  a  velocity  of 
about  eight  English  miles  an  hour.  Captain  Hewett  found  that  in  the 
Pentland  Firth,  the  stream,  in  ordinary  spring  tides,  runs  ten  miles  and 
a  half  an  hour,  and  about  thirteen  miles  during  violent  storms.  The 
greatest  velocity  of  the  tidal  current  through  the  "  Shoots"  or  New 
Passage,  in  the  Bristol  Channel,  is  fourteen  English  miles  an  hour ; 
and  Captain  King  observed,  in  his  survey  of  the  Straits  of  Magellan, 
that  the  tide  ran  at  the  same  rate  through  the  "  First  Narrows,"  and 
about  eight  geographical  miles  an  hour,  in  other  parts  of  those  straits. 

Causes  of  currents. — That  movements  of  no  inconsiderable  magni- 
tude should  be  impressed  on  an  expansive  ocean,  by  winds  blowing 
for  many  months  in  one  direction,  may  easily  be  conceived,  when  we 
observe  the  effects  produced  in  our  own  seas  by  the  temporary  action 
of  the  same  cause.  It  is  well  known  that  a  strong  southwest  or  north- 
west wind  invariably  raises  the  tides  to  an  unusual  height  along  the 
west  coast  of  England  and  in  the  Channel ;  and  that  a  northwest  wind 

*  Rennell  on  Currents,  p.  58. 


294:  CAUSES   OF  CURRENTS.  [Cn.  XIX 

of  any  continuance  causes  the  Baltic  to  rise  two  feet  and  upwards 
above  its  ordinary  level.  Smeaton  ascertained  by  experiment,  that  in 
a  canal  four  miles  in  length,  the  water  was  kept  up  four  inches  higher 
at  one  end  than  at  the  other,  merely  by  the  action  of  the  wind  along 
the  canal ;  and  Rennell  informs  us  that  a  large  piece  of  water,  ten 
miles  broad,  and  generally  only  three  feet  deep,  has,  by  a  strong  wind, 
had  its  waters  driven  to  one  side,  and  sustained  so  as  to  become  six 
feet  deep,  while  the  windward  side  was  laid  dry.* 

As  water,  therefore,  he  observes,  when  pent  up  so  that  it  cannot 
escape,  acquires  a  higher  level,  so,  in  a  place  where  it  can  escape,  the 
same  operation  produces  a  current ;  and  this  current  will  extend  to  a 
greater  or  less  distance,  according  to  the  force  by  which  it  is  produced. 
By  the  side  of  the  principal  oceanic  currents,  such  as  the  Lagullas  and 
the  Gulf  Stream,  are  parallel  "  counter-currents"  running  steadily  in  an 
opposite  direction. 

Currents  flowing  alternately  in  opposite  directions  are  occasioned  by 
the  rise  and  fall  of  the  tides.  The  effect  of  this  cause  is,  as  before 
observed,  most  striking  in  estuaries  and  channels  between  islands. 

A  third  cause  of  oceanic  currents  is  evaporation  by  solar  heat,  of 
which  the  great  current  setting  through  the  Straits  of  Gibraltar  into  the 
Mediterranean  is  a  remarkable  example,  and  will  be  fully  considered 
in  the  next  chapter.  A  stream  of  colder  water  also  flows  from  the 
Black  Sea  into  the  Mediterranean.  It  must  happen  in  many  other 
parts  of  the  world  that  large  quantities  of  water  raised  from  one  tract 
of  the  ocean  by  solar  heat,  are  carried  to  some  other  where  the  vapor 
is  condensed  and  falls  in  the  shape  of  rain,  and  this,  in  flowing  back 
again  to  restore  equilibrium,  will  cause  sensible  currents. 

These  considerations  naturally  lead  to  the  inquiry  whether  the  level 
of  those  seas  out  of  which  currents  flow,  is  higher  than  that  of  seas  into 
which  they  flow.  If  not,  the  effect  must  be  immediately  equalized  by 
under-currents  or  counter -currents.  Arago  is  of  opinion  that,  so  far  as 
observations  have  gone,  there  are  no  exact  proofs  of  any  such  differ- 
ence of  level.  It  was  inferred  from  the  measurements  of  M.  Lepere,  that 
the  level  of  the  Mediterranean,  near  Alexandria,  was  lower  by  26  feet  6 
inches,  than  the  Red  Sea  near  Suez  at  low  water,  and  about  30  feet 
lower  than  the  Red  Sea  at  the  same  place  at  high  water,  f  but  Mr. 
Robert  Stevenson  affirms,  as  the  result  of  a  more  recent  survey,  that 
there  is  no  difference  of  level  between  the  two  seas.;); 

It  was  formerly  imagined  that  there  was  an  equal,  if  not  greater, 
diversity  in  the  relative  levels  of  the  Atlantic  and  Pacific,  on  the  oppo- 
site sides  of  the  Isthmus  of  Panama.  But  the  levellings  carried  across 
that  isthmus  by  Capt.  Lloyd,  in  1828,  to  ascertain  the  relative  height 
of  the  Pacific  Ocean  at  Panama,  and  of  the  Atlantic  at  the  mouth  of 
the  river  Chagres,  have  shown,  that  the  difference  of  mean  level  be- 

*  Rennell  on  the  Channel  current.  f  An.  du  Bureau  des  Long.  1836. 

\  Second  Parliamentary  Report  on  Steam  Communication  with  India,  July, 
1851. 


CH.  XIX.]  CAUSES   OF   CURRENTS.  295 

tween  those  oceans  is  not  considerable,  and,  contrary  to  expectation,  the 
difference  which  does  exist  is  in  favor  of  the  greater  height  of  the  Pacific. 
According  to  this  survey,  the  mean  height  of  the  Pacific  is  three  feet 
and  a  half,  or  3 '52  above  the  Atlantic,  if  we  assume  the  mean  level  of  a 
sea  to  coincide  with  the  mean  between  the  extremes  of  the  elevation 
and  depression  of  the  tides  ;  for  between  the  extreme  levels  of  the 
greatest  tides  in  the  Pacific,  at  Panama,  there  is  a  difference  of  2 7 '44 
feet;  and  at  the  usual  spring  tides  2T22  feet;  whereas  at  Chagres 
this  difference  is  only  T16  feet,  and  is  the  same  at  all  seasons  of  the 
year. 

The  tides,  in  short,  in  the  Caribbean  Sea  are  scarcely  perceptible,  not 
equalling  those  in  some  parts  of  the  Mediterranean,  whereas  the  rise  is 
very  high  in  the  Bay  of  Panama ;  so  that  the  Pacific  is  at  high  tide 
lifted  up  several  feet  above  the  surface  of  the  Gulf  of  Mexico,  and  then 
at  low  water  let  down  as  far  below  it.*  But  astronomers  are  agreed 
that,  on  mathematical  principles,  the  rise  of  the  tidal  wave  above  the 
mean  level  of  a  particular  sea  must  be  greater  than  the  fall  below  it ; 
and  although  the  difference  has  been  hitherto  supposed  insufficient  to 
cause  an  appreciable  error,  it  is,  nevertheless,  worthy  of  observation, 
that  the  error,  such  as  it  may  be,  would  tend  to  reduce  the  small  differ- 
ence, now  inferred,  from  the  observations  of  Mr.  Lloyd,  to  exist  between 
the  levels  of  the  two  oceans. 

There  is  still  another  way  in  which  heat  and  cold  must  occasion  great 
movements  in  the  ocean,  a  cause  to  which,  perhaps,  currents  are  prin- 
cipally due.  Whenever  the  temperature  of  the  surface  of  the  sea  is 
lowered,  condensation  takes  place,  and  the  superficial  water,  having  its 
specific  gravity  increased,  falls  to  the  bottom,  upon  which  lighter  water 
rises  immediately  and  occupies  its  place.  When  this  circulation  of 
ascending  and  descending  currents  has  gone  on  for  a  certain  time  in 
high  latitudes,  the  inferior  parts  of  the  sea  are  made  to  consist  of  colder 
or  heavier  fluid  than  the  corresponding  depths  of  the  ocean  between  the 
tropics.  If  there  be  a  free  communication,  if  no  chain  of  submarine 
mountains  divide  the  polar  from  the  equatorial  basins,  a  horizontal  move- 
ment will  arise  by  the  flowing  of  colder  water  from  the  poles  to  the 
equator,  and  there  will  then  be  a  reflux  of  warmer  superficial  water 
from  the  equator  to  the  poles.  A  well-known  experiment  has  been  ad- 
duced to  elucidate  this  mode  of  action  in  explanation  of  the  "  trade 
winds. "f  If  a  long  trough,  divided  in  the  middle  by  a  sluice  or  parti- 
tion, have  one  end  filled  with  water  and  the  other  with  quicksilver,  both 
fluids  will  remain  quiet  so  long  as  they  are  divided  ;  but  when  the  sluice 
is  drawn  up,  the  heavier  fluid  will  rush  along  the  bottom  of  the  trough, 
while  the  lighter,  being  displaced,  will  rise,  and,  flowing  in  an  opposite 
direction,  spread  itself  at  the  top.  In  like  manner  the  expansion  and 
contraction  of  sea-water  by  heat  and  cold,  have  a  tendency  to  set  un- 

*  Phil.  Trans.  1830,  p.  59. 

f  See  Capt.  B.  Hall,  On  Theory  of  Trade  Winds,  Fragments  of  Voy.  second 
series,  vol.  i.,  and  Appendix  to  Daniell's  Meteorology. 


296  CAUSES   OF  CURRENTS.  [On.  XIX. 

der-currents  in  motion  from  the  poles  to  the  equator,  and  to  cause 
counter- currents  at  the  surface,  which  are  impelled  in  a  direction  con- 
trary to  that  of  the  prevailing  trade  winds.  The  geographical  and 
other  circumstances  being  very  complicated,  we  cannot  expect  to  trace 
separately  the  movements  due  to  each  cause,  but  must  be  prepared  for 
many  anomalies,  especially  as  the  configuration  of  the  bed  of  the  ocean 
must  often  modify  and  interfere  with  the  course  of  the  inferior  currents, 
as  much  as  the  position  and  form  of  continents  and  islands  alter  the  di- 
rection of  those  on  the  surface.  Thus  on  sounding  at  great  depths  in 
the  Mediterranean,  Captains  Berard  and  D'Urville  have  found  that  the 
cold  does  not  increase  in  a  high  ratio  as  in  the  tropical  regions  of  the 
ocean,  the  thermometer  remaining  fixed  at  about  55°  F.  between  the 
depths  of  1000  and  6000  feet.  This  might  have  been  anticipated,  as 
Captain  Smyth  in  his  survey  had  shown  that  the  deepest  part  of  the 
Straits  of  Gibraltar  is  only  1320  feet,  so  that  a  submarine  barrier  exists 
there  which  must  prevent  the  influx  of  any  under-current  of  the  ocean 
cooled  by  polar  ice. 

Each  of  the  four  causes  above  mentioned,  the  wind,  the  tides,  evapo- 
ration, and  the  expansion  and  contraction  of  water  by  heat  and  cold, 
may  be  conceived  to  operate  independently  of  the  others,  and  although 
the  influence  of  all  the  rest  were  annihilated.  But  there  is  another 
cause,  the  rotation  of  the  earth  on  its  axis,  which  can  only  come  into 
play  when  the  waters  have  already  been  set  in  motion  by  some  one  or 
all  of  the  forces  above  described,  and  when  the  direction  of  the  cur- 
rent so  raised  happens  to  be  from  south  to  north,  or  from  north  to 
south. 

The  principle  on  which  this  cause  operates  is  probably  familiar  to  the 
reader,  as  it  has  long  been  recognized  in  the  case  of  the  trade  winds. 
Without  enlarging,  therefore,  on  the  theory,  it  will  be  sufficient  to  offer 
an  example  of  the  mode  of  action  alluded  to.  When  a  current  flows 
from  the  Cape  of  Good  Hope  towards  the  Gulf  of  Guinea,  it  consists  of 
a  mass  of  water,  which,  on  doubling  the  Cape,  in  lat.  35°,  has  a  rota- 
tory velocity  of  about  800  miles  an  hour  ;  but  when  it  reaches  the  line, 
where  it  turns  westward,  it  has  arrived  at  a  parallel  where  the  surface 
of  the  earth  is  whirled  round  at  the  rate  of  1000  miles  an  hour,  or 
about  200  miles  faster.  If  this  great  mass  of  water  was  transferred 
suddenly  from  the  higher  to  the  lower  latitude,  the  deficiency  of  its  ro- 
tatory motion,  relatively  to  the  land  and  water  with  which  it  would 
come  into  juxtaposition,  would  be  such  as  to  cause  an  apparent  motion 
of  the  most  rapid  kind  (of  no  less  than  200  miles  an  hour)  from  east 
to  west. 

In  the  case  of  such  a  sudden  transfer,  the  eastern  coast  of  America, 
being  carried  round  in  an  opposite  direction,  might  strike  against  a  large 
body  of  water  with  tremendous  violence,  and  a  considerable  part  of  the 
continent  might  be  submerged.  This  disturbance  does  not  occur,  be- 
cause the  water  of  the  stream,  as  it  advances  gradually  into  new  zones 
of  the  sea  which  are  moving  more  rapidly,  acquires  by  friction  an  ac- 


CH.  XIX.]  EFFECTS    OF    CURRENTS.  297 

celerated  velocity.  Yet  as  this  motion  is  not  imparted  instantaneously, 
the  fluid  is  unable  to  keep  up  with  the  full  speed  of  the  new  surface 
over  which  it  is  successively  brought.  Hence,  to  borrow  the  language 
of  Herschel,  when  he  speaks  of  the  trade  winds,  "it  lags  or  hangs  back, 
in  a  direction  opposite  to  the  earth's .  rotation,  that  is,  from  east  to 
west,"*  and  thus  a  current,  which  would  have  run  simply  towards 
the  north  but  for  the  rotation,  may  acquire  a  relative  direction  towards 
the  west. 

We  may  next  consider  a  case  where  the  circumstances  are  the  con- 
verse of  the  above.  The  Gulf  Stream  flowing  from  about  lat.  20°  is  at 
first  impressed  with  a  velocity  of  rotation  of  about  940  miles  an  hour, 
and  runs  to  the  lat.  40°,  where  the  earth  revolves  only  at  the  rate  of 
766  miles,  or  174  miles  slower.  In  this  case  a  relative  motion  of  an 
opposite  kind  may  result ;  and  the  current  may  retain  an  excess  of  rota- 
tory velocity,  tending  continually  to  deflect  it  eastward.  Polar  currents, 
therefore,  or  those  flowing  from  high  to  low  latitudes,  are  driven  towards 
the  eastern  shores  of  continents,  while  tropical  currents  flowing  towards 
the  poles  are  directed  against  their  western  shores. 

Thus  it  will  be  seen  that  currents  depend,  like  the  tides,  on  no  tem- 
porary or  accidental  circumstances,  but  on  the  laws  which  preside  over 
the  motions  of  the  heavenly  bodies.  But  although  the  sum  of  their 
influence  in  altering  the  surface  of  the  earth  may  be  very  constant 
throughout  successive  epochs,  yet  the  points  where  these  operations  are 
displayed  in  fullest  energy  shift  perpetually.  The  height  to  which  the 
tides  rise,  and  the  violence  and  velocity  of  currents,  depend  in  a  great 
measure  on  the  actual  configuration  of  the  land,  the  contour  of  a  long 
line  of  continental  or  insular  coast,  the  depth  and  breadth  of  channels, 
the  peculiar  form  of  the  bottom  of  seas — in  a  word,  on  a  combination  of 
circumstances  which  are  made  to  vary  continually  by  many  igneous  and 
aqueous  causes,  and,  amongst  the  rest,  by  the  tides  and  currents  them- 
selves. Although  these  agents,  therefore,  of  decay  and  reproduction  are 
local  in  reference  to  periods  of  short  duration,  such  as  those  which  history 
embraces,  they  are  nevertheless  universal,  if  we  extend  our  views  to  a 
sufficient  lapse  of  ages. 

Destroying  and  transporting  power  of  currents. — After  these  prelim- 
inary remarks  on  the  nature  and  causes  of  currents,  their  velocity  and 
direction,  we  may  next  consider  their  action  on  the  solid  materials  of  the 
earth.  We  shall  find  that  their  efforts  are,  in  many  respects,  strictly 
analogous  to  those  of  rivers.  I  have  already  treated  in  the  third  chap- 
ter, of  the  manner  in  which  currents  sometimes  combine  with  ice,  in 
carrying  mud,  pebbles,  and  large  fragments  of  rock  to  great  distances. 
Their  operations  are  more  concealed  from  our  view  than  those  of  rivers, 
but  extend  over  wider  areas,  and  are  therefore  of  more  geological 
importance. 

Waste  of  the  British  coasts. — Shetland  Islands.— If  we  follow  the 

*  Treatise  on  Astronomy,  chap.  8. 


298  ACTION   OF   THE   SEA  [On.  XIX. 

eastern  and  southern  shores  of  the  British  islands,  from  our  Ultima 
Thule  in  Shetland  to  the  Land's  End  in  Cornwall,  we  shall  find  evidence 
of  a  series  of  changes  since  the  historical  era,  very  illustrative  of  the 
kind  and  degree  of  force  exerted  by  tides  and  currents  co-operating  with 
the  waves  of  the  sea.  In  this  survey  we  shall  have  an  opportunity  of 
tracing  their  joint  power  on  islands,  promontories,  bays,  and  estuaries  ; 
on  bold,  lofty  cliffs,  as  well  as  on  low  shores  ;  and  on  every  description 
of  rock  and  soil,  from  granite  to  blown  sand. 

The  northernmost  group  of  the  British  islands,  the  Shetland,  are  com- 
posed of  a  great  variety  of  rocks,  including  granite,  gneiss,  mica-slate, 
serpentine,  greenstone,  and  many  others,  with  some  secondary  rocks, 
chiefly  sandstone  and  conglomerate.  These  islands  are  exposed  contin- 
ually to  the  uncontrolled  violence  of  the  Atlantic,  for  no  land  intervenes 
between  their  western  shores  and  America.  The  prevalence,  therefore, 
of  strong  westerly  gales,  causes  the  waves  to  be  sometimes  driven  with 
irresistible  force  upon  the  coast,  while  there  is  also  a  current  setting  from 
the  north.  The  spray  of  the  sea  aids  the  decomposition  of  the  rocks, 
and  prepares  them  to  be  breached  by  the  mechanical  force  of  the  waves. 
Steep  cliffs  are  hollowed  out  into  deep  caves  and  lofty  arches  ;  and  almost 
every  promontory  ends  in  a  cluster  of  rocks,  imitating  the  forms  of 
columns,  pinnacles,  and  obelisks. 

Drifting  of  large  masses  of  rock. — Modern  observations  show  that  the 
reduction  of  continuous  tracts  to  such  insular  masses  is  a  process  in 
which  nature  is  still  actively  engaged.  "  The  isle  of  Stenness,"  says  Dr. 
Hibbert,  "  presents  a  scene  of  unequalled  desolation.  In  stormy  winters, 
huge  blocks  of  stones  are  overturned,  or  are  removed  from  their  native 
beds,  and  hurried  up  a  slight  acclivity  to  a  distance  almost  incredible. 
In  the  winter  of  1802,  a  tabular-shaped  mass,  eight  feet  two  inches  by 
seven  feet,  and  five  feet  one  inch  thick,  was  dislodged  from  its  bed,  and 
removed  to  a  distance  of  from  eighty  to  ninety  feet.  I  measured  the 
recent  bed  from  which  a  block  had  been  carried  away  the  preceding 
winter  (A.  D.  1818),  and  found  it  to  be  seventeen  feet  and  a  half  by 
seven  feet,  and  the  depth  two  feet  eight  inches.  The  removed  mass  had 
been  borne  to  a  distance  of  thirty  feet,  when  it  was  shivered  into  thir- 
teen or  more  lesser  fragments,  some  of  which  were  carried  still  farther, 
from  30  to  120  feet.  A  block,  nine  feet  two  inches  by  six  feet  and  a 
half,  and  four  feet  thick,  was  hurried  up  the  acclivity  to  a  distance  of 
150  feet."* 

At  Northmavine,  also,  angular  blocks  of  stone  have  been  removed  in 
a  similar  manner  to  considerable  distances  by  the  waves  of  the  sea,  some 
of  which  are  represented  in  the  annexed  figure. 

Effects  of  lightning. — In  addition  to  numerous  examples  of  masses 
detached  and  driven  by  the  waves,  tides,  and  currents  from  their 
place,  some  remarkable  effects  of  lightning  are  recorded  in  these 

*  Descrip.  of  Shetland  Islands,  p.  627,  Edin.  1822,  to  which  work  I  am  in- 
debted for  the  following  representations  of  rocks  in  the  Shetland  Isles. 


CH.  XIX.] 


ON    THE   SHETLAND    ISLES. 
Fig.  27. 


299 


Stony  fragments  drifted  by  the  sea.    Northmavine,  Shetland. 

isles.  At  Funzie,  in  Fetlar,  about  the  middle  of  the  last  century,  a 
rock  of  mica-schist,  105  feet  long,  ten  feet  broad,  and  in  some  places 
four  feet  thick,  was  in  an  instant  torn  by  a  flash  of  lightning  from  its 
bed,  and  broken  into  three  large  and  several  smaller  fragments.  One 
of  these,  twenty-six  feet  long,  ten  feet  broad,  and  four  feet  thick,  was 
simply  turned  over.  The  second,  which  was  twenty-eight  feet  long, 
seventeen  broad,  and  five  feet  in  thickness,  was  hurled  across  a  high 
point  to  the  distance  of  fifty  yards.  Another  broken  mass,  about  forty 
feet  long,  was  thrown  still  farther,  but  in  the  same  direction,  quite  into 
the  sea.  There  were  also  many  smaller  fragments  scattered  up  and 
down.* 

When  we  thus  see  electricity  co-operating  with  the  violent  move- 
ments of  the  ocean  in  heaping  up  piles  of  shattered  rocks  on  dry  land 
and  beneath  the  waters,  we  cannot  but  admit  that  a  region  which  shall 
be  the  theatre,  for  myriads  of  ages,  of  the  action  of  such  disturbing 
causes,  might  present,  at  some  future  period,  if  upraised  far  above  the 
bosom  of  the  deep,  a  scene  of  havoc  and  ruin  that  may  compare  with 
any  now  found  by  the  geologist  on  the  surface  of  our  continents. 

In  some  of  the  Shetland  Isles,  as  on  the  west  of  Meikle  Roe,  dikes,  or 
veins  of  soft  granite,  have  mouldered  away ;  while  the  matrix  in  which 
they  were  inclosed,  being  of  the  same  substance,  but  of  a  firmer  tex- 
ture, has  remained  unaltered.  Thus,  long  narrow  ravines,  sometimes 
twenty  feet  wide,  are  laid  open,  and  often  give  access  to  the  waves. 
After  describing  some  huge  cavernous  apertures  into  which  the  sea 
flows  for  250  feet  in  Roeness,  Dr.  Hibbert,  writing  in  1822,  enumerates 
other  ravages  of  the  ocean.  "  A  mass  of  rock,  the  average  dimensions 
of  which  may  perhaps  be  rated  at  twelve  or  thirteen  feet  square,  and 
four  and  a  half  or  five  in  thickness,  was  first  moved  from  its  bed,  about 
fifty  years  ago,  to  a  distance  of  thirty  feet,  and  has  since  been  twice 
turned  over." 

Passage  forced  by  the  sea  through  porphyritic  rocks. — "  But  the  most 
sublime  scene  is  where  a  mural  pile  of  porphyry,  escaping  the  process 

*  Dr.  Hibbert,  from  MSS.  of  Rev.  George  Lo^,  of  Fetlar. 


300 


ACTION   OF   THE   SEA 


[On.  XIX. 


of  disintegration  that  is  devastating  the  coast,  appears  to  have  been  left 
as  a  sort  of  rampart  against  the  inroads  of  the  ocean; — the  Atlantic, 
when  provoked  by  wintry  gales,  batters  against  it  with  all  the  force  of 
real  artillery — the  waves  having,  in  their  repeated  assaults,  forced  them- 
selves an  entrance.  This  breach,  named  the  Grind  of  the  Navir  (fig. 
28),  is  widened  every  winter  by  the  overwhelming  surge  that,  finding  a 

Fig.  28. 


Grind  of  the  Navir— passage  forced  by  the  sea  through  rocks  of  hard  porphyry. 

passage  through  it,  separates  large  stones  from  its  sides,  and  forces 
them  to  a  distance  of  no  less  than  180  feet.  In  two  or  three  spots, 
the  fragments  which  have  been  detached  are  brought  together  in  im- 
mense heaps,  that  appear  as  an  accumulation  of  cubical  masses,  the 
product  of  some  quarry."* 

It  is  evident  from  this  example,  that  although  the  greater  indestructi- 
bility of  some  rocks  may  enable  them  to  withstand,  for  a  longer  time, 
the  action  of  the  elements,  yet  they  cannot  permanently  resist.  There 
are  localities  in  Shetland,  in  which  rocks  of  almost  every  variety  of 
mineral  composition  are  suffering  disintegration ;  thus  the  sea  makes 
great  inroads  on  the  clay  slate  of  Fitfel  Head,  on  the  serpentine  of  the 
Vord  Hill  in  Fetlar,  and  on  the  mica-schist  of  the  Bay  of  Triesta,  on 
the  east  coast  of  the  same  island,  which  decomposes  into  angular  blocks. 
The  quartz  rock  on  the  east  of  Walls,  and  the  gneiss  and  mica-schist  of 
Garthness,  suffer  the  same  fate. 

Destruction  of  islands. — Such  devastation  cannot  be  incessantly  com- 
mitted for  thousands  of  years  without  dividing  islands,  until  they  become 
at  last  mere  clusters  of  rocks,  the  last  shreds  of  masses  once  continuous. 
To  this  state  many  appear  to  have  been  reduced,  and  innumerable 
fantastic  forms  are  assumed  by  rocks  adjoining  these  islands  to  which 
the  name  of  Drongs  is  applied,  as  it  is  to  those  of  similar  shape  in  Feroe. 

*  Hibbert,  p.  528. 


CH.  XIX.] 


ON   THE    SHETLAND   ISLES. 


301 


The  granite  rocks  (fig.  29),  between  Papa  Stour  and  Hillswick  Ness 
afford  an  example.     A  still  more  singular  cluster  of  rocks  is  seen  to 

Fig.  29. 


Granitic  rocks  named  the  Drongs,  between  Papa  Stour  and  Hillswick  Ness. 

the  south  of  Hillswick  Ness  (fig.  30),  which  presents  a  variety  of  forms 
as  viewed  from  different  points,  and  has  often  been  likened  to  a  small 
fleet  of  vessels  with  spread  sails.*  We  may  imagine  that  in  the  course 

Fig.  30. 


Granitic  rocks  to  the  south  of  Hillswick  Ness,  Shetland. 

.of  time  Hillswick  Ness  itself  may  present  a  similar  wreck,  from  the 
unequal  decomposition  of  the  rocks  whereof  it  is  composed,  consisting  of 
gneiss  and  mica-schist  traversed  in  all  directions  by  veins  of  felspar- 
porphyry. 

Midway  between  the  groups  of  Shetland  and  Orkney  is  Fair  Island, 
said  to  be  composed  of  sandstone  with  high  perpendicular  cliffs.  The 
current  runs  with  such  velocity,  that  during  a  calm,  and  when  there  is 
no  swell,  the  rocks  on  its  shores  are  white  with  the  foam  of  the  sea 
driven  against  them.  The  Orkneys,  if  carefully  examined,  would  prob- 

*  Hibbert,  p.  519. 


302  FORCE   OF   WAVES    IN    ESTUARIES.  [~CH-  XIX- 

ably  illustrate  our  present  topic  as  much  as  the  Shetland  group.  The 
northeast  promontory  of  Sanda,  one  of  these  islands,  has  been  cut  off  in 
modern  times  by  the  sea,  so  that  it  became  what  is  now  called  Start 
Island,  where  a  lighthouse  was  erected  in  1807,  since  which  time  the 
new  strait  has  grown  broader. 

East  coast  of  Scotland. — To  pass  over  to  the  main  land  of  Scotland, 
we  find  that  in  Inverness-shire  there  have  been  inroads  of  the  sea  at 
Fort  George,  and  others  in  Morayshire,  which  have  swept  away  the  old 
town  of  Findhorn.  On  the  coast  of  Kincardineshire,  an  illustration  was 
afforded  at  the  close  of  the  last  century,  of  the  effect  of  promontories 
in  protecting  a  line  of  low  shore.  The  village  of  Mathers,  two  miles 
south  of  Johnshaven,  was  built  on  an  ancient  shingle  beach,  protected 
by  a  projecting  ledge  of  limestone  rock.  This  was  quarried  for  lime  to 
such  an  extent  that  the  sea  broke  through,  and  in  1795  carried  away 
the  whole  village  in  one  night,  and  penetrated  150  yards  inland,  where 
it  has  maintained  its  ground  ever  since,  the  new  village  having  been 
built  farther  inland  on  the  new  shore.  In  the  bay  of  Montrose,  we  find 
the  North  Esk  and  the  South  Esk  rivers  pouring  annually  into  the  sea 
large  quantities  of  sand  and  pebbles ;  yet  they  have  formed  no  deltas, 
for  the  waves,  aided  by  the  current,  setting  across  their  mouths,  sweep 
away  all  the  materials.  Considerable  beds  of  shingle,  brought  down  by 
the  North  Esk,  are  seen  along  the  beach. 

Proceeding  southwards,  we  learn  that  at  Arbroath,  in  Forfarshire, 
which  stands  on  a  rock  of  red  sandstone,  gardens  and  houses  have  been 
carried  away  since  the  commencement  of  the  present  century  by  en- 
croachments of  the  sea.  It  had  become  necessary  before  1828,  to 
remove  the  lighthouses  at  the  mouth  of  the  estuary  of  the  Tay,  in  the 
same  county,  at  Button  Ness,  which  were  built  on  a  tract  of  blown 
sand,  the  sea  having  encroached  for  three-quarters  of  a  mile. 

Force  of  waves  and  currents  in  estuaries. — The  combined  power 
which  waves  and  currents  can  exert  in  estuaries  (a  term  which  I 
confine  to  bays  entered  both  by  rivers  and  the  tides  of  the  sea), 
was  remarkably  exhibited  during  the  building  of  the  Bell  Rock  Light- 
house, off  the  mouth  of  the  Tay.  The  Bell  Rock  is  a  sunken  reef, 
consisting  of  red  sandstone,  being  from  twelve  to  sixteen  feet  under 
the  surface  at  high  water,  and  about  twelve  miles  from  the  main- 
land. At  the  distance  of  100  yards,  there  is  a  depth,  in  all  directions 
of  two  or  three  fathoms  at  low  water.  In  1807,  during  the  erection 
of  the  lighthouse,  six  large  blocks  of  granite,  which  had  been  landed 
on  the  reef,  were  removed  by  the  force  of  the  sea,  and  thrown  over 
a  rising  ledge  to  the  distance  of  twelve  or  fifteen  paces  ;  and  an  an- 
chor, weighing  about  22  cwt.,  was  thrown  up  upon  the  rock.*  Mr.  Ste- 
venson informs  us  moreover,  that  drift  stones,  measuring  upwards  of 
thirty  cubic  feet,  or  more  than  two  tons'  weight,  have,  during  storms, 
been  often  thrown  upon  the  rock  from  the  deep  water. f 

*  Account  of  Erection  of  Bell  Rock  Lighthouse,  p.  163. 
f  Ed.  Phil.  Journ.  vol.  iii.  p.  54,  1820. 


CH.  XIX.]  WASTE    OF   EAST    COAST    OF    ENGLAND.  303 

Submarine  forests. — Among  the  proofs  that  the  sea  has  encroached 
on  the  land  bordering  the  estuary  of  the  Tay,  Dr.  Fleming  has  men- 
tioned a  submarine  forest  which  has  been  traced  for  several  miles  along 
the  northern  shore  of  the  county  of  Fife.*  But  subsequent  surveys 
seem  to  have  shown  that  the  bed  of  peat  containing  tree-roots,  leaves, 
and  branches,  now  occurring  at  a  lower  level  than  the  Tay,  must  have 
come  into  its  present  position  by  a  general  sinking  of  the  ground  on 
which  the  forest  grew.  The  peat-bed  alluded  to  is  not  confined,  says 
Mr.  Buist,  to  the  present  channel  of  the  Tay,  but  extends  far  beyond  it, 
and  is  covered  by  stratified  clay  from  fifteen  to  twenty-five  feet  in  thick- 
ness, in  the  midst  of  which,  in  some  places,  is  a  bed  full  of  sea-shells.! 
Recent  discoveries  having  established  the  fact  that  upward  and  down- 
ward movements  have  affected  our  island  since  the  general  coast-line 
had  nearly  acquired  its  present  shape,  we  must  hesitate  before  we  at- 
tribute any  given  change  to  a  single  cause,  such  as  the  local  encroach- 
ment of  the  sea  upon  low  land. 

On  the  coast  of  Fife,  at  St.  Andrew's,  a  tract  of  land,  said  to  have 
intervened  between  the  castle  of  Cardinal  Beaton  and  the  sea,  has  been 
entirely  swept  away,  as  were  the  last  remains  of  the  Priory  of  Crail,  in 
the  same  county,  in  1803.  On  both  sides  of  the  Frith  of  Forth,  land 
has  been  consumed ;  at  North  Berwick  in  particular,  and  at  Newhaven, 
where  an  arsenal  and  dock,  built  in  the  reign  of  James  IV.,  in  the  fif- 
teenth century,  has  been  overflowed. 

East  coast  of  England. — If  we  now  proceed  to  the  English  coast,  we 
find  records  of  numerous  lands  having  been  destroyed  in  Northumber- 
land, as  those  near  Bamborough  and  Holy  Island,  and  at  Tynemouth 
Castle,  which  now  overhangs  the  sea,  although  formerly  separated  from 
it  by  a  strip  of  land.  At  Hartlepool,  and  several  other  parts  of  the 
coast  of  Durham  composed  of  magnesian  limestone,  the  sea  has  made 
considerable  inroads. 

Coast  of  Yorkshire. — Almost  the  whole  coast  of  Yorkshire,  from  the 
mouth  of  the  Tees  to  that  of  the  Humber,  is  in  a  state  of  gradual  dilap- 
idation. That  part  of  the  cliffs  which  consist  of  lias,  the  oolite  series, 
and  chalk,  decays  slowly.  They  present  abrupt  and  naked  precipices, 
often  300  feet  in  height ;  and  it  is  only  at  a  few  points  that  the  grassy 
covering  of  the  sloping  talus  marks  a  temporary  relaxation  of  the  erosive 
action  of  the  sea.  The  chalk  cliffs  are  worn  into  caves  and  needles  in 
the  projecting  headland  of  Flamborough,  where  they  are  decomposed 
by  the  salt  spray,  and  slowly  crumble  away.  But  the  waste  is  most 
rapid  between  that  promontory  and  Spurn  Point,  or  the  coast  of  Hol- 
derness,  as  it  is  called,  a  tract  consisting  of  beds  of  clay,  gravel,  sand, 
and  chalk  rubble.  The  irregular  intermixture  of  the  argillaceous  beds 
sauses  many  springs  to  be  thrown  out,  and  this  facilitates  the  under- 
mining process,  the  waves  beating  against  them,  and  a  strong  current 


*  Quart.  Journ.  of  Sci.  <fcc.,  No.  xiii.  N.  8.  March,  1830. 

f  Buist,  Quart.  Journ.  of  Agricult.  No.  xlv.  p.  34,  June,  1839. 


304  ENCROACHMENTS    OF   THE   SEA   ON  [Cn.  XIX. 

setting  chiefly  from  the  north.  The  wasteful  action  is  very  conspicuous 
at  Dimlington  Height,  the  loftiest  point  in  Holderness,  where  the  beacon 
stands  on  a  cliff  146  feet  above  high  water,  the  whole  being  composed 
of  clay,  with  pebbles  scattered  through  it.*  "  For  many  years,"  says 
Professor  Phillips,  "  the  rate  at  which  the  cliffs  recede  from  Bridlington 
to  Spurn,  a  distance  of  thirty-six  miles,  has  been  found  by  measurement 
to  equal  on  an  average  two  and  a  quarter  yards  annually,  which,  upon 
thirty-six  miles  of  coast,  would  amount  to  about  thirty  acres  a  year. 
At  this  rate,  the  coast,  the  mean  height  of  which  above  the  sea  is  about 
forty  feet,  has  lost  one  mile  in  breadth  since  the  Norman  Conquest,  and 
more  than  two  miles  since  the  occupation  of  York  (Eboracum)  by  the 
Romans."f  The  extent  of  this  denudation,  as  estimated  by  the  number 
of  cubic  feet  of  matter  removed  annually,,  will  be  again  spoken  of  in 
chapter  22. 

In  the  old  maps  of  Yorkshire,  we  find  spots,  now  sand-banks  in  the  sea, 
marked  as  the  ancient  sites  of  the  towns  and  villages  of  Auburn,  Hart- 
burn,  and  Hyde.  "  Of  Hyde,"  says  Pennant,  "  only  the  tradition  is 
left ;  and  near  the  village  of  Hornsea,  a  street  called  Hornsea  Beck  has 
long  since  been  swallowed. "J  Owthorne  and  its  church  have  also  been 
in  great  part  destroyed,  and  the  village  of  Kilnsea ;  but  these  places 
are  now  removed  farther  inland.  The  annual  rate  of  encroachment  at 
Owthorne  for  several  years  preceding  1830,  is  stated  to  have  averaged 
about  four  yards.  Not  unreasonable  fears  are  entertained  that  at  some 
future  time  the  Spurn  Point  will  become  an  island,  and  that  the  ocean, 
entering  into  the  estuary  of  the  Humber,  will  cause  great  devastation. § 
Pennant,  after  speaking  of  the  silting  up  of  some  ancient  ports  in  that 
estuary,  observes,  "  But,  in  return,  the  sea  has  made  most  ample  repri- 
sals ;  the  site,  and  even  the  very  names  of  several  places,  once  towns 
of  note  upon  the  Humber,  are  now  only  recorded  in  history ;  and 
Ravensper  was  at  one  time  a  rival  to  Hull  (Madox,  Ant.  Exch.  i.  422), 
and  a  port  so  very  considerable  in  1332,  that  Edward  Baliol  and  the 
confederated  English  barons  sailed  from  hence  to  invade  Scotland ;  and 
Henry  IV.,  in  1399,  made  choice  of  this  port  to  land  at,  to  effect  the 
deposal  of  Richard  II. ;  yet  the  whole  of  this  has  long  since  been  de- 
voured by  the  merciless  ocean ;  extensive  sands,  dry  at  low  water,  are 
to  be  seen  in  their  stead."| 

Pennant  describes  Spurn  Head  as  a  promontory  in  the  form  of  a 
sickle,  and  says  the  land,  for  some  miles  to  the  north,  was  "  perpetually 
preyed  on  by  the  fury  of  the  German  Sea,  which  devours  whole  acres 
at  a  time,  and  exposes  on  the  shores  considerable  quantities  of  beautiful 
amber." 

Lincolnshire. — The  maritime  district  of  Lincolnshire  consists  chiefly 
of  lands  that  lie  below  the  level  of  the  sea,  being  protected  by  embank- 

*  Phillips's  Geology  of  Yorkshire,  p.  61. 

f  Rivers,  Mountains,  and  Sea-coast  of  Yorkshire  p.  122,  1853,  London. 

\.  Arctic  Zoology,  vol.  i.  p.  10,  Introduction. 

§  Phillips's  Geol.  of  York.  p.  60. 

||   Arct.  Zool.  vol.  i.  p.  13,  Introd. 


CH.  XIX.]          THE  EAST  COAST  OF  ENGLAND.  305 

ments.  Some  of  the  fens  were  embanked  and  drained  by  the  Romans  ; 
but  after  their  departure  the  sea  returned,  and  large  tracts  were  covered 
with  beds  of  silt,  containing  marine  shells,  now  again  converted  into 
productive  lands.  Many  dreadful  catastrophes  are  recorded  by  incur- 
sions of  the  sea,  whereby  several  parishes  have  been  at  different  times 
overwhelmed. 

Norfolk. — The  decay  of  the  cliffs  of  Norfolk  and  Suffolk  is  incessant. 
At  Hunstanton,  on  the  north,  the  undermining  of  the  lower  arenaceous 
beds  at  the  foot  of  the  cliff,  causes  masses  of  red  and  white  chalk  to  be 
precipitated  from  above.  Between  Hunstanton  and  Weyboume,  low 
hills,  or  dunes,  of  blown  sand,  are  formed  along  the  shore,  from  fifty  to 
sixty  feet  high.  They  are  composed  of  dry  sand,  bound  in  a  compact 
mass  by  the  long  creeping  roots  of  the  plant  called  Marram  (Arundo 
arenaria).  Such  is  the  present  set  of  the  tides,  that  the  harbors  of 
Clay,  Wells,  and  other  places  are  securely  defended  by  these  barriers  ; 
affording  a  clear  proof  that  it  is  not  the  strength  of  the  material  at  par- 
ticular points  that  determines  whether  the  sea  shall  be  progressive  or 
stationary,  but  the  general  contour  of  the  coast. 

The  waves  constantly  undermine  the  low  chalk  cliffs,  covered  with 
sand  and  clay,  between  Weybourne  and  Sherringham,  a  certain  portion 
of  them  being  annually  removed.  At  the  latter  town  I  ascertained,  in 
1829,  some  facts  which  throw  light  on  the  rate  at  which  the  sea  gains 
upon  the  land.  It  was  computed,  when  the  present  inn  was  built,  in 
1805,  that  it  would  require  seventy  years  for  the  sea  to  reach  the  spot : 
the  mean  loss  of  land  being  calculated,  from  previous  observations,  to 
be  somewhat  less  than  one  yard,  annually.  The  distance  between  the 
house  and  the  sea  was  fifty  yards ;  but  no  allowance  was  made  for  the 
slope  of  the  ground  being  from  the  sea,  in  consequence  of  which  the 
waste  was  naturally  accelerated  every  year,  as  the  cliff  grew  lower, 
there  being  at  each  succeeding  period  less  matter  to  remove  when  por- 
tions of  equal  area  fell 'down.  Between  the  years  1824  and  1829,  no 
less  than  seventeen  yards  were  swept  away,  and  only  a  small  garden 
was  then  left  between  the  building  and  the  sea.  There  was,  in  1829, 
a  depth  of  twenty  feet  (sufficient  to  float  a  frigate)  at  one  point  in  the 
harbor  of  that  port,  where,  only  forty-eight  years  before,  there  stood  a 
cliff  fifty  feet  high,  with  houses  upon  it !  If  once  in  half  a  century  an 
equal  amount  of  change  were  produced  suddenly  by  the  momentary 
shock  of  an  earthquake,  history  would  be  filled  with  records  of  such  won- 
derful revolutions  of  the  earth's  surface  ;  but,  if  the  conversion  of  high 
land  into  deep  sea  be  gradual,  it  excites  only  local  attention.  The  flag- 
staff of  the  Preventive  Service  station,  on  the  south  side  of  this  harbor, 
was  thrice  removed  inland  between  the  years  1814  and  1829,  in  conse- 
quence of  the  advance  of  the  sea. 

Farther  to  the  south  we  find  cliffs,  composed,  like  those  of  Holder- 
ness  before  mentioned,  of  alternating  strata  of  blue  clay,  gravel,  loam, 
and  fine  sand.  Although  they  sometimes  exceed  300  feet  in  height,  the 
havoc  made  on  the  coast  is  most  formidable.  The  whole  site  of  ancient 

20 


306 


ENCROACHMENTS    OF   THE   SEA. 


[OH.  XIX. 


Cromer  now  forms  part  of  the  German  Ocean,  the  inhabitants  having 
gradually  retreated  inland  to  their  present  situation,  from  whence  the 
sea  still  threatens  to  dislodge  them.  In  the  winter  of  1825,  a  fallen 
mass  was  precipitated  from  near  the  lighthouse,  which  covered  twelve 
acres,  extending  far  into  the  sea,  the  cliffs  being  250  feet  in  height.* 
The  undermining  by  springs  has  sometimes  caused  large  portions  of  the 
upper  part  of  the  cliffs,  with  houses  still  standing  upon  them,  to  give 
way,  so  that  it  is  impossible,  by  erecting  breakwaters  at  the  base  of  the 
cliffs,  permanently  to  ward  off  the  danger. 

On  the  same  coast,  says  Mr.  R.  C.  Taylor,  the  ancient  villages  of 
Shipden,  Wimpwell,  and  Eccles  have  disappeared ;  several  manors  and 
large  portions  of  neighboring  parishes  having,  piece  after  piece,  been 
swallowed  up ;  nor  has  there  been  any  intermission,  from  time  imme- 
morial, in  the  ravages  of  the  sea  along  a  line  of  coast  twenty  miles  in 
length,  in  which  these  places  stood.f  Of  Eccles,  however,  a  monu- 
ment still  remains  in  the  ruined  tower  of  the  old  church,  which  is  half 
buried  in  the  dunes  of  sand  within  a  few  paces  (60  ?)  of  the  sea-beach 
(fig.  31).  So  early  as  1605  the  inhabitants  petitioned  James  I.  for  a 

Fig.  31. 


Tower  of  the  buried  Church  of  Eccles,  Norfolk,  A.  D.  1839. 

The  inland  slope  of  the  hills  of  blown  sand  is  shown  in  this  view,  with  the  lighthouse  of 
Hasborough  in  the  distance. 

reduction  of  taxes,  as  300  acres  of  land,  and  all  their  houses,  save  four- 
teen, had  then  been  destroyed  by  the  sea.  Not  one  half  that  number 
of  acres  now  remains  in  the  parish,  and  hills  of  blown  sand  now  occupy 
the  site  of  the  houses  which  were  still  extant  in  1605.  When  I  visited 
the  spot  in  1839,  the  sea  was  fast  encroaching  on  the  sand-hills,  and 
had  laid  open  on  the  beach  the  foundations  of  a  house  fourteen  yards 
square,  the  upper  part  of  which  had  evidently  been  pulled  down  before 
it  had  been  buried  under  sand.  The  body  of  the  church  has  also  been 
long  buried,  but  the  tower  still  remains  visible. 


*  Taylor's  Geology  of  East  Norfolk,  p.  32. 


f  Ibid. 


CH.  XIX.]  SILTING    UP    OF   ESTUARIES.  307 

M.  E.  de  Beaumont  has  suggested  that  sand-dunes  in  Holland  and 
other  countries  may  serve  as  natural  chronometers,  by  which  the  date 
of  the  existing  continents  may  be  ascertained.  The  sands,  he  says,  are 
continually  blown  inland  by  the  force  of  the  winds,  and  by  observing 
the  rate  of  their  march  we  may  calculate  the  period  when  the  move- 
ment commenced.*  But  the  example  just  given  will  satisfy  every  ge- 
ologist that  we  cannot  ascertain  the  starting-point  of  dunes,  all  coasts 
being  liable  to  waste,  and  the  shores  of  the  Low  Countries  in  particular, 
being  not  only  exposed  to  inroads  of  the  sea,  but,  as  M.  de  Beaumont 
himself  has  well  shown,  having  even  in  historical  times  undergone  a 
change  of  level.  The  dunes  may  indeed,  in  some  cases,  be  made  use 
of  as  chronometers,  to  enable  us  to  assign  a  minimum  of  antiquity  to 
existing  coast-lines  ;  but  this  test  must  be  applied  with  great  caution,  so 
variable  is  the  rate  at  which  the  sands  may  advance  into  the  interior. 

Hills  of  blown  sand,  between  Eccles  and  Winterton,  have  barred  up 
and  excluded  the  tide  for  many  hundred  years  from  the  mouths  of 
several  small  estuaries  ;  but  there  are  records  of  nine  breaches,  from  20 
to  120  yards  wide,  having  been  made  through  these,  by  which  immense 
damage  was  done  to  the  low  grounds  in  the  interior.  A  few  miles 
south  of  Happisburgh,  also,  are  hills  of  blown  sand,  which  extend  to 
Yarmouth.  These  dunes  afford  a  temporary  protection  to  the  coast, 
and  an  inland  cliff  about  a  mile  long,  at  Winterton,  shows  clearly  that 
at  that  point  the  sea  must  have  penetrated  formerly  farther  than  at 
present. 

Silting  up  of  estuaries. — At  Yarmouth,  the  sea  has  not  advanced 
upon  the  sands  in  the  slightest  degree  since  the  reign  of  Elizabeth.  In 
the  time  of.  the  Saxons,  a  great  estuary  extended  as  far  as  Norwich, 
which  city  is  represented,  even  in  the  thirteenth  and  fourteenth  centu- . 
ries,  as  "  situated  on  the  banks  of  an  arm  of  the  sea."  The  sands 
whereon  Yarmouth  is  built,  first  became  firm  and  habitable  ground 
about  the  year  1008,  from  which  time  a  line  of  dunes  has  gradually  in- 
creased in  height  and  breadth,  stretching  across  the  whole  entrance  of 
the  ancient  estuary,  and  obstructing  the  ingress  of  the  tides  so  com- 
pletely, that  they  are  only  admitted  by  the  narrow  passage  which  the 
river  keeps  open,  and  which  has  gradually  shifted  several  miles  to  the 
south.  The  ordinary  tides  at  the  river's  mouth  rise,  at  present,  only  to 
the  height  of  three  or  four  feet,  the  spring  tides  to  about  eight  or  nine. 

By  the  exclusion  of  the  sea,  thousands  of  acres  in  the  interior  have 
become  cultivated  lands  ;  and,  exclusive  of  smaller  pools,  upwards  of 
sixty  freshwater  lakes  have  been  formed,  varying  in  depth  from  fifteen 
to  thirty  feet,  and  in  extent  from  one  acre  to  twelve  hundred. f  The 
Yare,  and  other  rivers,  frequently  communicate  with  these  sheets  of 
water ;  and  thus  they  are  liable  to  be  filled  up  gradually  with  lacus- 
trine and  fluviatile  deposits,  and  to  be  converted  into  land  covered  with 

*  De  Beaumont,  Geologic  Pratique,  p.  218. 
f  Taylor's  Geology  of  East  Norfolk,  p.  10. 


308  ENCROACHMENTS   OF  THE  SEA  [Ca  XIX. 

forests.  Yet  it  must  not  be  imagined,  that  the  acquisition  of  new  land 
fit  for  cultivation  in  Norfolk  and  Suffolk  indicates  any  permanent  growth 
of  the  eastern  limits  of  our  island  to  compensate  its  reiterated  losses. 
No  delta  can  form  on  such  a  shore. 

Immediately  off  Yarmouth,  and  parallel  to  the  shore,  is  a  great  range 
of  sand-banks,  the  shape  of  which  varies  slowly  from  year  to  year,  and 
often  suddenly  after  great  storms.  Captain  Hewitt,  R.  N.,  found  in 
these  banks,  in  1836,  a  broad  channel  sixty-five  feet  deep,  where  there 
was  only  a  depth  of  four  feet  during  a  prior  survey  in  1822.  The  sea 
had  excavated  to  the  depth  of  sixty  feet  in  the  course  of  fourteen  years, 
or  perhaps  a  shorter  period.  The  new  channel  thus  formed  serves  at 
present  (1838),  for  the  entrance  of  ships  into  Yarmouth  Roads  ;  and 
the  magnitude  of  this  change  shows  how  easily  a  new  set  of  the  waves 
and  currents  might  endanger  the  submergence  of  the  land  gained  within 
the  ancient  estuary  of  the  Yare. 

That  great  banks  should  be  thrown  across  the  mouths  of  estuaries  on 
our  eastern  coast,  where  there  is  not  a  large  body  of  river- water  to 
maintain  an  open  channel,  is  perfectly  intelligible,  when  we  bear  in  mind 
that  the  marine  current,  sweeping  along  the  coast,  is  charged  with  the 
materials  of  wasting  cliffs,  and  ready  to  form  a  bar  anywhere  the  instant 
its  course  is  interrupted  or  checked  by  any  opposing  stream.  The  mouth 
of  the  Yare  has  been,  within  the  last  five  centuries,  diverted  about  four 
miles  to  the  south.  In  like  manner  it  is  evident  that,  at  some  remote 
period,  the  river  Aide  entered  the  sea  at  Aldborough,  until  its  ancient 
outlet  was  barred  up  and  at  length  transferred  to  a  point  no  less  than 
ten  miles  distant  to  the  southwest.  In  this  case,  ridges  of  sand  and 
shingle,  like  those  of  Lowestoff  Ness,  which  will  be  described  by  and 
by,  have  been  thrown  up  between  the  river  and  the  sea ;  and  an  an- 
cient sea-cliff  is  to  be  seen  now  inland. 

It  may  be  asked  why  the  rivers  on  our  east  coast  are  always  deflected 
southwards,  although  the  tidal  current  flows  alternately  from  the  south 
and  north  ?  The  cause  is  to  be  found  in  the  superior  force  of  what  is 
commonly  called  "  the  flood  tide  from  the  north,"  a  tidal  wave  derived 
from  the  Atlantic,  a  small  part  of  which  passes  eastward  up  the  English 
Channel,  and  through  the  Straits  of  Dover  and  then  northwards,  while 
the  principal  body  of  water,  moving  much  more  rapidly  in  a  more  open 
sea,  on  the  western  side  of  Britain,  first  passes  the  Orkneys,  and  then 
turning,  flows  down  between  Norway  and  Scotland,  and  sweeps  with 
great  velocity  along  our  eastern  coast.  It  is  well  known  that  the  high- 
est tides  on  this  coast  are  occasioned  by  a  powerful  northwest  wind, 
which  raises  the  eastern  part  of  the  Atlantic,  and  causes  it  to  pour  a 
greater  volume  of  water  into  the  German  Ocean.  This  circumstance  of 
a  violent  off-shore  wind  being  attended  with  a  rise  of  the  waters,  instead 
of  a  general  retreat  of  the  sea,  naturally  excites  the  wonder  of  the  in- 
habitants of  our  coast.  In  many  districts  they  look  with  confidence  for 
a  rich  harvest  of  that  valuable  manure,  the  sea-weed,  when  the  north- 
westerly gales  prevail,  and  are  rarely  disappointed. 


OH.  XIX.1 


ON  THE  SUFFOLK  COAST. 


309 


Coast  of  Suffolk. — The  cliffs  of  Suffolk,  to  which  we  next  proceed, 
are  somewhat  less  elevated  than  those  of  Norfolk,  but  composed  of 
similar  alternations  of  clay,  sand,  and  gravel.  From  Gorleston  in  Suf- 
folk, to  within  a  few  miles  north  of  Lowestoff,  the  cliffs  are  slowly 
undermined.  Near  the  last-mentioned  town,  there  is  an  inland  cliff 
about  sixty  feet  high,  the  sloping  talus  of  which  is  covered  with  turf 
and  heath.  Between  the  cliff  and  the  sea  is  a  low  flat  tract  of  sand 
called  the  Ness,  nearly  three  miles  long,  and  for  the  most  part  out  of 
reach  of  the  highest  tides.  The  point  of  the  Ness  projects  from  the 

Fig.  32. 


Map  of  Lowestoff  Ness,  Suffolk.* 

a,  a.  The  dotted  lines  express  a,  series  of  sand  and  shingle,  forming  the  extremity  of  the  trian- 
gular space  called  the  Ness. 

&,  6,  b.  The  dark  line  represents  the  inland  cliff  on.  which  the  town  of  Lowestoff  stands,  be- 
tween which  and  the  sea  is  the  Ness. 

base  of  the  original  cliff  to  the  distance  of  660  yards.  This  accession 
of  land,  says  Mr.  Taylor,  has  been  effected  at  distinct  and  distant  inter- 
vals, by  the  influence  of  currents  running  between  the  land  and  a  shoal 
about  a  mile  off  Lowestoff,  called  the  Holm  Sand.  The  lines  of  growth 
in  the  Ness  are  indicated  by  a  series  of  concentric  ridges  or  embank- 
ments inclosing  limited  areas,  and  several  of  these  ridges  have  been 
formed  within  the  observation  of  persons  now  living.  A  rampart  of 
heavy  materials  is  first  thrown  up  to  an  unusual  altitude  by  some 
extraordinary  tide,  attended  with  a  violent  gale.  Subsequent  tides 
extend  the  base  of  this  high  bank  of  shingle,  and  the  interstices  are 
then  filled  with  sand  blown  from  the  beach.  The  Arundo  and  other 
marine  plants  by  degrees  obtain  a  footing ;  and  creeping  along  the 
ridge,  give  solidity  to  the  mass,  and  form  in  some  cases  a  matted  cov- 
ering of  turf.  Meanwhile  another  mound  is  forming  externally,  which 
by  the  like  process  rises  and  gives  protection  to  the  first.  If  the  sea 
forces  its  way  through  one  of  the  external  and  incomplete  mounds,  the 
breach  is  soon  repaired.  After  a  while  the  marine  plants  within  the 
areas  inclosed  by  these  embankments  are  succeeded  by  a  better  species 
of  herbage  affording  good  pasturage,  and  the  sands  become  sufficiently 
firm  to  support  buildings. 

Destruction  of  Dunwich  by  the  sea. — Of  the  gradual  destruction  of 
Dunwich,  once  the  most  considerable  seaport  on  this  coast,  we  have 
many  authentic  records.  Gardner,  in  his  history  of  that  borough,  pub- 

*  From  Mr.  R.  C.  Taylor's  Mem.,  see  Phil.  Mag.,  Oct.  1827,  p.  297. 


310  ENCROACHMENTS    OF   THE   SEA   ON  [Cn.  XIX. 

lished  in  1754,  shows,  by  reference  to  documents,  beginning  with 
Doomsday  Book,  that  the  cliffs  at  Dunwich,  South  wold,  Eastern,  and 
Pakefield,  have  been  always  subject  to  wear  away.  At  Dunwich,  in 
particular,  two  tracts  of  land  which  had  been  taxed  in  the  eleventh  cen- 
tury, in  the  time  of  King  Edward  the  Confessor,  are  mentioned  in  the 
Conqueror's  survey,  made  but  a  few  years  afterwards,  as  having  been 
devoured  by  the  sea.  The  losses,  at  a  subsequent  period,  of  a  monas- 
tery,— at  another  of  several  churches, — afterwards  of  the  old  port, — 
then  of  four  hundred  houses  at  once, — of  the  church  of  St.  Leonard, 
the  high-road,  town-hall,  jail,  and  many  other  buildings,  are  men- 
tioned, with  the  dates  when  they  perished.  It  is  stated  that,  in  the 
sixteenth  century,  not  one-quarter  of  the  town  was  left  standing  ;  yet 
the  inhabitants  retreating  inland,  the  name  was  preserved,  as  has  been 
the  case  with  many  other  ports  when  their  ancient  site  has  been  blot- 
ted out.  There  is,  however,  a  church  of  considerable  antiquity  still 
standing,  the  last  of  twelve  mentioned  in  some  records.  In  1740,  the 
laying  open  of  the  churchyard  of  St.  Nicholas  and  St.  Francis,  in  the 
sea-cliffs,  is  well  described  by  Gardner,  with  the  coffins  and  skeletons 
exposed  to  view — some  lying  on  the  beach,  and  rocked 

"  In  cradle  of  the  rude  imperious  surge.'1 

Of  these  cemeteries  no  remains  can  now  be  seen.  Ray  also  saj^s,  "  that 
ancient  writings  make  mention  of  a  wood  a  mile  and  a  half  to  the  east 
of  Dunwich,  the  site  of  which  must  at  present  be  so  far  within  the 
sea."  *  This  city,  once  so  flourishing  and  populous,  is  now  a  small 
village,  with  about  twenty  houses,  and  one  hundred  inhabitants. 

There  is  an  old  tradition,  "  that  the  tailors  sat  in  their  shops  at 
Dunwich,  and  saw  the  ships  in  Yarmouth  Bay  ;"  but  when  we  con- 
sider how  far  the  coast  at  Lowestoff  Ness  projects  between  these  places, 
we  cannot  give  credit  to  the  tale,  which,  nevertheless,  proves  how  much 
the  inroads  of  the  sea  in  times  of  old  had  prompted  men  of  lively  ima- 
gination to  indulge  their  taste  for  the  marvellous. 

Gardner's  description  of  the  cemeteries  laid  open  by  the  waves  re- 
minds us  of  the  scene  which  has  been  so  well  depicted  by  Be  wick,  f 
and  of  which  numerous  points  on  the  same  coast  might  have  suggested 
the  idea.  On  the  verge  of  a  cliff,  which  the  sea  has  undermined,  are 
represented  the  unshaken  tower  and  western  end  of  an  abbey.  The 
eastern  aisle  is  gone,  and  the  pillars  of  the  cloister  are  soon  to  follow. 
The  waves  have  almost  isolated  the  promontory,  and  invaded  the  cem- 
etery, where  they  have  made  sport  with  the  mortal  relics,  and  thrown 
up  a  skull  upon  the  beach.  In  the  foreground  is  seen  a  broken  tomb- 
stone, erected,  as  its  legend  tells,  "  to  perpetuate  the  memory" — of 
one  whose  name  is  obliterated,  as  is  that  of  the  county  for  which  he 
was  "  Gustos  Rotulorum."  A  cormorant  is  perched  on  the  monument, 

*  Consequences  of  the  Deluge,  Phys.  Theol.  Discourses 
f  History  of  British  Birds,  vol.  ii.  p.  220  ed.  1821. 


Ctt  XIX.]  THE    EAST    COAST    OF    ENGLAND.  311 

defiling  it,  us  if  to  remind  some  moralizcr  like  Hamlet,  of  "  the  base 
uses"  to  which  things  sacred  may  be  turned.  Had  this  excellent  artist 
desired  to  satirize  certain  popular  theories  of  geology,  he  might  have 
inscribed  the  stone  to  the  memory  of  some  philosopher  who  taught 
"  the  permanency  of  existing  continents" — "  the  era  of  repose" — "  the 
impotence  of  modern  causes." 

The  incursions  of  the  sea  at  Aldborough,  were  formerly  very  destruc- 
tive, and  this  borough  is  known  to  have  been  once  situated  a  quarter  of 
a  mile  east  of  the  present  shore.  The  inhabitants  continued  to  build 
farther  inland,  till  they  arrived  at  the  extremity  of  their  property,  and 
then  the  town  decayed  greatly ;  but  two  sand-banks,  thrown  up  at  a 
short  distance,  now  afford  a  temporary  safeguard  to  the  coast.  Between 
these  banks  and  the  present  shore,  where  the  current  now  flows,  the 
sea  is  twenty-four  feet  deep  on  the  spot  where  the  town  formerly  stood. 

Essex. — Harwich  is  said  to  have  owed  its  rise  to  the  destruction  of 
Orwell,  a  town  which  stood  on  the  spot  now  called  "  the  west  rocks," 
and  was  overwhelmed  by  an  inroad  of  the  sea  since  the  Conquest.  Ap- 
prehensions have  been  entertained  that  the  isthmus  on  which  Harwich 
stands  may  at  no  remote  period  become  an  island,  for  the  sea  may  be 
expected  to  make  a  breach  near  Lower  Dover  Court,  where  Beacon 
Cliff  is  composed  of  horizontal  beds  of  London  clay  containing  septaria. 
It  had  wasted  away  considerably  between  the  years  1829  and  1838,  at 
both  which  periods  I  examined  this  coast.  In  that  short  interval  seve- 
ral gardens  and  many  houses  had  been  swept  into  the  sea,  and  in  April, 
1838,  a  whole  street  was  threatened  with  destruction.  The  advance  of 
the  sea  is  much  accelerated  by  the  traffic  carried  on  in  septaria,  which 
are  shipped  off  for  cement  as  fast  as  they  fall  down  upon  the  beach. 
These  stones,  if  allowed  to  remain  in  heaps  on  the  shore,  would  break 
the  force  of  the  waves  and  retard  the  conversion  of  the  peninsula  into  an 
island,  an  event  which  might  be  followed  by  the  destruction  of  the  town 
of  Harwich.  Captain  Washington,  R.  N.,  ascertained  in  1847,  that 
Beacon  Cliff,  above  mentioned,  which  is  about  fifty  feet  high,  had  given 
way  at  the  rate  of  forty  feet  in  forty-seven  years,  between  1709  and 
1756;  eighty  feet  between  1756  and  1804;  and  three  hundred  and 
fifty  feet  between  the  latter  period  and  1841 ;  showing  a  rapidly  accel- 
erated rate  of  destruction.* 

Among  other  losses  it  is  recorded  that,  since  the  year  1807,  a  field 
called  the  Vicar's  Field,  which  belonged  to  the  living  of  Harwich,  has 
been  overwhelmed;!  an(^  m  tne  year  1820  there  was  a  considerable 
space  between  the  battery  at  Harwich,  built  in  the  beginning  of  the 
present  century,  and  the  sea;  part  of  the  fortification  had  been  swept 
away  in  1829,  and  the  rest  then  overhung  the  water. 

At  Walton  Naze,  in  the  same  county,  the  cliffs,  composed  of  London 
clay,  capped  by  the  shelly  sands  of  the  crag,  reach  the  height  of  about 

*  Tidal  Harbor  Commissioners'  First  Report,  1845,  p.  176. 
f  Ou  authority  of  Dr.  Mitchell,  F.  G.  S. 


312 


ENCROACHMENTS   OF   THE   SEA. 


CH.  XIX. 


100  feet,  and  are  annually  undermined  by  the  waves.  The  old  church- 
yard of  Walton  has  been  washed  away,  and  the  cliffs  to  the  south  are 
constantly  disappearing. 

Kent. — Isle  of  Sheppey. — On  the  coast  bounding  the  estuary  of  the 
Thames,  there  are  numerous  examples  both  of  the  gain  and  loss  of  land. 
The  Isle  of  Sheppey,  which  is  now  about  six  miles  long  by  four  in 
breadth,  is  composed  of  London  clay.  The  cliffs  on  the  north,  which 
are  from  sixty  to  eighty  feet  high,  decay  rapidly,  fifty  acres  having  been 
lost  in  twenty  years,  between  1810  and  1830.  The  church  at  Minster, 
now  near  the  coast,  is  said  to  have  been  in  the  middle  of  the  island  in 
1780  ;  and  if  the  present  rate  of  destruction  should  continue,  we  might 
calculate  the  period,  and  that  not  a  very  remote  one,  when  the  whole 
island  will  be  annihilated.  On  the  coast  of  the  mainland,  to  the  east  ot 
Sheppey,  is  Herne  Bay :  a  place  still  retaining  the  name  of  a  bay,  al- 
though it  is  no  longer  appropriate,  as  the  waves  and  currents  have 
swept  away  the  ancient  headlands.  There  was  formerly  a  small  prom- 
ontory in  the  line  of  the  shoals  where  the  present  pier  is  built,  by  which 
the  larger  bay  was  divided  into  two,  called  the  Upper  and  Lower.* 

Fig.  33. 


View  of  Eeculver  Church,  taken  in  the  year  1781. 

1.  Isle  of  Sheppey.    2.  Ancient  chapel  now  destroyed.    The  cottage  between  this  chapel  and  the 
cliff  was  demolished  by  the  sea,  in  1782. 

Still  farther  east  stands  the  church  of  Reculver,  upon  a  cliff  composed 
of  clay  and  sand,  about  twenty-five  feet  high.  Reculver  (Regulvium) 
was  an  important  military  station  in  the  time  of  the  Romans,  and  ap- 
pears, from  Leland's  account,  to  have  been,  so  late  as  Henry  VIII. 's 
reign,  nearly  one  mile  distant  from  the  sea.  In  the  "  Gentleman's  Mag- 
azine," there  is  a  view  of  it,  taken  in  1781,  which  still  represents  a  con- 
siderable space  as  intervening  between  the  north  wall  of  the  churchyard 
and  the  cliff,  f  Sometime  before  the  year  1780,  the  waves  had  reached 
the  site  of  the  ancient  Roman  camp  or  fortification,  the  walls  of  which 

*  On  the  authority  of  W.  Gunnell,  Esq.,  and  "W.  Richardson,  Esq.,  F.  G.  S. 
f  Vol.  ii.  New  Ser.  1809,  p.  801. 


CH.  XIX.] 


ISLE    OF   THANET. 


313 


had  continued  for  several  years  after  they  were  undermined  to  overhang 
the  sea,  being  firmly  cemented  into  one  mass.  They  were  eighty  yards 
nearer  the  sea  than  the  church,  and  they  are  spoken  of  in  the  "  Topo- 
graphica  Britannica,"  in  the  year  1780,  as  having  recently  fallen  down. 
In  1804,  part  of  the  churchyard  with  some  adjoining  houses  was  washed 
away,  and  the  ancient  church,  with  its  two  spires,  was  dismantled  and 
abandoned  as  a  place  of  worship,  but  kept  in  repair  as  a  landmark  well 
known  to  mariners.  I  visited  the  spot  in  June,  1851,  and  saw  human 
bones  and  part  of  a  wooden  coffin  projecting  from  the  cliff,  near  the 
top.  The  whole  building  would  probably  have  been  swept  away  long- 
Fig.  M. 


Keculver  Church,  in  1S34. 

ere  this,  had  not  the  force  of  the  waves  been  checked  by  an  artificial 
causeway  of  stones  and  large  wooden  piles  driven  into  the  sands  on  the 
beach  to  break  the  force  of  the  waves. 

Isle  of  Thanet. — The  isle  of  Thanet  was,  in  the  time  of  the  Romans, 
separated  from  the  rest  of  Kent  by  a  navigable  channel,  through  which 
the  Roman  fleets  sailed  on  their  way  to  and  from  London.  Bede  de- 
scribes this  small  estuary  as  being,  in  the  beginning  of  the  eighth 
century,  three  furlongs  in  breadth ;  and  it  is  supposed  that  it  began  to 
grow  shallow  about  the  period  of  the  Norman  conquest.  It  was  so  far 
silted  up  in  the  year  1485,  that  an  act  was  then  obtained  to  build  a 
bridge  across  it ;  and  it  has  since  become  marsh  land  with  small  streams 
running  through  it.  On  the  coast,  Bedlam  Farm,  belonging  to  the 
hospital  of  that  name,  lost  eight  acres  in  the  twenty  years  preceding 


314 


GOODWIN    SANDS. 


[On.  XIX 


1830,  the  land  being  composed  of  chalk  from  forty  to  fifty  feet  above 
the  level  of  the  sea.  It  has  been  computed  that  the  average  waste  of 
the  cliff  between  the  North  Foreland  and  the  Reculvers,  a  distance  of 
about  eleven  miles,  is  not  less  than  two  feet  per  annum.  The  chalk 
cliffs  on  the  south  of  Thanet,  between  Ramsgate  and  Pegwell  Bay,  have 
on  an  average  lost  three  feet  per  annum  for  the  last  ten  years  (preced- 
ing 1830). 

Goodwin  Sands. — The  Goodwin  Sands  lie  opposite  this  part  of  the 
Kentish  coast.  They  are  about  ten  miles  in  length,  and  are  in  some 
parts  three,  and  in  others  seven,  miles  distant  from  the  shore  ;  and,  for 
a  certain  space,  are  laid  bare  at  low  water.  That  they  are  a  remnant  of 
land,  and  not  "  a  mere  accumulation  of  sea  sand,"  as  Rennell  imagined,* 
may  be  presumed  from  the  fact  that,  when  the  erection  of  a  lighthouse 
on  this  shoal  was  in  contemplation  by  the  Trinity  Board  in  the  year 
1817,  it  was  found,  by  borings,  that  the  bank  consisted  of  fifteen  feet 
of  sand,  resting  on  blue  clay  ;  and,  by  subsequent  borings,  the  subjacent 
chalk  has  been  reached.  An  obscure  tradition  has  come  down  to  us, 
that  the  estates  of  Earl  Goodwin,  the  father  of  Harold,  who  died  in  the 
year  1053,  were  situated  here,  and  some  have  conjectured  that  they 
were  overwhelmed  by  the  flood  mentioned  in  the  Saxon  chronicle,  sub 
anno  1099.  The  last  remains  of  an  island,  consisting,  like  Sheppey,  of 
clay,  may  perhaps  have  been  carried  away  about  that  time. 


Fig.  35. 


Shakspeare's  Cliff  in  1836,  seen  from  the  northeast. 

There  are  other  records  of  waste  in  the  county  of  Kent,  as  at  Deal ; 
and  at  Dover,  where  Shakspeare's  Cliff,  composed  entirely  of  chalk,  has 
suffered  greatly,  and  continually  diminishes  in  height,  the  slope  of  the 
hill  being  towards  the  land.  (See  fig.  35.)  There  was  an  immense 
landslip  from  this  cliff  in  1810,  by  which  Dover  was  shaken  as  if  by  an 

*  Geog.  of  Herod,  vol.  ii.  p.  326. 


OH.  XIX."|  FORMATION   OF  THE   STRAITS   OF   DOVER.  315 

earthquake,  and  a  still  greater  one  in  1772.*  We  may  suppose,  there- 
fore, that  the  view  from  the  top  of  the  precipice  in  the  year  1600,  when 
the  tragedy  of  King  Lear  was  written,  was  more  "  fearful  and  dizzy" 
than  it  is  now.  The  best  antiquarian  authorities  are  agreed,  that  Dover 
Harbor  was  formerly  an  estuary,  the  sea  flowing  up  a  valley  between 
the  chalk  hills.  The  remains  found  in  different  excavations  confirm  the 
description  of  the  spot  given  by  Caesar  and  Antoninus,  and  there  is 
clear  historical  evidence  to  prove  that  at  an  early  period  there  was  no 
shingle  at  all  at  Dover.f 

Straits  of  Dover. — In  proceeding  from  the  northern  parts  of  the 
German  Ocean  towards  the  Straits  of  Dover,  the  water  becomes  grad- 
ually more  shallow,  so  that,  in  the  distance  of  about  two  hundred 
leagues,  we  pass  from  a  depth  of  120  to  that  of  58,  38,  18,  and  even 
less  than  2  fathoms.  The  shallowest  part  follows  a  line  drawn  between 
Romney  Marsh  and  Boulogne.  From  this  point  the  English  Channel 
again  deepens  progressively  as  we  proceed  westward,  so  that  the  Straits 
of  Dover  may  be  said  to  part  two  seas.J 

Whether  England  was  formerly  united  with  France  has  often  been 
a  favorite  subject  of  speculation.  So  early  as  1605  our  countryman 
Verstegan,  in  his  "  Antiquities  of  the  English  Nation,"  observed  that 
many  preceding  writers  had  maintained  this  opinion,  but  without  sup- 
porting it  by  any  weighty  reasons.  He  accordingly  endeavors  himself 
to  confirm  it  by  various  arguments,  the  principal  of  which  are,  first,  the 
proximity  and  identity  of  the  composition  of  the  opposite  cliffs  and 
shores  of  Albion  and  Gallia,  which,  whether  flat  and  sandy,  or  steep 
and  chalky,  correspond  exactly  with  each  other  ;  secondly  the  occur- 
rence of  a  submarine  ridge,  called  "  our  Lady's  Sand,"  extending  from 
shore  to  shore  at  no  great  depth,  and  which,  from  its  composition, 
appears  to  be  the  original  basis  of  the  isthmus ;  thirdly,  the  identity  of 
the  noxious  animals  in  France  and  England,  which  could  neither  have 
swum  across,  nor  have  been  introduced  by  man.  Thus  no  one,  he  says, 
would  have  imported  wolves,  therefore  "these  wicked  beasts  did  of 
themselves  pass  over."  He  supposes  the  ancient  isthmus  to  have  been 
about  six  English  miles  in  breadth,  composed  entirely  of  chalk  and  flint, 
and  in  some  places  of  no  great  height  above  the  sea-level.  The  opera- 
tion of  the  waves  and  tides,  he  says,  would  have  been  more  powerful 
when  the  straits  were  narrower,  and  even  now  they  are  destroying  cliffs 
composed  of  similar  materials.  He  suggests  the  possible  co-operation 
of  earthquakes ;  and  when  we  consider  how  many  submarine  forests 
skirt  the  southern  and  eastern  shores  of  England,  and  that  there  are! 
raised  beaches  at  many  points  above  the  sea-level,  containing  fossil 
shells  of  recent  species,  it  seems  reasonable  to  suppose  that  such  up- 

*  Dodsley's  Ann.  Regist.  1772. 

f  See  J.  B.  Redman  on  Changes  of  S.  E.  Coast  of  England,  Proceed.  Instit. 
Civil  Engin.  vol.  ii.  1851,  1852. 

\  Stevenson,  Ed.  Phil.  Journ.  No.  v.  p.  45,  and  Dr.  Fittou,  Geol.  Trans.  2d 
series,  vol.  iv.  plate  9. 


316  ENCROACHMENTS    OF   THE   SEA   ON  [On.  XIX. 

ward  and  downward  movements,  taking  place  perhaps  as  slowly  as  those 
now  in  progress  in  Sweden  and  Greenland,  may  have  greatly  assisted  the 
denuding  force  of  "  the  ocean  stream,"  noraf/,oio  fi^/a  dAevos  '-xsavofo. 

folks  tone. — At  Folkstone,  the  sea  undermines  the  chalk  and  subja- 
cent strata.  About  the  year  1716  there  was  a  remarkable  sinking  of  a 
tract  of  land  near  the  sea,  so  that  houses  became  visible  from  certain 
points  at  sea,  and  from  particular  spots  on  the  sea  cliffs,  from  whence 
they  could  not  be  seen  previously.  In  the  description  of  this  subsi- 
dence in  the  Phil.  Trans.  1716,  it  is  said,  "  that  the  land  consisted  of  a 
solid  stony  mass  (chalk),  resting  on  wet  clay  (gault),  so  that  it  slid 
forwards  towards  the  sea,  just  as  a  ship  is  launched  on  tallowed  planks." 
It  is  also  stated  that,  within  the  memory  of  persons  then  living,  the 
cliff  there  had  been  washed  away  to  the  extent  of  ten  rods. 

Encroachments  of  the  sea  at  Hythe  are  also  on  record  ;  but  between 
this  point  and  Rye  there  has  been  a  gain  of  land  within  the  times  of 
history ;  the  rich  level  tract  called  Romney  Marsh,  or  Dungeness,  about 
ten  miles  in  width  and  five  in  breadth,  and  formed  of  silt,  having  re- 
ceived great  accession.  It  has  been  necessary,  however,  to  protect  it 
from  the  sea,  from  the  earliest  periods,  by  embankments,  the  towns  of 
Lydd  and  Romney  being  the  only  parts  of  the  marsh  above  the  level  of 
the  highest  tides.*  Mr.  Redman  has  cited  numerous  old  charts  and 
trustworthy  authorities  to  prove  that  the  average  annual  increase  of  the 
promontory  of  shingle  called  Dungeness  amounted  for  two  centuries, 
previous  to  1844,  to  nearly  six  yards.  Its  progress,  however,  has 
fluctuated  during  that  period;  for  between  1689  and  1794,  a  term  of 
105  years,  the  rate  was  as  much  as  8j  yards  per  annum. f  It  is  ascer- 
tained that  the  shingle  is  derived  from  the  westward.  Whether  the 
pebbles  are  stopped  by  the  meeting  of  the  tide  from  the  north  flowing 
through  the  Straits  of  Dover,  with  that  which  comes  up  the  Channel 
from  the  west,  as  was  formerly  held,  or  by  the  check  given  to  the  tidal 
current  by  the  waters  of  the  Rother,  as  some  maintain,  is  still  a  disputed 
question. 

Rye,  situated  to  the  south  of  Romney  Marsh,  was  once  destroyed  by 
the  sea,  but  it  is  now  two  miles  distant  from  it.  The  neighboring  town 
of  Winchelsea  was  destroyed  in  the  reign  of  Edward  L,  the  mouth  of 
the  Rother  stopped  up,  and  the  river  diverted  into  another  channel. 
In  its  old  bed,  an  ancient  vessel,  apparently  a  Dutch  merchantman, 
was  found  about  the  year  1824.  It  was  built  entirely  of  oak,  and  much 
blackened.^  Large  quantities  of  hazel-nuts,  peat,  and  wood  are  found 
in  digging  in  Romney  Marsh. 

South  coast  of  IJnff  land. -^Westward  of  Hastings,  or  of  St.  Leonard's, 
the  shore  line  has  been  giving  way  as  far  as  Pevensey  Ba'y,  where  for- 
merly there  existed  a  haven  now  entirely  blocked  up  by  shingle.  The 


*  On  the  authority  of  Mr.  J.  Meryon,  of  Rye. 

f  Redman,  ibid,  see  p.  315. 

\  Edin.  Journ.  of  Sci.  No.  xix.  p.  56. 


CH.  XIX.]         THE  SOUTH  COAST  OF  ENGLAND.  317 

degradation  has  equalled  for  a  series  of  years  seven  feet  per  annum  in 
some  places,  and  several  martello  towers  had  in  consequence,  before 
1851,  been  removed  by  the  Ordnance.*  At  the  promontory  of  Beachy 
Head  a  mass  of  chalk,  three  hundred  feet  in  length,  and  from  seventy 
to  eighty  in  breadth,  fell  in  the  year  1813  with  a  tremendous  crash; 
and  similar  slips  have  since  been  frequent.f 

About  a  mile  to  the  west  of  the  town  of  Newhaven,  the  remains  of  an 
ancient  intrenchment  are  seen  on  the  brow  of  Castle  Hill.  This  earth- 
work, supposed  to  be  Roman,  was  evidently  once  of  considerable  extent 
and  of  an  oval  form,  but  the  greater  part  has  been  cut  away  by  the  sea. 
The  cliffs,  which  are  undermined  here,  are  high  ;  more  than  one  hun- 
dred feet  of  chalk  being  covered  by  tertiary  clay  and  sand,  from  sixty  to 
seventy  feet  in  thickness.  In  a  few  centuries  the  last  vestiges  of  the 
plastic  clay  formation  on  the  southern  borders  of  the  chalk  of  the  South 
Downs  on  this  coast  will  probably  be  annihilated,  and  future  geologists 
will  learn,  from  historical  documents,  the  ancient  geographical  boundaries 
of  this  group  of  strata  in  that  direction.  On  the  opposite  side  of  the 
estuary  of  the  Ouse,  on  the  east  of  Newhaven  harbor,  a  bed  of  shingle, 
composed  of  chalk  flints  derived  from  the.  waste  of  the  adjoining  cliffs, 
had  accumulated  at  Seaford  for  several  centuries.  In  the  great  storm 
of  November,  1824,  this  bank  was  entirely  swept  away,  and  the  town 
of  Seaford  inundated.  Another  great  beach  of  shingle  is  now  forming 
from  fresh  materials. 

The  whole  coast  of  Sussex  has  been  incessantly  encroached  upon  by 
the  sea  from  time  immemorial ;  and,  although  sudden  inundations  only, 
which  overwhelmed  fertile  or  inhabited  tracts,  are  noticed  in  history,  the 
records  attest  an  extraordinary  amount  of  loss.  During  a  period  of  no 
more  than  eighty  years,  there  are  notices  of  about  twenty  inroads,  in 
which  tracts  of  land  of  from  twenty  to  four  hundred  acres  in  extent  were 
overwhelmed  at  once,  the  value  of  the  tithes  being  .mentioned  in  the 
Taxatio  Ecclesiastica.J  In  the  reign  of  Elizabeth,  the  town  of  Brighton 
was  situated  on  that  tract  where  the  chain  pier  now  extends  into  the  sea. 
In  the  year  1665,  twenty-two  tenements  had  been  destroyed  under  the 
cliff.  At  that  period  there  still  remained  under  the  cliff  113  tenements, 
the  whole  of  which  were  overwhelmed  in  1703  and  1705.  No  traces  of 
the  ancient  town  are  now  perceptible,  yet  there  is  evidence  that  the  sea 
has  merely  resumed  its  ancient  position  at  the  base  of  the  cliffs,  the  site 
of  the  whole  town  having  been  merely  a  beach  abandoned  by  the  ocean 
for  ages. 

Hampshire. — Isle  of  Wight. — It  would  be  endless  to  allude  to  all 
the  localities  on  the  Sussex  and  Hampshire  coasts  where  the  land  has 
given  way  ;  but  I  may  point  out  the  relation  which  the  geological  struc- 
ture of  the  Isle  of  Wight  bears  to  its  present  shape,  as  attesting  that  the 

*  Redman  as  cited,  p.  315. 

f  Webster,  Geol.  Trans,  vol.  ii.  p.  192,  1st  series. 

\  Mantell,  Geology  of  Sussex,  p.  293. 


318  ENCROACHMENTS   OF  THE   SEA   ON  [Cn.  XIX. 

coast  owes  its  outline  to  the  continued  action  of  the  sea.  Through  the 
middle  of  the  island  runs  a  high  ridge  of  chalk  strata,  in  a  vertical  posi- 
tion, and  in  a  direction  east  and  west.  This  chalk  forms  the  projecting 
promontory  of  Culver  Cliff  on  the  east,  and  of  the  Needles  on  the  west; 
while  Sandown  Bay  on  the  one  side,  and  Compton  Bay  on  the  other, 
have  been  hollowed  out  of  the  softer  sands  and  argillaceous  strata,  which 
are  inferior,  in  geological  position,  to  the  chalk. 

The  same  phenomena  are  repeated  in  the  Isle  of  Purbeck,  where  the 
line  of  vertical  chalk  forms  the  projecting  promontory  of  Handfast 
Point;  and  Swanagc  Bay  marks  the  deep  excavation  made  by  the  waves 
in  the  softer  strata,  corresponding  to  those  of  Sandown  Bay. 

Hurst  Castle  bank — progressive  motion  of  sea  beaches. — Although  the 
loose  pebbles  and  grains  of  sand  composing  any  given  line  of  sea- beach 
are  carried  sometimes  one  way,  sometimes  another,  they  have,  neverthe- 
less, an  ultimate  motion  in  one  particular  direction.*  Their  progress, 
for  example,  on  the  south  coast  of  England,  is  from  west  to  east,  which 
is  owing  partly  to  the  action  of  the  waves  driven  eastwards  by  the  pre- 
vailing wind,  and  partly  to  the  current,  or  the  motion  of  the  general 
body  of  water  caused  by  the  tides  and  winds.  The  force  of  the  waves 
gives  motion  to  pebbles  which  the  velocity  of  the  currents  alone  would 
be  unable  to  carry  forwards ;  but  as  the  pebbles  are  finally  reduced  tc 
sand  or  mud,  by  continual  attrition,  they  are  brought  within  the  influence 
of  a  current ;  and  this  cause  must  determine  the  course  which  the  main 
body  of  matter  derived  from  wasting  cliffs  will  eventually  take. 

It  appears,  from  the  observations  of  Mr.  Palmer  and  others,  that  if 
a  pier  or  groin  be  erected  anywhere  on  our  southern  or  southeastern 
coast  to  stop  the  progress  of  the  beach,  a  heap  of  shingle  soon  collects 
on  the  western  side  of  such  artificial  barriers.  The  pebbles  continue  to 
accumulate  till  they  rise  as  high  as  the  pier  or  groin,  after  which  they 
pour  over  in  great  numbers  during  heavy  gales.f 

The  western  entrance  of  the  Channel,  called  the  Solent,  is  crossed  for 
more  than  two-thirds  of  its  width  by  the  shingle-bank  of  Hurst  Castle, 
which  is  about  two  miles  long,  seventy  yards  broad,  and  twelve  feet 
high,  presenting  an  inclined  plane  to  the  west.  This  singular  bar  con- 
sists of  a  bed  of  rounded  chalk  flints,  resting  on  a  submarine  argillaceous 
base.  The  flints  and  a  few  other  pebbles,  intermixed,  are  derived  from 
the  waste  of  Hordwell,  and  other  cliffs  to  the  westward,  where  tertiary 
strata,  capped  with  a  covering  of  broken  chalk  flints,  from  five  to  fifty 
feet  thick,  are  rapidly  undermined.  In  the  great  storm  of  November, 
1824,  this  bank  of  shingle  was  moved  bodily  forwards  for  forty  yards 
towards  the  northeast ;  and  certain  piles,  which  served  to  mark  the 
boundaries  of  two  manors,  were  found  after  the  storm  on  the  opposite 
side  of  the  bar.  At  the  same  time  many  acres  of  pasture  land  were 

*  Sec  Palmer  on  Shingle  Beaches,  Phil.  Trans.  1834,  p.  568. 

Groins  are  formed  of  piles  and  wooden  planks,  or  of  fagots  staked  down 
are  used  either  to  break  the  force  of  the  waves,  or  to  retain  the  beach. 


CH.  XIX.]         THE  SOUTH  COAST  OF  ENGLAND.  319 

covered  by  shingle,  on  the  farm  of  Westover,  near  Lymington.  But  the 
bar  was  soon  restored  in  its  old  position  by  pebbles  drifted  from  the 
west ;  and  it  appears  from  ancient  maps  that  it  has  preserved  the  same 
general  outline  and  position  for  centuries.* 

Mr.  Austen  remarks  that,  as  a  general  rule,  it  is  only  when  high 
tides  concur  with  a  gale  of  wind,  that  the  sea  reaches  the  base  of  cliffs 
so  as  to  undermine  them  and  throw  down  earth  and  stone.  But  the 
waves  are  perpetually  employed  in  abrading  and  fashioning  the  mate- 
rials already  strewed  over  the  beach.  Much  of  the  gravel  and  shingle 
is  always  travelling  up  and  down,  between  high- water  mark  and  a  slight 
depth  below  the  level  of  the  lowest  tides,  and  occasionally  the  materials 
are  swept  away  and  carried  into  deeper  water.  Owing  to  these  move- 
ments every  portion  of  our  southern  coast  may  be  seen  at  one  time  or 
other  in  the  condition  of  bare  rock.  Yet  other  beds  of  sand  and  shingle 
soon  collect,  and,  although  composed  of  new  materials,  invariably  ex- 
hibit on  the  same  spots  precisely  similar  characters.f 

The  cliffs  between  Hurst  Shingle  Bar  and  Christchurch  are  under- 
mined continually,  the  sea  having  often  encroached  for  a  series  of  years 
at  the  rate  of  a  yard  annually.  Within  the  memory  of  persons  now 
living,  it  has  been  necessary  thrice  to  remove  the  coast-road  farther  in- 
land. The  tradition,  therefore,  is  probably  true,  that  the  church  of 
Hordwell  was  once  in  the  middle  of  that  parish,  although  now  (1830) 
very  near  the  sea.  The  promontory  of  Christchurch  Head  gives 
way  slowly.  It  is  the  only  point  between  Lymington  and  Poole  Har- 
bor, in  Dorsetshire,  where  any  hard  stony  masses  occur  in  the  cliffs. 
Five  layers  of  large  ferruginous  concretions,  somewhat  like  the  septaria 
of  the  London  clay,  have  occasioned  a  resistance  at  this  point,  to  which 
we  may  ascribe  this  headland.  In  the  mean  time,  the  waves  have  cut 
deeply  into  the  soft  sands  and  loam  of  Poole  Bay ;  and,  after  severe 
frosts,  great  landslips  take  place,  which  by  degrees  become  enlarged 
into  narrow  ravines,  or  chines,  as  they  are  called,  with  vertical  sides. 
One  of  these  chines,  near  Boscomb,  has  been  deepened  twenty  feet 
within  a  few  years.  At  the  head  of  each  there  is  a  spring,  the  waters 
of  which  have  been  chiefly  instrumental  in  producing  these  narrow  ex- 
cavations, which  are  sometimes  from  100  to  150  feet  deep. 

Isle  of  Portland. — The  peninsulas  of  Purbeck  and  Portland  are  con- 
tinually wasting  away.  In  the  latter,  the  soft  argillaceous  substratum 
(Kimmeridge  clay)  hastens  the  dilapidation  of  the  superincumbent  mass 
of  limestone. 

In  1655  the  cliffs  adjoining  the  principal  quarries  in  Portland  gave 
way  to  the  extent  of  one  hundred  yards,  and  fell  into  the  sea ;  and  in 
December,  1*734,  a  slide  to  the  extent  of  150  yards  occurred  on  the 
east  side  of  the  isle,  by  which  several  skeletons  buried  between  slabs  of 
stone,  were  discovered.  But  a  much  more  memorable  occurrence  of 


*  Redman  as  cited,  p.  315. 

Rob.  A.  ~ 
vol.  vi.  p.  72. 


j.vcumo.11  as    uneu,  p.  oiu. 

f  Rob.  A.  C  Austen  on  the  Valley  of  the  English  Channel,  Quart.  Journ.  Q-.  SL 
•1. 


320  CHESIL    BANK.  [Cn.  XIX 

this  nature,  in  1792,  occasioned  probably  by  the  undermining  of  the  cliffs, 
is  thus  described  in  Hutchin's  History  of  Dorsetshire  : — "  Early  in  the 
morning  the  road  was  observed  to  crack :  this  continued  increasing,  and 
before  two  o'clock  the  ground  had  sunk  several  feet,  and  was  in  one 
continued  motion,  but  attended  with  no  other  noise  than  what  was  occa- 
sioned by  the  separation  of  the  roots  and  brambles,  and  now  and  then  a 
falling  rock.  At  night  it  seemed  to  stop  a  little,  but  soon  moved  again  ; 
and,  before  morning,  the  ground  from  the  top  of  the  cliff  to  the  water- 
side had  sunk  in  some  places  fifty  feet  perpendicular.  The  extent  of 
ground  that  moved  was  about  a  mile  and  a  quarter  from  north  to  south, 
and  600  yards  from  east  to  west." 

Formation  of  the  Chesil  Bank. — Portland  is  connected  with  the  main- 
land by  the  Chesil  Bank,  a  ridge  of  shingle  about  seventeen  miles  in 
length,  and,  in  most  places,  nearly  a  quarter  of  a  mile  in  breadth.  The 
pebbles  forming  this  immense  barrier  are  chiefly  siliceous,  all  loosely 
thrown  together,  and  rising  to  the  height  of  from  twenty  to  thirty  feet 
above  the  ordinary  high- water  mark ;  and  at  the  southeastern  end, 
which  is  nearest  the  Isle  of  Portland,  where  the  pebbles  are  largest, 
forty  feet.  The  fundamental  rocks  whereon  the  shingle  rests  are  found 
at  the  depth  of  a  few  yards  only  below  the  level  of  the  sea.  The  for- 
mation of  that  part  of  the  bar  which  attaches  Portland  to  the  mainland 
may  have  been  due  to  an  original  shoal  or  reef,  or  to  the  set  of  the 
tides  in  the  narrow  channel,  by  which  the  course  of  the  pebbles,  which 
are  always  coming  from  the  west,  has  been  arrested.  It  is  a  singular 
fact  that,  throughout  the  Chesil  Bank,  the  pebbles  increase  gradually  in 
size  as  we  proceed  southeastward,  or  as  we  go  farther  from  the  quarter 
which  supplied  them.  Had  the  case  been  reversed,  we  should  naturally 
have  attributed  the  circumstance  to  the  constant  wearing  down  of  the 
pebbles  by  friction,  as  they  are  rolled  along  a  beach  seventeen  miles  in 
length.  But  the  true  explanation  of  the  phenomenon  is  doubtless  this : 
the  tidal  current  runs  strongest  from  west  to  east,  and  its  power  is 
greater  in  the  more  open  channel  or  farther  from  the  land.  In  other 
words  its  force  increases  southwards,  and  as  the  direction  of  the  bank 
is  from  northwest  to  southeast,  the  size  of  the  masses  coming  from, 
the  westward  and  thrown  ashore  must  always  be  largest  where  the 
motion  of  the  water  is  most  violent.  Colonel  Reid  states  that  all  cal- 
careous stones  rolled  along  from  the  west  are  soon  ground  into  sand, 
and  in  this  form  they  pass  round  Portland  Island.* 

The  storm  of  1824  burst  over  the  Chesil  Bank  with  great  fury,  and 
the  village  of  Chesilton,  built  upon  its  southern  extremity,  was  over- 
whelmed, with  many  of  the  inhabitants.  The  same  storm  carried  away 
part  of  the  Breakwater  at  Plymouth,  and  huge  masses  of  rock,  from 
two  to  five  tons  in  weight,  were  lifted  from  the  bottom  of  the  weather 
side,  and  rolled  fairly  to  the  top  of  the  pile.  One  block  of  limestone, 

*  See  Palmer  on  Motion  of  Shingle  Beaches,  Phil.  Trans.  1834,  p.  668 ;  and 
Col.  Sir  W.  Reid,  Papers  of  Royal  Engineers,  1838,  voL  ii.  p.  128. 


Ca  XIX. 


DORSETS  HIRE. DEVONSHIRE. 


321 


weighing  seven  tons,  was  washed  round  the  western  extremity  of  the 
Breakwater,  and  canned  1 50  feet.*  The  propelling  power  is  derived  in 
these  cases  from  the  breaking  of  the  waves,  which  run  fastest  in  shallow 
water,  and  for  a  short  space  far  exceed  the  most  rapid  currents  in  swift- 
ness. It  was  in  the  same  month,  and  also  during  a  spring-tide,  that  a 
great  flood  is  mentioned  on  the  coasts  of  England,  in  the  year  1099. 
Florence  of  Worcester  says,  "  On  the  third  day  of  the  nones  of  Nov. 
1099,  the  sea  came  out  upon  the  shore  and  buried  towns  and  men  very 
many,  and  oxen  and  sheep  innumerable."  We  also  read  in  the  Saxon 
Chronicle,  for  the  year  1099,  "This  year  eke  on  St.  Martin's  mass  day, 
the  llth  of  Novembre,  sprung  up  so  much  of  the  sea  flood,  and  so 
myckle  harm  did,  as  no  man  minded  that  it  ever  afore  did,  and  there 
was  the  ylk  day  a  new  moon." 

South  of  the  Bill,  or  southern  point  of  Portland,  is  a  remarkable 
shoal  in  the  channel  at  the  depth  of  seven  fathoms,  called  "  the  Sham- 
bles,"*' consisting  entirely  of  rolled  and  broken  shells  of  Purpura  lapillus, 
Mytilus  edulis,  and  other  species  now  living.  This  mass  of  light  mate- 
rials is  always  in  motion,  varying  in  height  from  day  to  day,  and  yet 
the  shoal  remains  constant. 

Dorsetshire. — Devonshire. — At  Lyme  Regis,  in  Dorsetshire,  the 
"  Church  Cliffs,"  as  they  are  called,  consisting  of  lias  about  one  hun- 
dred feet  in  height,  gradually  fell  away  at  the  rate  of  one  yard  a  year, 
from  1800  to  1829.f 

An  extraordinary  landslip  occurred  on  the  24th  of  December,  1839, 
on  the  coast  between  Lyme  Regis  and  Axmouth,  which  has  been  de- 
scribed by  the  Rev.  W.  D.  Conybeare,  to  whose  kindness  I  am  indebted 
for  the  accompanying  section,  fig.  36.  The  tract  of  downs  ranging 

Fig.  36. 


Landslip,  near  Axmouth,  Dec. 


(Eev.  W.  D.  Conybeare.) 


A.  Tract  of  Downs  still  remaining  at  their  original  level. 

B.  New  ravine. 

C,  D.  Sunk  and  fractured  strip  united  to  A,  before  the  convulsion. 

D,  E.  Bendon  undercliff  as  before,  but  more  fissured,  and  thrust  forward  about  fifty  feet,  to* 

wards  the  sea. 

F.  Pyramidal  crag,  sunk  from  seventy  to  twenty  feet  in  height. 

G.  New  reef  upheaved  from  the  sea. 

*  De  la  Beche,  Geolog.  Manual,  p.  82. 
f  According  to  the  measurement  of  Carpenter  of  Lyme* 
21 


322  LANDSLIP   NEAR   AXMOUTH.  [On.  XIX. 

there  along  the  coast  is  capped  by  chalk  (h),  which  rests  on  sandstone, 
alternating  with  chert  (i),  beneath  which  is  more  than  100  feet  of  loose 
sand  (&),  with  concretions  at  the  bottom,  and  belonging  like  i  to  the 
green-sand  formation ;  the  whole  of  the  above  masses,  h,  i,  Tc,  reposing 
on  retentive  beds  of  clay  (I),  belonging  to  the  lias,  which  shelves  to- 
wards the  sea.  Numerous  springs  issuing  from  the  loose  sand  (k),  have 
gradually  removed  portions  of  it,  and  thus  undermined  the  superstra- 
tum, so  as  to  have  caused  subsidences  at  former  times,  and  to  have  pro- 
duced a  line  of  undercliff  between  D  and  E.  In  1839  an  excessively 
wet  season  had  saturated  all  the  rocks  with  moisture,  so  as  to  increase 
the  weight  of  the  incumbent  mass,  from  which  the  support  had  already 
been  withdrawn  by  the  action  of  springs.  Thus  the  superstrata  were 
precipitated  into  hollows  prepared  for  them,  and  the  adjacent  masses  of 
partially  undermined  rock,  to  which  the  movement  was  communicated, 
were  made  to  slide  down  on  a  slippery  basis  of  watery  sand  towards  the 
sea.  These  causes  gave  rise  to  a  convulsion,  which  began  on  the  morn- 
ing of  the  24th  of  December,  with  a  crashing  noise  ;  and,  on  the  eve- 
ning of  the  same  day,  fissures  were  seen  opening  in  the  ground,  and 
the  walls  of  tenements  rending  and  sinking,  until  a  deep  chasm  or 
ravine,  B,  was  formed,  extending  nearly  three-quarters  of  a  mile  in 
length,  with  a  depth  of  from  100  to  150  feet,  and  a  breadth  exceeding 
240  feet.  At  the  bottom  of  this  deep  gulf  lie  fragments  of  the  origi- 
nal surface  thrown  together  in  the  wildest  confusion.  In  consequence 
of  lateral  movements,  the  tract  intervening  between  the  new  fissure  and 
the  sea,  including  the  ancient  undercliff,  was  fractured,  and  the  whole 
line  of  sea-cliff  carried  bodily  forwards  for  many  yards.  "  A  remarka- 
ble pyramidal  crag,  F,  off  Culverhole  Point,  which  lately  formed  a  dis- 
tinguishing landmark,  has  sunk  from  a  height  of  about  seventy  to  twen- 
ty feet,  and  the  main  cliff,  E,  before  more  than  fifty  feet  distant  from 
this  insulated  crag,  is  now  brought  almost  close  to  it.  This  motion  of 
the  sea-cliff  has  produced  a  farther  effect,  which  may  rank  among  the 
most  striking  phenomena  of  this  catastrophe.  The  lateral  pressure  of 
the  descending  rocks  has  urged  the  neighboring  strata,  extending  be- 
neath the  shingle  of  the  shore,  by  their  state  of  unnatural  condensation, 
to  burst  upwards  in  a  line  parallel  to  the  coast — thus  an  elevated 
ridge,  Gr,  more  than  a  mile  in  length,  and  rising  more  than  forty  feet, 
covered  by  a  confused  assemblage  of  broken  strata,  and  immense  blocks 
of  rock,  invested  with  sea- weed  and  corallines,  and  scattered  over  with 
shells  and  star-fish,  and  other  productions  of  the  deep,  forms  an  extend- 
ed reef  in  front  of  the  present  range  of  cliffs."* 

A  full  account  of  this  remarkable  landslip,  with  a  plan,  sections,  and 
many  fine  illustrative  drawings,  was  published  by  Messrs.  Conybeare 
and  Buckland,f  from  one  of  which  the  annexed  cut  has  been  reduced, 
fig.  37. 

*  Rev.  W.  D.  Conybeare,  letter  dated  Axminster,  Dec.  31, 1839. 
f  London,  J.  Murray,  1840. 


CH.  XIX.1 


LOSS   OF   LAND   IN   CORNWALL. 
Fig.  37. 


323 


View  of  the  Axmouth  landslip  from  Great  Bindon,  looking  westward  to  the  Sidmouth  hills, 
and  estuary  of  the  Exe.    From  an  original  drawing  by  Mrs.  Buckland. 

Cornwall. — Near  Penzance,  in  Cornwall,  there  is  a  projecting  tongue 
of  land,  called  the  "  Green,"  formed  of  granitic  sand,  from  which  more 
than  thirty  acres  of  pasture  land  have  been  gradually  swept  away,  in 
the  course  of  the  last  two  or  three  centuries.*  It  is  also  said  that  St. 
Michael's  Mount,  now  an  insular  rock,  was  formerly  situated  in  a  wood, 
several  miles  from  the  sea ;  and  its  old  Cornish  name  (Caraclowse  in 
Cowse)  signifies,  according  to  Carew,  the  Hoar  Rock  in  the  wood.f 
Between  the  .Mount  and  Newlyn  there  is  seen  under  the  sand,  black 
vegetable  mould,  full  of  hazel-nuts,  and  the  branches,  leaves,  roots,  and 
trunks  of  forest-trees,  all  of  indigenous  species.  This  stratum  has  been 
traced  seaward  as  far  as  the  ebb  permits,  and  many  proofs  of  a  sub- 
merged vegetable  accumulation,  with  stumps  of  trees  in  the  position  in 
which  they  grew,  have  been  traced,  says  Sir  Henry  De  la  Beche,  round 
the  shores  of  Devon,  Cornwall,  and  Western  Somerset.  The  facts  not 
only  indicate  a  change  in  the  relative  level  of  the  sea  and  land,  since 
the  species  of  animals  and  plants  were  the  same  as  those  now  living  in 
this  district ;  but,  what  is  very  remarkable,  there  seems  evidence  of  the 
submergence  having  been  effected,  in  part  at  least,  since  the  country 
was  inhabited  by  man.J 

A  submarine  forest  occurring  at  the  mouth  of  the  Parret  in  Somer- 
setshire, on  the  south  side  of  the  Bristol  Channel,  was  described  by 
Mr.  L.  Homer,  in  1815,  and  its  position  attributed  to  subsidence.  A 
bed  of  peat  is  there  seen  below  the  level  of  the  sea,  and  the  trunks  of 

*  Boase,  Trans.  Royal  Geol.  Soc.  of  Cornwall,  voL  ii.  p.  129. 

f  Boase,  ibid.  vol.  ii.  p.  135. 

J  De  la  Beche's  Report  on  the  Geology  of  Devon,  <fec.  chap.  xiii. 


324  LOSS   OF   LAND   ON   COAST   OF  FRANCE.  [Cn.  XIX 

large  trees,  such  as  the  oak  and  yew,  having  their  roots  still  diverging 
as  they  grew,  and  fixed  in  blue  clay.* 

Tradition  of  loss  of  land  in  Cornwall. — The  oldest  historians  men- 
tion a  tradition  in  Cornwall,  of  the  submersion  of  the  Lionnesse,  a  coun- 
try said  to  have  stretched  from  the  Land's  End  to  the  Scilly  Islands. 
The  tract,  if  it  existed,  must  have  been  thirty  miles  in  length,  and  per- 
haps ten  in  breadth.  The  land  now  remaining  on  either  side  is  from 
two  hundred  to  three  hundred  feet  high ;  the  intervening  sea  about 
three  hundred  feet  deep.  Although  there  is  no  authentic  evidence  for 
this  romantic  tale,  it  probably  originated  in  some  former  inroads  of  the 
Atlantic,  accompanying,  perhaps,  a  subsidence  of  land  on  this  coast.f 

West  coast  of  England. — Having  now  brought  together  an  ample 
body  of  proofs  of  the  destructive  operations  of  the  waves,  tides,  and 
currents,  on  our  eastern  and  southern  shores,  it  will  be  unnecessary  to 
enter  into  details  of  changes  on  the  western  coast,  for  they  present 
merely  a  repetition  of  the  same  phenomena,  and  in  general  on  an  infe- 
rior scale.  On  the  borders  of  the  estuary  of  the  Severn  the  flats  of 
Somersetshire  and  Gloucestershire  have  received  enormous  accessions, 
while,  on  the  other  hand,  the  coast  of  Cheshire,  between  the  rivers 
Mersey  and  Dee,  has  lost,  since  the  year  1764,  many  hundred  yards, 
and  some  affirm  more  than  half  a  mile,  by  the  advance  of  the  sea  upon 
the  abrupt  cliffs  of  red  clay  and  marls.  Within  the  period  above  men- 
tioned several  lighthouses  have  been  successively  abandoned. J  There 
are  traditions  in  Pembrokeshire§  and  Cardiganshire]!  of  far  greater  losses 
of  territory  than  that  which  the  Lionnesse  tale  of  Cornwall  pretends  to 
commemorate.  They  are  all  important,  as  demonstrating  that  the 
earliest  inhabitants  were  familiar  with  the  phenomenon  of  incursions  of 
the  sea. 

Loss  of  land  on  the  coast  of  France. — The  French  coast,  particularly 
that  part  of  Brittany,  where  the  tides  rise  to  an  extraordinary  height,  is 
the  constant  prey  of  the  waves.  In  the  ninth  century  many  villages 
and  woods  are  reported  to  have  been  carried  away,  the  coast  undergo- 
ing great  change,  whereby  the  hill  of  St.  Michael  was  detached  from 
the  mainland.  The  parish  of  Bourgneuf,  and  several  others  in  that 
neighborhood,  were  overflowed  in  the  year  1500.  In  1735,  during  a 
great  storm,  the  ruins  of  Palnel  were  seen  uncovered  in  the  sea.^[ 

*  Geol.  Trans.  1st  series,  vol.  iii.  p.  383. 

f  Boase,  vol.  ii.  p.  130. 

1  Stevenson,  Jameson's  Ed.  New  Phil.  Journ.  No.  8,  p.  386. 

§  Camden.who  cites  Gyraldus;  also  Ray,  "On the  Deluge,"  Phys.TheoL  p. 228. 

I  Meyrick's  Cardigan. 

*JT  Von  Hoff,  Geschichte,  <fec.  Vol.  i.  p.  49. 


CHAPTER  XX. 

ACTION    OF    TIDES    AND    CURRENTS Continued. 

Inroads  of  the  sea  at  the  mouths  of  the  Rhine  in  Holland — Changes  in  the  arms 
of  the  Rhine — Proofs  of  subsidence  of  land — Estuary  of  the  Bies  Bosoh,  formed 
in  1421 — Zuyder  Zee,  in  the  13th  century— Islands  destroyed — Delta  of  the 
Ems  converted  into  a  bay — Estuary  of  the  Dollart  formed — Encroachment  ol 
the  sea  on  the  coast  of  Sleswick — On  shores  of  North  America — Tidal  wave, 
called  the  Bore — Influence  of  tides  and  currents  on  the  mean  level  of  seas — 
Action  of  currents  in  inland  lakes  and  seas — Baltic — Cimbrian  deluge — Straits 
of  Gibraltar — No  under-current  there — Whether  salt  is  precipitated  in  the 
Mediterranean — Waste  of  shores  of  Mediterranean. 

Inroads  of  the  sea  at  the  mouths  of  the  Rhine. — THE  line  of  British 
coast  considered  in  the  preceding  chapter  offered  no  example  of  the 
conflict  of  two  great  antagonist  forces  ;  the  influx,  on  the  one  hand,  of 
a  river  draining  a  large  continent,  and,  on  the  other,  the  action  of  the 
waves,  tides,  and  currents  of  the  ocean.  But  when  we  pass  over  by 
the  Straits  of  Dover  to  the  Continent,  and  proceed  northeastwards,  we 
find  an  admirable  illustration  of  such  a  contest,  where  the  ocean  and  the 
Rhine  are  opposed  to  each  other,  each  disputing  the  ground  now  occu- 
pied by  Holland ;  the  one  striving  to  shape  out  an  estuary,  the  other 
to  form  a  delta.  There  was  evidently  a  period  when  the  river  obtained 
the  ascendancy,  when  the  shape  and  perhaps  the  relative  level  of  the 
coast  and  set  of  the  tides  were  very  different ;  but  for  the  last  two 
thousand  years,  during  which  man  has  witnessed  and  actively  partici- 
pated in  the  struggle,  the  result  has  been  in  favor  of  the  ocean  ;  the 
area  of  the  whole  territory  having  become  more  and  more  circumscribed  ; 
natural  and  artificial  barriers  having  given  away,  one  after  another ; 
and  many  hundred  thousand  human  beings  having  perished  in  the 
waves. 

Changes  in  the  arms  of  the  Rhine. — The  Rhine,  after  flowing  from 
the  Grison  Alps,  copiously  charged  with  sediment,  first  purifies  itself  in 
the  Lake  of  Constance,  where  a  large  delta  is  formed  ;  then  swelled  by 
the  Aar  and  numerous  other  tributaries,  it  flows  for  more  than  six  hun- 
dred miles  towards  the  north ;  when,  entering  a  low  tract,  it  divides  into 
two  arms,  about  ten  miles  northeast  of  Cleves, — a  point  which  must 
therefore  be  considered  the  head  of  its  delta.  (See*,  map,  fig.  8.)  In 
speaking  of  the  delta,  I  do  not  mean  to  assume  that  all  that  part  of 
Holland  which  is  comprised  within  the  several  arms  of  the  Rhine  can 
be  called  a  delta  in  the  strictest  sense  of  the  term  ;  because  some  por- 
tion of  the  country  thus  circumscribed,  as,  for  example,  a  part  of  Gel- 
derland  and  Utrecht,  consists  of  strata  which  may  have  been  deposited 
in  the  sea  before  the  Rhine  existed.  These  older  tracts  may  either  have 
been  raised  like  the  Ullah  Bund  in  Cutch,  during  the  period  when  the 


326 


INKOADS    OF   THE    SEA   AT   THE 

Fig.  38. 


[On.  XX. 


Line  of  coast  from  Nieuport 
to  the  mouth  of  the  Elbe, 

in  which 
Changes  have  been  observed 

since  the 
Historical  Period. 


The  dark  tint  between  Antwerp  and  Nieuport,  represents  part  of  the  Netherlands  which  was 
land  in  the  time  of  the  Komans,  then  overflowed  by  the  sea  before  and  during  the  5th  century, 
and  afterwards  reconverted  into  land. 

sediment  of  the  Rhine  was  converting  a  part  of  the  sea  into  land,  or 
they  may  have  constituted  islands  previously. 

When  the  river  divides  north  of  Cleves,  the  left  arm  takes  the  name 
of  the  Waal ;  and  the  right,  retaining  that  of  the  Rhine,  is  connected,  a 
little  farther  to  the  north,  by  an  artificial  canal  with  the  river  Yssel. 
The  Rhine  then  flowing  westward  divides  again  southeast  of  Utrecht, 
and  from  this  point  it  takes  the  name  of  the  Leek,  a  name  which  was 
given  to  distinguish  it  from  the  northern  arm  called  the  old  Rhine, 
which  was  sanded  up  until  the  year  1825,  when  a  channel  was  cut  for 
it,  by  which  it  now  enters  the  sea  at  Catwyck.  It  is  common,  in  all 
great  deltas,  that  the  principal  channels  of  discharge  should  shift  from 
time  to  time,  but  in  Holland  so  many  magnificent  canals  have  been 
constructed,  and  have  so  diverted,  from  time  to  time,  the  course  of  the 
waters,  that  the  geographical  changes  in  this  delta  are  endless,  and 
their  history,  since  the  Roman  era,  forms  a  complicated  topic  of  anti- 
quarian research.  The  present  head  of  the  delta  is  about  forty  geo- 
graphical miles  from  the  nearest  part  of  the  gulf  called  the  Zuyder  Zee, 
and  more  than  twice  that  distance  from  the  general  coast-line.  The 
present  head  of  the  delta  of  the  Nile  is  about  80  or  90  geographical 
miles  from  the  sea ;  that  of  the  Ganges,  as  before  stated,  220  ;  and 
that  of  the  Mississippi  about  180,  reckoning  from  the  point  where  the 
Atchafalaya  branches  off  to  the  extremity  of  the  new  tongue  of  land  in 
the  Gulf  of  Mexico.  But  the  comparative  distance  between  the  heads 


CH.  XX.]  MOUTHS    OF   THE    RHINE.  327 

of  deltas  and  the  sea  affords  no  positive  data  for  estimating  the  relative 
magnitude  of  the  alluvial  tracts  formed  by  their  respective  rivers,  for 
the  ramifications  depend  on  many  varying  and  temporary  circumstan- 
ces, and  the  area  over  which  they  extend  does  not  hold  any  constant 
proportion  to  the  volume  of  water  in  the  river. 

The  Rhine  therefore  has  at  present  three  mouths.  About  two-thirds 
of  its  waters  flow  to  the  sea  by  the  Waal,  and  the  remainder  is  carried 
partly  to  the  Zuyder  Zee  by  the  Yssel,  and  partly  to  the  ocean  by  the 
Leek.  As  the  whole  coast  to  the  south  as  far  as  Ostend,  and  on  the 
north  to  the  entrance  of  the  Baltic,  has,  with  few  exceptions,  from  time 
immemorial,  yielded  to  the  force  of  the  waves,  it  is  evident  that  the 
common  delta  of  the  Rhine,  Meuse,  and  Scheldt,  for  these  three  rivers 
may  all  be  considered  as  discharging  their  waters  into  the  same  part  of 
the  sea,  would,  if  its  advance  had  not  been  checked,  have  become  ex- 
tremely prominent ;  and  even  if  it  had  remained  stationary,  would  long 
ere  this  have  projected  far  beyond  the  rounded  outline  of  the  coast,  like 
that  strip  of  land  already  described  at  the  mouth  of  the  Mississippi. 
But  we  find,  on  the  contrary,  that  the  islands  which  skirt  the  coast 
have  not  only  lessened  in  size,  but  in  number  also,  while  great  bays 
have  been  formed  in  the  interior  by  incursions  of  the  sea. 

In  order  to  explain  the  incessant  advance  of  the  ocean  on  the  shores 
and  inland  country  of  Holland,  M.  E.  de  Beaumont  has  suggested  that 
there  has  in  all  probability  been  a  general  depression  or  sinking  of  the 
land  below  its  former  level  over  a  wide  area.  Such  a  change  of  level 
would  enable  the  sea  to  break  through  the  ancient  line  of  sand-banks 
and  islands  which  protected  the  coast, — would  lead  to  the  enlargement 
of  bays,  the  formation  of  new  estuaries,  and  ultimately  to  the  entire 
submergence  of  land.  These  views  appear  to  be  supported  by  the  fact 
that  several  peat-mosses  of  fresh-water  origin  now  occur  under  the 
level  of  the  sea,  especially  on  the  site  of  the  Zuyder  Zee  and  Lake 
Flevo,  presently  to  be  mentioned.  Several  excavations  also  made  for 
wells  at  Utrecht,  Amsterdam,  and  Rotterdam  have  proved,  that  below 
the  level  of  the  ocean,  the  soil  near  the  coast  consists  of  alternations  of 
sand  with  marine  shells,  and  beds  of  peat  and  clay,  which  have  been 
traced  to  the  depth  of  fifty  feet  and  upwards.* 

I  have  said  that  the  coast  to  the  south  as  far  as  Ostend  has  given 
way.  This  statement  may  at  first  seem  opposed  to  the  fact,  that  the 
tract  between  Antwerp  and  Nieuport,  shaded  black  in  the  annexed  map 
(fig.  38),  although  now  dry  land,  and  supporting  a  large  population, 
has,  within  the  historical  period,  been  covered  with  the  sea.  This 
region,  however,  consisted,  in  the  time  of  the  Romans,  of  woods, 
marshes,  and  peat-mosses,  protected  from  the  ocean  by  a  chain  of 
sandy  dunes,  which  were  afterwards  broken  through  during  storms, 
especially  in  the  fifth  century.  The  waters  of  the  sea  during  these 
irruptions  threw  down  upon  the  barren  peat  a  horizontal  bed  of  fertile 

*  E.  de  Beaumont,  Geologic  Pratique,  vol.  i.  p.  316,  and  ibid.  p.  260. 


328  FORMATION   OF  THE   ZUYDER   ZEE,  [Ca  XX. 

clay,  which  is  in  some  places  three  yards  thick,  full  of  recent  shells  and 
works  of  art.  The  inhabitants,  by  the  aid  of  embankments  and  the 
sand  dunes  of  the  coast,  have  succeeded,  although  not  without  frequent 
disasters,  in  defending  the  soil  thus  raised  by  the  marine  deposit.* 

Inroads  of  the  Sea  in  Holland. — If  we  pass  to  the  northward  of  the 
territory  just  alluded  to,  and  cross  the  Scheldt,  we  find  that  between 
the  fourteenth  and  eighteenth  centuries  parts  of  the  islands  Walcheren 
and  Beveland  were  swept  away,  and  several  populous  districts  of  Kad- 
zand,  losses  which  far  more  than  counterbalance  the  gain  of  land  caused 
by  the  sanding  up  of  some  pre-existing  creeks.  In  1658  the  Island 
Orisant  was  annihilated.  One  of  the  most  memorable  inroads  of  the 
sea  occurred  in  1421,  when  the  tide,  pouring  into  the  mouth  of  the 
united  Meuse  and  Waal,  burst  through  a  dam  in  the  district  between 
Dort  and  Gertrudenberg,  and  overflowed  seventy-two  villages,  forming 
a  large  sheet  of  water  called  the  Bies  Bosch.  (See  map,  fig.  38.) 
Thirty-five  of  the  villages  were  irretrievably  lost,  and  no  vestige,  even 
of  their  ruins,  was  afterwards  seen.  The  rest  were  redeemed,  and  the 
site  of  the  others,  though  still  very  generally  represented  on  maps  as 
an  estuary,  has  in  fact  been  gradually  filled  up  by  alluvial  deposits,  and 
had  become  in  1835,  as  I  was  informed  by  Professor  Moll,  an  immense 
plain,  yielding  abundant  crops  of  hay,  though  still  uninhabited.  To 
the  north  of  the  Meuse  is  a  long  line  of  shore  covered  with  sand  dunes, 
where  great  encroachments  have  taken  place  from  time  to  time,  in  con- 
sequence chiefly  of  the  prevalence  of  southeasterly  winds,  which  blow 
down  the  sands  towards  the  sea.  The  church  of  Scheveningen,  not  far 
from  the  Hague,  was  once  in  the  middle  of  the  village,  and  now  stands 
on  the  shore,  half  the  place  having  been  overwhelmed  by  the  waves  in 
1570.  Catwyck,  once  far  from  the  sea,  is  now  upon  the  shore  ;  two 
of  its  streets  having  been  overflowed,  and  land  torn  away  to  the  extent 
of  200  yards,  in  1719.  It  is  only  by  the  aid  of  embankments  that 
Petten,  and  several  other  places  farther  north,  have  been  defended 
against  the  sea. 

Formation  of  the  Zuyder  Zee  and  Straits  of  Staveren. — Still  more 
important  are  the  changes  which  have  taken  place  on  the  coast  oppo- 
site the  right  arm  of  the  Rhine,  or  the  Yssel,  where  the  ocean  has 
burst  through  a  large  isthmus,  and  entered  the  inland  lake  Flevo, 
which,  in  ancient  times,  was,  according  to  Pomponius  Mela,  formed  by 
the  overflowing  of  the  Rhine  over  certain  lowlands.  It  appears  that, 
in  the  time  of  Tacitus,  there  were  several  lakes  on  the  present  site  of 
the  Zuyder  Zee,  between  Friesland  and  Holland.  The  successive  in- 
roads by  which  these  and  a  great  part  of  the  adjoining  territory,  were 
transformed  into  a  great  gulf,  began  about  the  commencement,  and 
were  completed  towards  the  close,  of  the  thirteenth  century.  Alting 
gives  the  following  relation  of  the  occurrence,  drawn  from  manu- 
script documents  of  contemporary  inhabitants  of  the  neighboring  prov- 

*  Belpaire,  Mem.  de  1'Acacl.  Roy.  de  Bruxelles,  torn.  x.  1837.  Dumont,  Bulletin 
of  the  same  Soc.  torn.  v.  p.  643. 


CH.  XX.]  THE  DOLLART  FORMED.  329 

'  inces.  In  the  year  1205,  the  island  now  called  Wieringen,  to  the  south 
of  the  Texel,  was  still  a  part  of  the  mainland,  but  during  several  high 
floods,  of  which  the  dates  are  given,  ending  in  December,  1251,  it  was 
separated  from  the  continent.  By  subsequent  incursions  the  sea  con- 
sumed great  parts  of  the  rich  and  populous  isthmus,  a  low  tract  which 
stretched  on  the  north  of  Lake  Flevo,  between  Staveren  in  Friesland 
and  Medemblick  in  Holland,  till  at  length  a  breach  was  completed 
about  the  year  1282,  and  afterwards  widened.  Great  destruction  ot 
land  took  place  when  the  sea  first  broke  in,  and  many  towns  were 
swept  away  ;  but  there  was  afterwards  a  reaction  to  a  certain  extent, 
large  tracts,  at  first  submerged,  having  been  gradually  redeemed. 
The  new  straits  south  of  Staveren  are  more  than  half  the  width  of 
those  of  Dover,  but  are  very  shallow,  the  greatest  depth  not  exceeding 
two  or  three  fathoms.  The  new  bay  is  of  a  somewhat  circular  form, 
and  between  thirty  and  forty  miles  in  diameter.  How  much  of  this 
space  may  formerly  have  been  occupied  by  Lake  Flevo  is  unknown. 
(See  map,  fig.  38.) 

Destruction  of  islands. — A  series  of  islands  stretching  from  the  Texel 
to  the  mouths  of  the  Weser  and  Elbe  are  probably  the  last  relics  of  a 
tract  once  continuous.  They  have  greatly  diminished  in  size,  and 
have  lost  about  a  third  of  their  number,  since  the  time  of  Pliny ;  for 
that  naturalist  counted  twenty-three  islands  between  the  Texel  and 
Eider,  whereas  there  are  now  only  sixteen,  including  Heligoland  and 
Neuwerk.*  The  island  of  Heligoland,  at  the  mouth  of  the  Elbe,  con- 
sists of  a  rock  of  red  marl  of  the  Keuper  formation  (of  the  Germans), 
and  is  bounded  by  perpendicular  red  cliffs,  above  200  feet  high.  Al- 
though, according  to  some  accounts,  it  has  been  greatly  reduced  in 
size  since  the  year  800,  M.  Wiebel  assures  us,  that  the  ancient  map  by 
Meyer  cannot  be  depended  upon,  and  that  the  island,  according  to  the 
description  still  extant  by  Adam  of  Bremen,  was  not  much  larger  than 
now,  in  the  time  of  Charlemagne.  On  comparing  the  map  made  in 
the  year  1793  by  the  Danish  engineer  Wessel,  the  average  encroach- 
ment of  the  sea  on  the  cliffs,  between  that  period  and  the  year  1848 
(or  about  half  a  century),  did  not  amount  to  more  than  three  feet.f 
On  the  other  hand,  some  few  islands  have  extended  their  bounds  in 
one  direction,  or  become  connected  with  others,  by  the  sanding-up 
of  channels  ;  but  even  these,  like  Juist,  have  generally  given  way  as 
much  on  the  north  towards  the  sea  as  they  have  gained  on  the  south, 
or  land  side. 

The  Dollart  formed. — While  the  delta  of  the  Rhine  has  suffered  so 
materially  from  the  movements  of  the  ocean,  it  can  hardly  be  supposed 
that  minor  rivers  on  the  same  coast  should  have  been  permitted  to  ex- 
tend their  deltas.  It  appears  that  in  the  time  of  the  Romans  there 
was  an  alluvial  plain  of  great  fertility,  where  the  Ems  entered  the  sea 

*  Von  Hoff,  vol.  i.  p.  364. 

f  Quart.  Journ.  Geol.  Soc.  vol.  iv.  p.  32 ;  Memoirs. 


330  DESTRUCTION    OF   NORTHSTRAND.  [On.  XX. 

by  three  arms.  This  low  country  stretched  between  Groningen  and 
Friesland,  and  sent  out  a  peninsula  to  the  northeast  towards  Emden.  A 
flood  in  1277  first  destroyed  part  of  the  peninsula.  Other  inundation? 
followed  at  different  periods  throughout  the  fifteenth  century.  In 
1507,  a  part  only  of  Torum,  a  considerable  town,  remained  standing; 
and  in  spite  of  the  erection  of  dams,  the  remainder  of  that  place,  to- 
gether with  market-towns,  villages,  and  monasteries,  to  the  number  of 
fifty,  were  finally  overwhelmed.  The  new  gulf,  which  was  called  the 
Dollart,  although  small  in  comparison  to  the  Zuyder  Zee,  occupied  nc 
less  than  six  square  miles  at  first ;  but  part  of  this  space  was,  in  the 
course  of  the  two  following  centuries,  again  redeemed  from  the  sea. 
TUe  small  bay  of  Leybucht,  farther  north,  was  formed  in  a  similar  man- 
ner in  the  thirteenth  century  ;  and  the  bay  of  Harlbucht  in  the  middle 
of  the  sixteenth.  Both  of  these  have  since  been  partially  reconverted 
into  dry  land.  Another  new  estuary,  called  the  Gulf  of  Jahde,  near 
the  mouth  of  the  Weser,  scarcely  inferior  in  size  to  the  Dollart,  has 
been  gradually  hollowed  out  since  the  year  1016,  between  which  era 
and  1651  a  space  of  about  four  square  miles  has  been  added  to  the 
sea.  The  rivulet  which  now  enters  this  inlet  is  very  small ;  but 
Arens  conjectures  that  an  arm  of  the  Weser  had  once  an  outlet  in 
that  direction. 

Coast  of  Sleswick. — Farther  north  we  find  so  many  records  of  waste 
on  the  western  coast  of  Sleswick,  as  to  lead  us  to  anticipate  that,  at  no 
distant  period  in  the  history  of  the  physical  geography  of  Europe,  Jut- 
land may  become  an  island,  and  the  ocean  may  obtain  a  more  direct 
entrance  into  the  Baltic.  Indeed,  the  temporary  insulation  of  the 
northern  extremity  of  Jutland  has  been  affected  no  less  than  four  times 
within  the  records  of  history,  the  ocean  having  as  often  made  a  breach 
through  the  bar  of  sand,  which  usually  excludes  it  from  the  Lym  Fiord. 
This  long  frith  is  120  miles  in  length  including  its  windings,  and  com- 
municates at  its  eastern  end  with  the  Baltic.  The  last  irruption  of  salt 
water  happened  in  1824,  and  the  fiord  was  still  open  in  1837,  when 
some  vessels  of  thirty  tons'  burden  passed  through. 

The  Marsh  islands  between  the  rivers  Elbe  and  Eider  are  mere  banks, 
like  the  lands  formed  of  the  "  warp"  in  the  Humber,  protected  by  dikes. 
Some  of  them,  after  having  been  inhabited  with  security  for  more  than 
ten  centuries,  have  been  suddenly  overwhelmed.  In  this  manner,  in 
1216,  no  less  than  ten  thousand  of  the  inhabitants  of  Eiderstede  and 
Ditmarsch  perished;  and  on  the  llth  of  October,  1634,  the  islands 
and  the  whole  coast,  as  far  as  Jutland,  suffered  by  a  dreadful  deluge. 

Destruction  of  Northstrand  by  the  sea. — Northstrand,  up  to  the  year 
1240,  was,  with  the  islands  Sylt  and  Fohr,  so  nearly  connected  with  the 
mainland  as  to  appear  a  peninsula,  and  was  called  North  Friesland,  a 
highly  cultivated  and  populous  district.  It  measured  from  nine  to 
eleven  geographical  miles  from  north  to  south,  and  six  to  eight  from 
east  to  west.  In  the  above-mentioned  year  it  was  torn  asunder  from 
the  continent,  and  in  part  overwhelmed.  The  Isle  of  Northstrand, 


CH.    XX.]  CIMBRIAN    DELUGE.  331 

thus  formed,  was,  towards  the  end  of  the  sixteenth  century,  only  foui 
geographical  miles  in  circumference,  and  was  still  celebrated  for  its 
cultivation  and  numerous  population.  After  many  losses,  it  still  con 
tained  nine  thousand  inhabitants.  At  last,  in  the  year  1634,  on  the 
evening  of  the  llth  of  October,  a  flood  passed  over  the  whole  island, 
whereby  1300  houses,  with  many  churches,  were  lost ;  fifty  thousand 
head  of  cattle  perished,  and  above  six  thousand  men.  Three  small 
islets,  one  of  them  still  called  Northstrand,  alone  remained,  which  are 
how  continually  wasting. 

The  redundancy  of  river  water  in  the  Baltic,  especially  during  the 
melting  of  ice  and  snow  in  spring,  causes  in  general  an  outward  current 
through  the  channel  called  the  Cattegat.  But  after  a  continuance  of 
northwesterly  gales,  especially  during  the  height  of  the  spring-tides,  the 
Atlantic  rises,  and  pouring  a  flood  of  water  into  the  Baltic,  commits 
dreadful  devastations  on  the  isles  of  the  Danish  Archipelago.  This 
current  even  acts,  though  with  diminished  force,  as  far  eastward  as  the 
vicinity  of  Dantzic.*  Accounts  written  during  the  last  ten  centuries 
attest  the  wearing  down  of  promontories  on  the  Danish  coast,  the  deep- 
ening of  gulfs,  the  severing  of  peninsulas  from  the  mainland,  and  the 
waste  of  islands,  while  in  several  cases  marsh  land,  defended  for  cen- 
turies by  dikes,  has  at  last  been  overflowed,  and  thousands  of  the 
inhabitants  whelmed  in  the  waves.  Thus  the  island  Barsoe,  on  the 
coast  of  Sleswick,  has  lost,  year  after  year,  an  acre  at  a  time,  and  the 
island  Alsen  suffers  in  like  manner. 

Cimbrian  deluge. — As  we  have  already  seen  that  during  the  flood 
before  mentioned,  6000  men  and  50,000  head  of  cattle  perished  on 
Northstrand  on  the  western  coast  of  Jutland,  we  are  all  well  prepared 
to  find  that  this  peninsula,  the  Cimbrica  Chersonesus  of  the  ancients, 
has  from  a  remote  period  been  the  theatre  of  like  catastrophes.  Ac- 
cordingly, Strabo  records  a  story,  although  he  treats  it  as  an  incredible 
fiction, 'that,  during  a  high  tide,  the  ocean  rose  upon  this  coast  so  rap- 
idly, that  men  on  horseback  were  scarcely  able  to  escape.f  Florus, 
alluding  to  the  same  tradition,  says,  "  Cimbri,  Teutoni,  atque  Tigurini, 
ab  extremis  Galliae  profugi,  cum  terras  eorum  inundasset  Oceanus,  no- 
vas sedes  toto  orbe  quserebant/'J;  This  event,  commonly  called  the 
"  Cimbrian  Deluge,"  is  supposed  to  have  happened  about  three  centu- 
ries before  the  Christian  era  ;  but  it  is  not  improbable  that  the  principal 
catastrophe  was  preceded  and  followed  by  many  devastations  like  those 
experienced  in  modern  times  on  the  islands  and  shores  of  Jutland,  and 
such  calamities  may  well  be  conceived  to  have  forced  on  the  migration 
of  some  maritime  tribes. 

Inroads  of  the  sea  OH  the  eastern  shores  of  North  America. — After  so 
many  authentic  details  respecting  the  destruction  of  the  coast  in  parts 
of  Europe  best  known,  it  will  be  unnecessary  to  multiply  examples  of 

*  See  examples  in  Von  Hoff,  vol.  i.  p.  73,  who  cites  Pisansky. 
f  Book  vii.  Cimbri.  \  Lib.  iii.  cap  3. 


332  TIDAL   WAVE   CALLED    "  THE  BORE."  [On.  XX. 

analogous  changes  in  more  distant  regions  of  the  world.  It  must  not, 
however,  be  imagined  that  our  own  seas  form  any  exception  to  the 
general  rule.  Thus,  for  example,  if  we  pass  over  to  the  eastern  coast 
of  North  America,  where  the  tides  rise,  in  the  Bay  of  Fundy,  to  a  great 
elevation,  we  find  many  facts  attesting  the  incessant  demolition  of  land. 
Cliffs,  often  several  hundred  feet  high,  composed  of  sandstone,  red  marl, 
and  other  rocks,  which  border  that  bay  and  its  numerous  estuaries,  are 
perpetually  undermined.  The  ruins  of  these  cliffs  are  gradually  carried, 
in  the  form  of  mud,  sand,  and  large  boulders,  into  the  Atlantic  by  pow- 
erful currents,  aided  at  certain  seasons  by  drift  ice,  which  forms  along 
the  coast,  and  freezes  round  large  stones. 

At  Cape  May,  on  the  north  side  of  Delaware  Bay,  in  the  United 
States,  the  encroachment  of  the  sea  was  shown  by  observations  made 
consecutively  for  sixteen  years,  from  1804  to  1820,  to  average  about 
nine  feet  a  year  ;*  and  at  Sullivan's  Island,  which  lies  on  the  north 
side  of  the  entrance  of  the  harbor  of  Charleston,  in  South  Carolina, 
the  sea  carried  away  a  quarter  of  a  mile  of  land  in  three  years,  ending 
in  I786.f 

Tidal  wave  called  "  the  Bore" — Before  concluding  my  remarks  on 
the  action  of  the  tides,  I  must  not  omit  to  mention  the  wave  called  "  the 
Bore,"  which  is  sometimes  produced  in  a  river  where  a  large  body  of 
water  is  made  to  rise  suddenly,  in  consequence  of  the  contraction  of  the 
channel.  This  wave  terminates  abruptly  on  the  inland  side  ;  because 
the  quantity  of  water  contained  in  it  is  so  great,  and  its  motion  so  rapid, 
that  time  is  not  allowed  for  the  surface  of  the  river  to  be  immediately 
raised  by  means  of  transmitted  pressure.  A  tide  wave  thus  rendered 
abrupt  has  a  close  analogy,  observes  Mr.  Whewell,  to  the  waves  which 
curl  over  and  break  on  a  shelving  shore.J 

The  Bore  which  enters  the  Severn,  where  the  phenomenon  is  of  al- 
most daily  occurrence,  is  sometimes  nine  feet  high,  and  at  spring-tides 
rushes  up  the  estuary  with  extraordinary  rapidity.  The  finest  example 
which  I  have  seen  of  this  wave  was  at  Nova  Scotia,§  where  the  tide  is 
said  to  rise  in  some  places  seventy  feet  perpendicular,  and  to  be  the 
highest  in  the  world.  In  the  large  estuary  of  the  Shubenacadie,  which 
connects  with  another  estuary  called  the  Basin  of  Mines,  itself  an  em- 
branchment of  the  Bay  of  Fundy,  a  vast  body  of  water  comes  rushing 
up,  with  a  roaring  noise,  into  a  long  narrow  channel,  and  while  it  is 
ascending,  has  all  the  appearance  of  pouring  down  a  slope  as  steep 
as  that  of  the  celebrated  rapids  of  the  St.  Lawrence.  In  picturesque 
effect,  however,  it  bears  no  comparison,  for  instead  of  the  transparent 
green  water  and  snow-white  foam  of  the  St.  Lawrence,  the  whole  cur- 
rent of  the  Shubenacadie  is  turbid  and  densely  charged  with  red  mud. 
The  same  phenomenon  is  frequently  witnessed  in  the  principal  branches 
of  the  Ganges  and  in  the  Megna  as  before  mentioned  (p.  279).  "In 

*  New  Monthly  Mag.  vol.  vi.  p.  69. 

f  Von  Hoff,  vol.  i.  p.  96.  }  Phil.  Trans.  1833,  p.  204. 

§  See  Lyell's  Travels  in  North  America,  in  1842,  vol.  ii.  p.  166.     London,  1845. 


CH.  XX. J          CURRENTS   LN"   THE   STRAITS    OF    GIBRALTAR.  333 

the  Hoogly,"  says  Rennell,  "  the  Bore  commences  at  Hoogly  Point,  the 
place  where  the  river  first  contracts  itself,  and  is  perceptible  above 
Hoogly  Town ;  and  so  quick  is  its  motion,  that  it  hardly  employs  four 
hours  in  travelling  from  one  to  the  other,  though  the  distance  is  nearly 
seventy  miles.  At  Calcutta  it  sometimes  occasions  an  instantaneous 
rise  of  five  feet ;  and  both  here,  and  in  every  other  part  of  its  track, 
the  boats,  on  its  approach,  immediately  quit  the  shore,  and  make  for 
safety  to  the  middle  of  the  river.  In  the  channels,  between  the  islands 
in  the  mouth  of  the  Megna,  the  height  of  the  Bore  is  said  to  exceed 
twelve  feet ;  and  is  so  terrific  in  its  appearance,  and  dangerous  in  its  con- 
sequences, that  no  boat  will  venture  to  pass  at  spring-tide."*  These 
waves  may  sometimes  cause  inundations,  undermine  cliffs,  and  still 
more  frequently  sweep  away  trees  and  land  animals  from  low  shores,  so 
that  they  may  be  carried  down,  and  ultimately  imbedded  in  fluviatile  or 
submarine  deposits. 

CURRENTS    IN    INLAND    LAKES    AND    SEAS. 

In  such  large  bodies  of  water  as  the  North  American  lakes,  the  con- 
tinuance of  a  strong  wind  in  one  direction  often  causes  the  elevation  of 
the  water,  and  its  accumulation  on  the  leeward  side ;  and  while  the 
equilibrium  is  restoring  itself,  powerful  currents  are  occasioned.  In 
October,  1833,  a  strong  current  in  Lake  Erie,  caused  partly  by  the  set 
of  the  waters  towards  the  outlet  of  the  lake,  and  partly  by  the  prevail- 
ing wind,  burst  a  passage  through  the  extensive  peninsula  called  Long 
Point,  and  soon  excavated  a  channel  more  than  nine  feet  deep  and  nine 
hundred  feet  wide.  Its  width  and  depth  have  since  increased,  and  a 
new  and  costly  pier  has  been  erected  ;  for  it  is  hoped  that  this  event  will 
permanently  improve  the  navigation  of  Lake  Erie  for  steamboats.f  On 
the  opposite,  or  southern  coast  of  this  lake,  in  front  of  the  town  of  Cleve- 
land, the  degradation  of  the  cliffs  had  been  so  rapid  for  several  years 
preceding  a  survey  made  in  1837,  as  to  threaten  many  towns  with  demo- 
lition. J  In  the  Black  Sea,  also,  although  free  from  tides,  we  learn  from 
Pallas  that  there  is  a  sufficiently  strong  current  to  undermine  the  cliffs 
in  many  parts,  and  particularly  in  the  Crimea. 

Straits  of  Gibraltar. — It  is  well  known  that  a  powerful  current  sets 
constantly  from  the  Atlantic  into  the  Mediterranean,  and  its  influence 
extends  along  the  whole  southern  borders  of  that  sea,  and  even  to  the 
shores  of  Asia  Minor.  Captain  Smyth  found,  during  his  survey,  that 
the  central  current  ran  constantly  at  the  rate  of  from  three  to  six  miles 
an  hour  eastward  into  the  Mediterranean,  the  body  of  water  being  three 
miles  and  a  half  wide.  But  there  are  also  two  lateral  currents — one  on 
the  European,  and  one  on  the  African  side  ;  each  of  them  about  two 
miles  and  a  half  broad,  and  flowing  at  about  the  same  rate  as  the  central 
stream.  These  lateral  currents  ebb  and  flow  with  the  tide,  setting  alter- 

*  Rennell,  Phil.  Trans.  1781.  f  MS.  of  Capt.  Bay  field,  R.  N. 

\  Silliman's  Journ.  vol.  xxxiv.  p.  349. 


334:  ACTION  OF  CURRENTS  [Cn.  XX. 

t 

nately  into  the  Mediterranean  and  into  the  Atlantic.  The  excess  of 
water  constantly  flowing  in  is  very  great,  and  there  is  only  one  cause  to 
which  this  can  be  attributed,  the  loss  of  water  in  the  Mediterranean  by 
evaporation.  That  the  level  of  this  sea  should  be  considerably  depress- 
ed by  this  cause  is  quite  conceivable,  since  we  know  that  the  winds 
blowing  from  the  shores  of  Africa  are  hot  and  dry  ;  and  hygrometrical 
experiments  recently  made  in  Malta  and  other  places,  show  that  the 
mean  quantity  of  moisture  in  the  air  investing  the  Mediterranean  is  equal 
only  to  one  half  of  that  in  the  atmosphere  of  England.  The  temperature 
also  of  the  great  inland  sea  is  upon  an  average  higher,  by  3^°  of  Fahren- 
heit, than  the  eastern  part  of  the  Atlantic  Ocean  in  the  same  latitude, 
which  must  greatly  promote  its  evaporation.  The  Black  Sea  being 
situated  in  a  higher  latitude,  and  being  the  receptacle  of  rivers  flowing 
from  the  north,  is  much  colder,  and  its  expenditure  far  less  ;  accordingly 
it  does  not  draw  any  supply  from  the  Mediterranean,  but,  on  the  con- 
trary, contributes  to  it  by  a  current  flowing  outwards,  for  the  most  part 
of  the  year,  through  the  Dardanelles.  The  discharge,  however,  at  the 
Bosphorus  is  so  small,  when  compared  to  the  volume  of  water  carried  in 
by  rivers,  as  to  imply  a  great  amount  of  evaporation  in  the  Black  Sea. 

Whether  salt  be  precipitated  in  the  Mediterranean. — It  is,  however, 
objected,  that  evaporation  carries  away  only  fresh  water,  and  that  the 
current  from  the  Atlantic  is  continually  bringing  in  saltwater:  why, 
then,  do  not  the  component  parts  of  the  waters  of  the  Mediterranean 
vary  ?  or  how  can  they  remain  so  nearly  the  same  as  those  of  the  ocean  ? 
Some  have  imagined  that  the  excess  of  salt  might  be  carried  away  by 
an  under-current  running  in  a  contrary  direction  to  the  superior  ;  and 
this  hypothesis  appeared  to  receive  confirmation  from  a  late  discovery, 
that  the  water  taken  up  about  fifty  miles  within  the  Straits,  from  a  depth 
of  670  fathoms,  contained  a  quantity  of  salt  four  times  greater  than  the 
water  of  the  surface.  Dr.  Wollaston,*  who  analyzed  this  water  obtain- 
ed by  Captain  Smyth,  truly  inferred  that  an  under-current  of  such 
denser  water  flowing  outward,  if  of  equal  breadth  and  depth  with  the 
current  near  the  surface,  would  carry  out  as  much  salt  below  as  is  brought 
in  above,  although  it  moved  with  less  than  one-fourth  part  of  the  velo- 
city, and  would  thus  prevent  a  perpetual  increase  of  saltness  in  the 
Mediterranean  beyond  that  existing  in  the  Atlantic.  It  was  also  remark- 
ed by  others,  that  the  result  would  be  the  same,  if  the  swiftness  being 
equal,  the  inferior  current  had  only  one-fourth  of  the  volume  of  the 
superior.  At  the  same  time  there  appeared  reason  to  conclude  that  this 
great  specific  gravity  was  only  acquired  by  water  at  immense  depths  ; 
for  two  specimens  of  the  water,  taken  within  the  Mediterranean,  at  the 
distance  of  some  hundred  miles  from  the  Straits,  and  at  depths  of  400 
and  even  450  fathoms,  were  found  by  Dr.  Wollaston  not  to  exceed  in 
density  that  of  many  ordinary  samples  of  sea-water.  Such  being  the 
case,  we  can  now  prove  that  the  vast  amount  of  salt  brought  into  the 

*  Phil.  Trans.  1829,  part  i  p.  29. 


CH,  XX.]  IN   THE   MEDITEKKANEAN.  335 

Mediterranean  does  not  pass  out  again  by  the  Straits ;  for  it  appears  by 
Captain  Smyth's  soundings,  which  Dr.  Wallaston  had  not  seen,  that 
between  the  capes  of  Trafalgar  and  Spartel,  which  are  twenty -two  miles 
apart,  and  where  the  Straits  are  shallowest,  the  deepest  part,  which  is 
on  the  side  of  Cape  Spartel,  is  only  220  fathoms.  It  is  therefore  evi- 
dent, that  if  water  sinks  in  certain  parts  of  the  Mediterranean,  in  conse- 
quence of  the  increase  of  its  specific  gravity,  to  greater  depths  than  220 
fathoms,  it  can  never  flow  out  again  into  the  Atlantic,  since  it  must  be 
stopped  by  the  submarine  barrier  which  crosses  the  shallowest  part  of 
the  Straits  of  Gibraltar. 

The  idea  of  the  existence  of  a  counter-current,  at  a  certain  depth, 
first  originated  in  the  following  circumstances  : — M.  De  1'Aigle,  com- 
mander of  a  privateer  called  the  Phoenix  of  Marseilles,  gave  chase  to  a 
Dutch  merchant-ship,  near  Ceuta  Point,  and  coming  up  with  her  in  the 
middle  of  the  gut,  between  Tariffa  and  Tangier,  gave  her  one  broadside, 
which  directly  sunk  her.  A  few  days  after,  the  sunken  ship,  with  her 
cargo  of  brandy  and  oil,  was  cast  ashore  near  Tangier,  which  is  at  least 
four  leagues  to  the  westward  of  the  place  where  she  went  down,  and 
to  which  she  must  have  floated  in  a  direction  contrary  to  the  course  of 
the  central  current.*  This  fact,  however,  affords  no  evidence  of  an 
under- current,  because  the  ship,  when  it  approached  the  coast,  would 
necessarily  be  within  the  influence  of  a  lateral  current,  which  running 
westward  twice  every  twenty-four  hours,  might  have  brought  back  the 
vessel  to  Tangier. 

What,  then,  becomes  of  the  excess  of  salt  ? — for  this  is  an  inquiry  of 
the  highest  geological  interest.  The  Rhone,  the  Po,  the  Nile,  and 
many  hundred  minor  streams  and  springs,  pour  annually  into  the  Med- 
iterranean large  quantities  of  carbonate  of  lime,  together  with  iron,  mag- 
nesia, silica,  alumina,  sulphur,  and  other  mineral  ingredients  in  a  state  of 
chemical  solution.  To  explain  why  the  influx  of  this  matter  does  not 
alter  the  composition  of  this  sea  has  never  been  regarded  as  a  difficulty ; 
for  it  is  known  that  calcareous  rocks  are  forming  in  the  delta  of  the 
Rhone,  in  the  Adriatic,  on  the  coast  of  Asia  Minor,  and  in  other  locali- 
ties. Precipitation  is  acknowledged  to  be  the  means  whereby  the  sur- 
plus mineral  matter  is  disposed  of,  after  the  consumption  of  a  certain 
portion  in  the  secretions  of  testacea,  zoophytes,  and  other  marine  ani- 
mals. But  before  muriate  of  soda  can,  in  like  manner,  be  precipitated, 
the  whole  Mediterranean  ought,  according  to  the  received  principles  of 
chemistry,  to  become  as  much  saturated  with  salt  as  Lake  Aral,  the 
Dead  Sea,  or  the  brine-springs  of  Cheshire. 

It  is  undoubtedly  true,  in  regard  to  small  bodies  of  water,  that  every 
particle  must  be  fully  saturated  with  muriate  of  soda  before  a  single 
crystal  of  salt  can  be  formed  ;  such  is  probably  the  case  in  all  natural 
salterns  :  such,  for  example,  as  th'ose  described  by  travellers  as  occur- 
ring on  the  western  borders  of  the  Black  Sea,  where  extensive  marshes 

*  PhiL  Trans.  1724. 


336  ACTION   OF   CURRENTS.  [On.  XX. 

are  said  to  be  covered  by  thin  films  of  salt  after  a  rapid  evaporation  of 
sea-water.  The  salt  £tangs  of  the  Rhone,  where  salt  has  sometimes 
been  precipitated  in  considerable  abundance,  have  been  already  men- 
tioned. In  regard  to  the  depth  of  the  Mediterranean,  it  appears  that 
between  Gibraltar  and  Ceuta,  Captain  Smyth  sounded  to  the  enormous 
depth  of  950  fathoms,  and  found  there  a  gravelly  bottom,  with  frag- 
ments of  broken  shells.  Saussure  sounded  to  the  depth  of  two  thou- 
sand feet,  within  a  few  yards  of  the  shore,  at  Nice  ;  and  M.  Berard  has 
lately  fathomed  to  the  depth  of  more  than  six  thousand  feet  in  several 
places  without  reaching  the  bottom.* 

The  central  abysses,  therefore,  of  this  sea  are,  in  all  likelihood,  at  least 
as  deep  as  the  Alps  are  high  ;  and,  as  at  the  depth  of  seven  hundred 
fathoms  only,  water  has  been  found  to  contain  a  proportion  of  salt  four 
times  greater  than  at  the  surface,  we  may  presume  that  the  excess  of 
salt  may  be  much  greater  at  the  depth  of  two  or  three  miles.  After 
evaporation,  the  surface  water  becomes  impregnated  with  a  slight  ex- 
cess of  salt,  and  its  specific  gravity  being  thus  increased,  it  instantly 
falls  to  the  bottom,  while  lighter  water  rises  to  the  top,  or  flows  in  lat- 
erally, being  always  supplied  by  rivers  and  the  current  from  the  Atlan- 
tic. The  heavier  fluid,  when  it  arrives  at  the  bottom,  cannot  stop  if  it 
can  gain  access  to  any  lower  part  of  the  bed  of  the  sea,  not  previously 
occupied  by  water  of  the  same  density. 

How  far  this  accumulation  of  brine  can  extend  before  the  inferior 
strata  of  water  will  part  with  any  of  their  salt,  and  what  difference  in 
such  a  chemical  process  the  immense  pressure  of  the  incumbent  ocean, 
or  the  escape  of  heated  vapors,  thermal  springs,  or  submarine  volcanic 
eruptions,  might  occasion,  are  questions  which  cannot  be  answered  in 
the  present  state  of  science. 

The  Straits  of  Gibraltar  are  said  to  become  gradually  wider  by  the 
wearing  down  of  the  cliffs  on  each  side  at  many  points ;  and  the  cur- 
rent sets  along  the  coast  of  Africa,  so  as  to  cause  considerable  inroads 
in  various  parts,  particularly  near  Carthage.  Near  the  Canopic  mouth 
of  the  Nile,  at  Aboukir,  the  coast  was  greatly  devastated  in  the  yeai 
1784,  when  a  small  island  was  nearly  consumed.  By  a  series  of  simi- 
lar operations,  the  old  site  of  the  cities  of  Nicropolis,  Taposiris,  Parva 
and  Canopus,  have  become  a  sand-bank.f 

*  Bull,  de  la  Soc.  Ge"oL  de  France,— Resume*,  p.  72,  1832. 
f  Clarke's,  Travels  in  Europe,  Asia,  and  Africa,  vol.  iii.  pp.  340  and  363,  4th 
edition. 


CHAPTER  XXL 

REPRODUCTIVE    EFFECTS    OF    TIDES    AND    CURRENTS. 

Estuaries,  how  formed — Silting  up  of  estuaries  does  not  compensate  the  loss  of 
land  on  the  borders  of  the  ocean — Bed  of  the  German  Ocean — Composition  and 
extent  of  its  sand-banks — Strata  deposited  by  currents  in  the  English  channel 
— On  the  shores  of  the  Mediterranean — At  the  mouths  of  the  Amazon,  Orinoco, 
and  Mississippi — Wide  area  over  which  strata  may  be  formed  by  this  cause. 

FROM  the  facts  enumerated  in  the  last  chapter,  it  appears  that  on  the 
borders  of  the  ocean,  currents  and  tides  co-operating  with  the  waves  of 
the  sea  are  most  powerful  instruments  in  the  destruction  and  transpor- 
tation of  rocks  ;  and  as  numerous  tributaries  discharge  their  alluvial  bur- 
den into  the  channel  of  one  great  river,  so  we  find  that  many  rivers 
deliver  their  earthy  contents  to  one  marine  current,  to  be  borne  by  it  to 
a  distance,  and  deposited  in  some  deep  receptacle  of  the  ocean.  The 
current,  besides  receiving  this  tribute  of  sedimentary  matter  from  streams 
draining  the  land,  acts  also  itself  on  the  coast,  as  does  a  river  on  the 
cliffs  which  bound  a  valley.  Yet  the  waste  of  cliffs  by  marine  currents 
constitutes  on  the  whole  a  very  insignificant  portion  of  the  denudation 
annually  effected  by  aqueous  causes,  as  I  shall  point  out  in  the  sequel 
of  this  chapter  (p.  339). 

In  inland  seas,  where  the  tides  are  insensible,  or  on  those  parts  of  the 
borders  of  the  ocean  where  they  are  feeble,  it  is  scarcely  possible  to 
prevent  a  harbor  at  a  river's  mouth  from  silting  up ;  for  a  bar  of  sand 
or  mud  is  formed  at  points  where  the  velocity  of  the  turbid  river  is 
checked  by  the  sea,  or  where  the  river  and  a  marine  current  neutralize 
each  other's  force.  For  the  current,  as  we  have  seen,  may,  like  the 
river,  hold  in  suspension  a  large  quantity  of  sediment,  or,  co-operating 
with  the  waves,  may  cause  the  progressive  motion  of  a  shingle  beach  in 
one  direction.  I  have  already  alluded  to  the  erection  of  piers  and  groins 
at  certain  places  on  our  southern  coast,  to  arrest  the  course  of  the  shingle 
and  sand  (see  p.  3 1 8).  The  immediate  effect  of  these  temporary  obstacles 
is  to  cause  a  great  accumulation  of  pebbles  on  one  side  of  the  barrier, 
after  which  the  beach  still  moves  on  round  the  end  of  the  pier  at  a 
greater  distance  from  the  land.  This  system,  however,  is  often  attended 
with  a  serious  evil,  for  during  storms  the  waves  throw  suddenly  into 
the  harbor  the  vast  heap  of  pebbles  which  have  collected  for  years 
behind  the  groin  or  pier,  as  happened  during  a  great  gale  (Jan.  1839) 
at  Dover. 

The  formation  and  keeping  open  of  large  estuaries  are  due  to  the 
combined  influence  of  tidal  currents  and  rivers ;  for  when  the  tide  rises, 
a  large  body  of  water  suddenly  enters  the  mouth  of  the  river,  where, 
becoming  confined  within  narrower  bounds,  while  its  momentum  is  not 
destroyed,  it  is  urged  on,  and,  having  to  pass  through  a  contracted 

22 


338  FORMATION   OF   ESTUARIES.  [On.  XXI. 

channel,  rises  and  runs  with  increased  velocity,  just  as  a  stream  when  it 
reaches  the  arch  of  a  bridge  scarcely  large  enough  to  give  passage  to 
its  waters,  rushes  with  a  steep  fall  through  the  arch.  During  the  ascent 
of  the  tide,  a  body  of  fresh  water,  flowing  down  in  an  opposite  direc- 
tion from  the  higher  country,  is  arrested  in  its  course  for  several  hours ; 
and  thus  a  large  lake  of  fresh  and  brackish  water  is  accumulated,  which, 
when  the  sea  ebbs,  is  let  loose,  as  on  the  removal  of  an  artificial  sluice 
or  dam.  By  the  force  of  this  retiring  water,  the  alluvial  sediment  both 
of  the  river  and  of  the  sea  is  swept  away,  and  transported  to  such  a 
distance  from  the  mouth  of  the  estuary,  that  a  small  part  only  can 
return  with  the  next  tide. 

It  sometimes  happens,  that  during  a  violent  storm  a  large  bar  of  sand 
is  suddenly  made  to  shift  its  position,  so  as  to  prevent  the  free  influx  of 
the  tides,  or  efflux  of  river  water.  Thus  about  the  year  1500  the  sands 
at  Bayonne  were  suddenly  thrown  across  the  mouth  of  the  Adour. 
That  river,  flowing  back  upon  itself,  soon  forced  a  passage  to  the  north- 
ward along  the  sandy  plain  of  Capbreton,  till  at  last  it  reached  the  sea 
at  Boucau,  at  the  distance  of  seven  leagues  from  the  point  where  it  had 
formerly  entered.  It  was  not  till  the  year  1579  that  the  celebrated 
architect  Louis  de  Foix  undertook,  at  the  desire  of  Henry  III.,  to  reopen 
the  ancient  channel,  which  he  at  last  effected  with  great  difficulty.* 

In  the  estuary  of  the  Thames  at  London,  and  in  the  Gironde,  the 
tide  rises  only  for  five  hours  and  ebbs  seven,  and  in  all  estuaries  the 
water  requires  a  longer  time  to  run  down  than  up  ;  so  that  the  prepon- 
derating force  is  always  in  the  direction  which  tends  to  keep  open  a 
deep  and  broad  passage.  But  for  reasons  already  explained,  there  is 
naturally  a  tendency  in  all  estuaries  to  silt  up  partially,  since  eddies, 
and  backwaters,  and  points  where  opposing  streams  meet,  are  very 
numerous,  and  constantly  change  their  position. 

Many  writers  have  declared  that  the  gain  on  our  eastern  coast,  since 
the  earliest  periods  of  history,  has  more  than  counterbalanced  the  loss ; 
but  they  have  been  at  no  pains  to  calculate  the  amount  of  loss,  and  have 
often  forgotten  that,  while  the  new  acquisitions  are  manifest,  there  are 
rarely  any  natural  monuments  to  attest  the  former  existence  of  the  land 
that  has  been  carried  away.  They  have  also  taken  into  their  account 
those  tracts  artificially  recovered,  which  are  often  of  great  agricultural 
importance,  and  may  remain  secure,  perhaps,  for  thousands  of  years, 
but  which  are  only  a  few  feet  above  the  mean  level  of  the  sea,  and  are 
therefore  exposed  to  be  overflowed  again  by  a  small  proportion  of  the 
force  required  to  move  cliffs  of  considerable  height  on  our  shores.  If  it 
were  true  that  the  area  of  land  annually  abandoned  by  the  sea  in  estu- 
aries were  equal  to  that  invaded  by  it,  there  would  still  be  no  compen- 
sation in  kind. 

The  tidal  current  which  flows  out  from  the  northwest,  and  bears 
against  the  eastern  coast  of  England,  transports,  as  we  have  seen,  mate- 

*  Nouvelle  Chronique  de  la  Ville  de  Bayonne,  pp.  118,  139  :  1827. 


CH.  XXL]  FORMATION   OF   ESTUARIES.  339 

rials  of  various  kinds.  Aided  by  the  waves,  it  undermines  and  sweeps 
away  the  granite,  gneiss,  trap-rocks,  and  sandstone  of  Shetland,  and 
removes  the  gravel  and  loam  of  the  cliffs  of  Holderness,  Norfolk,  and 
Suffolk,  which  are  between  twenty  and  three  hundred  feet  in  height, 
and  which  waste  at  various  rates  of  from  one  foot  to  six  yards  annually. 
It  also  bears  away,  in  co-operation  with  the  Thames  and  the  tides,  the 
strata  of  London  clay  on  the  coast  of  Essex  and  Sheppey.  The  sea  at 
the  same  time  consumes  the  chalk  with  its  flints  for  many  miles  con- 
tinuously on  the  shores  of  Kent  and  Sussex — commits  annual  ravages 
on  the  freshwater  beds,  capped  by  a  thick  covering  of  chalk-flint  gravel, 
in  Hampshire,  and  continually  saps  the  foundations  of  the  Portland  lime- 
stone. It  receives,  besides,  during  the  rainy  months,  large  supplies  of 
pebbles,  sand,  and  mud,  which  numerous  streams  from  the  Grampians, 
Cheviots,  and  other  chains,  send  down  to  the  sea.  To  what  regions, 
then,  is  all  this  matter  consigned  ?  It  is  not  retained  in  mechanical 
suspension  by  the  waters  of  the  ocean,  nor  does  it  mix  with  them  in  a 
state  of  chemical  solution — it  is  deposited  somewhere,  yet  certainly  not 
in  the  immediate  neighborhood  of  our  shores ;  for,  in  that  case,  there- 
would  soon  be  a  cessation  of  the  encroachment  of  the  sea,  and  large 
tracts  of  low  land,  like  Romney  Marsh,  would  almost  everywhere  encir- 
cle our  island. 

As  there  is  now  a  depth  of  water  exceeding  thirty  feet,  in  some  spots 
where  towns  like  Dunwich  flourished  but  a  few  centuries  ago,  it  is  clear 
that  the  current  not  only  carries  far  away  the  materials  of  the  wasted 
cliffs,  but  is  capable  also  of  excavating  the  bed  of  the  sea  to  a  certain 
moderate  depth. 

So  great  is  the  quantity  of  matter  held  in  suspension  by  the  tidal 
current  on  our  shores,  that  the  waters  are  in  some  places  artificially 
introduced  into  certain  lands  below  the  level  of  the  sea  ;  and  by  repeat- 
ing this  operation,  which  is  called  "  warping,"  for  two  or  three  years, 
considerable  tracts  have  been  raised,  in  the  estuary  of  the  Humber,  to 
the  height  of  about  six  feet.  If  a  current,  charged  with  such  materials, 
meets  with  deep  depressions  in  the  bed  of  the  ocean,  it  must  often  fill 
them  up  ;  just  as  a  river,  when  it  meets  with  a  lake  in  its  course,  fills  it 
gradually  with  sediment. 

I  have  said  (p.  337)  that  the  action  of  the  waves  and  currents  on  sea- 
cliffs,  or  their  power  to  remove  matter  from  above  to  below  the  sea- 
level,  is  insignificant  in  comparison  with  the  power  of  rivers  to  perform 
the  same  task.  As  an  illustration  we  may  take  the  coast  of  Holderness 
described  in  the  last  chapter  (p.  304).  It  is  composed,  as  we  have 
seen,  of  very  destructible  materials,  is  thirty-six  miles  long,  and  its  aver- 
age height  may  be  taken  at  forty  feet.  As  it  has  wasted  away  at  the 
rate  of  two  and  a  quarter  yards  annually,  for  a  long  period,  it  will  be 
found  on  calculation  that  the  quantity  of  matter  thrown  down  into  the 
sea  every  year,  and  removed  by  the  current,  amounts  to  51,321,600 
cubic  feet.  It  has  been  shown  that  the  united  Ganges  and  Brahma- 
pootra carry  down  to  the  Bay  of  Bengal  40,000,000,000  of  cubic  feet 


34:0  FILLING   UP   OF   THE   GERMAN   OCEAN.  [On.  XXL 

of  solid  matter  every  year,  so  that  their  transporting  power  is  no  less 
than  780  times  greater  than  that  of  the  sea  on  the  coast  above-men- 
tioned ;  and  in  order  to  produce  a  result  equal  to  that  of  the  two  Indian 
rivers,  we  must  have  a  line  of  wasting  coast,  like  that  of  Holderness, 
nearly  28,000  miles  in  length,  or  longer  than  the  entire  circumference 
of  the  globe  by  above  3000  miles.  The  reason  of  so  great  a  difference 
in  the  results  may  be  understood  when  we  reflect  that  the  operations 
of  the  ocean  are  limited  to  a  single  line  of  cliff  surrounding  a  large  area, 
whereas  great  rivers  with  their  tributaries,  and  the  mountain  torrents  which 
flow  into  them,  act  simultaneously  on  a  length  of  bank  almost  indefinite. 

Nevertheless  we  are  by  no  means  entitled  to  infer,  that  the  denuding 
force  of  the  great  ocean  is  a  geological  cause  of  small  efficacy,  or  in- 
ferior to  that  of  rivers.  Its  chief  influence  is  exerted  at  moderate  depths 
below  the  surface,  on  all  those  areas  which  are  slowly  rising,  or  are 
attempting,  as  it  were,  to  rise  above  the  sea.  From  data  hitherto  ob- 
tained respecting  subterranean  movements,  we  can  scarcely  speculate 
on  an  average  rate  of  upheaval  of  more  than  two  or  three  feet  in  a 
century.  An  elevation  to  this  amount  is  taking  place  in  Scandinavia, 
and  probably  in  many  submarine  areas  as  vast  as  those  which  we  know 
to  be  sinking  from  the  proofs  derived  from  circular  lagoon  islands  or 
coral  atolls.  (See  chap.  50.)  Suppose  strata  as  destructible  as  those 
of  the  Wealden,  or  the  lower  and  upper  cretaceous  formation,  or  the 
tertiary  deposits  of  the  British  Isles  to  be  thus  slowly  upheaved,  how 
readily  might  they  all  be  swept  away  by  waves  and  currents  in  an 
open  sea !  How  entirely  might  each  stratum  disappear  as  it  was 
brought  up  successively  and  exposed  to  the  breakers  !  Shoals  of  wide 
extent  might  be  produced,  but  it  is  difficult  to  conceive  how  any  con- 
tinent could  ever  be  formed  under  such  circumstances.  Were  it  not 
indeed  for  the  hardness  and  toughness  of  the  crystalline  and  volcanic 
rocks,  which  are  often  capable  of  resisting  the  action  of  the  waves,  few 
lands  might  ever  emerge  from  the  midst  of  an  open  sea. 

Supposed  filling  up  of  the  German  Ocean. — The  German  Ocean  is 
deepest  on  the  Norwegian  side,  where  the  soundings  give  190  fathoms; 
but  the  mean  depth  of  the  whole  basin  may  be  stated  at  no  more  than 
thirty-one  fathoms.*  The  bed  of  this  sea  is  traversed  by  several  enor- 
mous banks,  the  greatest  of  which  is  the  Dogger  Bank,  extending  for 
upwards  of  354  miles  from  north  to  south.  The  whole  superficies  of 
these  shoals  is  equal  to  about  one-third  of  the  whole  extent  of  England 
and  Scotland.  The  average  height  of  the  banks  measures,  according  to 
Mr.  Stevenson,  about  seventy-eight  feet ;  the  upper  portion  of  them 
consisting  of  fine  and  coarse  siliceous  sand,  mixed  with  comminuted 
corals  and  shells.f  It  had  been  supposed  that  these  vast  submarine 
hills  were  made  up  bodily  of  loose  materials  supplied  from  the  waste  of 
the  English,  Dutch,  and  other  coasts  ;  but  the  survey  of  the  North  Sea, 

*  Stevenson  on  bed  of  German  Ocean,  Ed.  Phil.  Journ.  No.  v.  p.  44  :  1820. 
f  Stevenson,  ibid.  p.  47  :  1820. 


CH.  XXL]  STRATA    DEPOSITED   BY    CURRENTS.  341 

conducted  by  Captain  Hewett,  affords  ground  for  suspecting  this  opin- 
ion to  be  erroneous.  If  such  immense  mounds  of  sand  and  mud  had 
been  accumulated  under  the  influence  of  currents,  the  same  causes  ought 
nearly  to  have  reduced  to  one  level  the  entire  bottom  of  the  German 
Ocean  ;  instead  of  which  some  long  narrow  ravines  are  found  to  inter- 
sect the  banks.  One  of  these  varies  from  seventeen  to  forty-four 
fathoms  in  depth,  and  has  very  precipitous  sides  ;  in  one  part,  called 
the  "  Inner  Silver  Pits,"  it  is  fifty-five  fathoms  deep.  The  shallowest 
parts  of  the  Dogger  Bank  were  found  to  be  forty-two  feet  under  water, 
except  in  one  place,  where  the  wreck  of  a  ship  had  caused  a  shoal. 
Such  uniformity  in  the  minimum  depth  of  water  seems  to  imply  that 
the  currents,  which  vary  in  their  velocity  from  a  mile  to  two  miles  and 
a  half  per  hour,  have  power  to  prevent  the  accumulation  of  drift  matter 
in  places  of  less  depth. 

Strata  deposited  by  currents. — It  appears  extraordinary,  that  in  some 
tracts  of  the  sea,  adjoining  the  coast  of  England,  where  we  know  that 
currents  are  not  only  sweeping  along  rocky  masses,  thrown  down,  from 
time  to  time,  from  the  high  cliffs,  but  also  occasionally  scooping  out 
channels  in  the  regular  strata,  there  should  exist  fragile  shells  and  ten- 
der zoophytes  in  abundance,  which  live  uninjured  by  these  violent  move- 
ments. The  ocean,  however,  is  in  this  respect  a  counterpart  of  the 
land  ;  and  as,  on  the  continents,  rivers  may  undermine  their  banks,  up- 
root trees,  and  roll  along  sand  and  gravel,  while  their  waters  are  inhabit- 
ed by  testacea  and  fish,  and  their  alluvial  plains  are  adorned  with  rich 
vegetation  and  forests,  so  the  sea  may  be  traversed  by  rapid  currents, 
and  its  bed  may  here  and  there  suffer  great  local  derangement,  without 
any  interruption  of  the  general  order  and  tranquillity.  It  has  been  as- 
certained by  soundings  in  all  parts  of  the  world,  that  where  new  deposits 
are  taking  place  in  the  sea,  coarse  sand  and  small  pebbles  commonly 
occur  near  the  shore,  while  farther  from  land,  and  in  deeper  water,  finer 
sand  and  broken  shells  are  spread  out  over  the  bottom.  Still  farther 
out,  the  finest  mud  and  ooze  are  alone  met  with.  Mr.  Austen  observes 
that  this  rule  holds  good  in  every  part  of  the  English  Channel  examined 
by  him.  He  also  informs  us,  that  where  the  tidal  current  runs  rap- 
idly in  what  are  called  "  races,''  where  surface  undulations  are  perceived 
in  the  calmest  weather,  over  deep  banks,  the  discoloration  of  the  water 
does  not  arise  from  the  power  of  such  a  current  to  disturb  the  bottom 
at  a  depth  of  40  or  80  fathoms,  as  some  have  supposed.  In  these  cases, 
a  column  of  water  sometimes  500  feet  in  height,  is  moving  onwards  with 
the  tide  clear  and  transparent  above,  while  the  lower  portion  holds  fine 
sediment  in  suspension  (a  fact  ascertained  by  soundings),  when  sud- 
denly it  impinges  upon  a  bank,  and  its  height  is  reduced  to  300  feet. 
It  is  thus  made  to  boil  up  and  flow  off  at  the  surface,  a  process  which 
forces  up  the  lower  strata  of  water  charged  with  fine  particles  of  mud, 
which  in  their  passage  from  the  coast  had  gradually  sunk  to  a  depth  of 
300  feet  or  more.* 

*  Robt.  A.  C.  Austen,  Quart.  Journ.  GeoL  Soc.  vol.  vi.  p.  16. 


342  SEDIMENT   OF  THE   AMAZON.  [On.  XXI 

One  important  character  in  the  formations  produced  by  currents  is, 
the  immense  extent  over  which  they  may  be  the  means  of  diffusing 
homogeneous  mixtures,  for  these  are  often  coextensive  with  a  great 
line  of  coast ;  and,  by  comparison  with  their  deposits,  the  deltas  of 
rivers  must  shrink  into  significance.  In  the  Mediterranean,  the  same 
current  which  is  rapidly  destroying  many  parts  of  the  African  coast, 
between  the  Straits  of  Gibraltar  and  the  Nile,  checks  also  the  growth 
of  the  delta  of  the  Nile,  and  drifts  the  sediment  of  that  great  river  to 
the  eastward.  To  this  source  may  be  attributed  the  rapid  accretions 
of  land  on  parts  of  the  Syrian  shores  where  rivers  do  not  enter. 

Among  the  greatest  deposits  now  in  progress,  and  of  which  the  dis- 
tribution is  chiefly  determined  by  currents,  we  may  class  those  between 
the  mouths  of  the  Amazon  and  the  southern  coast  of  North  America. 
Captain  Sabine  found  that  the  equatorial  current  before  mentioned 
(p.  292)  was  running  with  the  rapidity  of  four  miles  an  hour  where  it  crosses 
the  stream  of  the  Amazon,  which  river  preserves  part  of  its  original 
impulse,  and  has  its  waters  not  wholly  mingled  with  those  of  the  ocean 
at  the  distance  of  300  miles  from  its  mouth.*  The  sediment  of  the 
Amazon  is  thus  constantly  carried  to  the  northwest  as  far  as  to  the 
mouths  of  the  Orinoco,  and  an  immense  tract  of  swamp  is  formed  along 
the  coast  of  Guiana,  with  a  long  range  of  muddy  shoals  bordering  the 
marshes,  and  becoming  converted  into  land.f  The  sediment  of  the 
Orinoco  is  partly  detained,  and  settles  near  its  mouth,  causing  the 
shores  of  Trinidad  to  extend  rapidly,  and  is  partly  swept  away  into  the 
Carribean  Sea  by  the  Guinea  current.  According  to  Humboldt,  much 
sediment  is  carried  again  out  of  the  Carribean  Sea  into  the  Gulf  of 
Mexico. 

It  should  not  be  overlooked  that  marine  currents,  even  on  coasts 
where  there  are  no  large  rivers,  may  still  be  the  agents  of  spreading  not 
only  sand  and  pebbles,  but  the  finest  mud,  far  and  wide  over  the  bottom 
of  the  ocean.  For  several  thousand  miles  along  the  western  coast  of 
South  America,  comprising  the  larger  parts  of  Peru  and  Chili,  there  is 
a  perpetual  rolling  of  shingle  along  the  shore,  part  of  which,  as  Mr. 
Darwin  has  shown,  are  incessantly  reduced  to  the  finest  mud  by  the 
waves,  and  swept  into  the  depths  of  the  Pacific  by  the  tides  and  cur- 
rents. The  same  author  however  has  remarked  that,  notwithstanding 
the  great  force  of  the  waves  on  that  shore,  all  rocks  60  feet  under  water 
are  covered  by  sea- weed,  showing  that  the  bed  of  the  sea  is  not  denuded 
at  that  depth,  the  effects  of  the  winds  being  comparatively  superficial. 

In  regard  to  the  distribution  of  sediment  by  currents  it  may  be  ob- 
served, that  the  rate  of  subsidence  of  the  finer  mud  carried  down  by 
every  great  river  into  the  ocean,  or  of  that  caused  by  the  rolling  of  the 
waves  upon  a  shore,  must  be  extremely  slow  ;  for  the  more  minute  the 
separate  particles  of  mud,  the  slower  will  they  sink  to  the  bottom,  and 

*  Experiments  to  determine  the  Figure  of  the  Earth,  <fec.  p.  445. 
|  Lochead  on  Nat.  Hist,  of  Guiana,  Edin.  Trans,  vol.  iv. 


CH.  XXL]  REPRODUCTIVE   EFFECTS   OF   CURRENTS.  343 

the  sooner  will  they  acquire  what  is  called  their  terminal  velocity.  It 
is  well  known  that  a  solid  body,  descending  through  a  resisting  me- 
dium, falls  by  the  force  of  gravity,  which  is  constant,  but  its  motion  is 
resisted  by  the  medium  more  and  more  as  its  velocity  increases,  until 
the  resistance  becomes  sufficient  to  counteract  the  farther  increase  of 
velocity.  For  example,  a  leaden  ball,  one  inch  diameter,  falling  through 
air  of  density  as  at  the  earth's  surface,  will  never  acquire  greater  veloci- 
ty than  260  feet  per  second,  and,  in  water,  its  greatest  velocity  will  be 
8  feet  6  inches  per  second.  If  the  diameter  of  the  ball  were  y^-  of  an 
inch,  the  terminal  velocities  in  air  would  be  26  feet,  and  in  water  '86  of 
a  foot  per  second. 

Now,  every  chemist  is  familiar  with  the  fact,  that  minute  particles 
descend  with  extreme  slowness  through  water,  the  extent  of  their 
surface  being  very  great  in  proportion  to  their  weight,  and  the  resist- 
ance of  the  fluid  depending  on  the  amount  of  surface.  A  precipitate  of 
sulphate  of  baryta,  for  example,  will  sometimes  require  more  than  five 
or  six  hours  to  subside  one  inch  ;*  while  oxalate  and  phosphate  of  lime 
require  nearly  an  hour  to  subside  about  an  inch  and  a  half  and  two 
inches  respectively,!  so  exceedingly  small  are  the  particles  of  which 
these  substances  consist. 

When  we  recollect  that  the  depth  of  the  ocean  is  supposed  frequently 
to  exceed  three  miles,  and  that  currents  run  through  different  parts  of 
that  ocean  at  the  rate  of  four  miles  an  hour,  and  when  at  the  same  time 
we  consider  that  some  fine  mud  carried  away  from  the  mouths  of  rivers 
and  from  sea-beaches,  where  there  is  a  heavy  surf,  as  well  as  the  im- 
palpable powder  showered  down  by  volcanoes,  may  subside  at  the  rate 
of  only  an  inch  per  hour,  we  shall  be  prepared  to  find  examples  of  the 
transportation  of  sediment  over  areas  of  indefinite  extent. 

It  is  not  uncommon  for  the  emery  powder  used  in  polishing  glass  to 
take  more  than  an  hour  to  sink  one  foot.  Suppose  mud  composed  of 
coarser  particles  to  fall  at  the  rate  of  two  feet  per  hour,  and  these  to  be 
discharged  into  that  part  of  the  Gulf  Stream  which  preserves  a  mean 
velocity  of  three  miles  an  hour  for  a  distance  of  two  thousand  miles ;  in 
twenty-eight  days  these  particles  will  be  carried  2016  miles,  and  will 
have  fallen  only  to  a  depth  of  224  fathoms. 

In  this  example,  however,  it  is  assumed  that  the  current  retains  its 
superficial  velocity  at  the  depth  of  224  fathoms,  for  which  we  have  as 
yet  no  data,  although  we  have  seen  that  the  motion  of  a  current  may 
continue  at  the  depth  of  100  fathoms.  (See  above,  p.  28.)  Experi- 
ments should  be  made  to  ascertain  the  rate  of  currents  at  considerable 
distances  from  the  surface,  and  the  time  taken  by  the  finest  sediment  to 
settle  in  sea- water  of  a  given  depth,  and  then  the  geologist  may  deter- 
mine the  area  over  which  homogeneous  mixtures  may  be  simultaneously 
distributed  in  certain  seas. 

*  On  the  authority  of  Mr.  Faraday.         f  On  the  authority  of  Mr.  R.  Phillips. 


CHAPTER  XXII. 

IGNEOUS    CAUSES. 

Changes  of  the  inorganic  world,  continued — Igneous  causes — Division  of  the  sub- 
ject— Distinct  volcanic  regions — Region  of  the  Andes — System  of  volcanoes 
extending  from  the  Aleutian  isles  to  the  Molucca  and  Sunda  islands — Poly- 
nesian archipelago — Volcanic  region  extending  from  Central  Asia  to  the  Azores 
— Tradition  of  deluges  on  the  shores  of  the  Bosphorus,  Hellespont,  and  Grecian 
isles — Periodical  alternation  of  earthquakes  in  Syria  and  Southern  Italy — 
"Western  limits  of  the  European  region — Earthquakes  rarer  and  more  feeble  as 
we  recede  from  the  centres  of  volcanic  action.  Extinct  volcanoes  not  to  be  in- 
cluded in  lines  of  active  vents. 

WE  have  hitherto  considered  the  changes  wrought,  since  the  times  of 
history  and  tradition,  by  the  continued  action  of  aqueous  causes  on  the 
earth's  surface  ;  and  we  have  next  to  examine  those  resulting  from  ig- 
neous agency.  As  the  rivers  and  springs  on  the  land,  and  the  tides 
and  currents  in  the  sea,  have,  with  some  slight  modifications,  been  fixed 
and  constant  to  certain  localities  from  the  earliest  periods  of  which  we 
have  any  records,  so  the  volcano  and  the  earthquake  have,  with  few  ex- 
ceptions, continued,  during  the  same  lapse  of  time,  to  disturb  the  same 
regions.  But  as  there  are  signs,  on  almost  every  part  of  our  continent, 
of  great  power  having  been  exerted  by  running  water  on  the  surface  of 
the  land,  and  by  waves,  tides,  and  currents  on  cliffs  bordering  the  sea, 
where,  in  modern  times,  no  rivers  have  excavated,  and  no  waves  or 
tidal  currents  undermined — so  we  find  signs  of  volcanic  vents  and  vio- 
lent subterranean  movements  in  places  where  the  action  of  fire  or  inter- 
nal heat  has  long  been  dormant.  We  can  explain  why  the  intensity  of 
the  force  of  aqueous  causes  should  be  developed  in  succession  in  differ- 
ent districts.  Currents,  for  example,  tides,  and  the  waves  of  the  sea, 
cannot  destroy  coasts,  shape  out  or  silt  up  estuaries,  break  through 
isthmuses,  and  annihilate  islands,  form  shoals  in  one  place,  and  remove 
them  from  another,  without  the  direction  and  position  of  their  destroy- 
ing and  transporting  power  becoming  transferred  to  new  localities. 
Neither  can  the  relative  levels  of  the  earth's  crust,  above  and  beneath 
the  waters,  vary  from  time  to  time,  as  they  are  admitted  to  have  varied 
at  former  periods,  and  as  it  will  be  demonstrated  that  they  still  do, 
without  the  continents  being,  in  the  course  of  ages,  modified,  and  even 
entirely  altered,  in  their  external  configuration.  Such  events  must 
clearly  be  accompanied  by  a  complete  change  in  the  volume,  velocity, 
and  direction  of  the  streams  and  land  floods  to  which  certain  regions 
give  passage.  That  we  should  find,  therefore,  cliffs  where  the  sea  once 
committed  ravages,  and  from  which  it  has  now  retired — estuaries  where 
high  tides  once  rose,  but  which  are  now  dried  up — valleys  hollowed 
gut  by  water,  where  no  streams  now  flow,  is  no  more  than  we  should 


CH.  XXTL]  POSITION   OF   VOLCANIC   VENTS.  345 

expect ;  these  and  similar  phenomena  are  the  necessary  consequences 
of  physical  causes  now  in  operation ;  and  if  there  be  no  instability  in 
the  laws  of  nature,  similar  fluctuations  must  recur  again  and  again  in 
time  to  come. 

But,  however  natural  it  may  be  that  the  force  of  running  water  in 
numerous  valleys,  and  of  tides  and  currents  in  many  tracts  of  the  sea, 
should  now  be  spent,  it  is  by  no  means  so  easy  to  explain  why  the  vio- 
lence of  the  earthquake  and  the  fire  of  the  volcano  should  also  have 
become  locally  extinct  at  successive  periods.  We  can  look  back  to  the 
time  when  the  marine  strata,  whereon  the  great  mass  of  Etna  rests,  had 
no  existence ;  and  that  time  is  extremely  modern  in  the  earth's  history. 
This  alone  affords  ground  for  anticipating  that  the  eruptions  of  Etna  will 
one  day  cease. 

N"ec  quae  sulfureis  ardet  fornacibus  JEtna 

Ignea  semper  erit,  neque  enim  fuit  ignea  semper, 

(Ovio,  Metam.  lib.  15-340,) 

are  the  memorable  words  which  are  put  into  the  mouth  of  Pythagoras 
by  the  Roman  poet,  and  they  are  followed  by  speculations  as  to  the 
cause  of  volcanic  vents  shifting  their  positions.  Whatever  doubts  the 
philosopher  expresses  as  to  the  nature  of  these  causes,  it  is  assumed,  as 
incontrovertible,  that  the  points  of  eruption  will  hereafter  vary,  because 
they  have  formerly  done  so  ;  a  principle  of  reasoning  which,  as  I  have 
endeavored  to  show  in  former  chapters,  has  been  too  much  set  at  naught 
by  some  of  the  earlier  schools  of  geology,  which  refused  to  conclude 
that  great  revolutions  in  the  earth's  surface  are  now  in  progress,  or  that 
they  will  take  place  hereafter,  because  they  have  often  been  repeated  in 
former  ages. 

Division  of  the  subject. — Volcanic  action  may  be  defined  to  be  "  the 
influence  exerted  by  the  heated  interior  of  the  earth  on  its  external 
covering."  If  we  adopt  this  definition,  without  connecting  it,  as  Hum- 
boldt  has  done,  with  the  theory  of  secular  refrigeration,  or  the  cooling 
down  of  an  original  heated  and  fluid  nucleus,  we  may  then  class  under 
a  general  head  all  the  subterranean  phenomena,  whether  of  volcanoes,  or 
earthquakes,  and  those  insensible  movements  of  the  land,  by  which,  as 
will  afterwards  appear,  large  districts  may  be  depressed  or  elevated, 
without  convulsions.  According  to  this  view,  I  shall  consider  first,  the 
volcano  ;  secondly,  the  earthquake  ;  thirdly,  the  rising  or  sinking  of  land 
in  countries  where  there  are  no  volcanoes  or  earthquakes ;  fourthly,  the 
probable  causes  of  the  changes  which  result  from  subterranean  agency. 

It  is  a  very  general  opinion  that  earthquakes  and  volcanoes  have  a 
common  origin ;  for  both  are  confined  to  certain  regions,  although  the 
subterranean  movements  are  least  violent  in  the  immediate  proximity  of 
volcanic  vents,  especially  where  the  discharge  of  aeriform  fluids  and 
melted  rock  is  made  constantly  from  the  same  crater.  But  as  there  are 
particular  regions,  to  which  both  the  points  of  eruption  and  the  move- 
ments of  great  earthquakes  are  confined,  I  shall  begin  by  tracing  out  the 

15* 


346  GEOGRAPHICAL  BOUNDARIES  [On.  XXII. 

geographical  boundaries  of  some  of  these,  that  the  reader  may  be  aware 
of  the  magnificent  scale  on  which  the  agency  of  subterranean  fire  is  now 
simultaneously  developed.  Over  the  whole  of  the  vast  tracts  alluded  to, 
active  volcanic  vents  are  distributed  at  intervals,  and  most  commonly 
arranged  in  a  linear  direction.  Throughout  the  intermediate  spaces  there 
is  often  abundant  evidence  that  the  subterranean  fire  is  at  work  continu- 
ously, for  the  ground  is  convulsed  from  time  to  time  by  earthquakes  ; 
gaseous  vapors,  especially  carbonic  acid  gas,  are  disengaged  plentifully 
from  the  soil ;  springs  often  issue  at  a  very  high  temperature,  and  their 
waters  are  usually  impregnated  with  the  same  mineral  matters  as  are 
discharged  by  volcanoes  during  eruptions.  . 

^VOLCANIC    REGIONS. 

Region  of  the  Andes. — Of  these  great  regions,  that  of  the  Andes  of 
South  America  is  one  of  the  best  defined,  extending  from  the  southward 
of  Chili  to  the  northward  of  Quito,  from  about  lat.  43°  S.  to  about  2°  K 
of  the  equator.  In  this  range,  however,  comprehending  forty-five  de- 
grees of  latitude,  there  is  an  alternation  on  a  grand  scale  of  districts  of 
active  with  those  of  extinct  volcanoes,  or  which,  if  not  spent,  have  at 
least  been  dormant  for  the  last  three  centuries.  How  long  an  interval 
of  rest  may  entitle  us  to  consider  a  volcano  as  entirely  extinct  is  not 
easily  determined ;  but  we  know  that  in  Ischia  there  intervened  between 
two  consecutive  eruptions  a  pause  of  seventeen  centuries  ;  and  the  dis- 
covery of  America  is  an  event  of  far  too  recent  a  date  to  allow  us  even 
to  conjecture  whether  different  portions  of  the  Andes,  nearly  the  whole 
of  which  are  subject  to  earthquakes,  may  not  experience  alternately  a 
cessation  and  renewal  of  eruptions. 

The  first  line  of  active  vents  which  have  been  seen  in  eruption  in  the 
Andes  extends  from  lat.  43°  28'  S. ;  or,  from  Yantales,  opposite  the  isle 
of  Chiloe,  to  Coquimbo,  in  lat.  30°  S. ;  to  these  thirteen  degrees  of  lati- 
tude succeed  more  than  eight  degrees  in  which  no  recent  volcanic  erup- 
tions have  been  observed.  We  then  come  to  the  volcanoes  of  Bolivia 
and  Peru,  reaching  six  degrees  from  S.  to  N.,  or  from  lat.  21°  S.  to  lat- 
15°  S.  Between  the  Peruvian  volcanoes  and  those  of  Quito,  another 
space  intervenes  of  no  less  than  fourteen  degrees  of  latitude,  said  to  be 
free  from  volcanic  action  so  far  as  yet  known.  The  volcanoes  of  Quito 
then  succeed,  beginning  about  100  geographical  miles  south  of  the  equa- 
tor, and  continuing  for  about  130  miles  north  of  the  line,  when  there 
occurs  another  undisturbed  interval  of  more  than  six  degrees  of  latitude, 
after  which  we  arrive  at  the  volcanoes  of  Guatemala  or  Central  America, 
north  of  the  Isthmus  of  Panama.* 

Having  thus  traced  out  the  line  from  south  to  north,  I  may  first  state, 
in  regard  to  the  numerous  vents  of  Chili,  that  the  volcanoes  of  Yantales 

*  See  Von  Buch's  Description  of  Canary  Islands  (Paris,  ed.  1836)  for  a  valuable 
sketch  of  the  principal  volcanoes  of  the  globe. 


CH.  XXII.]  OF   VOLCANIC   REGIONS.  347 

and  Osorno  were  in  eruption  during  the  great  earthquake  of  1835,  at  the 
same  moment  that  the  land  was  shaken  in  Chiloe,  and  in  some  parts  of 
the  Chilian  coast  permanently  upheaved ;  whilst  at  Juan  Fernandez,  at 
the  distance  of  no  less  than  720  geographical  miles  from  Yantales,  an 
eruption  took  place  beneath  the  sea.  Some  of  the  volcanoes  of  Chili  are 
of  great  height,  as  that  of  Antuco,  in  lat.  37°  40'  S.,  the  summit  of 
which  is  at  least  16,000  feet  above  the  sea.  From  the  flanks  of  this 
volcano,  at  a  great  height,  immense  currents  of  lava  have  issued,  one  of 
which  flowed  in  the  year  1828.  This  event  is  said  to  be  an  exception 
in  the  general  rule ;  few  volcanoes  in  the  Andes,  and  none  of  those  in 
Quito,  having  been  seen  in  modern  times  to  pour  out  lava,  but  having 
merely  ejected  vapor  or  scoriae. 

Both  the  basaltic  (or  augitic)  lavas,  and  those  of  the  felspathic  class, 
occur  in  Chili  and  other  parts  of  the  Andes  ;  but  the  volcanic  rocks  of 
the  felspathic  family  are  said  by  Von  Buch  to  be  generally  not  trachyte, 
but  a  rock  which  has  been  called  andesite,  or  a  mixture  of  augite  and 
albite.  The  last-mentioned  mineral  contains  soda  instead  of  the  potash 
found  in  common  felspar. 

The  volcano  of  Rancagua,  lat.  34°  15'  S.,  is  said  to  be  always  throw- 
ing out  ashes  and  vapors  like  Stromboli,  a  proof  of  the  permanently 
heated  state  of  certain  parts  of  the  interior  of  the  earth  below.  A  year 
rarely  passes  in  Chili  without  some  slight  shocks  of  earthquakes,  and  in 
certain  districts  not  a  month.  Those  shocks  which  come  from  the  side 
of  the  ocean  are  the  most  violent,  and  the  same  is  said  to  be  the  case  in 
Peru.  The  town  of  Copiapo  was  laid  waste  by  this  terrible  scourge  in 
the  years  1773,  1796,  and  1819,  or  in  both  cases  after  regular  intervals 
of  twenty-three  years.  There  have,  however,  been  other  shocks  in  that 
country  in  the  periods  intervening  between  the  dates  above  mentioned, 
although  probably  all  less  severe,  at  least  on  the  exact  site  of  Copiapo. 
The  evidence  against  a  regular  recurrence  of  volcanic  convulsions  at 
stated  periods  is  so  strong  as  a  general  fact,  that  we  must  be  on  our 
guard  against  attaching  too  much  importance  to  a  few  striking  but 
probably  accidental  coincidences.  Among  these  last  might  be  adduced 
the  case  of  Lima,  violently  shaken  by  an  earthquake  on  the  17th  of  June, 
1578,  and  again  on  the  very  same  day,  1678  ;  or  the  eruptions  of 
Coseguina  in  the  year  1709  and  1809,  which  are  the  only  two  recorded 
of  that  volcano  previous  to  that  of  1835.* 

Of  the  permanent  upheaval  of  land  after  earthquakes  in  Chili,  I  shall 
have  occasion  to  speak  in  the  next  chapter,  when  it  will  also  be  seen 
that  great  shocks  often  coincide  with  eruptions,  either  submarine  or 
from  the  cones  of  the  Andes,  showing  the  identity  of  the  force  which 
elevates  continents  with  that  which  causes  volcanic  outbursts.f 

The  space  between  Chili  and  Peru,  in  which  no  volcanic  action  has 
been  observed,  is  160  nautical  leagues  from  south  to  north.  It  is, 
however,  as  Yon  Buch  observes,  that  part  of  the  Andes  which  is  least 

*  Darwin,  Geol.  Trans.  2d  series,  vol.  v.  p.  612.  f  Ibid.  p.  606. 


348  GEOGRAPHICAL   BOUNDARIES  [On.  XXII. 

known,  being  thinly  peopled,  and  in  some  parts  entirely  desert.  The 
volcanoes  of  Peru  rise  from  a  lofty  platform  to  vast  heights  above  the 
level  of  the  sea,  from  17,000  to  20,000  feet.  The  lava  which  has  issued 
from  VWjo,  lat.  16°  55'  S.,  accompanied  by  pumice,  is  composed  of  a 
mixture  of  crystals  of  albitic  felspar,  hornblende,  and  mica,  a  rock 
which  has  been  considered  as  one  of  the  varieties  of  andesite.  Some 
tremendous  earthquakes  which  have  visited  Peru  in  modern  times  will 
be  mentioned  in  a  subsequent  chapter. 

The  volcanoes  of  Quito,  occurring  between  the  second  degree  of  south 
and  the  third  degree  of  north  latitude,  rise  to  vast  elevations  above  the 
sea,  many  of  them  being  between  14,000  and  18,000  feet  high.  The 
Indians  of  Lican  have  a  tradition  that  the  mountain  called  L' Altar,  or 
Capac  Urcu,  which  means  "  the  chief,"  was  once  the  highest  of  those 
near  the  equator,  being  higher  than  Chimborazo ;  but  in  the  reign  of 
Ouamia  Abomatha,  before  the  discovery  of  America,  a  prodigious  erup- 
tion took  place,  which  lasted  eight  years,  and  broke  it  down.  The  frag- 
ments of  trachyte,  says  M.  Boussingault,  which  once  formed  the  conical 
summit  of  this  celebrated  mountain,  are  at  this  day  spread  over  the 
plain.*  Cotopaxi  is  the  most  lofty  of  all  the  South  American  volcanoes 
which  have  been  in  a  state  of  activity  in  modern  times,  its  height  being 
18,858  feet  ;  and  its  eruptions  have  been  more  frequent  and  destructive 
than  those  of  any  other  mountain.  It  is  a  perfect  cone,  usually  covered 
with  an  enormous  bed  of  snow,  which  has,  however,  been  sometimes 
melted  suddenly  during  an  eruption;  as  in  January,  1803,  for  example, 
when  the  snows  were  dissolved  in  one  night. 

Deluges  are  often  caused  in  the  Andes  by  the  liquefaction  of  great 
masses  of  snow,  and  sometimes  by  the  rending  open,  during  earth- 
quakes, of  subterranean  cavities  filled  with  water.  In  these  inundations 
fine  volcanic  sand,  loose  stones,  and  other  materials  which  the  water 
meets  with  in  its  descent,  are  swept  away,  and  a  vast  quantity  of  mud, 
called  "  moya,"  is  thus  formed  and  carried  down  into  the  lower  regions. 
Mud  derived  from  this  source  descended,  in  1797,  from  the  sides  of 
Tunguragua  in  Quito,  and  filled  valleys  a  thousand  feet  wide  to  the 
depth  of  six  hundred  feet,  damming  up  rivers  and  causing  lakes.  In 
these  currents  and  lakes  of  moya,  thousands  of  small  fish  are  some- 
times enveloped,  which,  according  to  Humboldt,  have  lived  and  mul- 
tiplied in  subterranean  cavities.  So  great  a  quantity  of  these  fish  were 
ejected  from  the  volcano  of  Imbaburu  in  1691,  that  fevers,  which  pre- 
vailed at  the  period,  were  attributed  to  the  effluvia  arising  from  the 
putrid  animal  matter. 

In  Quito,  many  important  revolutions  in  the  physical  features  of  the 
country  are  said  to  have  resulted,  within  the  memory  of  man,  from  the 
earthquakes  by  which  it  has  been  convulsed.  M.  Boussingault  declares 
his  belief,  that  if  a  full  register  had  been  kept  of  all  the  convulsions  ex- 
perienced here  and  in  other  populous  districts  of  the  Andes,  it  would 

*  Bull,  de  la  Soc.  G6ol.  torn.  vi.  p.  55. 


CH.  XXII.]  OF   VOLCANIC   REGIONS.  349 

be  found  that  the  trembling  of  the  earth  had  been  incessant.  The  fre- 
quency of  the  movement,  he  thinks,  is  not  due  to  volcanic  explosions, 
but  to  the  continual  falling  in  of  masses  of  rock  which  have  been  frac- 
tured and  upheaved  in  a  solid  form  at  a  comparatively  recent  epoch  ; 
but  a  longer  series  of  observations  would  be  requisite  to  confirm  this 
opinion.  According  to  the  same  author,  the  height  of  several  moun- 
tains of  the  Andes  has  diminished  in  modern  times.* 

The  great  crest  or  cordillera  of  the  Andes  is  depressed  at  the  Isthmus 
of  Panama  to  a  height  of  about  1000  feet,  and  at  the  lowest  point  of 
separation  between  the  two  seas  near  the  Gulf  of  San  Miguel,  to  150 
feet.  What  some  geographers  regard  as  a  continuation  of  that  chain 
in  Central  America  lies  to  the  east  of  a  series  of  volcanoes,  many  of 
which  are  active  in  the  provinces  of  Pasto,  Popayan,  and  Guatemala. 
Coseguina,  on  the  south  side  of  the  Gulf  of  Fonseca,  was  in  eruption  in 
January,  1835,  and  some  of  its  ashes  fell  at  Truxillo,  on  the  shores  of 
the  Gulf  of  Mexico.  What  is  still  more  remarkable,  on  the  same  day, 
at  Kingston,  in  Jamaica,  the  same  shower  of  ashes  fell,  having  been  car- 
ried by  an  upper  counter-current  against  the  regular  east  wind  which 
was  then  blowing.  Kingston  is  about  700  miles  distant  from  Coseguina, 
and  these  ashes  must  have  been  more  than  four  days  in  the  air,  having 
travelled  170  miles  a  day.  Eight  leagues  to  the  southward  of  the  cra- 
ter, the  ashes  covered  the  ground  to  the  depth  of  three  yards  and  a  half, 
destroying  the  woods  and  dwellings.  Thousands  of  cattle  perished,  their 
bodies  being  in  many  instances  one  mass  of  scorched  flesh.  Deer  and 
other  wild  animals  sought  the  towns  for  protection ;  many  birds  and 
quadrupeds  were  found  suffocated  in  the  ashes,  and  the  neighboring 
streams  were  strewed  with  dead  fish.f  Such  facts  throw  light  on  geo- 
logical monuments,  for  in  the  ashes  thrown  out  at  remote  periods  from 
the  volcanoes  of  Auvergne,  now  extinct,  we  find  the  bones  and  skeletons 
of  lost  species  of  quadrupeds. 

Mexico. — The  great  volcanic  chain,  after  having  thus  pursued  its 
course  for  several  thousand  miles  from  south  to  north,  sends  off  a 
branch  in  a  new  direction  in  Mexico,  in  the  parallel  of  the  city  of  that 
name,  and  is  prolonged  in  a  great  platform  between  the  eighteenth  and 
twenty-second  degrees  of  north  latitude.  Five  active  volcanoes  traverse 
Mexico  from  west  to  east — Tuxtla,  Orizaba,  Popocatepetl,  Jorullo,  and 
Colima.  Jorullo,  which  is  in  the  centre  of  the  great  platform,  is  no  less 
than  120  miles  from  the  nearest  ocean — an  important  circumstance,  as 
showing  that  the  proximity  of  the  sea  is  not  a  necessary  condition, 
although  certainly  a  very  general  characteristic  of  the  position  of  active 
volcanoes.  The  extraordinary  eruption  of  this  mountain,  in  1759,  will 
be  described  in  the  sequel.  If  the  line  which  connects  these  five  vents 
be  prolonged  in  a  westerly  direction,  it  cuts  the  volcanic  group  of  islands 
called  the  Isles  of  Revillagigedo. 


*  Bull,  de  la  Soc.  Geol.  de  France,  torn.  vi.  p.  56. 
f  Caldcleugh,  Phil.  Trans.  1836,  p.  27. 


350  GEOGRAPHICAL   BOUNDARIES  [On.  XXII. 

To  the  north  of  Mexico  there  are  said  to  be  three,  or  according  to 
some,  five  volcanoes  in  the  peninsula  of  California;  and  a  volcano  is 
reported  to  have  been  in  eruption  in  the  N.  W.  coast  of  America,  near 
the  Colombia  river,  lat.  45°  37'  N. 

West  Indies. — To  return  to  the  Andes  of  Quito :  Von  Buch  inclines 
to  the  belief  that  if  we  were  better  acquainted  with  the  region  to  the 
east  of  the  Madalena,  and  with  New  Granada  and  the  Caraccas,  we 
might  find  the  volcanic  chain  of  the  Andes  to  be  connected  with  that 
of  the  West  Indian  or  Carribee  Islands.  The  truth  of  this  conjecture 
has  almost  been  set  at  rest  by  the  eruption,  in  1848,  of  the  volcano  of 
Zamba,  in  New  Grenada,  at  the  mouth  of  the  river  Madalena.* 

Of  the  West  Indian  islands  there  are  two  parallel  series :  the  one  to 
the  west,  which  are  all  volcanic,  and  which  rise  to  the  height  of  several 
thousand  feet ;  the  others  to  the  east,  for  the  most  part  composed  of 
calcareous  rocks,  and  very  low.  In  the  former  or  volcanic  series,  are 
Granada,  St.  Vincent,  St.  Lucia,  Martinique,  Dominica,  Guadaloupe, 
Montserrat,  Nevis,  and  St.  Eustace.  In  the  calcareous  chain  are  Toba- 
go, Barbadoes,  Mariegallante,  Grandeterre,  Desirade,  Antigua,  Barbuda, 
St.  Bartholomew,  and  St.  Martin.  The  most  considerable  eruptions  in 
modern  times  have  been  those  of  St.  Vincent.  Great  earthquakes  have 
agitated  St.  Domingo,  as  will  be  seen  in  the  twenty-ninth  chapter. 

I  have  before  mentioned  (p.  270)  the  violent  earthquake  which  in 
1812  convulsed  the  valley  of  the  Mississippi  at  New  Madrid,  for  the 
space  of  300  miles  in  length,  of  which  more  will  be  said  in  the  twenty- 
seventh  chapter.  This  happened  exactly  at  the  same  time  as  the  great 
earthquake  of  Caraccas,  so  that  it  is  possible  that  these  two  points  are 
parts  of  one  subterranean  volcanic  region.  The  island  of  Jamaica,  with 
a  tract  of  the  contiguous  sea,  has  often  experienced  tremendous  shocks  ; 
and  these  are  frequent  along  a  line  extending  from  Jamaica  to  St.  Do- 
mingo and  Porto  Rico. 

Thus  it  will  be  seen  that,  without  taking  account  of  the  West  Indian 
and  Mexican  branches,  a  linear  train  of  volcanoes  and  tracts  shaken  by 
earthquakes  may  be  traced  from  the  island  of  Chiloe  and  opposite  coast 
to  Mexico,  or  even  perhaps  to  the  mouth  of  the  Colombia  river— a  dis  • 
tance  upon  the  whole  as  great  as  from  the  pole  to  the  equator.  In  re- 
gard to  the  western  limits  of  the  region,  they  lie  deep  beneath  the 
waves  of  the  Pacific,  and  must  continue  unknown  to  us.  On  the  east 
they  are  not  prolonged,  except  where  they  include  the  West  Indian 
Islands,  to  a  great  distance ;  for  there  seem  to  be  no  indications  of  vol- 
canic disturbances  in  Buenos  Ayres,  Brazil,  and  the  United  States  of 
North  America. 

Volcanic  region  from  the  Aleutian  Isles  to  the  Moluccas  and  Isles  of 
Sunda. — On  a  scale  which  equals  or  surpasses  that  of  the  Andes,  is 
another  line  of  volcanic  action,  which  commences,  on  the  north,  with 
the  Aleutian  Isles  in  Russian  America,  and  extends,  first  in  a  westerly 

*  Comptes  Rendus,  1849,  vol.  xxix.  p.  531. 


CH.  XXIL] 


OF   VOLCANIC   REGIONS. 


351 


352  GEOGRAPHICAL   BOUNDARIES  [Cu.  XXII. 

direction  for  nearly  200  geographical  miles,  and  then  southwards,  with 
few  interruptions,  throughout  a  space  of  between  sixty  and  seventy  de- 
grees of  latitude  to  the  Moluccas,  where  it  sends  off  a  branch  to  the 
southeast  while  the  principal  train  continues  westerly  through  Sum- 
bawa  and  Java  to  Sumatra,  and  then  in  a  northwesterly  direction  to  the 
Bay  of  Bengal.*  This  volcanic  line,  observes  Von  Buch,  may  be  said 
to  follow  throughout  its  course  the  external  border  of  the  continent  of 
Asia ;  while  the  branch  which  has  been  alluded  to  as  striking  southeast 
from  the  Moluccas,  passes  from  New  Guinea  to  New  Zealand,  conform- 
ing, though  somewhat  rudely,  to  the  outline  of  Australia.f 

The  connection,  however,  of  the  New  Guinea  volcanoes  with  the  line 
in  Java  (as  laid  down  in  Von  Buch's  map)  is  not  clearly  made  out.  By 
consulting  Darwin's  map  of  coral  reefs  and  active  volcanoes^  the  reader 
will  see  that  we  might  almost  with  equal  propriety  include  the  Mariana 
and  Bonin  volcanoes  in  a  band  with  New  Guinea.  Or  if  we  allow  so 
much  latitude  in  framing  zones  of  volcanic  action,  we  must  also  suppose 
the  New  Hebrides,  Solomon  Isles,  and  New  Ireland  to  constitute  one 
line  (see  map,  fig.  39,  p.  351). 

The  northern  extremity  of  the  volcanic  region  of  Asia,  as  described 
by  Von  Buch,  is  on  the  borders  of  Cook's  Inlet,  northeast  of  the  Penin- 
sula of  Alaska,  where  one  volcano,  in  about  the  sixtieth  degree  of  lati- 
tude, is  said  to  be  14,000  feet  high.  In  Alaska  itself  are  cones  of  vast 
height,  which  have  been  seen  in  eruption,  and  which  are  covered  for 
two-thirds  of  their  height  downwards  with  perpetual  snow.  The  sum- 
mit of  the  loftiest  peak  is  truncated,  and  is  said  to  have  fallen  in  during 
an  eruption  in  1786.  From  Alaska  the  line  is  continued  through  the 
Aleutian  or  Fox  Islands  to  Kamtschatka.  In  the  Aleutian  Archipelago 
eruptions  are  frequent,  and  about  thirty  miles  to  the  north  of  Unalaska, 
near  the  Isle  of  Umnack,  a  new  island  was  formed  in  1796.  It  was 
first  observed  after  a  storm,  at  a  point  in  the  sea  from  which  a  column 
of  smoke  had  been  seen  to  rise.  Flames  then  issued  from  the  new  islet 
which  illuminated  the  country  for  ten  miles  round ;  a  frightful  earth- 
quake shook  the  new-formed  cone,  and  showers  of  stones  were  thrown 
as  far  as  Umnack.  The  eruption  continued  for  several  months,  and 
eight  years  afterwards,  in  1804,  when  it  was  explored  by  some  hunters, 
the  soil  was  so  hot  in  some  places  that  they  could  not  walk  on  it.  Ac- 
cording to  Langsdorf  and  others,  this  new  island,  which  is  now  several 
thousand  feet  high,  and  two  or  three  miles  in  circumference,  has  been 
continually  found  to  have  increased  in  size  when  successively  visited  by 
different  travellers ;  but  we  have  no  accurate  means  of  determining  how 
much  of  its  growth,  if  any,  has  been  due  to  upheaval,  or  how  far  it  has 
been  exclusively  formed  by  the  ejection  of  ashes  and  streams  of  lava. 
It  seems,  however,  to  be  well  attested  that  earthquakes  of  the  most 

*  See  map  of  volcanic  lines  in  Von  Buch's  work  on  the  Canaries. 

j  Von  Buch,  ibid.  p.  409. 

\  Darwin,  Structure  an  1  Distrib.  of  Coral  reefs,  «fec.,  London,  1842.  In  the 
subjoined  map,  fig.  39, 1  have  copied  with  permission  a  small  part  of  the  valuable 
map  accompanying  this  work. 


CH.  XXIL]  OF   VOLCANIC    REGIONS.  353 

terrific  description  agitate  and  alter  the  bed  of  the  sea  and  surface  of 
the  land  throughout  this  tract. 

The  line  is  continued  in  the  southern  extremity  of  the  Peninsula  of 
Kamtschatka,  where  there  are  many  active  volcanoes,  which,  in  some 
eruptions,  have  scattered  ashes  to  immense  distances.  The  largest  and 
most  active  of  these  is  Klutschew,  lat.  56°  3'  N.,  which  rises  at  once 
from  the  sea  to  the  prodigious  height  of  15,000  feet.  Within  700  feet 
of  the  summit,  Erman  saw,  in  1829,  a  current  of  lava,  emitting  a  vivid 
light,  flow  down  the  northwest  side  to  the  foot  of  the  cone.  A  flow  of 
lava  from  the  summit  of  Mont  Blanc  to  its  base  in  the  valley  of  Cha- 
mouni  would  afford  but  an  inadequate  idea  of  the  declivity  down  which 
this  current  descended.  Large  quantities  of  ice  and  snow  opposed  for 
a  time  a  barrier  to  the  lava,  until  at  length  the  fiery  torrent  overcame, 
by  its  heat  and  pressure,  this  obstacle,  and  poured  down  the  mountain 
side  with  a  frightful  noise,  which  was  heard  for  a  distance  of  more  than 
fifty  miles.* 

The  Kurile  chain  of  islands  constitutes  the  prolongation  of  the  Kamt- 
schatka range,  where  a  train  of  volcanic  mountains,  nine  of  which  are 
known  to  have  been  in  eruption,  trends  in  a  southerly  direction.  The 
line  is  then  continued  to  the  southwest  in  the  great  island  of  Jesso,  and 
again  in  Nipon,  the  principal  of  the  Japanese  group.  It  then  extends 
by  Loo  Choo  and  Formosa  to  the  Philippine  Islands,  and  thence  by 
Sangir  and  the  northeastern  extremity  of  Celebes  to  the  Moluccas  (see 
map,  fig.  39).  Afterwards  it  passes  westward  through  Sumbawa  to 
Java. 

There  are  said  to  be  thirty-eight  considerable  volcanoes  in  Java,  some 
of  which  are  more  than  10,000  feet  high.  They  are  remarkable  for  the 
quantity  of  sulphur  and  sulphureous  vapors  which  they  discharge. 
They  rarely  emit  lava,  but  rivers  of  mud  issue  from  them,  like  the  moya 
of  the  Andes  of  Quito.  The  memorable  eruption  of  Galongoon,  in 
1822,  will  be  described  in  the  twenty-fifth  chapter.  The  crater  of 
Taschem,  at  the  eastern  extremity  of  Java,  contains  a  lake  strongly 
impregnated  with  sulphuric  acid,  a  quarter  of  a  mile  long,  from  which 
a  river  of  acid  water  issues,  which  supports  no  living  creature,  nor  can 
fish  live  in  the  sea  near  its  confluence.  There  is  an  extinct  crater  near 
Batur,  called  Guevo  Upas,  or  the  Valley  of  Poison,  about  half  a  mile  in 
circumference,  which  is  justly  an  object  of  terror  to  the  inhabitants  of 
the  country.  Every  living  being  which  penetrates  into  this  valley  falls 
down  dead,  and  the  soil  is  covered  with  the  carcasses  of  tigers,  deer, 
birds,  and  even  the  bones  of  men ;  all  killed  by  the  abundant  emanations 
of  carbonic  acid  gas,  by  which  the  bottom  of  the  valley  is  filled. 

In  another  crater  in  this  land  of  wonders,  near  the  volcano  of  Talaga 
Bodas,  we  learn  from  M.  Reinwardt,  that  the  sulphureous  exhalations 
have  killed  tigers,  birds,  and  innumerable  insects ;  and  the  soft  parts 
of  these  animals,  such  as  as  the  fibres,  muscles,  nails,  hair,  and  skin,  are 

*  Von  Buch,  Descrip.  dcs  lies  Canar.  p.  450,  who  cites  Erman  and  others. 

23 


354:  GEOGRAPHICAL   BOUNDARIES  [On.  XXIL 

very  well  preserved,  while  the  bones  are  corroded,  and  entirely  de- 
stroyed. 

We  learn  from  observations  made  in  1844,  by  Mr.  Jukes,  that  a 
recent  tertiary  formation  composed  of  limestone  and  resembling  the 
coral  rock  of  a  fringing  reef,  clings  to  the  flanks  of  all  the  volcanic 
islands  from  the  east  end  of  Timor  to  the  west  end  of  Java.  These 
modern  calcareous  strata  are  often  white  and  chalk-like,  sometimes  1000 
feet  and  upwards  above  the  sea,  regularly  stratified  in  thick  horizontal 
beds,  and  they  show  that  there  has  been  a  general  elevation  of  these 
islands  at  a  comparatively  modern  period.* 

The  same  linear  arrangement  which  is  observed  in  Java  holds  good 
in  the  volcanoes  of  Sumatra,  some  of  which  are  of  great  height,  as  Berapi, 
which  is  more  than  12,000  feet  above  the  sea,  and  is  continually  smok- 
ing. Hot  springs  are  abundant  at  its  base.  The  volcanic  line  then  in- 
clines slightly  to  the  northwest,  and  points  to  Barren  Island,  lat.  12° 
15'  N.,  in  the  Bay  of  Bengal.  This  volcano  was  in  eruption  in  1792, 
and  will  be  described  in  the  twenty-sixth  chapter.  The  volcanic  train 
then  extends,  according  to  Dr.  Macclelland,  to  the  island  of  Narcon- 
dam,  lat.  13°  22'  1ST.,  which  is  a  cone  seven  or  eight  hundred  feet  high, 
rising  from  deep  water,  and  said  to  present  signs  of  lava  currents  de- 
scending from  the  crater  to  the  base.  Afterwards  the  train  stretches 
in  the  same  direction  to  the  volcanic  island  of  Ramree,  about  lat.  19°  N., 
and  the  adjoining  island  of  Cheduba,  which  is  represented  in  old  charts 
as  a  burning  mountain.  Thus  we  arrive  at  the  Chittagong  coast,  which 
in  1762  was  convulsed  by  a  tremendous  earthquake  (see  chap.  29).f 

To  enumerate  all  the  volcanic  regions  of  the  Indian  and  Pacific  oceans 
would  lead  me  far  beyond  the  proper  limits  of  this  treatise  ;  but  it  will 
appear  in  the  last  chapter  of  this  volume,  when  coral  reefs  are  treated 
of,  that  the  islands  of  the  Pacific  consist  alternately  of  linear  groups  of 
two  classes,  the  one  lofty,  and  containing  active  volcanoes,  and  marine 
strata  above  the  sea-level,  and  which  have  been  undergoing  upheaval  in 
modern  times ;  the  other  very  low,  consisting  of  reefs  of  coral,  usually 
with  lagoons  in  their  centres,  and  in  which  there  is  evidence  of  a  grad- 
ual subsidence  of  the  ground.  The  extent  and  direction  of  these  par- 
allel volcanic  bands  have  been  depicted  with  great  care  by  Darwin  in  his 
map  before  cited  (p.  351). 

The  most  remarkable  theatre  of  volcanic  activity  in  the  Northern 
Pacific — or,  perhaps,  in  the  whole  world — occurs  in  the  Sandwich 
Islands,  which  have  been  admirably  treated  of  in  a  recent  work  by  Mr. 
Dana.J 

Volcanic  region  from  central  Asia  to  the  Azores. — Another  great 
region  ot  subterranean  disturbance  is  that  which  has  been  imagined  to 
extend  through  a  large  part  of  Central  Asia  to  the  Azores,  that  is  to 

*  Paper  read  at  meeting  of  Brit.  Assoc.  Southampton,  Sept.  1846. 
f  Macclelland,  Report  on  Coal  and  Min.  Resources  of  India.  Calcutta,  1838. 
\.  Geology  of  the  American  Exploring  Expedition.     See  also  Ly ell's  Manual, 
"Sandwich  I.  Volcanoes" — Index. 


CH.  XXIL]  OF   VOLCANIC   REGIONS.  355 

say,  from  China  and  Tartary  through  Lake  Aral  and  the  Caspian  to  the 
Caucasus,  and  the  countries  bordering  the  Black  Sea,  then  again  through 
part  of  Asia  Minor  to  Syria,  and  westward  to  the  Grecian  Islands, 
Greece,  Naples,  Sicily,  the  southern  part  of  Spain,  Portugal  and  the 
Azores.  Respecting  the  eastern  extremity  of  this  line  in  China,  we 
have  little  information,  but  many  violent  earthquakes  are  known  to 
have  occurred  there.  The  volcano  said  to  have  been  in  eruption  in  the 
seventh  century  in  Central  Tartary  is  situated  on  the  northern  declivity 
of  the  Celestial  Mountains,  not  far  distant  from  the  large  lake  called 
Issikoul ;  and  Humboldt  mentions  other  vents  and  solfataras  in  the 
same  quarter,  which  are  all  worthy  of  notice,  as  being  far  more  distant 
from  the  ocean  (260  geographical  miles)  than  any  other  known  points 
of  eruption. 

We  find  on  the  western  shores  of  the  Caspian,  in  the  country  round 
Baku,  a  tract  called  the  Field  of  Fire,  which  continually  emits  inflam- 
mable gas,  while  springs  of  naphtha  and  petroleum  occur  in  the  same 
vicinity,  as  also  mud  volcanoes.  Syria  and  Palestine  abound  in  volcanic 
appearances,  and  very  extensive  areas  have  been  shaken,  at  different 
periods,  with  great  destruction  of  cities  and  loss  of  lives.  Continual 
mention  is  made  in  history  of  the  ravages  committed  by  earthquakes  in 
Sidon,  Tyre,  Berytus,  Laodicea,  and  Antioch,  and  in  the  Island  of 
Cyprus.  The  country  around  the  Dead  Sea  appears  evidently,  from 
the  accounts  of  modern  travellers,  to  be  volcanic.  A  district  near 
Smyrna,  in  Asia  Minor,  was  termed  by  the  Greeks  Catacecaumene,  or 
"  the  burnt  up,"  where  there  is  a  large  arid  territory,  without  trees, 
and  with  a  cindery  soil.*  This  country  was  visited  in  1841  by  Mr.  W. 
J.  Hamilton,  who  found  in  the  valley  of  the  Hermus  perfect  cones  of 
scoriae,  with  lava-streams,  like  those  of  Auvergne,  conforming  to  the 
existing  river-channels,  and  with  their  surface  undecomposed.f 

Grecian  Archipelago. — Proceeding  westwards,  we  reach  the  Grecian 
Archipelago,  where  Santorin,  afterwards  to  be  described,  is  the  grand 
centre  of  volcanic  action. 

It  was  Von  Buch's  opinion  that  the  volcanoes  of  Greece  were  arranged 
in  a  line  running  N.  N.  W.  and  S.  S.  E.,  and  that  they  afforded  the 
only  example  in  Europe  of  active  volcanoes  having  a  linear  direction  ; 
but  M.  Virlet,  on  the  contrary,  announces  as  the  result  of  his  investiga- 
tions, made  during  the  French  expedition  to  the  Morea  in  1829,  that 
there  is  no  one  determinate  line  of  direction  for  the  volcanic  phenomena 
in  Greece,  whether  we  follow  the  points  of  eruptions,  or  the  earthquakes* 
or  any  other  signs  of  igneous  agency. J 

Macedonia,  Thrace,  and  Epirus,  have  always  been  subject  to  earth- 
quakes, and  the  Ionian  Isles  are  continually  convulsed. 

Respecting  Southern  Italy,  Sicily,  and  the  Lipari  Isles,  it  is  unneces- 
sary to  enlarge  here,  as  I  shall  have  occasion  again  to  allude  to  them. 

*  Strabo,  ed  Fal.,  p.  900. 

1  Researches  in  Asia  Minor,  vol.  ii.  p.  39. 
Virlet,  Bulletin  de  la  Soc.  G6ol.  de  France,  torn.  iii.  p.  109. 


356  GEOGRAPHICAL   BOUNDARIES  [Cn.  XXII. 

I  may  mention,  however,  that  a  band  of  volcanic  action  has  been  traced 
by  Dr.  Daubeny  across  the  Italian  Peninsula,  from  Ischia  to  Mount 
Vultur,  in  Apulia,  the  commencement  of  the  line  being  found  in  the 
hot  springs  of  Ischia,  after  which  it  is  prolonged  through  Vesuvius  to 
the  Lago  d'Ansanto,  where  gases  similar  to  those  of  Vesuvius  are 
evolved.  Its  farther  extension  strikes  Mount  Vultur,  a  lofty  cone  com- 
posed of  tuff  and  lava,  from  one  side  of  which  carbonic  acid  and  sul- 
phuretted hydrogen  are  emitted.* 

Traditions  of  deluges. — The  traditions  which  have  come  down  to  us 
from  remote  ages  of  great  inundations  said  to  have  happened  in  Greece 
and  on  the  confines  of  the  Grecian  settlements,  had  doubtless  their  ori- 
gin in  a  series  of  local  catastrophes,  caused  principally  by  earthquakes. 
The  frequent  migrations  of  the  earlier  inhabitants,  and  the  total  want  of 
written  annals  long  after  the  first  settlement  of  each  country,  make  it 
impossible  for  us  at  this  distance  of  time  to  fix  either  the  true  localities 
or  probable  dates  of  these  events.  The  first  philosophical  writers  of 
Greece  were,  therefore,  as  much  at  a  loss  as  ourselves  to  offer  a  reason- 
able conjecture  on  these  points,  or  to  decide  how  many  catastrophes 
might  sometimes  have  become  confounded  in  one  tale,  or  how  much  this 
tale  may  have  been  amplified,  in  after  times,  or  obscured  by  mytholo- 
gical fiction.  The  floods  of  Ogyges  and  Deucalion  are  commonly  said 
to  have  happened  before  the  Trojan  war  ;  that  of  Ogyges  more  than 
seventeen,  and  that  of  Deucalion  more  than  fifteen  centuries  before  our 
era.  As  to  the  Ogygian  flood,  it  is  generally  described  as  having  laid 
waste  Attica,  and  was  referred  by  some  writers  to  a  great  overflowing 
of  rivers,  to  which  cause  Aristotle  also  attributed  the  deluge  of  Deuca- 
lion, which,  he  says,  affected  Hellas  only,  or  the  central  part  of  Thessaly. 
Others  imagined  the  same  event  to  have  been  due  to  an  earthquake, 
which  drew  down  masses  of  rock,  and  stopped  up  the  course  of  the 
Peneus  in  the  narrow  defile  between  mounts  Ossa  and  Olympus. 

As  to  the  deluge  of  Samothrace,  which  is  generally  referred  to  a  dis- 
tinct date,  it  appears  that  the  shores  of  that  small  island  and  the  ad- 
joining mainland  of  Asia  were  inundated  by  the  sea.  Diodorus  Siculus 
says  that  the  inhabitants  had  time  to  take  refuge  in  the  mountains,  and 
save  themselves  by  flight ;  he  also  relates,  that  long  after  the  event  the 
fishermen  of  the  island  drew  up  in  their  nets  the  capitals  of  columns, 
which  were  the  remains  of  cities  submerged  by  that  terrible  catastro- 
phe, "f  These  statements  scarcely  leave  any  doubt  that  there  occurred, 
at  the  period  alluded  to,  a  subsidence  of  the  coast,  accompanied  by 
earthquakes  and  inroads  of  the  sea.  It  is  not  impossible  that  the  story 
of  the  bursting  of  the  Black  Sea  through  the  Thracian  Bosphorus  into 
the  Grecian  Archipelago,  which  accompanied,  and,  as  some  say,  caused 
the  Samothracian  deluge,  may  have  reference  to  a  wave,  or  succession 
of  waves,  raised  in  the  Euxine  by  the  same  convulsion. 

*  Daubeny  on  Mount  Vultur,  Ashmolean  Memoirs.     Oxford,  1835. 
f  Book  v.  ch.  xlvi.— See  letter  of  M.  Virlet,  Bulletin  de  la  Soc.  Geol.  de  France, 
torn.  ii.  p.  341. 


CH.  XXIL]  OF   VOLCANIC   REGIONS.  357 

We  know  that  subterranean  movements  and  volcanic  eruptions  are 
often  attended  not  only  by  incursions  of  the  sea,  but  also  by  violent 
rains,  and  the  complete  derangement  of  the  river  drainage  of  the  inland 
country,  and  by  the  damming  up  of  the  outlets  of  lakes  by  landslips,  or 
obstructions  in  the  courses  of  subterranean  rivers,  such  as  abound  in 
Thessaly  and  the  Morea.  We  need  not  therefore  be  surprised  at  the 
variety  of  causes  assigned  for  the  traditional  floods  of  Greece,  by  Herod- 
otus, Aristotle,  Diodorus,  Strabo,  and  others.  As  to  the  area  em- 
braced, had  all  the  Grecian  deluges  occurred  simultaneously,  instead  of 
being  spread  over  many  centuries,  and  had  they,  instead  of  being  ex- 
tremely local,  reached  at  once  from  the  Euxine  to  the  southwestern 
limit  of  the  Peloponnese,  and  from  Macedonia  to  Rhodes,  the  devasta- 
tion would  still  have  been  more  limited  than  that  which  visited  Chili  in 
1835,  when  a  volcanic  eruption  broke  out  in  the  Andes,  opposite  Chiloe, 
and  another  at  Juan  Fernandez,  distant  720  geographical  miles,  at  the 
same  time  that  several  lofty  cones,  in  the  Cordillera,  400  miles  to  the 
eastward  of  that  island,  threw  out  vapor  and  ignited  matter.  Through- 
out a  great  part  of  the  space  thus  recently  shaken  in  South  America, 
cities  were  laid  in  ruins,  or  the  land  was  permanently  upheaved,  or 
mountainous  waves  rolled  inland  from  the  Pacific. 

Periodical  alternation  of  Earthquakes  in  Syria  and  Southern  Italy. — 
It  has  been  remarked  by  Von  Hoff,  that  from  the  commencement  of  the 
thirteenth  to  the  latter  half  of  the  seventeenth  century,  there  was  an 
almost  entire  cessation  of  earthquakes  in  Syria  and  Judea ;  and,  during 
this  interval  of  quiescence,  the  Archipelago,  together  with  part  of  the 
adjacent  coast  of  Lesser  Asia,  as  also  Southern  Italy  and  Sicily,  suffered 
greatly  from  earthquakes ;  while  volcanic  eruptions  were  unusually  fre- 
quent in  the  same  regions.  A  more  extended  comparison,  also,  of  the 
history  of  the  subterranean  convulsions  of  these  tracts  seems  to  confirm 
the  opinion,  that  a  violent  crisis  of  commotion  never  visits  both  at  the 
same  time.  It  is  impossible  for  us  to  declare,  as  yet,  whether  this  phe- 
nomenon is  constant  in  this  and  other  regions,  because  we  can  rarely 
trace  back  a  connected  series  of  events  farther  than  a  few  centuries  ;  but 
it  is  well  known  that,  where  numerous  vents  are  clustered  together 
within  a  small  area,  as  in  many  archipelagoes  for  instance,  two  of  them 
are  never  in  violent  eruption  at  once.  If  the  action  of  one  becomes  very 
great  for  a  century  or  more,  the  others  assume  the  appearance  of  spent 
volcanoes.  It  is,  therefore,  not  improbable  that  separate  provinces  of 
the  same  great  range  of  volcanic  fires  may  hold  a  relation  to  one  deep- 
seated  focus,  analogous  to  that  which  the  apertures  of  a  small  group 
bear  to  some  more  superficial  rent  or  cavity.  Thus,  for  example,  we 
may  conjecture  that,  at  a  comparatively  small  distance  from  the  surface, 
Ischia  and  Vesuvius  mutually  communicate  with  certain  fissures,  and 
that  each  affords  relief  alternately  to  elastic  fluids  and  lava  there  gene- 
rated. So  we  may  suppose  Southern  Italy  and  Syria  to  be  connected, 
at  a  much  greater  depth,  with  a  lower  part  of  the  very  same  system  of 
fissures  ;  in  which  case  any  obstruction  occurring  in  one  duct  may  have 


358  GEOGRAPHICAL   BOUNDARIES  [Cn.  XXIL 

the  effect  of  causing  almost  all  the  vapor  and  melted  matter  to  be  forced 
up  the  other,  and  if  they  cannot  get  vent,  they  may  be  the  cause  of 
violent  earthquakes.  Some  objections  advanced  against  this  doctrine 
that  "  volcanoes  act  as  safety-valves,"  will  be  considered  in  the  sequel.* 

The  northeastern  portion  of  Africa,  including  Egypt,  which  lies  six 
or  seven  degrees  south  of  the  volcanic  line  already  traced,  has  been  al- 
most always  exempt  from  earthquakes  ;  but  the  northwestern  portion, 
especially  Fez  and  Morocco,  which  fall  within  the  line,  suffer  greatly 
from  time  to  time.  The  southern  part  of  Spain  also,  and  Portugal, 
have  generally  been  exposed  to  the  same  scourge  simultaneously  with 
Northern  Africa.  The  provinces  of  Malaga,  Murcia,  and  Granada,  and 
in  Portugal  the  country  round  Lisbon,  are  recorded  at  several  periods 
to  have  been  devastated  by  great  earthquakes.  It  will  be  seen,  from 
Michell's  account  of  the  great  Lisbon  shock,  in  1755,  that  the  first 
movement  proceeded  from  the  bed  of  the  ocean  ten  or  fifteen  leagues 
from  the  coast.  So  late  as  February  2,  1816,  when  Lisbon  was  vehe- 
mently shaken,  two  ships  felt  a  shock  in  the  ocean  west  from  Lisbon  ; 
one  of  them  at  the  distance  of  120,  and  the  other  262  French  leagues 
from  the  coastf — a  fact  which  is  more  interesting,  because  a  line  drawn 
through  the  Grecian  Archipelago,  the  volcanic  region  of  Southern  Italy, 
Sicily,  Southern  Spain,  and  Portugal,  will,  if  prolonged  westward 
through  the  ocean,  strike  the  volcanic  group  of  the  Azores,  which  may 
possibly  therefore  have  a  submarine  connection  with  the  European  line. 

In  regard  to  the  volcanic  system  of  Southern  Europe,  it  may  be  ob- 
served, that  there  is  a  central  tract  where  the  greatest  earthquakes 
prevail,  in  which  rocks  are  shattered,  mountains  rent,  the  surface  eleva- 
vated  or  depressed,  and  cities  laid  in  ruins.  On  each  side  of  this  line  of 
greatest  commotion  there  are  parallel  bands  of  country  where  the 
shocks  are  less  violent.  At  a  still  greater  distance  (as  in  Northern 
Italy,  for  example,  extending  to  the  foot  of  the  Alps),  there  are  spaces 
where  the  shocks  are  much  rarer  and  more  feeble,  yet  possibly  of  suffi- 
cient force  to  cause,  by  continued  repetition,  some  appreciable  alteration 
in  the  external  form  of  the  earth's  crust.  Beyond  these  limits,  again, 
all  countries  are  liable  to  slight  tremors,  at  distant  intervals  of  time, 
when  some  great  crisis  of  subterranean  movement  agitates  an  adjoining 
volcanic  region ;  but  these  may  be  considered  as  mere  vibrations,  propa- 
gated mechanically  through  the  external  covering  of  the  globe,  as  sounds 
travel  almost  to  indefinite  distances  through  the  air.  Shocks  of  this 
kind  have  been  felt  in  England,  Scotland,  Northern  France,  and  Ger- 
many— particularly  during  the  Lisbon  earthquake.  But  these  countries 
cannot,  on  this  account,  be  supposed  to  constitute  parts  of  the  southern 
volcanic  region,  any  more  than  the  Shetland  and  Orkney  islands  can  be 
considered  as  belonging  to  the  Icelandic  circle,  because  the  sands  ejected 
from  Hecla  have  been  wafted  thither  by  the  winds. 

*  See  ch.  32,  Cause  of  Volcanic  Eruptions. 

\  Verneur,  Journal  des  Voyages,  torn.  iv.  p.  111.     Von  Hoff,  vol.  ii.  p.  275. 


CH.  XXIL]  OF   VOLCANIC    REGIONS.  359 

Besides  the  continuous  spaces  of  subterranean  disturbance,  of  which 
we  have  merely  sketched  the  outline,  there  are  other  disconnected  vol- 
canic groups,  of  which  several  will  be  mentioned  hereafter. 

Lines  of  active  and  extinct  Volcanoes  not  to  be  confounded. — We  must 
always  be  careful  to  distinguish  between  lines  of  extinct  and  active  vol- 
canoes, even  where  they  appear  to  run  in  the  same  direction  ;  for  ancient 
and  modern  systems  may  interfere  with  each  other.  Already,  indeed, 
we  have  proof  that  this  is  the  case ;  so  that  it  is  not  by  geographical 
position,  but  by  reference  to  the  species  of  organic  beings  alone,  whether 
aquatic  or  terrestrial,  whose  remains  occur  in  beds  interstratified  with 
lavas,  that  we  can  clearly  distinguish  the  relative  age  of  volcanoes  of 
which  no  eruptions  are  recorded.  Had  Southern  Italy  been  known  to 
civilized  nations  for  as  short  a  period  as  America,  we  should  have  had 
no  record  of  eruptions  in  Ischia ;  yet  we  might  have  assured  ourselves 
that  the  lavas  of  that  isle  had  flowed  since  the  Mediterranean  was  in- 
habited by  the  species  of  testacea  now  living  in  the  Neapolitan  seas. 
With  this  assurance,  it  would  not  have  been  rash  to  include  the  numer- 
ous vents  of  that  island  in  the  modern  volcanic  group  of  Campania. 

On  similar  grounds  we  may  infer,  without  much  hesitation,  that  the 
eruptions  of  Etna,  and  the  modern  earthquakes  of  Calabria,  are  a  con- 
tinuation of  that  action  which,  at  a  somewhat  earlier  period,  produced 
the  submarine  lavas  of  the  Val  di  Noto  in  Sicily.  But  on  the  other 
hand,  the  lavas  of  the  Euganean  hills  and  the  Vicentin,  although  not 
wholly  beyond  the  range  of  earthquakes  in  Northern  Italy,  must  not 
be  confounded  with  any  existing  volcanic  system  ;  for  when  they  flowed, 
the  seas  were  inhabited  by  animals  almost  all  of  them  distinct  from 
those  now  known  to  live,  whether  in  the  Mediterranean  or  other  parts  of 
the  globe. 


CHAPTER  XXIII. 

VOLCANIC    DISTRICT    OF    NAPLES. 

History  of  the  volcanic  eruptions  in  the  district  round  Naples — Early  convulsions 
in  the  island  of  Ischia — Numerous  cones  thrown  up  there — Lake  Avernus — 
The  Solfatara — Renewal  of  the  eruptions  of  Vesuvius,  A.  D.  79 — Pliny's  descrip- 
tion of  the  phenomena — His  silence  respecting  the  destruction  of  Herculaneum 
and  Pompeii — Subsequent  history  of  Vesuvius — Lava  discharged  in  Ischia  in 
1302 — Pause  in  the  eruptions  of  Vesuvius — Monte  Nuovo  thrown  up — Uni- 
formity of  the  volcanic  operations  of  Vesuvius  and  Phlegrsean  Fields  in  ancient 
and  modern  times. 

I  SHALL  next  give  a  sketch  of  the  history  of  some  of  the  volcanic  vents 
dispersed  throughout  the  great  regions  before  described,  and  consider 
the  composition  and  arrangement  of  their  lavas  and  ejected  matter. 
The  only  volcanic  region  known  to  the  ancients  was  that  of  the  Medi- 
terranean ;  and  even  of  this  they  have  transmitted  to  us  very  imperfect 
records  relating  to  the  eruptions  of  the  three  principal  districts,  namely, 
that  round  Naples,  that  of  Sicily  and  its  isles,  and  that  of  the  Grecian 
Archipelago.  By  far  the  most  connected  series  of  records  throughout  a 
long  period  relates  to  the  first  of  these  provinces ;  and  these  cannot  be 
too  attentively  considered,  as  much  historical  information  is  indispensa- 
ble in  order  to  enable  us  to  obtain  a  clear  view  of  the  connection  and 
alternate  mode  of  action  of  the  different  vents  in  a  single  volcanic  group. 

Early  convulsions  in  the  Island  of  Ischia,- — The  Neapolitan  volcanoes 
extend  from  Vesuvius,  through  the  Phlegraean  Fields,  to  Procida  and 
Ischia,  in  a  somewhat  linear  arrangement,  ranging  from  the  northeast 
to  the  southwest,  as  will  be  seen  in  the  annexed  map  of  the  volcanic 
district  of  Naples  (fig.  40).  Within  the  space  above  limited,  the  vol- 
canic force  is  sometimes  developed  in  single  eruptions  from  a  consider- 
able number  of  irregularly  scattered  points ;  but  a  great  part  of  its 
action  has  been  confined  to  one  principal  and  habitual  vent,  Vesuvius  or 
Somma.  Before  the  Christian  era,  from  the  remotest  periods  of  which 
we  have  any  tradition,  this  principal  vent  was  in  a  state  of  inactivity. 
But  terrific  convulsions  then  took  place  from  time  to  time  in  Ischia 
(Pithecusa),  and  seem  to  have  extended  to  the  neighboring  isle  of  Pro- 
cida (Prochyta)  ;  for  Strabo*  mentions  a  story  of  Procida  having  been 
torn  asunder  from  Ischia ;  and  Plinyf  derives  its  name  from  its  having 
been  poured  forth  by  an  eruption  from  Ischia. 

The  present  circumference  of  Ischia  along  the  water's  edge  is  eighteen 
miles,  its  length  from  west  to  east  about  five,  and  its  breadth  from  north 

*  Lib.  v.  f  Nat.  Hist.  lib.  iii.  c.  6. 


CH.  XXIIL] 


VOLCANIC   ERUPTIONS   OF   ISCHIA. 


361 


to  south  three  miles.  Several  Greek  colonies  which  settled  there  before 
the  Christian  era  were  compelled  to  abandon  it  in  consequence  of  the 
violence  of  the  eruptions.  First  the  Erythrseans,  and  afterwards  the 
Chalcidians,  are  mentioned  as  having  been  driven  out  by  earthquakes 
and  igneous  exhalations.  A  colony  was  afterwards  established  by  Hiero, 

Fig.  40. 


.JJAversa, 


• 

Nola 


Eloria 


VOLCANIC  DISTRICT 

OF 

NAPLES. 


P1-?  diCampancllo 


A.  Astroni. 


B.  Monte  Barbaro. 


M.  Monte  Nuovo. 


S.  The  Solfatara. 


king  of  Syracuse,  about  380  years  before  the  Christian  era  ;  but  when 
they  had  built  a  fortress,  they  were  compelled  by  an  eruption  to  fly, 
and  never  again  returned.  Strabo  tells  us  that  Timseus  recorded  a  tra- 
dition, that,  a  little  before  his  time,  Epomeus,  the  principal  mountain  in 
the  centre  of  the  island,  vomited  fire  during  great  earthquakes  ;  that 
the  land  between  it  and  the  coast  had  ejected  much  fiery  matter,  which 
flowed  into  the  sea,  and  that  the  sea  receded  for  the  distance  of  three 
stadia,  and  then  returning,  overflowed  the  island.  This  eruption  is 
supposed  by  some  to  have  been  that  which  formed  the  crater  of  Monte 
Corvo  on  one  of  the  higher  flanks  of  Epomeo,  above  Foria,  the  lava- 
current  of  which  may  still  be  traced,  by  aid  of  the  scoriae  on  its  surface, 
from  the  crater  to  the  sea. 

To  one  of  the  subsequent  eruptions  in  the  lower  parts  of  the  isle, 
which  caused  the  expulsion  of  the  first  Greek  colony,  Monte  Rotaro 
has  been  attributed,  and  it  bears  every  mark  of  recent  origin.  The 
cone,  which  I  examined  in  1828,  is  remarkably  perfect,  and  has  a  cra- 
ter on  its  summit  precisely  resembling  that  of  Monte  Nuovo  near  Naples ; 
but  the  hill  is  larger,  and  resembles  some  of  the  more  considerable 
cones  of  single  eruption  near  Clermont  in  Auvergne,  and,  like  some  of 
them,  it  has  given  vent  to  a  lava-stream  at  its  base,  instead  of  its  sum- 
mit. A  small  ravine  swept  out  by  a  torrent  exposes  the  structure  of 


362  VOLCANIC   ERUPTIONS   IN   ISCHIA.  [On.  XXIIL 

the  cone,  whicli  is  composed  of  innumerable  inclined  and  slightly  undu- 
lating layers  of  pumice,  scoriae,  white  lapilli,  and  enormous  angular 
blocks  of  trachyte.  These  last  have  evidently  been  thrown  out  by  vio- 
lent explosions,  like  those  which  in  1822  launched  from  Vesuvius  a 
mass  of  augitic  lava,  of  many  tons'  weight,  to  the  distance  of  three 
miles,  which  fell  in  the  garden  of  Prince  Ottajano.  The  cone  of  Ro- 
taro  is  covered  with  the  arbutus,  and  other  beautiful  evergreens.  Such 
is  the  strength  of  the  virgin  soil,  that  the  shrubs  have  become  almost 
arborescent ;  and  the  growth  of  some  of  the  smaller  wild  plants  has 
been  so  vigorous,  that  botanists  have  scarcely  been  able  to  recognize 
the  species. 

The  eruption  which  dislodged  the  Syracusan  colony  is  supposed  to 
have  given  rise  to  that  mighty  current  which  forms  the  promontory  of 
Zaro  and  Caruso.  The  surface  of  these  lavas  is  still  very  arid  and 
bristling,  and  is  covered  with  black  scoriae  ;  so  that  it  is  not  without 
great  labor  that  human  industry  has  redeemed  some  small  spots,  and 
converted  them  into  vineyards.  Upon  the  produce  of  these  vineyards 
the  population  of  the  island  is  almost  entirely  supported.  It  amounted 
when  I  was  there,  in  1828,  to  about  twenty-five  thousand,  and  was  on 
the  increase. 

From  the  date  of  the  great  eruption  last  alluded  to,  down  to  our  own 
time,  Ischia  has  enjoyed  tranquillity,  with  the  exception  of  one  emission 
of  lava  hereafter  to  be  described,  which,  although  it  occasioned  much 
local  damage,  does  not  appear  to  have  devastated  the  whole  country, 
in  the  manner  of  more  ancient  explosions.  There  are,  upon  the  whole, 

Fig  41. 


Part  of  Ischia  seen  from  the  West. 

a.  Monte  Epomeo  or  San  Niccola.  6.  Monte  Vico. 

c.  Another  of  the  minor  cones  with  a  crater.* 

on  different  parts  of  Epomeo,  or  scattered  through  the  lower  tracts  of 
Ischia,  twelve  considerable  volcanic  cones  which  have  been  thrown  up 
since  the  island  was  raised  above  the  surface  of  the  deep  ;  and  many 
streams  of  lava  may  have  flowed,  like  that  of  "  Arso"  in  1302,  without 
cones  having  been  produced  ;  so  that  this  island  may,  for  ages  before 
the  period  of  the  remotest  traditions,  have  served  as  a  safety-valve  to 
the  whole  Terra  di  Lavoro,  while  the  fires  of  Vesuvius  were  dormant. 

*  See  Poulett  Scrope,  Geol.  Trans.  2d  series,  vol.  ii.  pi.  34 


On.  XXIIL]  LAKE   AVERNUS. VESUVIUS.  363 

Lake  Avernus. — It  seems  also  clear  that  Avernus,  a  circular  lake 
near  Puzzuoli,  about  half  a  mile  in  diameter,  which  is  now  a  salubrious 
and  cheerful  spot,  once  exhaled  mephitic  vapors,  such  as  are  often  emit- 
ted by  craters  after  eruptions.  There  is  no  reason  for  discrediting  the 
account  of  Lucretius,  that  birds  could  not  fly  over  it  without  being 
stifled,  although  they  may  now  frequent  it  uninjured.*  There  must 
have  been  a  time  when  this  crater  was  in  action ;  and  for  many  centu- 
ries afterwards  it  may  have  deserved  the  appellation  of  "  atri  jauna 
Ditis,"  emitting,  perhaps,  gases  as  destructive  of  animal  life  as  those 
suffocating  vapors  given  out  by  Lake  Quilotoa,  in  Quito,  in  1797,  by 
which  whole  herds  of  cattle  on  its  shores  were  killed,f  or  as  those  dele- 
terious emanations  which  annihilated  all  the  cattle  in  the  island  of  Lan- 
cerote,  one  of  the  Canaries,  in  1730.J  Bory  St.  Vincent  mentions,  that 
in  the  same  isle  birds  fell  lifeless  to  the  ground ;  and  Sir  William  Ham- 
ilton informs  us  that  he  picked  up  dead  birds  on  Vesuvius  during  an 
eruption. 

Solfatara. — The  Solfatara,  near  Puzzuoli,  which  may  be  considered 
as  a  nearly  extinguished  crater,  appears,  by  the  accounts  of  Strabo  and 
others,  to  have  been  before  the  Christian  era  in  very  much  the  same 
state  as  at  present,  giving  vent  continually  to  aqueous  vapor,  together 
with  sulphureous  and  muriatic  acid  gases,  like  those  evolved  by  Vesu- 
vius. 

Ancient  history  of  Vesuvius. — Such,  then,  were  the  points  where  the 
subterranean  fires  obtained  vent,  from  the  earliest  period  to  which  tra- 
dition reaches  back,  down  to  the  first  century  of  the  Christian  era ;  but 
we  then  arrive  at  a  crisis  in  the  volcanic  action  of  this  district — one  of 
the  most  interesting  events  witnessed  by  man  during  the  brief  period 
throughout  which  he  has  observed  the  physical  changes  on  the  earth's 
surface.  From  the  first  colonization  of  Southern  Italy  by  the  Greeks, 
Vesuvius  afforded  no  other  indications  of  its  volcanic  character  than 
such  as  the  naturalist  might  infer,  from  the  analogy  of  its  structure  to 
other  volcanoes.  These  were  recognized  by  Strabo,  but  Pliny  did  not 
include  the  mountain  in  his  list  of  active  vents.  The  ancient  cone  was 
of  a  very  regular  form,  terminating  not  as  at  present  in  two  peaks,  but 
with  a  summit  which  presented,  when  seen  from  a  distance,  the  even 
outline  of  an  abruptly  truncated  cone.  On  the  summit,  as  we  learn 
from  Plutarch,  there  was  a  crater  with  steep  cliffs,  and  having  its 
interior  overgrown  with  wild  vines,  and  with  a  sterile  plain  at  the  bot- 
tom. On  the  exterior,  the  flanks  of  the  mountain  were  clothed  with 
fertile  fields  richly  cultivated,  and  at  its  base  were  the  populous  cities 
of  Herculaneum  and  Pompeii.  But  the  scene  of  repose  was  at  length 
doomed  to  cease,  and  the  volcanic  fire  was  recalled  to  the  main  channel, 
which  at  some  former  unknown  period  had  given  passage  to  repeated 
streams  of  melted  lava,  sand,  and  scoriae. 

*  De  Rerum  Nat.  vi.  740. — Forbes,  on  Bay  of  Naples,  Edin.  Journ.  of  Sci.  No 
iii.  new  series,  p.  87.     Jan.  1830.  f  Humboldt,  Voy.  p.  317. 

|  Von  Buch,  Ueber  einen  vulcanischen  Ausbruch  auf  der  Insel  Lanzerote. 


364:  ERUPTION    OF    VESUVIUS,    A.  D.  79.  [Cu.  XXIII. 

Renewal  of  its  eruptions. — The  first  symptom  of  the  revival  of  the 
energies  of  this  volcano  was  the  occurrence  of  an  earthquake  in  the  year 
63  after  Christ,  which  did  considerable  injury  to  the  cities  in  its  vicinity. 
From  that  time  to  the  year  79  slight  shocks  were  frequent ;  and  in  the 
month  of  August  of  that  year  they  became  more  numerous  and  violent, 
till  they  ended  at  length  in  an  eruption.  The  elder  Pliny,  who  com- 
manded the  Roman  fleet,  was  then  stationed  at  Misenum ;  and  in  his 
anxiety  to  obtain  a  near  view  of  the  phenomena,  he  lost  his  life,  being 
suffocated  by  sulphureous  vapors.  His  nephew,  the  younger  Pliny, 
remained  at  Misenum,  and  has  given  us,  in  his  Letters,  a  lively  descrip- 
tion of  the  awful  scene.  A  dense  column  of  vapor  was  first  seen  rising 
vertically  from  Vesuvius,  and  then  spreading  itself  out  laterally,  so  that 
its  upper  portion  resembled  the  head,  and  its  lower  the  trunk  of  the 
pine,  which  characterizes  the  Italian  landscape.  This  black  cloud  was 
pierced  occasionally  by  flashes  of  fire,  as  vivid  as  lightning,  succeeded 
by  darkness  more  profound  than  night.  Ashes  fell  even  upon  the  ships 
at  Misenum,  and  caused  a  shoal  in  one  part  of  the  sea — the  ground 
rocked,  and  the  sea  receded  from  the  shores,  so  that  many  marine  ani- 
mals were  seen  on  the  dry  sand.  The  appearances  above  described 
agree  perfectly  with  those  witnessed  in  more  recent  eruptions,  especially 
those  of  Monte  Nuovo,  in  1538,  and  of  Vesuvius  in  1822. 

The  younger  Pliny,  although  giving  a  circumstantial  detail  of  so  many 
physical  facts,  and  describing  the  eruption  and  earthquake,  and  the  shower 
of  ashes  which  fell  at  Stabise,  makes  no  allusion  to  the  sudden  overwhelm- 
ing of  two  large  and  populous  cities,  Herculaneum  and  Pompeii.  In  ex- 
planation of  this  omission,  it  has  been  suggested  that  his  chief  object  was 
simply  to  give  Tacitus  a  full  account  of  the  particulars  of  his  uncle's  death. 
It  is  worthy,  however,  of  remark,  that  had  the  buried  cities  never  been 
discovered,  the  accounts  transmitted  to  us  of  their  tragical  end  might 
well  have  been  discredited  by  the  majority,  so  vague  and  general  are 
the  narratives,  or  so  long  subsequent  to  the  event.  Tacitus,  the  friend 
and  contemporary  of  Pliny,  when  adverting  in  general  terms  to  the  con- 
vulsions, says  merely  that  "  cities  were  consumed  or  buried."* 

Suetonius,  although  he  alludes  to  the  eruption  incidentally,  is  silent 
as  to  the  cities.  They  are  mentioned  by  Martial,  in  an  epigram,  as  im- 
mersed in  cinders ;  but  the  first  historian  who  alludes  to  them  by  name 
is  Dion  Cassius,|  who  flourished  about  a  century  and  a  half  after  Pliny. 
He  appears  to  have  derived  his  information  from  the  traditions  of  the 
inhabitants,  and  to  have  recorded,  without  discrimination,  all  the  facts 
and  fables  which  he  could  collect.  He  tells  us,  "  that  during  the  erup- 
tion a  multitude  of  men  of  superhuman  stature,  resembling  giants,  ap- 
peared, sometimes  on  the  mountain,  and  sometimes  in  the  environs — 
that  stones  and  smoke  were  thrown  out,  the  sun  was  hidden,  and  then 
the  giants  seemed  to  rise  again,  while  the  sounds  of  trumpets  were 
heard,  &c.,  &c. ;  and  finally,"  he  relates,  "  two  entire  cities,  Herculaneum 

*  Haustae  aut  obrutae  urbes. — Hist.  lib.  i.  f  Hist.  Rom.  lib.  Ixvi. 


CH.  XXIIL]  ERUPTION    IN    ISCHIA,    A.  D.    1302.  365 

and  Pompeii,  were  buried  under  showers  of  ashes,  while  all  the  people 
were  sitting  in  the  theatre."  That  many  of  these  circumstances  were 
invented,  would  have  been  obvious,  even  without  the  aid  of  Pliny's  let- 
ters ;  and  the  examination  of  Herculaneum  and  Pompeii  enables  us  to 
prove,  that  none  of  the  people  were  destroyed  in  the  theatres,  and  in- 
deed that  there  were  very  few  of  the  inhabitants  who  did  not  escape 
from  both  cities.  Yet  some  lives  were  lost,  and  there  was  ample  foun- 
dation for  the  tale  in  its  most  essential  particulars. 

It  does  not  appear  that  in  the  year  79  any  lava  flowed  from  Vesu- 
vius ;  the  ejected  substances,  perhaps,  consisted  entirely  of  lapilli,  sand, 
and  fragments  of  older  lava,  as  when  Monte  Nuovo  was  thrown  up  in 
1538.  The  first  era  at  which  we  have  authentic  accounts  of  the  flowing 
of  a  stream  of  lava,  is  the  year  1036,  which  is  the  seventh  eruption  from 
the  revival  of  the  fires  of  the  volcano.  A  few  years  afterwards,  in  1049, 
another  eruption  is  mentioned,  and  another  in  1138  (or  1139),  after 
which  a  great  pause  ensued  of  168  years.  During  this  long  interval  of 
repose,  two  minor  vents  opened  at  distant  points.  First,  it  is  on  tradi- 
tion that  an  eruption  took  place  from  the  Solfatara,  in  the  year  1198, 
during  the  reign  of  Frederick  II.,  Emperor  of  Germany;  and  although 
no  circumstantial  detail  of  the  event  has  reached  us  from  those  dark 
ages,  we  may  receive  the  fact  without  hesitation.*  Nothing  more,  how- 
ever, can  be  attributed  to  this  eruption,  as  Mr.  Scrope  observes,  than 
the  discharge  of  a  light  and  scoriform  trachytic  lava,  of  recent  aspect, 
resting  upon  the  strata  of  loose  tuff  which  covers  the  principal  mass  of 
trachyte,  f 

Volcanic  eruption  in  Ischia,  1302. — The  other  occurrence  is  well 
authenticated — the  eruption,  in  the  year  1302,  of  a  lava-stream  from  a 
new  vent  on  the  southeast  end  of  the  Island  of  Ischia.  During  part  of 
1301,  earthquakes  had  succeeded  one  another  with  fearful  rapidity  ;  and 
they  terminated  at  last  with  the  discharge  of  a  lava-stream  from  a  point 
named  the  Campo  del  Arso,  not  far  from  the  town  of  Ischia.  This  lava 
ran  quite  down  to  the  sea— a  distance  of  about  two  miles ;  in  color  it 
varies  from  iron-gray  to  reddish  black,  and  is  remarkable  for  the  glassy 
felspar  which  it  contains.  Its  surface  is  almost  as  sterile,  after  a  period 
of  five  centuries,  as  if  it  had  cooled  down  yesterday.  A  few  scantlings 
of  wild  thyme,  and  two  or  three  other  dwarfish  plants,  alone  appear  in 
the  interstices  of  the  scorise,  while  the  Vesuvian  lava  of  1767  is  already 
covered  with  a  luxuriant  vegetation.  Pontanus,  whose  country-houso 
was  burnt  and  overwhelmed,  describes  the  dreadful  scene  as  having 
lasted  two  months.;);  Many  houses  were  swallowed  up,  and  a  partial 
emigration  of  the  inhabitants  followed.  This  eruption  produced  no 
cone,  but  only  a  slight  depression,  hardly  deserving  the  name  of  a  cra- 

*  The  earliest  authority,  says  Mr.  Forbes,  given  for  this  fact,  appears  to  bo 
Capaccio.  quoted  in  the  Terra  Tremante  of  Bonito. — Edin.  Journ.  of  Sci.  <fec.  No. 
i.  new  series,  p.  127.  July,  1829. 

f  Geol.  Trans,  second  series,  vol.  ii.  p.  346. 

\  Lib.  vi.  de  Bello  Neap  in  Grtevii  Thesaur. 


366 


FORMATION   OF   MONTE   NUOVO. 


[CH.  XXIII 


ter,  where  heaps  of  black  and  red  scoriae  lie  scattered  around.  Until 
this  eruption,  Ischia  is  generally  believed  to  have  enjoyed  an  interval  of 
rest  for  about  seventeen  centuries ;  but  Julius  Obsequens,*  who  flour- 
ished A.  D.  214,  refers  to  some  volcanic  convulsions  in  the  year  662 
after  the  building  of  Rome  (91  B.  c.)  As  Pliny,  who  lived  a  century 
before  Obsequens,  does  not  enumerate  this  among  other  volcanic  erup- 
tions, the  statement  of  the  latter  author  is  supposed  to  have  been  erro- 
neous ;  but  it  would  be  more  consistent,  for  reasons  before  stated,  to 
disregard  the  silence  of  Pliny,  and  to  conclude,  that  some  kind  of  sub- 
terranean commotion,  probably  of  no  great  violence,  happened  at  the 
period  alluded  to. 

History  of  Vesuvius  after  1138. — To  return  to  Vesuvius: — the  next 
eruption  occurred  in  1306;  between  which  era  and  1631  there  was 
only  one  other  (in  1500),  and  that  a  slight  one.  It  has  been  remarked, 
that  throughout  this  period  Etna  was  in  a  state  of  such  unusual  activity, 
as  to  lend  countenance  to  the  idea  that  the  great  Sicilian  volcano  may 
sometimes  serve  as  a  channel  of  discharge  to  elastic  fluids  and  lava  that 
would  otherwise  rise  to  the  vents  in  Campania. 

Formation  of  Monte  Nuovo,  1538. — The  great  pause  was  also  marked 
by  a  memorable  event  in  the  Phlegraean  Fields — the  sudden  formation 
of  a  new  mountain  in  1538,  of  which  we  have  received  authentic  ac- 
counts from  contemporary  writers. 

The  height  of  this  mountain,  called  ever  since  Monte  Nuovo,  has  been 
determined  by  the  Italian  mineralogist  Pini,  to  be  440  English  feet 

Fig.  42. 


Monte  Nuovo,  formed  in  the  Bay  of  Baise,  Sept.  29th,  1538. 
1.  Cone  of  Monte  Nuovo.  2.  Brim  of  crater  of  ditto. 

3.  Thermal  spring,  called  Baths  of  Nero,  or  Stufe  di  Tritoli. 

above  the  level  of  the  bay ;  its  base  is  about  eight  thousand  feet,  or 
more  than  a  mile  and  a  half  in  circumference.     According  to  Pini,  the 

*  Prodig.  libel,  c.  cxiv. 


CH.  XXI  [I] 


ERUPTION  OF  MONTE  NUOVO. 


367 


depth  of  the  crater  is  421  English  feet  from  the  summit  of  the  hill,  so 
that  its  bottom  is  only  nineteen  feet  above  the  level  of  the  sea.  The 
cone  is  declared,  by  the  best  authorities,  to  stand  partly  on  the  site  of 
the  Lucrine  Lake  (4,  fig.  43),*  which  was  nothing  more  than  the  crater 
of  a  pre-existent  volcano,  and  was  almost  entirely  filled  during  the  ex- 
plosion of  1538.  Nothing  now  remains  but  a  shallow  pool,  separated 
from  the  sea  by  an  elevated  beach,  raised  artificially. 

Fijr.  43. 


HKfc 


1.  Monte  Nuovo. 

2.  Monte  Barbaro. 

3.  Lake  Avernus. 


The  Phlegraean  Fields. 


7.  BayofBaise. 


4.  Lucrine  Lake. 

5.  The  Solfatara. 

6.  Puzzuoli. 


Sir  William  Hamilton  has  given  us  two  original  letters  describing  this 
eruption.  The  first,  by  Falconi,  dated  1538,  contains  the  following 
passages.f  "  It  is  now  two  years  since  there  have  been  frequent  earth- 
quakes at  Puzzuoli,  Naples,  and  the  neighboring  parts.  On  the  day 
and  in  the  night  before  the  eruption  (of  Monte  Nuovo),  above  twenty 
shocks,  great  and  small,  were  felt.  The  eruption  began  on  the  29th  of 
September,  1538.  It  was  on  a  Sunday,  about  one  o'clock  in  the  night, 
when  flames  of  fire  were  seen  between  the  hot  baths  and  Tripergola. 
In  a  short  time  the  fire  increased  to  such  a  degree,  that  it  burst  open 
the  earth  in  this  place,  and  threw  up  so  great  a  quantity  of  ashes  and 
pumice-stones,  mixed  with  water,  as  covered  the  whole  country.  The 
next  morning  (after  the  formation  of  Monte  Nuovo)  the  poor  inhabitants 
of  Puzzuoli  quitted  their  habitations  in  terror,  covered  with  the  muddy 
and  black  shower  which  continued  the  whole  day  in  that  country — fly- 
ing from  death,  but  with  death  painted  in  their  countenances.  Some 
with  their  children  in  their  arms,  some  with  sacks  full  of  their  goods  ; 
others  leading  an  ass,  loaded  with  their  frightened  family,  towards  Na- 

*  This  representation  of  the  Phlegraean  Fields  is  reduced  from  part  of  Plate 
xxxi.  of  Sir  William  Hamilton's  great  work  "Campi  PblegrfflL"  The  faithfulness 
of  hia  colored  delineations  of  the  scenery  of  that  country  cannot  be  too  highly 
praised. 

f  Campi  Phlegraei,  p.  70. 


368  ERUPTION    OF   MONTE   NUOVO.  [Cn.  XXIIL 

pies  ;  others  carrying  quantities  of  birds,  of  various  sorts,  that  had  fallen 
dead  at  the  beginning  of  the  eruption ;  others,  again,  with  fish  which 
they  had  found,  and  which  were  to  be  met  with  in  plenty  on  the  shore, 
the  sea  having  left  them  dry  for  a  considerable  time.  I  accompanied 
Signor  Moramaldo  to  behold  the  wonderful  effects  of  the  eruption.  The 
sea  had  retired  on  the  side  of  Baise,  abandoning  a  considerable  tract, 
and  the  shore  appeared  almost  entirely  dry,  from  the  quantity  of  ashes 
and  broken  pumice-stones  thrown  up  by  the  eruption.  I  saw  two 
springs  in  the  newly  discovered  ruins  ;  one  before  the  house  that  was 
the  queen's,  of  hot  and  salt  water,"  &c. 

So  far  Falconi :  the  other  account  is  by  Pietro  Giacomo  di  Toledo, 
which  begins  thus  : — "  It  is  now  two  years  since  this  province  of  Cam- 
pagna  has  been  afflicted  with  earthquakes,  the  country  about  Puzzuoli 
much  more  so  than  any  other  parts  ;  but  the  27th  and  the  28th  of  the 
month  of  September  last,  the  earthquakes  did  not  cease  day  or  night 
in  the  town  of  Puzzuoli :  that  plain  which  lies  between  Lake  Avernus, 
the  Monte  Barbaro,  and  the  sea,  was  raised  a  little,  and  many  cracks 
were  made  in  it,  from  some  of  which  issued  water ;  at  the  same  time  the 
sea,  immediately  joining  the  plain,  dried  up  about  two  hundred  paces,  so 
that  the  fish  were  left  on  the  sand  a  prey  to  the  inhabitants  of  Puzzuoli. 
At  last,  on  the  29th  of  the  same  month,  about  two  o'clock  in  the  night, 
the  earth  opened  near  the  lake,  and  discovered  a  horrid  mouth,  from 
which  were  vomited  furiously  smoke,  fire,  stones,  and  mud,  composed  of 
ashes,  making  at  the  time  of  its  opening  a  noise  like  the  loudest  thun- 
der. The  stones  which  followed  were  by  the  flames  converted  to  pum- 
ice, and  some  of  these  were  larger  than  an  ox.  The  stones  went  about 
as  high  as  a  cross-bow  can  carry,  and  then  fell  down,  sometimes  on  the 
edge,  and  sometimes  into  the  mouth  itself.  The  mud  was  of  the  color 
of  ashes,  and  at  first  very  liquid,  then  by  degrees  less  so,  and  in  such 
quantities,  that  in  less  than  twelve  hours,  with  the  help  of  the  above- 
mentioned  stones,  a  mountain  was  raised  of  1000  paces  in  height.  Not 
only  Puzzuoli  and  the  neighboring  country  was  full  of  this  mud,  but  the 
city  of  Naples  also ;  so  that  many  of  its  palaces  were  defaced  by  it. 
Now  this  eruption  lasted  two  nights  and  two  days  without  intermission, 
though,  it  is  true,  not  always  with  the  same  force  ;  the  third  day  the 
eruption  ceased,  and  I  went  up  with  many  people  to  the  top  of  the  new 
hill,  and  saw  down  into  its  mouth,  which  was  a  round  cavity  about  a 
quarter  of  a  mile  in  circumference,  in  the  middle  of  which,  the  stones 
which  had  fallen  were  boiling  up,  just  as  a  caldron  of  water  boils  on 
the  fire.  The  fourth  day  it  began  to  throw  up  again,  and  the  seventh 
much  more,  but  still  with  less  violence  than  the  first  night.  At  this 
time  many  persons  who  were  on  the  hill  were  knocked  down  by  the 
stones  and  killed,  or  smothered  with  the  smoke.  In  the  day  the  smoke 
still  continues,  and  you  often  see  fire  in  the  midst  of  it  in  the  night- 
time."* 

It  will  be  seen  that  both  these  accounts,  written  immediately  after  the 

*  Campi  Phlegrsei,  p.  77. 


On.  XXIIL]  ERUPTION    OF    MONTE    NUOVO.  369 

birth  of  Monte  Nuovo,  agree  in  stating  that  the  sea  retired ;  and  one 
mentions  that  its  bottom  was  upraised  ;  but  they  attribute  the  origin  of 
the  new  hill  exclusively  to  the  jets  of  mud,  showers  of  scoriae,  and  large 
fragments  of  rock,  cast  out  from  a  central  orifice,  for  several  days  and 
nights.  Baron  Von  Buch,  however,  in  his  excellent  work  on  the  Canary 
Islands,  and  volcanic  phenomena  in  general,  has  declared  his  opinion 
that  the  crone  and  crater  of  Monte  Nuovo  were  for-med,  not  in  the  man- 
ner above  described,  but  by  the  upheaval  of  solid  beds  of  white  tuff, 
which  were  previously  horizontal,  but  which  were  pushed  up  in  1538, 
so  as  to  dip  away  in  all  directions  from  the  centre,  with  the  same  incli- 
nation as  the  sloping  surface  of  the  cone  itself.  "  It  is  an  error,"  he 
says,  "  to  imagine  that  this  hill  was  formed  by  eruption,  or  by  the  ejec- 
tion of  pumice,  scoriae,  and  other  incoherent  matter ;  for  the  solid  beds 
of  upraised  tuff  are  visible  all  round  the  crater,  and  it  is  merely  the  su- 
perficial covering  of  the  cone  which  is  made  up  of  ejected  scoriae."* 

In  confirmation  of  this  view,  M.  Dufrenoy  has  cited  a  passage  from 
the  works  of  Porzio,  a  celebrated  physician  of  that  period,  to  prove 
that  in  1538  the  ground  where  Monte  Nuovo  stands  was  pushed  up  in 
the  form  of  a  great  bubble  or  blister,  which  on  bursting,  gave  origin  to 
the  present  deep  crater.  Porzio,  says,  "  that  after  two  days  and  nights 
of  violent  earthquakes,  the  sea  retired  for  nearly  200  yards  ;  so  that  the 
inhabitants  could  collect  great  numbers  of  fish  on  this  part  of  the 
shore,  and  see  some  springs  of  fresh  water  which  rose  up  there.  At 
length,  on  the  third  day  of  the  calends  of  October  (September  29),  they 
saw  a  large  tract  of  ground  intervening  between  the  foot  of  Monte  Bar- 
baro,  and  part  of  the  sea,  near  the  Lake  Avernus,  rise,  and  suddenly 
assume  the  form  of  an  incipient  hill ;  and  at  two  o'clock  at  night,  this 
heap  of  earth,  opening  as  it  were  its  mouth,  vomited,  with  a  loud  noise, 
flames,  pumice-stones,  and  ashes. "f 

So  late  as  the  year  1846  a  fourth  manuscript  (written  immediately 
after  the  eruption)  was  discovered  and  published  in  Germany.  It  was 
written  in  1538  by  Francesco  del  Nero.J  who  mentions  the  drying  up 
of  the  bed  of  the  sea  near  Puzzuoli,  which  enabled  the  inhabitants  of 
the  town  to  carry  off  loads  of  fish.  About  eight  o'clock  in  the  morn- 
ing of  the  29th  September,  the  earth  sunk  down  about  14  feet  in  that 
place  where  the  volcanic  orifice  now  appears,  and  there  issued  forth  a 
small  stream  of  water,  at  first  cold,  and  afterwards  tepid.  At  noon,  on 
the  same  day,  the  earth  began  to  swell  up  in  the  same  spot  where  it 
had  sunk  down  14  feet,  so  as  to  form  a  hill.  About  this  time  fire 

*   P.  347.     Paris,  1836. 

f  "  Magnus  terras  tractus,  qtii  inter  radices  mentis,  quern  Barbarum  incolae  ap- 
pellant, et  mare  juxta  Avernum  jacet,  sese  erigere  videbatur,  et  montis  subit6 
nascentis  figuram  imitari.  Eo  ipso  die  hora  noctis  II.,  iste  terrae  cumulus,  aperto 
veluti  ore,  magno  cum  fremitu,  magnos  ignes  evomuit ;  pumicesque,  et  lapidea, 
cineresque." — Porzio,  Opera  Omnis,  Medica,  Phil.,  et  Mathemat.,  in  unum  collecta, 
1736,  cited  by  Dufrenoy,  Mem.  pour  servir  a  une  Description  Geologique  de  la 
France,  torn.  iv.  p.  274. 

\  See  Neues  Jahr  Buch  for  1846,  and  a  translation  in  the  Quarterly  Journ.  of 
the  Geol.  Soc.  for  1847,  vol  iii.  p.  20,  Memoirs. 

24 


370  ERUPTION   OF   MONTE   NUOVO.  [Cn.  XXIII. 

issued  forth,  and  gave  rise  to  the  great  gulf,  "  with  such  a  force,  noise, 
and  shining  light,  that  I,  who  was  standing  in  my  garden,  was  seized 
with  terror.  Forty  minutes  afterwards,  although  unwell,  I  got  upon  a 
neighboring  height,  from  which  I  saw  all  that  took  place,  and  by  my 
troth  it  was  a  splendid  fire,  that  threw  up  for  a  long  time  much  earth 
and  many  stones,  which  fell  back  again  all  round  the  gulf,  in  a  semicir- 
cle of  from  one  to  three  bow-shots  in  diameter,  and,  filling  up  part  of 
the  sea,  formed  a  hill  nearly  of  the  height  of  Monte  Morello.  Masses 
of  earth  and  stones,  as  large  as  an  ox,  were  shot  up  from  the  fiery  gulf 
into  the  air,  to  a  height  which  I  estimate  at  a  mile  and  a  half.  When 
they  descended,  some  were  dry,  others  in  a  soft  muddy  state."  He 
concludes  by  alluding  again  to  the  sinking  of  the  ground,  and  the  eleva- 
tion of  it  which  followed,  and  says  that  to  him  it  was  inconceivable  how 
such  a  mass  of  stones  and  ashes  could  have  been  poured  forth  from  the 
gulf.  He  also  refers  to  the  account  which  Porzio  was  to  draw  up  for 
the  Viceroy. 

On  comparing  these  four  accounts,  recorded  by  eye-witnesses,  there 
appears  to  be  no  real  discrepancy  between  them.  It  seems  clear  that 
the  ground  first  sunk  down  14  feet  on  the  site  of  the  future  volcano, 
and  after  having  subsided  it  was  again  propelled  upwards  by  the  lava 
mingled  with  steam  and  gases,  which  were  about  to  burst  forth.  Jets 
of  red-hot  lava,  fragments  of  fractured  rock,  and  occasionally  mud  com- 
posed of  a  mixture  of  pumice,  tuff,  and  sea- water,  were  hurled  into  the 
air.  Some  of  the  blocks  of  stone  were  very  large,  leading  us  to  infer 
that  the  ground  which  sank  and  rose  again  was  much  shattered  and 
torn  to  pieces  by  the  elastic  vapors.  The  whole  hill  was  not  formed  at 
once,  but  by  an  intermittent  action  extending  over  a  week  or  more.  It 
seems  that  the  chasm  opened  between  Tripergola  and  the  baths  in  its 
suburbs,  and  that  the  ejected  materials  fell  and  buried  that  small  town. 
A  considerable  part,  however,  of  the  hill  was  formed  in  less  than 
twenty-four  hours,  and  in  the  same  manner  as  on  a  smaller  scale  the 
mud  cones  of  the  air  volcanoes  are  produced,  with  a  cavity  in  the  mid- 
dle. There  is  no  difficulty  in  conceiving  that  the  pumiceous  mud,  if 
so  thrown  out,  may  have  set  into  a  kind  of  stone  on  drying,  just  as 
some  cements,  composed  of  volcanic  ashes,  are  known  to  consolidate 
with  facility. 

I  am  informed  that  Baron  Von  Buch  discovered  some  marine  shells 
of  existing  species,  such  as  occur  fossil  in  the  tuff  of  the  neighborhood, 
in  beds  exposed  low  down  in  the  walls  of  the  crater  of  Monte  Nuovo. 
These  may  have  been  ejected  in  the  mud  mixed  with  sea-water  which 
was  cast  out  of  the  boiling  gulf ;  or,  as  Signor  Arcangelo  Scacchi  has 
suggested,*  they  may  have  been  derived  from  the  older  tuff,  which 
contains  marine  shells  of  recent  species.  The  same  observer  remarks 
that  Porzio's  account  upon  the  whole  corroborates  the  doctrine  of  the 
cone  having  been  formed  by  eruption,  in  proof  of  which  he  cites  the 

*  Mem.  Roy.  Acad.  Nap.  1849. 


CH.  XXIIL]  ERUPTION    OF   MONTE   NUOVO.  371 

following  passage  : — "  But  what  was  truly  astonishing,  a  hill  of  pumice- 
stones  and  ashes  was  heaped  up  round  the  gulf  to  the  height  of  a  mile 
in  a  single  night."*  Signer  Scacchi  also  adds  that  the  ancient  temple 
of  Apollo,  now  at  the  foot  of  Monte  Nuovo,  and  the  walls  of  which 
still  retain  their  perfect  perpendicularity,  could  not  possibly  have  main- 
tained that  position  had  the  cone  of  Monte  Nuovo  really  been  the  result 
of  upheaval. 

Tripergola  was  much  frequented  as  a  watering-place,  and  contained 
a  hospital  for  those  who  resorted  there  for  the  benefit  of  the  thermal 
springs  ;  and  it  appears  that  there  were  no  fewer  than  three  inns  in  the 
principal  street.  Had  Porzio  stated  that  any  of  these  buildings,  or  the 
ruins  of  them,  were  seen  by  himself  or  others  raised  up  above  the  plain, 
a  short  time  before  the  first  eruption,  so  as  to  stand  on  the  summit  or 
slope  of  a  newly-raised  hillock,  we  might  have  been  compelled,  by  so 
circumstantial  a  narrative,  to  adopt  M.  Dufrenoy's  interpretation. 

But  in  the  absence  of  such  evidence,  we  must  appeal  to  the  crater 
itself,  where  we  behold  a  section  of  the  whole  mountain,  without  being 
able  to  detect  any  original  nucleus  of  upheaved  rock  distinct  from  the 
rest ;  on  the  contrary,  the  whole  mass  is  similar  throughout  in  composi- 
tion, and  the  cone  very  symmetrical  in  form  :  nor  are  there  any  clefts, 
such  as  might  be  looked  for,  as  the  effect  of  the  sudden  upthrow  of 
stony  masses.  M.  C.  Prevost  has  well  remarked,  that  if  beds  of  solid 
and  non-elastic  materials  had  yielded  to  a  violent  pressure  directed  from 
below  upward,  we  should  find  not  simply  a  deep  empty  cavity,  but  an 
irregular  opening,  where  many  rents  con- 
verged ;  and  these  rents  would  be  now 
seen  breaking  through  the  walls  of  the 
crater,  widening  as  they  approach  the 
centre.  (See  Fig.  44,  a,  b.)  f  Not  a 
single  fissure  of  this  kind  is  observable  in 
the  interior  of  Monte  Nuovo,  where  the 
walls  of  the  crater  are  continuous  and  en- 
tire ;  nor  are  there  any  dikes  implying  that 
rents  had  existed,  which  were  afterwards  filled  with  lava  or  other  matter. 

It  has  moreover  been  often  urged  by  Von  Buch,  De  Beaumont,  and 
others,  who  ascribe  the  conical  form  of  volcanoes  chiefly  to  upheaval 
from  below,  that  in  such  mountains  there  are  a  great  number  of  deep 
rents  and  ravines,  which  diverge  on  all  sides  like  the  spokes  of  a  wheel, 
from  near  the  central  axis  to  the  circumference  or  base  of  the  cone,  as 
in  the  case  of  Palma,  Cantal,  and  Teneriffe.  Yet  the  entire  absence  of 
such  divergent  fissures  or  ravines,  in  such  cases  as  Monte  Nuovo,  Somma, 
or  Etna,  is  passed  by  unnoticed,  and  appears  to  have  raised  in  their 
minds  no  objection  to  their  favorite  theory. 

It  is,  indeed,  admitted  by  M.  Dufrenoy  that  there  are  some  facts 

*  "  Verum  quod  omnem  superat  admirationem,  mons  circum  earn  voraginem 
ex  pummicibus  et  cincere  plusquam  mille  passuum  altitudine  uu£  nocte  congestua 
aspicitur."  f  Mem.  de  la  Soc.  Geol.  de  France,  torn.  ii.  p.  91. 


372  VOLCANOES    OF   THE   PHLEGK^AN   FIELDS.  [Cn.  XXIII. 

which  it  is  very  difficult  to  reconcile  with  his  own  view  of  Porzio's  rec- 
ord. Thus,  for  example,  there  are  certain  Roman  monuments  at  the 
base  of  Monte  Nuovo,  and  on  the  borders  of  Lake  Avernus,  such  as  the 
temples  of  Apollo  (before  mentioned)  and  Pluto,  which  do  not  seem  to 
have  suffered  in  the  least  degree  by  the  supposed  upheaval.  "  The 
walls  which  still  exist  have  preserved  their  vertical  position,  and  the 
vaults  are  in  the  same  state  as  other  monuments  on  the  shores  of  the 
Bay  of  Baise.  The  long  gallery  which  led  to  the  Sibyl's  Cave,  on  the 
other  side  of  Lake  Avernus,  has  in  like  manner  escaped  injury,  the  roof 
of  the  gallery  remaining  perfectly  horizontal,  the  only  change  being  that 
the  soil  of  the  chamber  in  which  the  Sibyl  gave  out  her  oracles  is  now 
covered  by  a  few  inches  of  w~ater,  which  merely  indicates  a  slight  alter- 
ation in  the  level  of  Lake  Avernus."*  On  the  supposition,  then,  that 
pre-existing  beds  of  pumiceous  tuff  were  upraised  in  1538,  so  as  to  form 
Monte  Nuovo,  it  is  acknowledged  that  the  perfectly  undisturbed  state 
of  the  contiguous  soil  on  which  these  ancient  monuments  stand,  is  very 
different  from  what  might  have  been  expected. 

Mr.  Darwin,  in  his  "  Volcanic  Islands,"  has  described  several  crateri- 
form  hills  in  the  Galapagos  Archipelago  as  composed  of  tuff  which  has 
evidently  flowed  like  mud,  and  yet  on  consolidating  has  preserved  an 
inclination  of  twenty  and  even  thirty  degrees.  The  tuff  does  not  fold  in 
continuous  sheets  round  the  hills  as  would  have  happened  if  they  had 
been  formed  by  the  upheaval  of  horizontal  layers.  The  author  describes 
the  composition  of  the  tuff  as  very  similar  to  that  of  Monte  Nuovo,  and 
the  high  angles  at  which  the  beds  slope,  both  those  which  have  flowed 
and  those  which  have  fallen  in  the  form  of  ashes,  entirely  removes  the 
difficulty  supposed  by  M.  Dufrenoy  to  exist  in  regard  to  the  slope  of 
Monte  Nuovo,  where  it  exceeds  an  angle  of  18°  to  20°. f  Mr.  Dana, 
also,  in  his  account  of  the  Sandwich  Islands,};  shows  that  in  the  "  cinder 
cones"  of  that  region,  the  strata  have  an  original  inclination  of  between 
35°  and  40°,  while  in  the  "tufa  cones"  formed  near  the  sea,  the  beds 
slope  at  about  an  angle  of  30°.  The  same  naturalist  also  observed  in 
the  Sarnoan  or  Navigator  Islands  in  Polynesia,  that  fragments  of  fresh 
coral  had  been  thrown  up  together  with  volcanic  matter  to  the  height  of 
200  feet  above  the  level  of  the  sea  in  cones  of  tufa.§ 

I  shall  again  revert  to  the  doctrine  of  the  origin  of  volcanic  cones  by 
upheaval,  when  speaking  of  Vesuvius,  Etna,  and  Santorin,  and  shall  now 
merely  add,  that,  in  1538,  the  whole  coast,  from  Monte  Nuovo  to  be- 
yond Puzzuoli,  was  upraised  to  the  height  of  many  feet  above  the  bed 
of  the  Mediterranean,  and  has  since  retained  the  greater  part  of  the 
elevation  then  acquired.  The. proofs  of  these  remarkable  changes  of 
level  will  be  considered  at  length  when  the  phenomena  of  the  temple  of 
Serapis  are  described. || 

*  Dufrenoy,  Mem.  pour  servir,  Ac.  p.  277. 

f  Darwin's  Volcanic  Islands,  106,  note. 

\  Geology  of  the  American  Exploring  Expedition,  in  183S-1842,  p.  354. 

§  Ibid.  p.  328.  |   See  chap.  29. 


CH.  XXIIL]  VOLCANOES    OF   THE    PHLEGR.EAN   FIELDS.  373 

Volcanoes  of  the  Phlegrcean  Fields. — Immediately  adjoining  Monte 
Nuovo  is  the  larger  volcanic  cone  of  Monte  Barbaro  (2,  fig.  43,  p.  367), 
the  "  Gaurus  inanis"  of  Juvenal — an  appellation  given  to  it  probably 
from  its  deep  circular  crater,  which  is  about  a  mile  in  diameter.  Large 
as  is  this  cone,  it  was  probably  produced  by  a  single  eruption ;  and  it 
does  not,  perhaps,  exceed  in  magnitude  some  of  the  largest  of  those 
formed  in  Ischia,  within  the  historical  era.  It  is  composed  chiefly  of 
indurated  tufa  like  Monte  Nuovo,  stratified  conformably  to  its  conical 
surface.  This  hill  was  once  very  celebrated  for  its  wines,  and  is  still 
covered  with  vineyards ;  but  when  the  vine  is  not  in  leaf  it  has  a  sterile 
appearance,  and,  late  in  the  year,  when  seen  from  the  beautiful  Bay  of 
Baise,  it  often  contrasts  so  strongly  in  verdure  with  Monte  Nuovo,  which 
is  always  clothed  with  arbutus,  myrtle,  and  other  wild  evergreens,  that 
a  stranger  might  well  imagine  the  cone  of  older  date  to  be  that  thrown 
up  in  the  sixteenth  century.* 

There  is  nothing,  indeed,  so  calculated  to  instruct  the  geologist  as 
the  striking  manner  in  which  the  recent  volcanic  hills  of  Ischia,  and 
that  now  under  consideration,  blend  with  the  surrounding  landscape. 
Nothing  seems  wanting  or  redundant ;  every  part  of  the  picture  is  in 
such  perfect  harmony  with  the  rest,  that  the  whole  has  the  appearance 
of  having  been  called  into  existence  by  a  single  effort  of  creative  power. 
Yet  what  other  result  could  we  have  anticipated  if  nature  has  ever  been 
governed  by  the  same  laws  ?  Each  new  mountain  thrown  up — each 
new  tract  of  land  raised  or  depressed  by  earthquakes — should  be  in 
perfect  accordance  with  those  previously  formed,  if  the  entire  configura- 
tion of  the  surface  has  -been  due  to  a  long  series  of  similar  disturbances. 
Were  it  true  that  the  greater  part  of.  the  dry  land  originated  simulta- 
neously in  its  present  state,  at  some  era  of  paroxysmal  convulsion,  and 
that  additions  were  afterwards  made  slowly  and  successively  during  a 
period  of  comparative  repose  ;  then,  indeed,  there  might  be  reason  to 
expect  a  strong  line  of  demarcation  between  the  signs  of  the  ancient 
and  modern  changes.  But  the  very  continuity  of  the  plan,  and  the 
perfect  identity  of  the  causes,  are  to  many  a  source  of  deception  ;  since 
by  producing  a  unity  of  effect,  they  lead  them  to  exaggerate  the  energy 
of  the  agents  which  operated  in  the  earlier  ages.  In  the  absence  of  all 
historical  information,  they  are  as  unable  to  separate  the  dates  of  the 
origin  of  different  portions  of  our  continents,  as  the  stranger  is  to  deter- 
mine, by  their  physical  features  alone,  the  distinct  ages  of  Monte  Nuovo, 
Monte  Barbara,  Astroni,  and  the  Solfatara. 

The  vast  scale  and  violence  of  the  volcanic  operations  in  Campania, 
in  the  olden  time,  has  been  a  theme  of  declamation,  and  has  been  con- 
trasted with  the  comparative  state  of  quiescence  of  this  delightful  region 
in  the  modern  era.  Instead  of  inferring,  from  analogy,  that  the  ancient 
Vesuvius  was  always  at  rest  when  the  craters  of  the  Phlegrsean  Fields 

*  Hamilton  (writing  in  1770)  says,  "the  new  mountain  produces  as  yet  but  a 
very  slender  vegetation." — Campi  Phlegraei,  p.  69.  This  remark  was  no  longer 
applicable  when  I  saw  it,  in  1828. 


374  MODERN  ERUPTIONS   OF  MOUNT  VESUVIUS.          [Ce.  XXIII. 

were  burning — that  each  cone  rose  in  succession, — and  that  many  years, 
and  often  centuries,  of  repose  intervened  between  different  eruptions, — 
geologists  seem  to  have  generally  conjectured  that  the  whole  group 
sprung  up  from  the  ground  at  once,  like  the  soldiers  of  Cadmus  when 
he  sowed  the  dragon's  teeth.  As  well  might  they  endeavor  to  persuade 
us  that  on  these  Phlegraean  Fields,  as  the  poets  feigned,  the  giants 
warred  with  Jove,  ere  yet  the  puny  race  of  mortals  were  in  being. 

Modern  eruptions  of  Vesuvius. — For  nearly  a  century  after  the  birth 
of  Monte  Nuovo,  Vesuvius  continued  in  a  state  of  tranquillity.  There 
had  been  no  violent  eruption  for  492  years ;  and  it  appears  that  the 
crater  was  then  exactly  in  the  condition  of  the  present  extinct  volcano 
of  Astroni,  near  Naples.  Bracini,  who  visited  Vesuvius  not  long  before 
the  eruption  of  1631,  gives  the  following  interesting  description  of  the 
interior : — "  The  crater  was  five  miles  in  circumference,  and  about  a 
thousand  paces  deep :  its  sides  were  covered  with  brushwood,  and  at 
the  bottom  there  was  a  plain  on  which  cattle  grazed.  In  the  woody 
parts  wild  boars  frequently  harbored.  In  one  part  of  the  plain,  covered 
with  ashes,  were  three  small  pools,  one  filled  with  hot  and  bitter  water, 
another  salter  than  the  sea,  and  a  third  hot,  but  tasteless."*  But  at 
length  these  forests  and  grassy  plains  were  consumed,  being  suddenly 
blown  into  the  air,  and  their  ashes  scattered  to  the  winds.  In  Decem- 
ber, 1631,  seven  streams  of  lava  poured  at  once  from  the  crater,  and 
overflowed  several  villages,  on  the  flanks  and  at  the  foot  of  the  moun- 
tain. Resina,  partly  built  over  the  ancient  site  of  Herculaneum,  was 
consumed  by  the  fiery  torrent.  Great  floods  of  mud  were  as  destruc- 
tive as  the  lava  itself, — no  uncommon  occurrence  during  these  catastro- 
phes ;  for  such  is  the  violence  of  rains  produced  by  the  evolutions  of 
aqueous  vapor,  that  torrents  of  water  descend  the  cone,  and  becoming 
charged  with  impalpable  volcanic  dust,  and  rolling  along  loose  ashes, 
acquire  sufficient  consistency  to  deserve  their  ordinary  appellation  of 
"  aqueous  lavas." 

A  brief  period  of  repose  ensued,  which  lasted  only  until  the  year 
1666,  from  which  time  to  the  present  there  has  been  a  constant  series 
of  eruptions,  with  rarely  an  interval  of  rest  exceeding  ten  years.  Dur- 
ing these  three  centuries,  no  irregular  volcanic  agency  has  convulsed 
other  points  in  this  district.  Brieslak  remarked,  that  such  irregular 
convulsions  had  occurred  in  the  Bay  of  Naples  in  every  second  century ; 
as,  for  example,  the  eruption  of  the  Solfatara,  in  the  twelfth  ;  of  the 
lava  of  Arso,  in  Ischia,  in  the  fourteenth ;  and  of  Monte  Nuovo  in  the 
sixteenth ;  but  the  eighteenth  has  formed  an  exception  to  this  rule,  and 
this  seems  accounted  for  by  the  unprecedented  number  of  eruptions  of 
Vesuvius  during  that  period ;  whereas,  when  the  new  vents  opened, 
there  had  always  been,  as  we  have  seen,  a  long  intermittence  of  activity 
in  the  principal  volcano. 

*  Hamilton's  Campi  Phlegraei,  folio,  vol.  i.  p.  62  ;  and  Brieslak,  Campanie,  tome 
».  p.  186. 


CHAPTER  XXIV. 

VOLCANIC    DISTRICT    OF    NAPLES continued. 

Dimensions  and  structure  of  the  cone  of  Vesuvius — Fluidity  and  motion  of  lava — 
Dikes— Alluviums  called  "aqueous  lavas" — Origin  and  composition  of  the 
matter  enveloping  Herculaneum  and  Pompeii — Condition  and  contents  of  the 
buried  cities — Small  number  of  skeletons — State  of  preservation  of  animal  and 
vegetable  substances — Rolls  of  papyrus — Stabiae — Torre  del  Greco — Conclud- 
ing remarks  on  the  Campanian  volcanoes. 

Structure  of  the  cone  of  Vesuvius. — BETWEEN  the  end  of  the  eigh- 
teenth century  and  the  year  1822,  the  great  crater  of  Vesuvius  had  been 
gradually  filled  by  lava  boiling  up  from  below,  and  by  scoriae  falling 
from  the  explosions  of  minor  mouths  which  were  formed  at  intervals  on 
its  bottom  and  sides.  In  place  of  a  regular  cavity,  therefore,  there 
was  a  rough  and  rocky  plain,  covered  with  blocks  of  lava  and  scoriae, 
and  cut  by  numerous  fissures,  from  which  clouds  of  vapor  were  evolved. 
But  this  state  of  things  was  totally  changed  by  the  eruption  of  Octo- 
ber, 1822,  when  violent  explosions,  during  the  space  of  more  than 
twenty  days,  broke  up  and  threw  out  all  this  accumulated  mass,  so  as 
to  leave  an  immense  gulf  or  chasm,  of  an  irregular,  but  somewhat  ellip- 
tical shape,  about  three  miles  in  circumference  when  measured  along 
the  very  sinuous  and  irregular  line  of  its  extreme  margin,  but  somewhat 
less  than  three  quarters  of  a  mile  in  its  longest  diameter,  which  was  di- 
rected from  N.  E.  to  S.  W.*  The  depth  of  this  tremendous  abyss  has 
been  variously  estimated  ;  for  from  the  hour  of  its  formation  it  increased 
daily  by  the  dilapidation  of  its  sides.  It  measured,  at  first,  according 
to  the  account  of  some  authors,  two  thousand  feet  in  depth  from  the 
extreme  part  of  the  existing  summit  ;f  but  Mr.  Scrope,  when  he  saw  it, 
soon  after  the  eruption,  estimated  its  depth  at  less  than  half  that 
amount.  More  than  eight  hundred  feet  of  the  cone  was  carried  away 
by  the  explosions,  so  that  the  mountain  was  reduced  in  height  from 
about  4200  to  3400  feet.J 

A.S  we  ascend  the  sloping  sides,  the  volcano  appears  a  mass  of  loose 
materials — a  mere  heap  of  rubbish,  thrown  together  without  the  slight- 
est order ;  but  on  arriving  at  the  brim  of  the  crater,  and  obtaining  a 
view  of  the  interior,  we  are  agreeably  surprised  to  discover  that  the 
conformation  of  the  whole  displays  in  every  part  the  most  perfect  sym- 
metry and  arrangement.  The  materials  are  disposed  in  regular  strata, 
slightly  undulating,  appearing,  when  viewed  in  front,  to  be  disposed  in 
horizontal  planes.  But,  as  we  make  the  circuit  of  the  edge  of  the  cra- 

*  Account  of  the  Eruption  of  Vesuvius  in  October,  1822,  by  G.  P.  Scrope,  Esq., 
Journ.  of  Sci.  <fcc.  vol.  xv.  p.  175. 

f  Mr.  Forbes,  Account  of  Mount  Vesuvius,  Edin.  Journ.  of  Sci.  No.  xviii.  p.  195. 
Oct.  1828. 

J  Ibid.  p.  194. 


376  STRUCTURE   OF  THE  CONE   OF   VESUVIUS.          [On.  XXIV 

ter,  and  observe  the  cliffs  by  which  it  is  encircled  projecting  or  receding 
in  salient  or  retiring  angles,  we  behold  transverse  sections  of  the  currents 
of  lava  and  beds  of  sand  and  scoriae,  and  recognize  their  true  dip.  We 
then  discover  that  they  incline  outwards  from  the  axis  of  the  cone,  at 
angles  varying  from  30°  to  40°.  The  whole  cone,  in* fact,  is  composed 
of  a  number  of  concentric  coatings  of  alternating  lavas,  sand,  and  sco- 
riae. Every  shower  of  ashes  which  has  fallen  from  above,  and  every 
stream  of  lava  descending  from  the  lips  of  the  crater,  have  conformed 
to  the  outward  surface  of  the  hill,  so  that  one  conical  envelope  may  be 
said  to  have  been  successively  folded  round  another,  until  the  aggrega- 
tion of  the  whole  mountain  was  completed.  The  marked  separation 
into  distinct  beds  results  from  the  different  colors  and  degrees  of  coarse- 
ness in  the  sands,  scorise,  and  lava,  and  the  alternation  of  these  with 
each  other.  The  greatest  difficulty,  on  the  first  view,  is  to  conceive 
how  so  much  regularity  can  be  produced,  notwithstanding  the  unequal 
distribution  of  sand  and  scoriae,  driven  by  prevailing  winds  in  particular 
eruptions,  and  the  small  breadth  of  each  sheet  of  lava  as  it  first  flows 
out  from  the  crater. 

But,  on  a  closer  examination,  we  find  that  the  appearance  of  extreme 
uniformity  is  delusive ;  for  when  a  number  of  beds  thin  out  gradually, 
and  at  different  points,  the  eye  does  not  without  difficulty  recognize 
the  termination  of  any  one  stratum,  but  usually  supposes  it  continuous 
with  some  other,  which  at  a  short  distance  may  lie  precisely  in  the 
same  plane.  The  slight  undulations,  moreover,  produced  by  inequali- 
ties on  the  sides  of  the  hill  on  which  the  successive  layers  were 
moulded,  assist  the  deception.  As  countless  beds  of  sand  and  scoriae 
constitute  the  greater  part  of  the  whole  mass,  these  may  sometimes 
mantle  continuously  round  the  whole  cone  ;  and  even  lava  streams  may 
be  of  considerable  breadth  when  first  they  overflow,  and  since,  in  some 
eruptions,  a  considerable  part  of  the  upper  portion  of  the  cone  breaks 
down  at  once,  may  form  a  sheet  extending  as  far  as  the  space  which 
the  eye  usually  takes  in,  in  a  single  section. 

The  high  inclination  of  some  of  the  beds,  and  the  firm  union  of  the 
particles  even  where  there  is  evidently  no  cement,  is  another  striking 
feature  in  the  volcanic  tuffs  and  breccias,  which  seems  at  first  not  very 
easy  of  explanation.  But  the  last  great  eruption  afforded  ample  illus- 
tration of  the  manner  in  which  these  strata  are  formed.  Fragments  of 
lava,  scoriae,  pumice,  and  sand,  when  they  fall  at  slight  distances  from  the 
summit,  are  only  half  cooled  down  from  a  state  of  fusion,  and  are  after- 
wards acted  upon  by  the  heat  from  within,  and  by  fumeroles  or  small 
crevices  in  the  cone  through  which  hot  vapors  are  disengaged.  Thus 
heated,  the  ejected  fragments  cohere  together  strongly  ;  and  the  whole 
mass  acquires  such  consistency  in  a  few  days,  that  fragments  cannot  be 
detached  without  a  smart  blow  of  the  hammer.  At  the  same  time  sand 
and  scoriaB,  ejected  to  a  greater  distance,  remain  incoherent.* 

*  Monticelli  and  Covelli,  Storia  di  Fenon.  del  Vesuv.  en  1821-28. 


CH.  XXIV.  FLUID   LAVA.  377 

Sir  William  Hamilton,  in  his  description  of  the  eruption  of  1779, 
says  that  jets  of  liquid  lava,  mixed  with  stones  and  scoriae,  were  thrown 
up  to  the  height  of  at  least  ten  thousand  feet,  having  the  appearance  of 
a  column  of  fire.*  Some  of  these  were  directed  by  the  winds  towards 
Ottajano,  and  some  of  them  falling  almost  perpendicularly,  still  red-hot 
and  liquid,  on  Vesuvius,  covered  its  whole  cone,  part  of  the  mountain 
of  Somma,  and  the  valley  between  them.  The  falling  matter  being 
nearly  as  vividly  inflamed  as  that  which  was  continually  issuing  fresh 
from  the  crater,  formed  with  it  one  complete  body  of  fire,  which  could 
not  be  less  than  two  miles  and  a  half  in  breadth,  and  of  the  extraordi- 
nary height  above  mentioned,  casting  a  heat  to  the  distance  of  at  least 
six  miles  round  it.  Dr.  Clarke,  also,  in  his  account  of  the  eruption  of 
1793,  says  that  millions  of  red-hot  stones  were  shot  into  the  air  full 
half  the  height  of  the  cone  itself,  and  then  bending,  fell  all  round  in  a 
fine  arch.  On  another  occasion  he  says  that,  as  they  fell,  they  covered 
nearly  half  the  cone  with  fire. 

The  same  author  has  also  described  the  different  appearance  of  the 
lava  at  its  source,  and  at  some  distance  from  it,  when  it  had  descended 
into  the  plains  below.  At  the  point  where  it  issued,  in  1793,  from  an 
arched  chasm  in  the  side  of  the  mountain,  the  vivid  torrent  rushed 
with  the  velocity  of  a  flood.  It  was  in  perfect  fusion,  unattended  with 
any  scoriae  on  its  surface,  or  any  gross  materials  not  in  a  state  of  com- 
plete solution.  It  flowed  with  the  translucency  of  honey,  "  in  regular 
channels,  cut  finer  than  art  can  imitate,  and  glowing  with  all  the  splen- 
dor of  the  sun." — "  Sir  William  Hamilton,"  he  continues,  "  had  con- 
ceived that  no  stones  thrown  upon  a  current  of  lava  would  make  any 
impression.  I  was  soon  convinced  of  the  contrary.  Light  bodies, 
indeed,  of  five,  ten,  and  fifteen  pounds'  weight,  made  little  or  no  im- 
pression even  at  the  source  ;  but  bodies  of  sixty,  seventy,  and  eighty 
pounds  were  seen  to  form  a  kind  of  bed  on  the  surface  of  the  lava,  and 
float  away  with  it.  A  stone  of  three  hundred  weight,  that  had  been 
thrown  out  by  the  crater,  lay  near  the  source  of  the  current  of  lava :  I 
raised  it  upon  one  end,  and  then  let  it  fall  in  upon  the  liquid  lava ; 
when  it  gradually  sunk  beneath  the  surface,  and  disappeared.  If  I 
wished  to  describe  the  manner  in  which  it  acted  upon  the  lava,  I  should 
say  that  it  was  like  a  loaf  of  bread  thrown  into  a  bowl  of  very  thick 
honey,  which  gradually  involves  itself  in  the  heavy  liquid,  and  then 
slowly  sinks  to  the  bottom. 

"  The  lava,  at  a  small  distance  from  its  source,  acquires  a  darker  tint 
upon  its  surface,  is  less  easily  acted  upon,  and,  as  the  stream  widens, 
the  surface,  having  lost  its  state  of  perfect  solution,  grows  harder  and 
harder,  and  cracks  into  innumerable  fragments  of  very  porous  matter, 
to  which  they  give  the  name  of  scoriae,  and  the  appearance  of  which 
has  led  many  to  suppose  ths^t  it  proceeded  thus  from  the  mountain. 
There  is,  however,  no  truth  in  this.  All  lava,  at  its  first  exk  from  its 

*  Campi  Phlegraei. 


378  FLUID  LAVA.  [Cn.  XXIV. 

native  volcano,  flows  out  in  a  liquid  state,  and  all  equally  in  fusion. 
The  appearance  of  the  scoriae  is  to  be  attributed  only  to  the  action  of 
the  external  air,  and  not  to  any  difference  in  the  materials  which  com- 
pose it,  since  any  lava  whatever,  separated  from  its  channel,  and  ex- 
posed to  the  action  of  the  external  air,  immediately  cracks,  becomes 
porous,  and  alters  its  form.  As  we  proceeded  downwards,  this  became 
more  and  more  evident ;  and  the  same  lava  which  at  its  original  source 
flowed  in  perfect  solution,  undivided,  and  free  from  incumbrances  of 
any  kind,  a  little  farther  down  had  its  surface  loaded  with  scorise  in 
such  a  manner,  that,  upon  its  arrival  at  the  bottom  of  the  mountain, 
the  whole  current  resembled  nothing  so  much  as  a  heap  of  unconnected 
cinders  from  an  iron-foundry."  In  another  place  he  says  that  "  the  rivers 
of  lava  in  the  plain  resembled  a  vast  heap  of  cinders,  or  the  scoriae  of 
an  iron-foundry,  rolling  slowly  along,  and  falling  with  a  rattling  noise 
over  one  another."*  Von  Buch,  who  was  in  company  with  MM.  de 
Humboldt  and  Gay-Lussac,  describes  the  lava  of  1805  (the  most  fluid 
on  record)  as  shooting  suddenly  before  their  eyes  from  top  to  bottom 
of  the  cone  in  one  single  instant.  Professor  J.  D.  Forbes  remarks  that 
the  length  of  the  slope  of  the  cone  proper  being  about  1300  feet,  this 
motion  must  correspond  to  a  velocity  of  many  hundred  feet  in  a  few 
seconds,  without  interpreting  Von  Buch's  expression  literally.  The 
same  lava,  when  it  reached  the  level  road  at  Torre  del  Greco,  moved  at 
the  rate  of  only  eighteen  inches  per  minute,  or  three-tenths  of  an  inch 
per  second.f  "  Although  common  lava/'  observes  Professor  Forbes, 
"  is  riearly  as  liquid  as  melted  iron,  when  it  issues  from  the  orifice  of  the 
crater,  its  fluidity  rapidly  diminishes,  and  as  it  becomes  more  and  more 
burdened  by  the  consolidated  slag  through  which  it  has  to  force  its 
way,  its  velocity  of  motion  diminishes  in  an  almost  inconceivable  degree ; 
and  at  length,  when  it  ceases  to  present  the  slightest  external  trace  of 
fluidity,  its  movement  can  only  be  ascertained  by  careful  and  repeated 
observations,  just  as  in  the  case  of  a  glacier. "J 

It  appears  that  the  intensity  of  the  light  and  heat  of  the  lava  varies 
considerably  at  different  periods  of  the  same  eruption,  as  in  that  of 
Vesuvius  in  1819  and  1820,  when  Sir  H.  Davy  remarked  different 
degrees  of  vividness  in  the  white  heat  at  the  point  where  the  lava 
originated. § 

When  the  expressions  "  flame"  and  "  smoke"  are  used  in  describing 
volcanic  appearances,  they  must  generally  be  understood  in  a  figurative 
sense.  We  are  informed,  indeed,  by  M.  Abich,  that  he  distinctly  saw, 
in  the  eruption  of  Vesuvius  in  1834,  the  flame  of  burning  hydrogen  ;|| 
but  what  is  usually  mistaken  for  flame  consists  of  vapor  or  scoriae,  and 
impalpable  dust  illuminated  by  that  vivid  light  which  is  emitted  from 
the  crater  below,  where  the  lava  is  said  to  glow  with  the  splendor  of 

*  Otter's  Life  of  Dr.  Clarke.  f  phil-  Trans.  1846,  p.  154. 

J  Ibid.  p.  148.  §  Ibid.  p.  241. 

I  Bulletin  de  la  Soc.  Geol.  de  France,  torn.  vii.  p.  43  ;  and  Illustrations  of  Ve- 
suvius and  Etna,  p.  3. 


CH.  XXIV.]  RECENT    DIKES.  379 

the  sun.  The  clouds  of  apparent  smoke  are  formed  either  of  aqueous 
and  other  vapor,  or  of  finely  comminuted  scoriae. 

Dikes  in  the  recent  cone,  how  formed. — The  inclined  strata  before 
mentioned  which  dip  outwards  in  all  directions  from  the  axis  of  the 
cone  of  Vesuvius,  are  intersected  by  veins  or  dikes  of  compact  lava,  for 
the  most  part  in  a  vertical  position.  In  1828  these  were  seen  to  be 
about  seven  in  number,  some  of  them  not  less  than  four  or  five  hundred 
feet  in  height,  and  thinning  out  before  they  reached  the  uppermost  part 
of  the  cone.  Being  harder  than  the  beds  through  which  they  pass, 
they  have  decomposed  less  rapidly,  and  therefore  stand  out  in  relief. 
When  I  visited  Vesuvius,  in  November,  1828,  I  was  prevented  from 
descending  into  the  crater  by  the  constant  ejections  then  thrown  out ; 
so  that  I  got  sight  of  three  only  of  the  dikes  ;  but  Signor  Monticelli  had 
previously  had  drawings  made  of  the  whole,  which  he  showed  me.  The 
dikes  which  I  saw  were  on  that  side  of  the  cone  which  is  encircled  by 
Somma.  The  eruption  before  mentioned,  of  1828,  began  in  March,  and 
in  the  November  following  the  ejected  matter  had  filled  up  nearly  one- 
third  of  the  deep  abyss  formed  at  the  close  of  the  eruption  of  1822.  In 
November  I  found  a  single  black  cone  at  the  bottom  of  the  crater  con- 
tinually throwing  out  scoriae,  while  on  the  exterior  of  the  cone  I  ob- 
served the  lava  of  1822,  which  had  flowed  out  six  years  before,  not  yet 
cool,  and  still  evolving  much  heat  and  vapor  from  crevices. 

Hoffmann,  in  1832,  saw  on  the  north  side  of  Vesuvius,  near  the 
peak  called  Palo,  a  great  many  parallel  bands  of  lava,  some  from  six  to 
eight  feet  thick,  alternating  with  scoriae  and  conglomerate.  These  beds, 
he  says,  were  cut  through  by  many  dikes,  some  of  them  five  feet  broad. 
They  resemble  those  of  Somma,  the  stone  being  composed  of  grains  of 
leucite  and  augite.* 

There  can  be  no  doubt  that  the  dikes  above  mentioned  have  been 
produced  by  the  filling  up  of  open  fissures  with  liquid  lava  ;  but  of  the 
date  of  their  formation  we  know  nothing  farther  than  that  they  are  all 
subsequent  to  the  year  79,  and,  relatively  speaking,  that  they  are  more 
modern  than  all  the  lavas  and  scoriae  which  they  intersect.  A  consid- 
erable number  of  the  upper  strata  are  not  traversed  by  them.  That  the 
earthquakes,  which  almost  invariably  precede  eruptions,  occasion  rents 
in  the  mass,  is  well  known  ;  and,  in  1822,  three  months  before  the  lava 
flowed  out,  open  fissures,  evolving  hot  vapors,  were  numerous.  It  is 
clear  that  such  rents  must  be  ejected  with  melted  matter  when  the  col- 
umn of  lava  rises,  so  that  the  origin  of  the  dikes  is  easily  explained,  as 
also  the  great  solidity  and  cystalline  nature  of  the  rock  composing  them, 
which  has  been  formed  by  lava  cooling  slowly  under  great  pressure. 

It  has  been  suggested  that  the  frequent  rending  of  volcanic  cones 
during  eruptions  may  be  connected  with  the  gradual  and  successive 
upheaval  of  the  whole  mass  in  such  a  manner  as  to  increase  the  incli- 
nation of  the  beds  composing  the  cone  ;  and  in  accordance  with  the 

*  Geognost.  Beobachtungen,  <fcc.,  p.  182.     Berlin,  1839. 


380  STRUCTURE    OF   THE   CONE   OF    VESUVIUS.         [Cn.  XXIV. 

hypothesis  before  proposed  for  the  origin  of  Monte  Nuovo,  Von  Buch 
supposes  that  the  present  cone  of  Vesuvius  was  formed  in  the  year  79, 
not  by  eruption,  but  by  upheaval.  It  was  not  produced  by  the  re- 
peated superposition  of  scoriae  and  lava  cast  out  or  flowing  from  a  cen- 
tral source,  but  by  the  uplifting  of  strata  previously  horizontal.  The 
entire  cone  rose  at  once,  such  as  we  now  see  it,  from  the  interior  and 
middle  of  Somma,  and  has  since  received  no  accession  of  height,  but,  on 
the  contrary,  has  ever  since  been  diminishing  in  elevation.* 

Although  I  consider  this  hypothesis  of  Von  Buch  to  be  quite  untena- 
ble, I  may  mention  some  facts  which  may  at  first  sight  seem  to  favor  it. 
These  are  recorded  by  M.  Abich  in  his  account  of  the  Vesuvian  erup- 
tions of  1833  and  1834,  a  work  illustrated  by  excellent  engravings  of 
the  volcanic  phenomena  which  he  witnessed.!  It  appears  that,  in  the 
year  1834,  the  great  crater  of  Vesuvius  had  been  filled  up  nearly  to  the 
top  with  lava,  which  had  consolidated  and  formed  a  level  and  unbroken 
plain,  except  that  a  small  cone  thrown  up  by  the  ejection  of  scoriae  rose 
in  the  middle  of  it  like  an  island  in  a  lake.  At  length  this  plain  of  lava 
was  broken  by  a  fissure  which  passed  from  N.  E.  to  S.  W.,  and  along 
this  line  a  great  number  of  minute  cones  emitting  vapor  were  formed. 
The  first  act  of  formation  of  these  minor  cones  is  said  to  have  consisted 
of  a  partial  upheaval  of  beds  of  lava  previously  horizontal,  and  which 
had  been  rendered  flexible  by  the  heat  and  tension  of  elastic  fluids, 
which,  rising  from  below,  escaped  from  the  centre  of  each  new  monti- 
cule. There  would  be  considerable  analogy  between  this  mode  of  ori- 
gin and  that  ascribed  by  Von  Buch  to  Vesuvius  and  Somma,  if  the 
dimensions  of  the  upraised  masses  were  not  on  so  different  a  scale,  and 
if  it  was  safe  to  reason  from  the  inflation  of  bladders  of  half-fused  lava, 
from  fifteen  to  twenty-five  feet  in  height,  to  mountains  attaining  an  alti- 
tude of  several  thousand  feet,  and  having  their  component  strata  strength- 
ened by  intersecting  dikes  of  solid  lava. 

At  the  same  time  M.  Abich  mentions,  that  when,  in  August,  1834, 
a  great  subsidence  took  place  in  the  platform  of  lava  within  the  great 
crater,  so  that  the  structure  of  the  central  cone  was  laid  open,  it  was 
seen  to  have  been  evidently  formed,  not  by  upheaval,  but  by  the  fall 
of  cinders  and  scoriae  which  had  been  thrown  out  during  successive 
eruptions.;); 

Previous  to  the  year  79,  Vesuvius  appears,  from  the  description  of 
its  figure  given  by  Strabo,  to  have  been  a  truncated  cone,  having  a  level 
and  even  outline  as  seen  from  a  distance.  That  it  had  a  crater  on  its 
summit,  we  may  infer  from  a  passage  in  Plutarch,  on  which  Dr.  Dau- 
beny  has  judiciously  commented  in  his  treatise  on  volcanoes. §  The  walls 
of  the  crater  were  evidently  entire,  except  on  one  side,  where  there  was 
a  single  narrow  breach.  When  Spartacus,  in  the  year  72,  encamped  his 

*  Von  Buch,  Descrip.  Phys.  des  lies  Canaries,  p.  342.     Paris,  1836. 

\  Vues  Illust.  de  Phenom.  Geol.  Observ.  sur  le  Vesuve  et  1'Etna.     Berlin,  1837. 

±  Ibid.  p.  2. 

§  2d  edit.  1848,  p.  216. 


CH.  XX1V.J 


ORIGIN    OF   THE    CONE    OF    VESUVIUS. 


381 


gladiators  in  this  hollow,  Clodius,  the  praetor,  besieged  him  there,  keep- 
ing the  single  outlet  carefully  guarded,  and  then  let  down  his  soldiers 
by  scaling-ladders  over  the  steep  precipices  which  surrounded  the  cra- 
ter, at  the  bottom  of  which  the  insurgents  were  encamped.  On  the 
side  towards  the  sea,  the  walls  of  this  original  cavity,  which  must  have 
been  three  miles  in  diameter,  have  been  destroyed,  and  Brieslak  was  the 
first  to  announce  the  opinion  that  this  destruction  happened  during  the 
tremendous  eruption  which  occurred  in  79,  when  the  new  cone,  now 
called  Vesuvius,  was  thrown  up,  which  stands  encircled  on  three  sides 
by  the  ruins  of  the  ancient  cone,  called  Monte  Somma. 

In  the  annexed  diagram  (fig.  45)  it  will  be  seen  that  on  the  side  of 
Vesuvius  opposite  to  that  where  a  portion  of  the  ancient  cone  of  Somma 
(a)  still  remains,  is  a  projection  (b)  called  the  Pedamentina,  which  some 


Supposed  section  of  Vesuvius  and  Somina. 


a,  Monte  Somma,  or  the  remains  of  the  ancient  cone  of  Vesuvius. 

&,  The  Pedamentina,  a  terrace-like  projection,  encircling  the  base  of  tho  recent  cone  of  Vesu 
vius  on  the  south  side. 

c,  Atrio  del  Cavallo.* 

d,  e,  Crater  left  by  eruption  of  1822. 

f,  Small  cone  thrown  up  in  1828,  at  the  bottom  of  the  great  crater. 

g,  ff,  Dikes  intersecting  Somma. 

h,  h,  Dikes  intersecting  the  recent  cone  of  Vesuvius. 

have  supposed  to  be  part  of  the  circumference  of  the  ancient  crater 
broken  down  towards  the  sea,  and  over  the  edge  of  which  the  lavas  of 
the  modern  Vesuvius  have  poured  ;  the  axis  of  the  present  cone  of  Ve- 
suvius being,  according  to  Visconti,  precisely  equidistant  from  the 
escarpment  of  Somma  and  the  Pedamentina. 

In  the  same  diagram  I  have  represented  the  slanting  beds  of  the  cone 
of  Vesuvius  as  becoming  horizontal  in  the  Atrio  del  Cavallo  (at  c), 
where  the  base  of  the  new  cone  meets  the  precipitous  escarpment  of 
Somma ;  for  when  the  lava  flows  down  to  this  point,  as  happened  in 
1822,  its  descending  course  is  arrested,  and  it  then  runs  in  another 
direction  along  this  small  valley,  circling  round  the  base  of  the  cone. 
Sand  and  scoriae,  also,  blown  by  the  winds,  collect  at  the  base  of  the 
cone,  and  are  then  swept  away  by  torrents ;  so  that  there  is  always 
here  a  flattish  plain,  as  represented.  In  the  same  manner,  the  small 

*  So  called  from  travellers  leaving  their  horses  and  mules  there  when  they 
prepare  to  ascend  the  cone  on  foot. 


382  SECTION   OF   VESUVIUS   AND   SOMMA.  [On.  XXIV, 

interior  cone  (/)  must  be  composed  of  sloping  beds,  terminating  in  a 
horizontal  plain  ;  for,  while  this  monticule  was  gradually  gaining  height 
by  successive  ejections  of  lava  and  scoriae,  in  1828,  it  was  always  sur- 
rounded by  a  flat  pool  of  semi-fluid  lava,  into  which  scoriae  and  sand 
were  thrown. 

In  the  steep  simicircular  escarpment  of  Somma,  which  faces  the 
modern  Vesuvius,  we  see  a  great  number  of  sheets  of  lava  inclined  at 
an  angle  of  about  26°.  They  alternate  with  scorige,  and  are  intersected 
by  numerous  dikes,  which,  like  the  sheets  of  lava,  are  composed  chiefly 
of  augite,  with  crystals  of  leucite,  but  the  rock  in  the  dikes  is  more 
compact,  having  cooled  and  consolidated  under  greater  press  ure.  Some 
of  the  dikes  cut  through  and  shift  others,  so  that  they  have  evidently 
been  formed  during  successive  eruptions.  While  the  higher  region  of 
Somma  is  made  up  of  these  igneous  products,  there  appear  on  its  flanks, 
for  some  depth  from  the  surface,  as  seen  in  a  ravine  called  the  "  Fossa 
Grande,"  beds  of  white  pumiceous  tuff,  resembling  the  tuff  which,  at 
Pausilippo,  and  other  places,  near  Naples,  contain  shells  of  living 
Mediterranean  species.  It  is  supposed  by  Pilla,  Von  Buch,  and  others, 
that  the  tufaceous  beds,  which  rise  in  Somma  to  more  than  half  the 
height  of  that  mountain,  are,  in  like  manner,  of  submarine  origin,  be- 
cause a  few  sea-shells  have  been  found  in  them,  here  and  there,  to- 
gether with  serpulee  of  recent  species  attached  to  included  blocks  of 
limestone.* 

It  is  contended,  therefore,  that  as  these  strata  were  once  accumulated 
beneath  the  sea,  they  may  have  been  subjected  as  they  rose  to  such  an 
upward  movement  as  may  have  given  rise  to  a  conical  hill ;  and  this 
hypothesis,  it  is  said,  acquires  confirmation  from  the  fact,  that  the  sheets 
of  lava  near  the  summit  of  Somma  are  so  compact  and  crystalline,  and 
of  such  breadth  individually,  as  would  not  have  been  the  case  had  they 
run  down  a  steep  slope.  They  must,  therefore,  have  consolidated  on  a 
nearly  level  surface,  and  have  been  subsequently  uplifted  into  their  pres- 
ent inclined  position. 

Unfortunately  there  are  no  sections  of  sufficient  depth  and  continuity 
on  the  flanks  of  Somma,  to  reveal  to  us  clearly  the  relations  of  the 
lava,  scoriae,  and  associated  dikes,  forming  the  highest  part  of  the 
mountain,  with  the  marine  tuffs  observed  on  its  declivity.  Both 
may,  perhaps,  have  been  produced  contemporaneously  when  Somma 
raised  its  he»d,  like  Stromboli,  above  the  sea,  its  sides  and  base  being 
then  submerged.  Such  a  state  of  things  may  be  indicated  by  a  fact 
noticed  by  Von  Buch,  namely,  that  the  pumiceous  beds  of  Naples, 
when  they  approach  Somma,  contain  fragments  of  the  peculiar  leucitic 
lava  proper  to  that  mountain,  which  are  not  found  in  the  same  tuff  at  a 
greater  distance.f  Portions,  therefore,  of  this  lava  were  either  thrown 


*  Dufr6noy,  Me'm.  pour  servir  a  une  Descrip.  Geol.  de  la  France,  torn.  ir. 
p.  294. 

f  Descrip.  Pbys.  des  lies  Canaries,  p.  344. 


CH.  XXIV.]  FLOWING   OF    LAVA    TJNDEK    WATER.  383 

out  by  explosions,  or  torn  off  by  the  waves,  during  the  deposition  of  the 
pumiceous  strata  beneath  the  sea. 

We  have  as  yet  but  a  scanty  acquaintance  with  the  laws  which  reg- 
ulate the  flow  of  lava  beneath  water,  or  the  arrangement  of  scoriae  and 
volcanic  dust  on  the  sides  of  a  submarine  cone.  There  can,  however, 
be  little  doubt  that  showers  of  ejected  matter  may  settle  on  a  steep 
slope,  and  may  include  shells  and  the  remains  of  aquatic  animals,  which 
flourish  in  the  intervals  between  eruptions.  Lava  under  the  pressure  of 
water  would  be  less  porous ;  but,  as  Dr.  Daubeny  suggests,  it  may 
retain  its  fluidity  longer  than  in  the  open  air ;  for  the  rapidity  with 
which  heated  bodies  are  cooled  by  being  plunged  into  water  arises 
chiefly  from  the  conversion  of  the  lower  portions  of  water  into  steam, 
which  steam  absorbing  much  heat,  immediately  ascends,  and  is  recon- 
verted into  water.  But  under  the  pressure  of  a  deep  ocean,  the  heat 
of  the  lava  would  be  carried  off  more  slowly,  and  only  by  the  circula- 
tion of  ascending  and  descending  currents  of  water,  those  portions  near- 
est the  source  of  heat  becoming  specifically  light,  and  consequently  dis- 
placing the  water  above.  This  kind  of  circulation  would  take  place 
with  much  less  rapidity  than  in  the  atmosphere,  inasmuch  as  the  ex- 
pansion of  water  by  equal  increments  of  heat  is  less  considerable  than 
that  of  air.* 

We  learn  from  the  valuable  observations  made  by  Mr.  Dana  on  the 
active  volcanoes  of  the  Sandwich  Islands,  that  large  sheets  of  compact 
basaltic  lava  have  been  poured  out  of  craters  at  the  top  or  near  the  sum- 
mits of  flattened  domes  higher  than  Etna,  as  in  the  case  of  Mount  Loa 
for  example,  where  a  copious  stream  two  miles  broad  and  twenty-five 
miles  long  proceeded  from  an  opening  13,000  feet  above  the  level  of  the 
sea.  The  usual  slope  of  these  sheets  of  lava  is  between  5°  and  10°; 
but  Mr.  Dana  convinced  himself  that,  owing  to  the  suddenness  with  which 
they  cool  in  the  air,  some  lavas  may  occasionally  form  on  slopes  equalling 
25°,  and  still  preserve  a  considerable  compactness  of  texture.  It  is  even 
proved,  he  says,  from  what  he  saw  in  the  great  lateral  crater  of  Kilauea, 
on  the  flanks  of  Mount  Loa,  that  a  mass  of  such  melted  rock  may  con- 
solidate at  an  inclination  of  30°,  and  be  continuous  for  300  or  400  feet. 
Such  masses  are  narrow,  he  admits,  "  but  if  the  source  had  been  more 
generous,  they  would  have  had  a  greater  breadth,  and  by  a  succession 
of  ejections  overspreading  each  cooled  layer,  a  considerable  thickness 
might  have  been  attained. "f  The  same  author  has  also  shown,  as  be- 
fore mentioned,  that  in  the  "  cinder  cones"  of  the  Sandwich  Islands,  the 
strata  have  an  original  inclination  of  between  35°  and  40°. J 

Mr.  Scrope,  writing  in  1827,  attributed  the  formation  of  a  volcanic 
cone  chiefly  to  matter  ejected  from  a  central  orifice,  but  partly  to  the 
injection  of  lava  into  dikes,  and  "  to  that  force  of  gaseous  expansion,  the 

*  See  Daubeny's  Volcanoes,  p.  400. 

f  Geol.  of  American  Explor.  Exped.  p.  359,  note.  Mr.  Dana  informed  me 
(Sept.  1852),  that  an  angle  of  60°  instead  of  30°,  was  given  by  mistake  in  his 
work.  %  Ibid.  p.  354. 


384  VESUVIAN   LAVAS.  [Cn.  XXIV. 

intensity  of  which,  in  the  central  parts  of  the  cone,  is  attested  by  local 
earthquakes,  which  so  often  accompany  eruptions.*  It  is  the  opinion 
of  MM.  Von  Buch,  De  Beaumont,  and  Dufrenoy,  that  the  sheets  of 
lava  on  Somma  are  so  uniform  and  compact,  that  their  original  inclina- 
tion did  not  exceed  four  or  five  degrees,  and  that  four-fifths,  therefore, 
of  their  present  slope  is  due  to  their  having  been  subsequently  tilted 
and  upraised.  Notwithstanding  the  light  thrown  by  M.  de  Beaumont 
on  the  laws  regulating  the  flow  and  consolidation  of  lava,  I  do  not  con- 
ceive that  these  laws  are  as  yet  sufficiently  determined  to  warrant  us  in 
assigning  so  much  of  the  inclined  position  of  the  beds  of  Somma  to  the 
subsequent  rending  and  dislocation  of  the  cone.  Even  if  this  were  ad- 
mitted, it  is  far  more  in  harmony  with  the  usual  mode  of  development 
of  volcanic  forces  to  suppose  the  movement  which  modified  the  shape  of 
the  cone  to  have  been  intermittent  and  gradual,  and  not  to  have  con- 
sisted of  a  single  effort,  or  one  sudden  and  violent  convulsion.f 

Vesuvian  lavas. — The  lavas  of  Somma  are  characterized  by  contain- 
ing disseminated  crystals  of  leucite  (called,  by  the  French,  amphigene), 
a  mineral  said  to  be  very  rare  in  the  modern  lavas  of  Vesuvius,  which 
are  in  general  much  more  scoriaceous  and  less  crystalline  than  those  of 
Somma.  J 

At  the  fortress  near  Torre  del  Greco  a  section  is  exposed,  fifteen  feet 
in  height,  of  a  current  which  ran  into  the  sea ;  and  it  evinces,  especially 
in  the  lower  part,  a  decided  tendency  to  divide  into  rude  columns.  A 
still  more  striking  example  may  be  seen  to  the  west  of  Torre  del  An- 
nunziata,  near  Forte  Scassato,  where  the  mass  is  laid  open  to  the  depth 
of  twenty  feet.  In  both  these  cases,  however,  the  rock  may  rather  be 
said  to  be  divided  into  numerous  perpendicular  fissures,  than  to  be  pris- 
matic, although  the  same  picturesque  effect  is  produced.  In  the  lava- 
currents  of  Central  France  (those  of  the  Vivarais,  in  particular),  the 
uppermost  portion,  often  forty  feet  or  more  in  thickness,  is  an  amorphous 
mass  passing  downwards  into  lava  irregularly  prismatic  ;  and  under  this 
there  is  a  foundation  of  regular  and  vertical  columns  ;  but  these  lavas 
are  often  one  hundred  feet  or  more  in  thickness.  We  can  scarcely  ex- 
pect to  discover  the  same  phenomenon  in  the  shallow  currents  of  Vesu- 
vius, where  the  lowest  part  has  cooled  more  rapidly,  although  it  may 
be  looked  for  in  modern  streams  in  Iceland,  which  exceed  even  those  of 
ancient  France  in  volume. 

Mr.  Scrope  mentions  that,  in  the  cliffs  encircling  the  modern  crater 
of  Vesuvius,  he  saw  many  currents  offering  a  columnar  division,  and  some 
almost  as  regularly  prismatic  as  any  ranges  of  the  older  basalts ;  and 
he  adds,  that  in  some  the  spheroidal  concretionary  structure,  on  a  large 
scale,  was  equally  conspicuous.^  Brieslak||  also  informs  us  that,  in  the 

*  Geol.  Trans.  2d  series,  vol.  ii.  p.  341. 

f  See  a  paper  by  the  Author  on  "  Craters  of  Denudation,"  Quart.  Journ.  GeoL 
Soc.  1850. 

\  Dufrenoy,  Mem.  pour  *ervir,  <fec.  torn.  iv.  p.  285. 

§•  Journal  of  Science,  vol.  xv.  p.  177. 

|  Voy.  dans  la  Campanie,  tome  i.  p.  201. 


CH.  XXIV.]  VESTJVIAN   MINERALS.  385 

siliceous  lava  of  1737,  which  contains  augite,  leucite,  tnd  crystals  of 
felspar,  he  found  very  regular  prisms  in  a  quarry  near  Torre  del  Greco ; 
an  observation  confirmed  by  modern  authorities.* 

Effects  of  decomposition  on  lavas. — The  decomposition  of  some  of  the 
felspathic  lavas,  either  by  simple  weathering,  or  by  gaseous  emanations, 
converts  them  from  a  hard  to  a  soft  clayey  state,  so  that  they  no  longer 
retain  the  smallest  resemblance  to  rocks  cooled  down  from  a  state  of 
fusion.  The  exhalations  of  sulphuretted  hydrogen  and  muriatic  acid, 
which  are  disengaged  continually  from  the  Solfatara,  also  produce  curious 
changes  on  the  trachyte  of  that  nearly  extinct  volcano:  the  rock  is 
bleached,  and  becomes  porous,  fissile,  and  honey-combed,  till  at  length 
it  crumbles  into  a  white  siliceous  powder.f  Numerous  globular  con- 
cretions, composed  of  concentric  laminae,  are  also  formed  by  the  same 
vapors  in  this  decomposed  rock.J 

Vesuvian  minerals. — A  great  variety  of  minerals  are  found  in  the 
lavas  of  Vesuvius  and  Somma;  augite,  leucite,  felspar,  mica,  olivine, 
and  sulphur  are  most  abundant.  It  is  an  extraordinary  fact,  that  in  an 
area  of  three  square  miles  round  Vesuvius,  a  greater  number  of  simple 
minerals  have  been  found  than  in  any  spot  of  the  same  dimensions  on 
the  surface  of  the  globe.  Hauy  enumerated  only  380  species  of  simple 
minerals  as  known  to  him  ;  and  no  less  than  eighty-two  had  been  found 
on  Vesuvius  and  in  the  tuffs  on  the  flanks  of  Somma  before  the  end  of 
the  year  1828.§  Many  of  these  are  peculiar  to  that  locality.  Some 
mineralogists  have  conjectured  that  the  greater  part  of  these  were  not 
of  Vesuvian  origin,  but  thrown  up  in  fragments  from  some  older  forma- 
tion, through  which  the  gaseous  explosions  burst.  But  none  of  the 
older  rocks  in  Italy,  or  elsewhere,  contain  such  an  assemblage  of  min- 
eral products  ;  and  the  hypothesis  seems  to  have  been  prompted  by  a 
disinclination  to  admit  that,  in  times  so  recent  in  the  earth's  history, 
the  laboratory  of  nature  could  have  been  so  prolific  in  the  creation  of 
new  and  rare  compounds.  Had  Vesuvius  been  a  volcano  of  high  anti- 
quity, formed  when  nature 

Wanton'd  as  in  her  prime,  and  play'd  at  will 
Her  virgin  fancies, 

it  would  have  been  readily  admitted  that  these,  or  a  much  greater  va- 
riety of  substances,  had  been  sublimed  in  the  crevices  of  lava,  just  as 
several  new  earthy  and  metallic  compounds  are  known  to  have  been 
produced  by  fumeroles,  since  the  eruption  of  1822. 

Mass  enveloping  Herculaneum  and  Pompeii. — In  addition  to  the 
ejections  which  fall  on  the  cone,  and  that  much  greater  mass  which 
finds  its  way  gradually  to  the  neighboring  sea,  there  is  a  third  portion, 
often  of  no  inconsiderable  thickness,  composed  of  alluviums,  spread  over 
the  valleys  and  plains  at  small  distances  from  the  volcano.  Aqueous 

*  Mr.  Forbes,  Edin.  Journ.  of  Sci.  No.  xviii.  Oct.  1828. 
f  Daubeny  on  Volcanoes,  p.  169. 
t  Scrope,  Geol.  Trans,  second  series,  vol.  ii.  p.  346. 
§  Monticelli  and  Covelli,  Prodrom.  della  Mineral.  Vesuv. 
25 


386  MASS   ENVELOPING  [Cn.  XXIY. 

vapors  are  evolved  copiously  from  volcanic  craters  during  eruptions, 
and  often  for  a  long  time  subsequently  to  the  discharge  of  scoriae  and 
lava :  these  vapors  are  condensed  in  the  cold  atmosphere  surrounding 
the  high  volcanic  peak,  and  heavy  rains  are  thus  caused.  The  floods 
thus  occasioned,  sweep  along  the  impalpable  dust  and  light  scoriae,  till 
a  current  of  mud  is  produced,  which  is  called  in  Campania  "  lava  d' 
acqua,"  and  is  often  more  dreaded  than  an  igneous  stream  (lava  di  fuo- 
co),  from  the  greater  velocity  with  which  it  moves.  So  late  as  the  27th 
of  October,  1822,  one  of  these  alluviums  descended  the  cone  of  Vesu- 
vius, and,  after  overspreading  much  cultivated  soil,  flowed  suddenly 
into  the  villages  of  St.  Sebastian  and  Massa,  where,  filling  the  streets 
and  interior  of  some  of  the  houses,  it  suffocated  seven  persons.  It  will, 
therefore,  happen  very  frequently  that,  towards  the  base  of  a  volcanic 
cone,  alternations  will  be  found  of  lava,  alluvium,  and  showers  of 
ashes. 

To  which  of  these  two  latter  divisions  the  mass  enveloping  Hercula- 
neum  and  Pompeii  should  be  referred,  has  been  a  question  of  the  keen- 
est controversy  ;  but  the  discussion  might  have  been  shortened,  if  the 
combatants  had  reflected  that,  whether  volcanic  sand  and  ashes  were 
conveyed  to  the  towns  by  running  water,  or  through  the  air,  during  an 
eruption,  the  interior  of  buildings,  so  long  as  the  roofs  remain  entire, 
together  with  all  underground  vaults  and  cellars,  could  be  filled  only 
by  an  alluvium.  We  learn  from  history,  that  a  heavy  shower  of  sand, 
pumice,  and  lapilli,  sufficiently  great  to  render  Pompeii  and  Herculane- 
um  uninhabitable,  fell  for  eight  successive  days  and  nights  in  the  year 
79,  accompanied  by  violent  rains.*  We  ought,  therefore,  to  find  a  very 
close  resemblance  between  the  strata  covering  these  towns  and  those 
composing  the  minor  cones  of  the  Phlegraean  Fields,  accumulated  rap- 
idly, like  Monte  Nuovo,  during  a  continued  shower  of  ejected  matter ; 
with  this  difference  however,  that  the  strata  incumbent  on  the  cities 
would  be  horizontal,  whereas  those  on  the  cones  are  highly  inclined ; 
and  that  large  angular  fragments  of  rock,  which  are  thrown  out  near  the 
vent,  would  be  wanting  at  a  distance  where  small  lapilli  only  can  be 
found.  Accordingly,  with  these  exceptions,  no  identity  can  be  more 
perfect  than  the  form  and  distribution  of  the  matter  at  the  base  of 
Monte  Nuovo,  as  laid  open  by  the  encroaching  sea,  and  the  appearance 
of  the  beds  superimposed  on  Pompeii.  That  city  is  covered  with  nu- 
merous alternations  of  different  horizontal  beds  of  tuff  and  lapilli,  for  the 
most  part  thin,  and  subdivided  into  very  fine  layers.  I  observed  the 
following  section  near  the  amphitheatre,  in  November,  1828 — (descend- 
ing series) : — 

*  The  great  eruption,  in  1822,  caused  a  covering  only  a  few  inches  thick  on 
Pompeii.  Several  feet  are  mentioned  by  Prof.  J.  D.  Forbes. — Ed.  Journ.  of 
Science,  No.  xix.  p.  131,  Jan.  1829.  But  he  must  have  measured  in  spots  where 
it  had  drifted.  The  dust  and  ashes  were  five  feet  thick  at  the  top  of  the  crater, 
and  decreased  gradually  to  ten  inches  at  Torre  del  Annunziata.  The  size  and 
weight  of  the  ejected  fragments  diminished  very  regularly  in  the  same  continu- 
ous stratum,  as  the  distance  from  the  centre  of  projection  was  greater. 


CH.  XXIV.]                      HERCULANETJM   AND   POMPEII.  387 

Feet  Inches. 

1.  Black  sparkling  sand  from  the  eruption  of  1822,  containing 

minute  regularly  formed  crystals  of  augite  and  tourmaline   -         0  2£ 

2.  Vegetable  mould                         -                          -                                    3  0 

3.  Brown  incoherent  tuff,  full  of  pisolitic  globules  in  layers,  from 


half  an  inch  to  three  inches  in  thickness 
4.  Small  scoriae  and  white  lapilli  - 
6.  Brown  earthy  tuff,  with  numerous  pisolitic  globules 

6.  Brown  earthy  tuff,  with  lapilli  divided  into  layers 

7.  Layer  of  whitish  lapilli 

8.  Gray  solid  tuff 

9.  Pumice  and  white  lapilli 


1  6 

0  3 

0  9 

4  0 

0  1 

0  3 

0  3 

10  3 


Many  of  the  ashes  in  these  beds  are  vitrified,  and  harsh  to  the  touch. 
Crystals  of  leucite,  both  fresh  and  farinaceous,  have  been  found  inter- 
mixed.* The  depth  of  the  bed  of  ashes  above  the  houses  is.^ariable, 
but  seldom  exceeds  twelve  or  fourteen  feet,  and  it  is  said  that  the  higher 
part  of  the  amphitheatre  always  projected  above  the  surface ;  though  if 
this  were  the  case,  it  seems  inexplicable  that  the  city  should  never  have 
been  discovered  till  the  year  1750.  It  will  be  observed  in  the  above 
section  that  two  of  the  brown,  half-consolidated  tuffs  are  filled  with  small 
pisolitic  globules.  This  circumstance  is  not  alluded  to  in  the  animated 
controversy  which  the  Royal  Academy  of  Naples  maintained  with  one 
of  their  members,  Signer  Lippi,  as  to  the  origin  of  the  strata  incumbent 
on  Pompeii.  The  mode  of  aggregation  of  these  globules  has  been  fully 
explained  by  Mr.  Scrope,  who  saw  them  formed  in  great  numbers  in 
1822,  by  rain  falling  during  the  eruption  on  fine  volcanic  sand,  and  some- 
times also  produced  like  hail  in  the  air,  by  the  mutual  attraction  of  the 
minutest  particles  of  fine  damp  sand.  Their  occurrence,  therefore,  agrees 
remarkably  well  with  the  account  of  heavy  rain,  and  showers  of  sand  and 
ashes  recorded  in  history.f 

Lippi  entitled  his  work,  "  Fu  il  fuoco  o  1'  acqua  che  sottero  Pompei  ed 
Ercolano  ?"J  and  he  contended  that  neither  were  the  two  cities  destroyed 
in  the  year  79,  nor  by  a  volcanic  eruption,  but  purely  by  the  agency  of 
water  charged  with  transported  matter.  His  letters,  wherein  he  endeav- 
ored to  dispense,  as  far  as  possible,  with  igneous  agency,  even  at  the 
foot  of  the  volcano,  were  dedicated,  with  great  propriety,  to  Werner, 
and  afford  an  amusing  illustration  of  the  polemic  style  in  which  geologi- 
cal writers  of  that  day  indulged  themselves.  His  arguments  were  partly 
of  an  historical  nature,  derived  from  the  silence  of  contemporary  histo- 
rians, respecting  the  fate  of  the  cities,  which,  as  we  have  already  stated, 
is  most  remarkable,  and  partly  drawn  from  physical  proofs.  He  pointed 
out  with  great  clearness  the  resemblance  of  the  tufaceous  matter  in  the 
vaults  and  cellars  at  Herculaneum  and  Pompeii  to  aqueous  alluviums, 
and  its  distinctness  from  ejections  which  had  fallen  through  the  air. 
Nothing,  he  observes,  but  moist  pasty  matter  could  have  received  the 
impression  of  a  woman's  breast,  which  was  found  in  a  vault  at  Pompeii, 

*  Forbes,  Ed.  Journ.  of  Sci.  No.  xix.  p.  130,  Jan.  1829. 

f  Scrope,  Geol.  Trans,  second  series,  vol.  ii.  p.  346.  \  Napoli,  1816. 


388  POMPEII. — INFUSORIAL   TUFF.  [On.  XXIV 

or  have  given  the  cast  of  a  statue  discovered  in  the  theatre  at  Hercula- 
neum.  It  was  objected  to  him,  that  the  heat  of  the  tuff  in  Herculaneum 
and  Pompeii  was  proved  by  the  carbonization  of  the  timber,  corn,  pcipy- 
rus-rolls,  and  other  vegetable  substances  there  discovered ;  but  Lippi 
replied  with  truth,  that  the  papyri  would  have  been  burnt  up  if  they 
had  come  in  contact  with  fire,  and  that  their  being  only  carbonized  was 
a  clear  demonstration  of  their  having  been  enveloped,  like  fossil  wood, 
in  a  sediment  deposited  from  water.  The  Academicians,  in  their  report 
on  his  pamphlet,  assert,  that  when  the  amphitheatre  was  first  cleared 
out,  the  matter  was  arranged  on  the  steps  in  a  succession  of  concave 
layers,  accommodating  themselves  to  the  interior  form  of  the  building, 
just  as  snow  would  lie  if  it  had  fallen  there.  This  observation  is  highly 
interesting,  and  points  to  the  difference  between  the  stratification  of  ashes 
in  an  open  building  and  of  mud  derived  from  the  same  in  the  interior  of 
edifices  and  cellars.  Nor  ought  we  to  call  the  allegation  in  question, 
because  it  could  not  be  substantiated  at  the  time  of  the  controversy  after 
the  matter  had  been  all  removed ;  although  Lippi  took  advantage  of 
this  removal,  and  met  the  argument  of  his  antagonists  by  requiring  them 
to  prove  the  fact.  There  is  decisive  evidence  that  no  stream  of  lava  has 
ever  reached  Pompeii  since  it  was  first  built,  although  the  foundations 
of  the  town  stand  upon  the  old  leucitic  lava  of  Somma ;  several  streams 
of  which,  with  tuff  interposed,  had  been  cut  through  in  excavations. 

Infusorial  beds  covering  Pompeii. — A  most  singular  and  unexpected 
discovery  has  been  recently  made  (1844-5)  by  Professor  Ehrenberg, 
respecting  the  remote  origin  of  many  of  the  layers  of  ashes  and  pumice 
enveloping  Pompeii.  They  are,  he  says,  in  great  part,  of  organic  and 
freshwater  origin,  consisting  of  the  siliceous  cases  of  microscopic  infuso- 
ria. What  is  still  more  surprising,  this  fact  proves  to  be  by  no  means 
an  isolated  or  solitary  example  of  an  intimate  relation  between  organic 
life  and  the  results  of  volcanic  activity.  On  the  Rhine,  several  beds  of 
tuff  and  pumiceous  conglomerate,  resembling  the  mass  incumbent  upon 
Pompeii  and  closely  connected  with  extinct  volcanoes,  are  now  ascer- 
tained to  be  made  up  to  a  great  extent  of  the  siliceous  cases  of  infusoria 
(or  Diatomacese),  invisible  to  the  naked  eye,  and  often  half  fused.*  No 
less  than  94  distinct  species  have  already  been  detected  in  one  mass  of 
this  kind,  more  than  150  feet  thick,  at  Hochsimmer,  on  the  left  bank  of 
the  Rhine,  near  the  Laacher-see.  Some  of  these  Rhenish  infusorial 
accumulations  appear  to  have  fallen  in  showers,  others  to  have  been 
poured  out  of  lake-craters  in  the  form  of  mud,  as  in  the  Brohl  valley. 

In  Mexico,  Peru,  the  Isle  of  France,  and  several  other  volcanic  regions, 
analogous  phenomena  have  been  observed,  and  everywhere  the  species 
of  infusoria  belong  to  freshwater  and  terrestrial  genera,  except  in  the 
case  of  the  Patagonian  pumiceous  tuffs,  specimens  of  which,  brought 

*  Not  a  few  of  the  organic  bodies,  called  by  Ehrenberg  "  infusoria,"  such  as 
Galionella  and  Bacillaria,  have  been  recently  claimed  by  many  botanists  as  be- 
longing to  the  vegetable  kingdom,  and  are  referred  to  the  classes  called  Diatoma- 
cese and  Desmidise. 


CH.  XXIV.]  HERCULANEUM.  389 

home  by  Mr.  Darwin,  are  found  to  contain  the  remains  of  marine  ani- 
malcules. In  various  kinds  of  pumice  ejected  by  volcanoes,  the  micro- 
scope has  revealed  to  Professor  Ehrenberg  the  siliceous  cases  of  infusoria 
often  half  obliterated  by  the  action  of  heat,  and  the  fine  dust  thrown  out 
into  the  air  during  eruptions,  is  sometimes  referable  to  these  most  minute 
organic  substances,  brought  up  from  considerable  depths,  and  sometimes 
mingled  with  small  particles  of  vegetable  matter. 

In  what  manner  did  the  solid  coverings  of  these  most  minute  plants 
and  animalcules,  which  can  only  originate  and  increase  at  the  surface 
of  the  earth,  sink  down  and  penetrate  into  subterranean  cavities,  so  as 
to  be  ejected  from  the  volcanic  orifices  ?  We  have  of  late  years  become 
familiar  with  the  fact,  in  the  process  of  boring  Artesian  wells,  that  the 
seeds  of  plants,  the  remains  of  insects,  and  even  small  fish,  with  other 
organic  bodies,  are  carried  in  an  uninjured  state  by  the  underground 
circulation  of  waters,  to  the  depth  of  many  hundred  feet.  With  still 
greater  facility  in  a  volcanic  region  we  may  conjecture,  that  water  and 
mud  full  of  invisible  infusoria  may  be  sucked  down,  from  time  to  time, 
into  subterranean  rents  and  hollows  in  cavernous  lava  which  has  been 
permeated  by  gases,  or  in  rocks  dislocated  by  earthquakes.  It  often 
happens  that  a  lake  which  has  endured  for  centuries  in  a  volcanic  crater, 
disappears  suddenly  on  the  approach  of  a  new  eruption.  Violent 
shocks  agitate  the  surrounding  region,  and  ponds,  rivers,  and  wells  are 
dried  up.  Large  cavities  far  below  may  thus  become  filled  with  fen- 
mud  chiefly  composed  of  the  more  indestructible  and  siliceous  portions 
of  infusoria,  destined  perhaps  to  be  one  day  ejected  in  a  fragmentary  or 
half-fused  state,  yet  without  the  obliteration  of  all  traces  of  organic 
structure.* 

Herculaneum. — It  was  remarked  that  no  lava  has  flowed  over  the 
site  of  Pompeii,  since  that  city  was  built,  but  with  Herculaneum  the 
case  is  different.  Although  the  substance  which  fills  the  interior  of  the 
houses  and  the  vaults  must  have  been  introduced  in  a  state  of  mud,  like 
that  found  in  similar  situations  in  Pompeii ;  yet  the  superincumbent 
mass  differs  wholly  in  composition  and  thickness.  Herculaneum  was 
situated  several  miles  nearer  to  the  volcano,  and  has,  therefore,  been  al- 
ways more  exposed  to  be  covered,  not  only  by  showers  of  ashes,  but  by 
alluviums  and  streams  of  lava.  Accordingly,  masses  of  both  have  accu- 


*  See  Ehrenberg,  Proceedings  (Berichte)  of  the  Royal  Acad.  of  Sci.  Berlin,  1844, 
1845,  and  an  excellent  abstract  of  his  papers  by  Mr.  Ansted  in  the  Quart.  Journ. 
of  the  Geol.  Soc.  London,  No.  7,  Aug.  1846.  In  regard  to  marine  infusoria  found 
in  volcanic  tuff,  it  is  well  known  that  on  the  shores  of  the  island  of  Cephalonia  in 
the  Mediterranean  (Proceedings,  Geol.  Soc.  vol.  ii.  p.  220),  there  is  a  cavity  in  the 
rock,  into  which  the  sea  has  been  flowing  for  ages,  and  many  others  doubtless 
exist  in  the  leaky  bottom  of  the  ocean.  The  marine  current  has  been  rushing  in 
for  many  years,  and  as  the  infusoria  inhabiting  the  waters  of  the  Mediterranean 
are  exceedingly  abundant,  a  vast  store  of  their  cases  may  accumulate  in  subma- 
rine caverns  (the  water,  perhaps,  being  converted  into  steam,  and  so  escaping  up- 
wards), and  they  may  then  be  cast  up  again  to  furnish  the  materials  of  volcanic 
tuff,  should  an  eruption  occur  like  that  which  produced  Graham  Island,  off  the 
coast  of  Sicily,  in  1831. 


390  OBJECTS   DISCOVEKED  IN  [Cn.  XXIV. 

mulated  on  each  other  above  the  city,  to  a  depth  of  nowhere  less  than 
70,  and  in  many  places  of  112  feet.f 

The  tuff  which  envelops  the  buildings  consists  of  comminuted  vol- 
canic ashes,  mixed  with  pumice.  A  mask  imbedded  in  this  matrix  has 
left  a  cast,  the  sharpness  of  which  was  compared  by  Hamilton  to  those 
in  plaster  of  Paris  ;  nor  was  the  mask  in  the  least  degree  scorched,  as 
if  it  had  been  imbedded  in  heated  matter.  This  tuff  is  porous  ;  and, 
when  first  excavated,  is  soft  and  easily  worked,  but  acquires  a  consider- 
able degree  of  induration  on  exposure  to  the  air.  Above  this  lowest 
stratum  is  placed,  according  to  Hamilton,  "the  matter  of  six  eruptions," 
each  separated  from  the  other  by  veins  of  good  soil.  In  these  soils 
Lippi  states  that  he  collected  a  considerable  number  of  land  shells — an 
observation  which  is  no  doubt  correct ;  for  many  snails  burrow  in  soft 
soils,  and  some  Italian  species  descend,  when  they  hybernate,  to  the 
depth  of  five  feet  and  more  from  the  surface.  Delia  Torre  also  informs 
us  that  there  is  in  one  part  of  this  superimposed  mass  a  bed  of  true 
siliceous  lava  (lava  di  pietra  dura) ;  and,  as  no  such  current  is  believed 
to  have  flowed  till  near  one  thousand  years  after  the  destruction  of  Her- 
culaneum,  we  must  conclude,  that  the  origin  of  a  large  part  of  the  cov- 
ering of  Herculaneum  was  long  subsequent  to  the  first  inhumation  of 
the  place.  That  city,  as  well  as  Pompeii,  was  a  seaport.  Herculaneum 
is  still  very  near  the  shore,  but  a  tract  of  land,  a  mile  in  length,  inter- 
venes between  the  borders  of  the  Bay  of  Naples  and  Pompeii.  In  both 
cases  the  gain  of  land  is  due  to  the  filling  up  of  the  bed  of  the  sea  with 
volcanic  matter,  and  not  to  elevation  by  earthquakes,  for  there  has  been 
no  change  in  the  relative  level  of  land  and  sea.  Pompeii  stood  on  a 
slight  eminence  composed  of  the  lavas  of  the  ancient  Vesuvius,  and 
flights  of  steps  led  down  to  the  water's  edge.  The  lowermost  of  these 
steps  are  said  to  be  still  on  an  exact  level  with  the  sea. 

Condition  and  contents  of  the  buried  cities. — After  these  observations 
on  the  nature  of  the  strata  enveloping  and  surrounding  the  cities,  we 
may  proceed  to  consider  their  internal  condition  and  contents,  so  far  at 
least  as  they  offer  facts  of  geological  interest.  Notwithstanding  the 
much  greater  depth  at  which  Herculaneum  was  buried,  it  was  discov- 
ered before  Pompeii,  by  the  accidental  circumstance  of  a  well  being 
sunk,  in  1713,  which  came  right  down  upon  the  theatre,  where  the  stat- 
ues of  Hercules  and  Cleopatra  were  soon  found.  Whether  this  city  or 
Pompeii,  both  of  them  founded  by  Greek  colonies,  was  the  more  con- 
siderable, is  not  yet  determined  ;  but  both  are  mentioned  by  ancient 
authors  as  among  the  seven  most  flourishing  cities  in  Campania.  The 
walls  of  Pompeii  were  three  "miles  in  circumference ;  but  we  have,  as 
yet,  no  certain  knowledge  of  the  dimensions  of  Herculaneum.  In  the 
latter  place  .the  theatre  alone  is  open  for  inspection ;  the  Forum,  Temple 
of  Jupiter,  and  other  buildings,  having  been  filled  up  with  rubbish  as 
the  workmen  proceeded,  owing  to  the  difficulty  of  removing  it  from  so 

*  Hamilton,  Observ.  on  Mount  Vesuvius,  p.  94.     London,  1 774. 


CH.  XXIV.]  HERCULANEUM    AND   POMPEII.  391 

great  a  depth  below  ground.  Even  the  theatre  is  only  seen  by  torch- 
light, and  the  most  interesting  information,  perhaps,  which  the  geologist 
obtains  there,  is  the  continual  formation  of  stalactite  in  the  galleries  cut 
through  the  tuff ;  for  there  is  a  constant  percolation  of  water  charged 
with  carbonate  of  lime  mixed  with  a  small  portion  of  magnesia.  Such 
mineral  waters  must,  in  the  course  of  time,  create  great  changes  in 
many  rocks  ;  especially  in  lavas,  the  pores  of  which  they  may  fill  with 
calcareous  spar,  so  as  to  convert  them  into  amygdaloids. '  Some  geolo- 
gists, therefore,  are  unreasonable  when  they  expect  that  volcanic  rocks 
of  remote  eras  should  accord  precisely  with  those  of  modern  date  ; 
since  it  is  obvious  that  many  of  those  produced  in  our  own  time  will 
not  long  retain  the  same  aspect  and  internal  composition. 

Both  at  Herculaneum  and  Pompeii,  temples  have  been  found  with 
inscriptions  commemorating  the  rebuilding  of  the  edifices  after  they  had 
been  thrown  down  by  an  earthquake.*  This  earthquake  happened  in 
the  reign  of  Nero,  sixteen  years  before  the  cities  were  overwhelmed.  In 
Pompeii,  one-fourth  of  which  is  now  laid  open  to  the  day,  both  the 
public  and  private  buildings  bear  testimony  to  the  catastrophe.  The 
walls  are  rent,  and  in  many  places  traversed  by  fissures  still  open. 
Columns  are  lying  on  the  ground  only  half  hewn  from  huge  blocks  of 
travertin,  and  the  temple  for  which  they  were  designed  is  seen  half 
repaired.  In  some  few  places  the  pavement  had  sunk  in,  but  in  general 
it  was  undisturbed,  consisting  of  large  irregular  flags  of  lava  joined 
neatly  together,  in  which  the  carriage  wheels  have  often  worn  ruts  an 
inch  and  a  half  deep.  In  the  wider  streets,  the  ruts  are  numerous  and 
irregular ;  in  the  narrower,  there  are  only  two,  one  on  each  side,  which 
are  very  conspicuous.  It  is  impossible  not  to  look  with  some  interest 
even  on  these  ruts,  which  were  worn  by  chariot  wheels  more  than 
seventeen  centuries  ago  ;  and,  independently  of  their  antiquity,  it  is 
remarkable  to  see  such  deep  incisions  so  continuous  in  a  stone  of  great 
hardness. 

Small  number  of  skeletons. — A  very  small  number  of  skeletons  have 
been  discovered  in  either  city ;  and  it  is  clear  that  most  of  the  inhabit- 
ants not  only  found  time  to  escape,  but  also  to  carry  with  them  the 
principal  part  of  their  valuable  effects.  In  the  barracks  at  Pompeii 
\vete  the  skeletons  of  two  soldiers  chained  to  the  stocks,  and  in  the 
vaults  of  a  country-house  in  the  suburbs  were  the  skeletons  of  seven- 
teen persons,  who  appear  to  have  fled  there  to  escape  from  the  shower 
of  ashes.  They  were  found  inclosed  in  an  indurated  tuff,  and  in  this 
matrix  was  preserved  a  perfect  cast  of  a  woman,  perhaps  the  mistress 
of  the  house,  with  an  infant  in  her  arms.  Although  her  form  was  im- 
printed on  the  rock,  nothing  but  the  bones  remained.  To  these  a  chain 
of  gold  was  suspended,  and  on  the  fingers  of  the  skeletons  were  rings 
with  jewels.  Against  the  sides  of  the  same  vault  was  ranged  a  long 
line  of  earthen  amphorae. 

*  Swinburne  and  Lalande.     Paderni,  Phil.  Trans.  1758,  vol.  i.  p.  619. 


392  HERCULANEUM   AND    POMPEII.  [Cfl.  XXIV. 

The  writings  scribbled  by  the  soldiers  on  the  walls  of  their  barracks, 
and  the  names  of  the  owners  of  each  house  written  over  the  doors,  are 
still  perfectly  legible.  The  colors  of  fresco  paintings  on  the  stuccoed 
walls  in  the  interior  of  buildings  are  almost  as  vivid  as  if  they  were  just 
finished.  There  are  public  fountains  decorated  with  shells  laid  out  in 
patterns  in  the  same  fashion  as  those  now  seen  in  the  town  of  Naples ; 
and  in  the  room  of  a  painter,  who  was  perhaps  a  naturalist,  a  large  col- 
lection of  shells  was  found,  comprising  a  great  variety  of  Mediterranean 
species,  in  as  good  a  state  of  preservation  as  if  they  had  remained  for 
the  same  number  of  years  in  a  museum.  A  comparison  of  these 
remains,  with  those  found  so  generally  in  a  fossil  state  would  not  assist 
us  in  obtaining  the  least  insight  into  the  time  required  to  produce  a  cer- 
tain degree  of  decomposition  or  mineralization  ;  for,  although  under 
favorable  circumstances  much  greater  alteration  might  doubtless  have 
been  brought  about  in  a  shorter  period,  yet  the  example  before  us  shows 
that  an  inhumation  of  seventeen  centuries  may  sometimes  effect  nothing 
towards  the  reduction  of  shells  to  the  state  in  which  fossils  are  usually 
found. 

The  wooden  beams  in  the  houses  at  Herculaneum  are  black  on  the 
exterior,  but,  when  cleft  open,  they  appear  to  be  almost  in  the  state  of 
ordinary  wood,  and  the  progress  made  by  the  whole  mass  towards  the 
state  of  lignite  is  scarcely  appreciable.  Some  animal  and  vegetable 
substances  of  more  perishable  kinds  have  of  course  suffered  much 
change  and  decay,  yet  the  state  of  preservation  of  these  is  truly  re- 
markable. Fishing-nets  are  very  abundant  in  both  cities,  often  quite 
entire  ;  and  their  number  at  Pompeii  is  the  more  interesting  from  the 
sea  being  now,  as  we  stated,  a  mile  distant.  Linen  has  been  found  at 
Herculaneum,  with  the  texture  well  defined ;  and  in  a  fruiterer's  shop 
in  that  city  were  discovered  vessels  full  of  almonds,  chestnuts,  walnuts, 
and  fruit  of  the  "  carubiere,"  all  distinctly  recognizable  from  their 
shape.  A  loaf,  also,  still  retaining  its  form,  was  found  in  a  baker's 
shop,  with  his  name  stamped  upon  it.  On  the  counter  of  an  apothe- 
cary was  a  box  of  pills  converted  into  a  fine  earthy  substance  ;  and  by 
the  side  of  it  a  small  cylindrical  roll  evidently  prepared  to  be  cut  into 
pills.  By  the  side  of  these  was  a  jar  containing  medicinal  herbs.  In 
1827,  moist  olives  were  found  in  a  square  glass-case,  and  "  caviare,"  or 
roe  of  a  fish,  in  a  state  of  wonderful  preservation.  An  examination  of 
these  curious  condiments  has  been  published  by  Covelli  of  Naples,  and 
they  are  preserved  hermetically  sealed  in  the  museum  there.* 

Papyri. — There  is  a  marked  difference  in  the  condition  and  appear- 
ance of  the  animal  and  vegetable  substances  found  at  Pompeii  and 
Herculaneum  ;  those  of  Pompeii  being  penetrated  by  a  gray  pulver- 
ulent tuff,  those  in  Herculaneum  seeming  to  have  been  first  enveloped 
by  a  paste  which  consolidated  round  them,  and  then  allowed  them  to 
Decome  slowly  carbonized.  Some  of  the  rolls  of  papyrus  at  Pompeii 

*  Prof.  J.  D.  Forbes,  Edin.  Journ.  of  Sci.  No.  xix.  p.  130,  Jan.  1829. 


Cu.  XXIV.]  PAPYRI   IN    HERCULANEUM.  393 

still  retain  their  form ;  but  the  writing,  and  indeed  almost  all  the  vege- 
table matter,  appear  to  have  vanished,  and  to  have  been  replaced  by 
volcanic  tuff  somewhat  pulverulent.  At  Herculaneum  the  earthy  mat- 
ter has  scarcely  ever  penetrated  ;  and  the  vegetable  substance  of  the 
papyrus  has  become  a  thin  friable  black  matter,  almost  resembling  in 
appearance  the  tinder  which  remains  when  stiff  paper  has  been  burnt, 
in  which  the  letters  may  still  be  sometimes  traced.  The  small  bundles 
of  papyri,  composed  of  five  or  six  rolls  tied  up  together,  had  sometimes 
lain  horizontally,  and  were  pressed  in  that  direction,  but  sometimes 
they  had  been  placed  in  a  vertical  position.  Small  tickets  were  at- 
tached to  each  bundle,  on  which  the  title  of  the  work  was  inscribed. 
In  one  case  only  have  the  sheets  been  found  with  writing  on  both  sides 
of  the  pages.  So  numerous  are  the  obliterations  and  corrections,  that 
many  must  have  been  original  manuscripts.  The  variety  of  handwri- 
tings is  quite  extraordinary :  nearly  all  are  written  in  Greek,  but  there 
are  a  few  in  Latin.  They  were  almost  all  found  in  a  suburban  villa  in 
the  library  of  one  private  individual ;  and  the  titles  of  four  hundred  of 
those  least  injured,  which  have  been  read,  are  found  to  be  unimportant 
works,  but  all  entirely  new,  chiefly  relating  to  music,  rhetoric,  and 
cookery.  There  are  two  volumes  of  Epicurus  "  On  Nature,"  and  the 
others  are  mostly  by  writers  of  the  same  school,  only  one  fragment 
having  been  discovered,  by  an  opponent  of  the  Epicurean  system, 
Chrysippus.* 

Probability  of  future  discoveries  of  MSS. — In  the  opinion  of  some 
antiquaries,  not  one-hundredth  part  of  the  city  has  yet  been  explored : 
and  the  quarters  hitherto  cleared  out  at  a  great  expense,  are  those 
where  there  was  the  least  probability  of  discovering  manuscripts.  As 
Italy  could  already  boast  her  splendid  Roman  amphitheatres  and  Greek 
temples,  it  was  a  matter  of  secondary  interest  to  add  to  their  number 
those  in  the  dark  and  dripping  galleries  of  Herculaneum ;  and  having 
so  many  of  the  masterpieces  of  ancient  art,  we  could  have  dispensed 
with  the  inferior  busts  and  statues  which  could  alone  have  been  ex- 
pected to  reward  our  researches  in  the  ruins  of  a  provincial  town. 
But  from  the  moment  that  it  was  ascertained  that  rolls  of  papyrus  pre- 
served in  this  city  could  still  be  deciphered,  every  exertion  ought  to 
have  been  steadily  and  exclusively  directed  towards  the  discovery  of 
other  libraries.  Private  dwellings  should  have  been  searched,  before 
so  much  labor  and  expense  were  consumed  in  examining  public  edi- 
fices. A  small  portion  of  that  zeal  and  enlightened  spirit  which 
prompted  the  late  French  and  Tuscan  expedition  to  Egypt  might  long 
ere  this,  in  a  country  nearer  home,  have  snatched  from  oblivion  some 
of  the  lost  works  of  the  Augustan  age,  or  of  eminent  Greek  historians 
and  philosophers.  A  single  roll  of  papyrus  might  have  disclosed  more 

*  In  one  of  the  manuscripts  which  was  in  the  hands  of  the  interpreters  when  I 
visited  the  museum  in  1828,  the  author  indulges  in  the  speculation  that  all  the 
Homeric  personages  were  allegorical — that  Agamemnon  was  the  ether,  Achilles 
the  sun,  Helen  the  earth,  Paris  the  air,  Hector  the  moon,  <fec. 


394  DESTRUCTION   OF   TORRE   DEL   GRECO.  [On.  XXIV. 

matter  of  intense  interest  than  all  that  was  ever  written  in  hiero- 
glyphics. 

StaUw. — Besides  the  cities  already  mentioned,  Stabise,  a  small  town 
about  six  miles  from  Vesuvius,  and  near  the  site  of  the  modern  Castel-a- 
Mare  (see  map  of  volcanic  district  of  Naples),  was  overwhelmed  during 
the  eruption  of  79.  Pliny  mentions  that,  when  his  uncle  was  there,  he 
was  obliged  to  make  his  escape,  so  great  was  the  quantity  of  falling 
stones  and  ashes.  In  the  ruins  of  this  place,  a  few  skeletons  have  been 
found  buried  in  volcanic  ejections,  together  with  some  antiquities  of  no 
great  value,  and  rolls  of  papyrus,  which,  like  those  of  Pompeii,  were 
illegible. 

Torre  del  Greco  overflowed  by  lava. — Of  the  towns  hitherto  men- 
tioned, Herculaneum  alone  has  been  overflowed  by  a  stream  of  melted 
matter ;  but  this  did  not,  as  we  have  seen,  enter  or  injure  the  buildings, 
which  were  previously  enveloped  or  covered  over  with  tuff.  But  burn- 
ing torrents  have  often  taken  their  course  through  the  streets  of  Torre 
del  Greco,  and  consumed  or  inclosed  a  large  portion  of  the  town  in 
solid  rock.  It  seems  probable  that  the  destruction  of  three  thousand 
of  its  inhabitants  in  1631,  which  some  accounts  attribute  to  boiling  wa- 
ter, was  principally  due  to  one  of  those  alluvial  floods  which  we  before 
mentioned:  but,  in  1737,  the  lava  itself  flowed  through  the  eastern 
side  of  the  town,  and  afterwards  reached  the  sea;  and,  in  1794,  another 
current,  rolling  over  the  western  side,  filled  the  streets  and  houses,  and 
killed  more  than  four  hundred  persons.  The  main  street  is  now  quarried 
through  this  lava,  which  supplied  building  stones  for  new  houses  erected 
where  others  had  been  annihilated.  The  church  was  half  buried  in  a 
rocky  mass,  but  the  upper  portion  served  as  the  foundation  of  a  new 
edifice. 

The  number  of  the  population  at  present  is  estimated  at  fifteen  thou- 
sand ;  and  a  satisfactory  answer  may  readily  be  returned  to  those  who 
inquire  how  the  inhabitants  can  be  so  "  inattentive  to  the  voice  of  time 
and  the  warnings  of  nature,"*  as  to  rebuild  their  dwellings  on  a  spot  so 
often  devastated.  No  neighboring  site  unoccupied  by  a  town,  or  which 
would  not  be  equally  insecure,  combines  the  same  advantages  of  prox- 
imity to  the  capital,  to  the  sea,  and  to  the  rich  lands  on  the  flanks  of 
Vesuvius.  If  the  present  population  were  exiled,  they  would  imme- 
diately be  replaced  by  another,  for  the  same  reason  that  the  Maremma 
of  Tuscany  and  the  Campagna  di  Roma  will  never  be  depopulated, 
although  the  malaria  fever  commits  more  havoc  in  a  few  years  than  the 
Vesuvian  lavas  in  as  many  centuries.  The  district  around  Naples  sup- 
plies one  amongst  innumerable-  examples,  that  those  regions  where  the 
surface  is  most  frequently  renewed,  and  where  the  renovation  is  accom- 
panied, at  different  intervals  of  time,  by  partial  destruction  of  animal 
and  vegetable  life,  may  nevertheless  be  amongst  the  most  habitable  and 
delightful  on  our  globe. 

*  Sir  H.  Davy,  Consolations  in  Travel,  p.  66. 


CH.  XXIV.]  REFLECTIONS    ON    THE    BURIED    CITIES.  395 

I  have  already  made  a  similar  remark  when  speaking  of  tracts  where 
aqueous  causes  are  now  most  active ;  and  the  observation  applies  as 
well  to  parts  of  the  surface  which  are  the  abode  of  aquatic  animals,  as 
to  those  which  support  terrestrial  species.  The  sloping  sides  of  Vesu- 
vius give  nourishment  to  a  vigorous  and  healthy  population  of  about 
eighty  thousand  souls  ;  and  the  surrounding  hills  and  plains,  together 
with  several  of  the  adjoining  isles,  owe  the  fertility  of  their  soil  to  mat- 
ter ejected  by  prior  eruptions.  Had  the  fundamental  limestone  of  the 
Apennines  remained  uncovered  throughout  the  whole  area,  the  country 
could  not  have  sustained  a  twentieth  part  of  its  present  inhabitants.  This 
will  be  apparent  to  every  geologist  who  has  marked  the  change  in  the 
agricultural  character  of  the  soil  the  moment  he  has  passed  the  utmost 
boundary  of  the  volcanic  ejections,  as  when,  for  example,  at  the  dis- 
tance of  about  seven  miles  from  Vesuvius,  he  leaves  the  plain  and 
ascends  the  declivity  of  the  Sorrentine  Hills. 

Yet,  favored  as  this  region  has  been  by  Nature  from  time  immemorial, 
the  signs  of  the  changes  imprinted  on  it  during  the  period  that  it  has 
served  as  the  habitation  of  man  may  appear  in  after-ages  to  indicate 
a  series  of  unparalleled  disasters.  Let  us  suppose  that  at  some  future 
time  the  Mediterranean  should  form  a  gulf  of  the  great  ocean,  and  that 
the  waves  and  tidal  current  should  encroach  on  the  shores  of  Campania, 
as  it  now  advances  upon  the  eastern  coast  of  England  ;  the  geologist  will 
then  behold  the  towns  already  buried,  and  many  more  which  will  evi- 
dently be  entombed  hereafter,  laid  open  in  the  steep  cliffs,  where  he 
will  discover  buildings  superimposed  above  each  other,  with  thick  inter- 
vening strata  of  tuff  or  lava — some  unscathed  by  fire,  like  those  of 
Herculaneum  and  Pompeii ;  others  half  melted  down,  as  in  Torre  del 
Greco  ;  and  many  shattered  and  thrown  about  in  strange  confusion,  as 
in  Tripergola,  beneath  Monte  Nuovo.  Among  the  ruins  will  be  seen 
skeletons  of  men,  and  impressions  of  the  liuman  form  stamped  in  solid 
rocks  of  tuff.  Nor  will  the  signs  of  earthquakes  be  wanting.  The  pave- 
ment of  part  of  the  Domitian  Way,  and  the  temple  of  the  Nymphs,  sub- 
merged at  high  tide,  will  be  uncovered  at  low  water,  the  columns  re- 
maining erect  and  uninjured.  Other  temples  which  had  once  sunk  down, 
like  that  of  Serapis,  will  be  found  to  have  been  upraised  again  by  sub- 
sequent movements.  If  they  who  study  these  phenomena,  and  specu- 
late on  their  causes,  assume  that  there  were  periods  when  the  laws  of 
Nature  or  the  whole  course  of  natural  events  differed  greatly  from  those 
observed  in  their  own  time,  they  will  scarcely  hesitate  to  refer  the  won- 
derful monuments  in  question  to  those  primeval  ages.  When  they  con- 
sider the  numerous  proofs  of  reiterated  catastrophes  to  which  the  region 
was  subject,  they  may,  perhaps,  commiserate  the  unhappy  fate  of  beings 
condemned  to  inhabit  a  planet  during  its  nascent  and  chaotic  state,  and 
feel  grateful  that  their  favored  race  has  escaped  such  scenes  of  anarchy 
and  misrule. 

Yet  what  was  the  real  condition  of  Campania  during  those  years  of 
dire  convulsion  ?  "A  climate  where  heaven's  breath  smells  sweet  and 


396  ETNA.  [On.  XXV. 

wooingly — a  vigorous  and  luxuriant  nature  unparalleled  in  its  produc- 
tions— a  coast  which  was  once  the  fairy-land  of  poets,  and  the  favorite 
retreat  of  great  men.  Even  the  tyrants  of  the  creation  loved  this  allu- 
ring region,  spared  it,  adorned  it,  lived  in  it,  died  in  it."*  The  inhabit- 
ants, indeed,  have  enjoyed  no  immunity  from  the  calamities  which  are 
the  lot  of  mankind  ;  but  the  principal  evils  which  they  have  suffered 
must  be  attributed  to  moral,  not  to  physical,  causes — to  disastrous 
events  over  which  man  might  have  exercised  a  control,  rather  than  to 
the  inevitable  catastrophes  which  result  from  subterranean  agency. 
When  Spartacus  encamped  his  army  of  ten  thousand  gladiators  in  the 
old  extinct  crater  of  Vesuvius,  the  volcano  was  more  justly  a  subject  of 
terror  to  Campania,  than  it  has  ever  been  since  the  rekindling  of  its  fires. 


CHAPTER  XXV. 

ETNA. 

External  physiognomy  of  Etna — Lateral  cones — Their  successive  obliteration — 
Early  eruptions — Monti  Rossi  in  1669 — Towns  overflowed  by  lava — Part  of 
Catania  overflowed — Mode  of  advance  of  a  current  of  lava — Subterranean 
caverns — Marine  strata  at  base  of  Etna — Val  del  Bove  not  an  ancient  crater — 
Its  scenery — Form,  composition,  and  origin  of  the  dikes — Linear  direction  of 
cones  formed  in  1811  and  1819 — Lavas  and  breccias — Flood  produced  by  the 
melting  of  snow  by  lava — Glacier  covered  by  a  lava  stream — Val  del  Bove 
how  formed — Structure  and  origin  of  the  cone  of  Etna — Whether  the  inclined 
sheets  of  lava  were  originally  horizontal — Antiquity  of  Etna — Whether  signs 
of  diluvial  waves  are  observable  on  Etna. 

External  physiognomy  of  Etna. — AFTER  Vesuvius,  our  most  authentic 
records  relate  to  Etna,  which  rises  near  the  sea  in  solitary  grandeur  to 
the  height  of  nearly  eleven  thousand  feet.f  The  base  of  the  cone  is 
almost  circular,  and  eighty-seven  English  miles  in  circumference  ;  but 
if  we  include  the  whole  district  over  which  its  lavas  extend,  the  circuit 
is  probably  twice  that  extent. 

Divided  into  three  regions. — The  cone  is  divided  by  nature  into  three 
distinct  zones,  called  the  fertile,  the  woody,  and  the  desert  regions.  The 
first  of  these,  comprising  the  delightful  country  around  the  skirts  of  the 
mountain,  is  well  cultivated,  thickly  inhabited,  and  covered  with  olives, 

*  Forsyth's  Italy,  vol.  ii. 

f  In  1815,  Captain  Smyth  ascertained,  trigonometrically,  that  the  height  of  Etna 
was  10,874  feet.  The  Catanians,  disappointed  that  their  mountain  had  lost  nearly 
2000  feet  of  the  height  assigned  to  it  by  Recupero,  refused  to  acquiesce  in  the  deci- 
sion. Afterwards,  in  1824,  Sir  J.  Herschel,  not  being  aware  of  Captain  Smyth's 
conclusions,  determined  by  careful  barometrical  measurement  that  the  height  was 
10,872^  feet.  This  singular  agreement  of  results  so  differently  obtained  was  spo- 
ken of  by  Herschel  as  "  a  happy  accident ;"  but  Dr.  Wollaston  remarked  that  "it 
was  one  of  those  accidents  which  would  not  have  happened  to  two  fools." 


CH.  XXV.]  MINOR   VOLCANOES   ON    ETNA.  397 

vines,  corn,  fruit-trees,  and  aromatic  herbs.  Higher  up,  the  woody 
region  encircles  the  mountain — an  extensive  forest  six  or  seven  miles  in 
width,  affording  pasturage  for  numerous  flocks.  The  trees  are  of  various 
species,  the  chestnut,  oak,  and  pine  being  most  luxuriant ;  while  in  some 
tracts  are  groves  of  cork  and  beech.  Above  the  forest  is  the  desert 
region,  a  waste  of  black  lava  and  scoriae ;  where,  on  a  kind  of  plain, 
rises  a  cone  of  eruption  to  the  height  of  about  eleven  hundred  feet,  from 
which  sulphureous  vapors  are  continually  evolved. 

Cones  produced  by  lateral  eruption. — The  most  grand  and  original 
feature  in  the  physiognomy  of  Etna  is  the  multitude  of  minor  cones 
which  are  distributed  over  its  flanks,  and  which  are  most  abundant  in 
the  woody  region.  These,  although  they  appear  but  trifling  irregulari- 
ties when  viewed  from  a  distance  as  subordinate  parts  of  so  imposing 
and  colossal  a  mountain,  would,  nevertheless,  be  deemed  hills  of  consid- 
erable altitude  in  almost  any  other  region.  Without  enumerating  nu- 
merous monticules  of  ashes  thrown  out  at  different  points,  there  are 
about  eighty  of  these  secondary  volcanoes,  of  considerable  dimensions ; 
fifty-two  on  the  west  and  north,  and  twenty-seven  on  the  east  side  of 
Etna.  One  of  the  largest,  called  Monte  Minardo,  near  Bronte,  is  up- 
wards of  700  feet  in  height,  and  a  double  hill  near  Nicolosi,  called 
Monti  Rossi,  formed  in  1669,  is  450  feet  high,  and  the  base  two  miles  in 
circumference  ;  so  that  it  somewhat  exceeds  in  size  Monte  Nuovo,  be- 
fore described.  Yet  it  ranks  only  as  a  cone  of  the  second  magnitude 
amongst  those  produced  by  the  lateral  eruptions  of  Etna.  On  looking 
down  from  the  lower  borders  of  the  desert  region,  these  volcanoes  pre- 
sent us  with  one  of  the  most  delightful  and  characteristic  scenes  in 
Europe.  They  afford  every  variety  of  height  and  size,  and  are  arranged 
in  beautiful  and  picturesque  groups.  However  uniform  they  may  ap- 
pear when  seen  from  the  sea,  or  the  plains  below,  nothing  can  be  more 
diversified  than  their  shape  when  we  look  from  above  into  their  craters, 
one  side  of  which  is  generally  broken  down.  There  are,  indeed,  few 
objects  in  nature  more  picturesque  than  a  wooded  volcanic  crater.  The 
cones  situated  in  the  higher  parts  of  the  forest  zone  are  chiefly  clothed 
with  lofty  pines  ;  while  those  at  a  lower  elevation  are  adorned  with 
chestnuts,  oaks,  beech,  and  holm. 

Successive  obliteration  of  these  cones. — The  history  of  the  eruptions  of 
Etna,  imperfect  and  interrupted  as  it  is,  affords  us,  nevertheless,  much 
insight  into  the  manner  in  which  the  whole  mountain  has  successively  at- 
tained its  present  magnitude  and  internal  structure.  The  principal  cone 
has  more  than  once  fallen  in  and  been  reproduced.  In  1444  it  was  320 
feet  high,  and  fell  in  after  the  earthquakes  of  1537.  In.  the  year  1693, 
when  a  violent  earthquake  shook  the  whole  of  Sicily,  and  killed  sixty 
thousand  persons,  the  cone  lost  so  much  of  its  height,  says  Boccone, 
that  it  could  not  be  seen  from  several  places  in  Valdemone,  from  which 
it  was  before  visible.  The  greater  number  of  eruptions  happen  either 
from  the  great  crater,  or  from  lateral  openings  in  the  desert  region. 
When  hills  are  thrown  up  in  the  middle  zone,  and  project  beyond  the 


398  BUEIED  CONES  OF  ETNA.  [On.  XXV. 

general  level,  they  gradually  lose  their  height  during  subsequent  erup- 
tions ;  for  when  lava  runs  down  from  the  upper  parts  of  the  mountain, 
and  encounters  any  of  these  hills,  the  stream  is  divided,  and  flows  round 
them  so  as  to  elevate  the  gently  sloping  grounds  from  which  they  rise. 
In  this  manner  a  deduction  is  often  made  at  once  of  twenty  or  thirty 
feet,  or  even  more,  from  their  height.  Thus,  one  of  the  minor  cones, 
called  Monte  Peluso,  was  diminished  in  altitude  by  a  great  lava  stream 
which  encircled  it  in  1444  ;  and  another  current  has  recently  taken  the 
same  course — yet  this  hill  still  remains  four  or  five  hundred  feet  high. 

There  is  a  cone  called  Monte  Nucilla  near  Nicolosi,  round  the  base  of 
which  several  successive  currents  have  flowed,  and  showers  of  ashes 
have  fallen,  since  the  time  of  history,  till  at  last,  during  an  eruption  in 
1 536,  the  surrounding  plain  was  so  raised,  that  the  top  of  the  cone 
alone  was  left  projecting  above  the  general  level.  Monte  Nero,  situated 
above  the  Grotta  dell'  Capre,  was  in  1766  almost  submerged  by  a  cur- 
rent :  and  Monte  Capreolo  afforded,  in  the  year  1669,  a  curious  example 
of  one  of  the  last  stages  of  obliteration  ;  for  a  lava  stream,  descending  on 
a  high  ridge  which  had  been  built  up  by  the  continued  superposition 
of  successive  lavas,  flowed  directly  into  the  crater,  and  nearly  filled  it. 
The  lava,  therefore,  of  each  new  lateral  cone  tends  to  detract  from  the 
relative  height  of  lower  cones  above  their  base :  so  that  the  flanks  of 
Etna,  sloping  with  a  gentle  inclination,  envelop  in  succession  a  great 
multitude  of  minor  volcanoes,  while  new  ones  spring  up  from  time  to 
time. 

Early  eruptions  of  Etna. — Etna  appears  to  have  been  in  activity 
from  the  earliest  times  of  tradition ;  for  Diodorus  Siculus  mentions  an 
eruption  which  caused  a  district  to  be  deserted  by  the  Sicani  before  the 
Trojan  war.  Thucydides  informs  us,  that  in  the  sixth  year  of  the  Pelo- 
ponnesian  war,  or  in  the  spring  of  the  year  425  B.  c.,  a  lava  stream 
ravaged  the  environs  of  Catania,  and  this  he  says  was  the  third  eruption 
which  had  happened  in  Sicily  since  the  colonization  of  that  island  by 
the  Greeks.*  The  second  of  the  three  eruptions  alluded'  to  by  the  his- 
torian took  place  in  the  year  475  B.  c.,  and  was  that  so  poetically 
described  by  Pindar,  two  years  afterwards,  in  his  first  Pythian  ode  : — 

KlUiV 

A'  ovftavia  <7W£X£i 
Nt$o£oV  Atrva,  iraveres 
Xiovog  o£eias  ridriva. 

In  these  and  the  seven  verses  which  follow,  a  graphic  description  is 
given  of  Etna,  such  as  it  appeared  five  centuries  before  the  Christian 
era,  and  such  as  it  has  been  seen  when  in  eruption  in  modern  times.  The 
poet  is  only  making  a  passing  allusion  to  the  Sicilian  -volcano,  as  the 
mountain  under  which  Typhceus  lay  buried,  yet  by  a  few  touches  of  his 
master-hand  every  striking  feature  of  the  scene  has  been  faithfully  por- 

*  Book  iii.  at  the  end. 


Cn.  XXV.] 


ERUPTION   OF   ETNA. 


399 


trayed.  We  are  told  of  "  the  snowy  Etna,  the  pillar  of  heaven — the 
nurse  of  everlasting  frost,  in  whose  deep  caverns  lie  concealed  the  foun- 
tains of  unapproachable  fire — a  stream  of  eddying  smoke  by  day — a 
bright  and  ruddy  flame  by  night ;  and  burning  rocks  rolled  down  with 
loud  uproar  into  the  sea." 

Eruption  of  1669 — Monti  Rossi  formed. — The  great  eruption  which 
happened  in  the  year  1669  is  the  first  which  claims  particular  attention. 
An  earthquake  had  levelled  to  the  ground  all  the  houses  in  Nicolosi,  a 
town  situated  near  the  lower  margin  of  the  woody  region,  about  twenty 
miles  from  the  summit  of  Etna,  and  ten  from  the  sea  at  Catania.  Two 
gulfs  then  opened  near  that  town,,  from  whence  sand  and  scoriae  were 
thrown  up  in  such  quantity,  that  in  the  course  of  three  or  four  months 
a  double  cone  was  formed,  called  Monti  Rossi,  about  450  feet  high.  But 

Fig.  46. 


Minor  cones  on  the  flanks  of  Etna. 
1.  Monti  Kossi,  near  Nicolosi,  formed  in  1669. 


2.  Yampeluso  ?* 


the  most  extraordinary  phenomenon  occurred  at  the  commencement  of 
the  convulsion  in  the  plain  of  S.  Lio.  A  fissure  six  feet  broad,  and  of 
unknown  depth,  opened  with  a  loud  crash,  and  ran  in  a  somewhat  tor- 
tuous course  to  within  a  mile  of  the  summit  of  Etna.  Its  direction  was 
from  north  to  south,  and  its  length  twelve  miles.  It  emitted  a  most 
vivid  light.  Five  other  parallel  fissures  of  considerable  length  after- 
wards opened,  one  after  the  other,  and  emitted  smoke,  and  gave  out  bel- 
lowing sounds  which  were  heard  at  the  distance  of  forty  miles.  This 
case  seems  to  present  the  geologist  with  an  illustration  of  the  manner  in 
which  those  continuous  dikes  of  vertical  porphyry  were  formed,  which 
are  seen  to  traverse  some  of  the  older  lavas  of  Etna ;  for  the  light  emit- 
ted from  the  great  rent  of  S.  Lio  appears  to  indicate  that  the  fissure  was 
filled  to  a  certain  height  with  incandescent  lava,  probably  to  the  height 
of  an  orifice  not  far  distant  from  Monti  Rossi,  which  at  that  time  opened 
and  poured  out  a  lava  current.  When  the  melted  matter  in  such  a  rent 

*  The  hill  which  I  have  here  introduced  was  caller!  }>y  my  guide  Vampolara, 
but  the  name  given  in  the  text  is  the  nearest  to  this  which  I  find  in  Gemmellaro's 
Catalogue  of  Minor  Cones. 


400  ERUPTION  OF  ETNA,  A.  D.  1669.        [On.  XXV 

has  cooled,  it  must  become  a  solid  wall  or  dike,  intersecting  the  older 
rocks  of  which  the  mountain  is  composed ;  similar  rents  have  been 
observed  during  subsequent  eruptions,  as  in  1832,  when  they  ran  in  all 
directions  from  the  centre  of  the  volcano.  It  has  been  justly  remarked 
by  M.  Elie  de  Beaumont,  that  such  star-shaped  fractures  may  indicate 
a  slight  upheaval  of  the  whole  of  Etna.  They  may  be  the  signs  of  the 
stretching  of  the  mass,  which  may  thus  be  raised  gradually  by  a  force 
from  below.* 

The  lava  current  of  1669,  before  alluded  to,  soon  reached  in  its  course 
a  minor  cone  called  Mompiliere,  at  the  base  of  which  it  entered  a  sub- 
terranean grotto,  communicating  with  a  suite  of  those  caverns  which  are 
so  common  in  the  lavas  of  Etna.  Here  it  appears  to  have  melted  down 
some  of  the  vaulted  foundations  of  the  hill,  so  that  the  whole  of  that 
cone  became  slightly  depressed  and  traversed  by  numerous  open  fis- 
sures. 

Part  of  Catania  destroyed. — The  lava,  after  overflowing  fourteen 
towns  and  villages,  some  having  a  population  of  between  three  and  four 
thousand  inhabitants,  arrived  at  length  at  the  walls  of  Catania.  These 
had  been  purposely  raised  to  protect  the  city  ;  but  the  burning  flood 
accumulated  till  it  rose  to  the  top  of  the  rampart,  which  was  sixty  feet 
in  height,  and  then  it  fell  in  a  fiery  cascade  and  overwhelmed  part  of  the 
city.  The  wall,  however,  was  not  thrown  down,  but  was  discovered 
long  afterwards  by  excavations  made  in  the  rock  by  the  Prince  of  Bis- 
cari ;  so  that  the  traveller  may  now  see  the  solid  lava  curling  over  the 
top  of  the  rampart  as  if  still  in  the  very  act  of  falling. 

This  great  current  performed  the  first  thirteen  miles  of  its  course  in 
twenty  days,  or  at  the  rate  of  162  feet  per  hour,  but  required  twenty- 
three  days  for  the  last  two  miles,  giving  a  velocity  of  only  twenty-two 
feet  per  hour ;  and  we  learn  from  Dolomieu  that  the  stream  moved 
during  part  of  its  course  at  the  rate  of  1500  feet  an  hour,  and  in  others 
it  took  several  days  to  cover  a  few  yards.f  When  it  entered  the  sea  it 
was  still  six  hundred  yards  broad,  and  forty  feet  deep.  It  covered  some 
territories  in  the  environs  of  Catania  which  had  never  before  been  visited 
by  the  lavas  of  Etna.  While  moving  on,  its  surface  was  in  general  a 
mass  of  solid  rock ;  and  its  mode  of  advancing,  as  is  usual  with  lava 
streams,  was  by  the  occasional  fissuring  of  the  solid  walls.  A  gentle- 
man of  Catania,  named  Pappalardo,  desiring  to  secure  the  city  from  the 
approach  of  the  threatening  torrent,  went  out  with  a  party  of  fifty  men 
whom  he  had  dressed  in  skins  to  protect  them  from  the  heat,  and  armed 
with  iron  crows  and  hooks.  They  broke  open  one  of  the  solid  walls 
which  flanked  the  current  near  Belpasso,  and  immediately  forth  issued 
a  rivulet  of  melted  matter  which  took  the  direction  of  Paterno  ;  but  the 
inhabitants  of  that  town,  being  alarmed  for  their  safety,  took  up  arms 
and  put  a  stop  to  farther  operations.^ 

*  Mem.  pour  servir,  <te.  torn.  iv.  p.  116. 

f  See  Prof.  J.  D.  Forbes,  Phil.  Trans.  1846,  p.  155,  on  Velocity  of  Lava. 

$  Ferrara,  Descriz.  dell'  Etna,  p.  108. 


CH.  XXV.]  MARINE   STRATA    AT   BASE   OF   ETNA.  401 

As  another  illustration  of  the  solidity  of  the  walls  of  an  advancing 
lava  stream,  I  may  mention  an  adventure  related  by  Recupero,  who,  in 
17G6,  had  ascended  a  small  hill  formed  of  ancient  volcanic  matter,  to 
behold  the  slow  and  gradual  approach  of  a  fiery  current,  two  miles  and 
a  half  broad ;  when  suddenly  two  small  threads  of  liquid  matter  issuing 
from  a  crevice  detached  themselves  from  the  main  stream,  and  ran  rap- 
idly towards  the  hill.  He  and  his  guide  had  just  time  to  escape,  when 
they  saw  the  hill,  which  was  fifty  feet  in  height,  surrounded,  and  in  a 
quarter  of  an  hour  melted  down  into  the  burning  mass,  so  as  to  flow  on 
with  it. 

But  it  must  not  be  supposed  that  this  complete  fusion  of  rocky  matter 
coming  in  contact  with  lava  is  of  universal,  or  even  common,  occurrence. 
It  probably  happens  when  fresh  portions  of  incandescent  matter  come 
successively  in  contact  with  fusible  materials.  In  many  of  the  dikes 
which  intersect  the  tuffs  and  lavas  of  Etna,  there  is  scarcely  any  percep- 
tible alteration  effected  by  heat  on  the  edges  of  the  horizontal  beds,  in 
contact  with  the  vertical  and  more  crystalline  mass.  On  the  side  of 
Mompiliere,  one  of  the  towns  overflowed  in  the  great  eruption  above 
described,  an  excavation  was  made  in  1704  ;  and  by  immense  labor  the 
workmen  reached,  at  the  depth  of  thirty-five  feet,  the  gate  of  the  prin- 
cipal church,  were  there  were  three  statues,  held  in  high  veneration. 
One  of  these,  together  with  a  bell,  some  money,  and  other  articles,  were 
extracted  in  a  good  state  of  preservation  from  beneath  a  great  arch 
formed  by  the  lava.  It  seems  very  extraordinary  that  any  works  of  art, 
not  encased  with  tuff,  like  those  in  Herculaneum,  should  have  escaped 
fusion  in  hollow  spaces  left  open  in  this  lava-current,  which  was  so  hot 
at  Catania  eight  years  after  it  entered  the  town,  that  it  was  impossible 
to  hold  the  hand  in  some  of  the  crevices. 

Subterranean  caverns  on  Etna. — Mention  was  made  of  the  entrance 
of  a  lava-stream  into  a  subterranean  grotto,  whereby  the  foundations  of 
a  hill  were  partially  undermined.  Such  underground  passages  are  among 
the  most  curious  features  on  Etna,  and  appear  to  have  been  produced  by 
the  hardening  of  the  lava,  during  the  escape  of  great  volumes  of  elastic 
fluids,  which  are  often  discharged  for  many  days  in  succession,  after  the 
crisis  of  the  eruption  is  over.  Near  Nicolosi,  not  far  from  Monti  Rossi, 
one  of  these  great  openings  may  be  seen,  called  the  Fossa  della  Palom- 
ba,  625  feet  in  circumference  at  its  mouth,  and  seventy-eight  deep. 
After  reaching  the  bottom  of  this,  we  enter  another  dark  cavity,  and 
then  others  in  succession,  sometimes  descending  precipices  by  means  of 
ladders.  At  length  the  vaults  terminate  in  a  great  gallery  ninety  feet 
long,  and  from  fifteen  to  fifty  broad,  beyond  which  there  is  still  a  pas- 
sage, never  yet  explored ;  so  that  the  extent  of  these  caverns  remains 
unknown.*  The  walls  and  roofs  of  these  great  vaults  are  composed  of 
rough  and  bristling  scorise,  of  the  most  fantastic  forms. 

Marine  strata  at  base  of  Etna. — If  we  skirt  the  fertile  region  at  the 

*  F-errara,  Dcscriz.  dell'  Etna.     Palermo,  1818. 
26 


402 


MARINE   STRATA   AT   BASE   OF   ETNA. 


[Cn.  XXV. 


base  of  Etna  on  its  southern  and  eastern  sides,  we  behold  marine  strata 
of  clay  sand,  and  volcanic  tuff,  cropping  out  from  beneath  the  modern 
lavas.  The  marine  fossil  shells  occurring  in  these  strata  are  all  of  them, 
or  nearly  all,  identical  with  species  now  inhabiting  the  Mediterranean  ; 
and  as  they  appear  at  the  height  of  from  600  to  800  feet  above  the  sea 
near  Catania,  they  clearly  prove  that  there  has  been  in  this  region,  as  in 
other  parts  of  Sicily  farther  to  the  south,  an  upward  movement  of  the 
ancient  bed  of  the  sea.  It  is  fair,  therefore,  to  infer  that  the  whole 
mountain,  with  the  exception  of  those  parts  which  are  of  very  modern 
origin,  has  participated  in  this  upheaval. 

If  we  view  Etna  from  the  south,  we  see  the  marine  deposits  above 
alluded  to,  forming  a  low  line  of  hills  (e,  e,  Fig.  47),  or  a  steep  inland 
slope  or  cliff  (/),  as  in  the  annexed  drawing  taken  from  the  limestone 
platform  of  Primosole.  It  should  be  observed  however,  in  reference  to 
this  view,  that  the  height  of  the  volcanic  cone  is  ten  times  greater  than 
the  hills  at  its  base  (e,  e),  although  it  appears  less  elevated,  because  the 
summit  of  the  cone  is  ten  or  twelve  times  more  distant  from  the  plain  of 
Catania  than  is  Licodia. 

Fig.  47. 


M. 


View  of  Etna  from  the  summit  of  the  limestone  platform  of  Primosole. 

a,  Highest  cone.  &,  Montagnuola. 

c,  Monte  Minardo,  with  smaller  lateral  cones  above. 

<Z,  Town  of  Licodia  dei  Monaci. 

e,  Marine  formation  called  creta,  argillaceous  and  sandy  beds  with  a  few  shells,  and  associated 
volcanic  rocks. 

/;  Escarpment  of  stratified  subaqueous  volcanic  tuff,  &c.,  northwest  of  Catania. 

J7,  Town  of  Catania. 

h  i,  Dotted  line  expressing  the  highest  boundary  along  which  the  marine  strata  arc  occasion- 
ally seen. 

k,  Plain  of  Catania. 

Z,  Limestone  platform  of  Primosole  of  the  Newer  Pliocene  period. 

m,  La  Motta  di  Catania. 

The  mountain  is  in  general  of  a  very  symmetrical  form,  a  flattened 
cone  broken  on  its  eastern  side,  by  a  deep  valley,  called  the  Val  del 
Bove,  or  in  the  provincial  dialect  of  the  peasants,  "  Val  di  Bue,"  for  here 

the  herdsman 

".in  reductA  valle  mugientium 

Prospectat  errant  es  greges." 

Dr.  Buckland  was,  I  believe,  the  first  English  geologist  who  examined 
this  valley  with  attention,  and  I  am  indebted  to  him  for  having  described 
it  to  me,  before  I  visited  Sicily,  as  more  worthy  of  attention  than  any 
single  spot  in  that  island,  or  perhaps  in  Europe. 

The  Val  del  Bove  commences  near  the  summit  of  Etna,  and  descend- 


CH.  XXV.]  ETNA. VAL  DEL  BOVE.  403 

ing  into  the  woody  region,  is  farther  continued  on  one  side  by  a  second 
and  narrower  valley,  called  the  Val  di  Calanna.  Below  this  another, 
named  the  Val  di  St.  Giacomo,  begins, — a  long  narrow  ravine,  which 
is  prolonged  to  the  neighborhood  of  Zaffarana  (e,  fig.  48),  on  the  confines 
of  the  fertile  region.  These  natural  incisions  into  the  side  of  the  volca- 
no are  of  such  depth  that  they  expose  to  view  a  great  part  of  the  struc- 

Fig.  48.  a 


Great  valley  on  the  east  side  of  Etna. 

o,  Highest  cone.  &,  Montagnuola. 

c,  Head  of  Val  del  Bove.  d,  d,  Serre  del  Solfizio. 

<?,  Village  of  Zaft'arana  on  the  lower  border  of  the  woody  region. 
f,  One  of  the  lateral  cones.  fir,  Monti  Bossi. 

ture  of  the  entire  mass,  which,  in  the  Val  del  Bove,  is  laid  open  to  the 
depth  of  from  3000  to  above  4000  feet  from  the  summit  of  Etna.  The 
geologist  thus  enjoys  an  opportunity  of  ascertaining  how  far  the  internal 
conformation  of  the  cone  corresponds  with  what  he  might  have  antici- 
pated as  the  result  of  that  mode  of  increase  which  has  been  witnessed 
during  the  historical  era. 

Description  of  Plate  III. — The  accompanying  view  (PI.  III.)  is  part 
of  a  panoramic  sketch  which  I  made  in  November,  1828,  and  may  assist 
the  reader  in  comprehending  some  topographical  details  to  be  alluded 
to  in  the  sequel,  although  it  can  convey  no  idea  of  the  picturesque 
grandeur  of  the  scene. 

The  great  lava- currents  of  1819  and  1811  are  seen  pouring  down 
from  the  higher  parts  of  the  valley,  overrunning  the  forests  of  the  great 
plain,  and  rising  up  in  the  foreground  on  the  left  with  a  rugged  surface, 
on  which  many  hillocks  and  depressions  appear,  such  as  often  charac- 
terize a  lava-current  immediately  after  its  consolidation. 

The  small  cone,  No.  7,  was  formed  in  1811,  and  was  still  smoking 
when  I  saw  it  in  1828.  The  other  small  volcano  to  the  left,  from  which 
vapor  is  issuing,  was,  I  believe,  one  of  those  formed  in  1819. 

The  following  are  the  names  of  some  of  the  other  points  indicated  in 
the  sketch  : — 

1,  Montagnuola.  5,  Finocchio.  9,  Musara. 

2,  Torre  del  Filosofo.  6,  Capra.  10,  Zocolaro. 

3,  Highest  cone.  7,  Cone  of  1811.  11,  Rocca  di  Calanna. 

4,  Lepra.  8,  Cima  del  Asino. 

Description  of  Plate  IV. — The  second  view  (PI.  IV.)  represents  the 
same  valley  as  seen  from  above,  or  looking  directly  down  the  Val  del 
Bove,  from  the  summit  of  the  principal  crater  formed  in  1819.*  I  am 

*  Tin's  view  is  taken  from  a  sketch  made  by  Mr.  James  Bridges,  corrected  after 
comparison  with  several  sketches  of  my  own. 


404  ETNA. VAL   DEL    BOVE.  [Cfl.  XXV. 

unable  to  point  out  the  precise  spot  which  this  crater  would  occupy  in 
the  view  represented  in  Plate  III.  ;  but  I  conceive  that  it  would  appear 
in  the  face  of  the  great  precipice,  near  which  the  smoke  issuing  from 
the  cone  No.  7  is  made  to  terminate.  There  are  many  ledges  of  rock 
on  the  face  of  that  precipice  where  eruptions  have  occurred. 

The  circular  form  of  the  Val  del  Bove  is  well  shown  in  this  view. 
(PI.  IV.)  To  the  right  and  left  are  the  lofty  precipices  which  form  the 
southern  and  northern  sides  of  the  great  valley,  and  which  are  inter- 
sected by  dikes  projecting  in  the  manner  afterwards  to  be  described. 
In  the  distance  appears  the  "  fertile  region"  of  Etna,  extending  like  a 
great  plain  along  the  sea- coast. 

The  spots  particularly  referred  to  in  the  plate  are  the  following : — 

a,  Cape  Spartivento,  in  Italy,  of  which  the  outline  is  seen  in  the  distance. 

b,  The  promontory  of  Taormino,  on  the  Sicilian  coast. 

c,  The  river  Alcantra. 

d,  The  small  village  of  Riposto. 
/,  The  town  of  Aci  Reale. 

cft   Cyclopian  islands,  or  "  Faraglioni,"  in  the  Bay  of  Trezza. 

h ,  The  great  harbor  of  Syracuse. 

k,  The  Lake  of  Lentini. 

i,    The  city  of  Catania,  near  which  is  marked  the  course  of  the  lava  which  flowed 

from  the  Monti  Rossi  in  1669,  and  destroyed  part  of  the  city. 
I,   To  the  left  of  the  view  is  the  crater  of  1811,  which  is  also  shown  at  No.  7  in 

Plate  III. 
m,  Rock  of  Musara,  also  seen  at  No.  9  in  Plate  III. 

e,  Valley  of  Calanna. 

The  Val  del  Bove  is  of  truly  magnificent  dimensions,  a  vast  amphi- 
theatre four  or  five  miles  in  diameter,  surrounded  by  nearly  vertical 
precipices,  varying  from  1000  to  above  3000  feet  in  height,  the  loftiest 
being  at  the  upper  end,  and  the  height  gradually  diminishing  on  both 
sides.  The  feature  which  first  strikes  the  geologist  as  distinguishing 
the  boundary  cliffs  of  this  valley,  is  the  prodigious  multitude  of  verticle 
dikes  which  are  seen  in  all  directions  traversing  the  volcanic  beds.  The 
circular  form  of  this  great  chasm,  and  the  occurrence  of  these  countless 
dikes,  amounting  perhaps  to  several  thousands  in  number,  so  forcibly 
recalled  to  my  mind  the  phenomena  of  the  Atrio  del  Cavallo,  on  Vesuvius, 
that  I  at  first  imagined  that  I  had  entered  a  vast  crater,  on  a  scale  as 
far  exceeding  that  of  Somma,  as  Etna  surpasses  Vesuvius  in  magnitude. 

But  I  was  soon  undeceived  when  I  had  attentively  explored  the  dif- 
ferent sides  of  the  great  amphitheatre,  in  order  to  satisfy  myself  whether 
the  semicircular  wall  of  the  Val  del  Bove  had  ever  formed  the  boundary 
of  a  crater,  and  whether  the  beds  had  the  same  quaqua-versal  dip 
which  is  so  beautifully  exhibited  in  the  escarpment  of  Somma.  Had 
the  supposed  analogy  between  Somma  and  the  Val  del  Bove  held  true, 
the  tufts  and  lavas  at  the  head  of  the  valley  would  have  dipped  to  the 
west,  those  on  the  north  side  towards  the  north,  and  those  on  the 
southern  side  to  the  south.  But  such  I  did  not  find  to  be  the  inclina- 
tion of  the  beds ;  they  all  dip  towards  the  sea,  or  nearly  east,  as  in  the 
valleys  of  St.  Giacomo  and  Calanna  below. 


CH.  XXV.]  SCENERY    OF  THE   VAL   DEL    BOVE.  405 

Scenery  of  Ike  Val  del  Bove. — Let  the  reader  picture  to  himself  a 
large  amphitheatre,  five  miles  in  diameter,  and  surrounded  on  three  sides 
by  precipices  from  2000  to  3000  feet  in  height.  If  he  has  beheld  that 
most  picturesque  scene  in  the  chain  of  the  Pyrenees,  the  celebrated 
"  cirque  of  Gavarnie,"  he  may  form  some  conception  of  the  magnificent 
circle  of  precipitous  rocks  which  inclose,  on  three  sides,  the  great  plain 
of  the  Val  del  Bove.  This  plain  has  been  deluged  by  repeated  streams 
of  lava ;  and  although  it  appears  almost  level,  when  viewed  from  a  dis- 
tance, it  is,  in  fact,  more  uneven  than  the  surface  of  the  most  tempestuous 
sea.  Besides  the  minor  irregularities  of  the  lava,  the  valley  is  in  one 
part  interrupted  by  a  ridge  of  rocks,  two  of  which,  Musara  and  Capra, 
are  very  prominent.  It  can  hardly  be  said  that  they 

"  like  giants  stand 


To  sentinel  enchanted  land ;" 

for  although,  like  the  Trosachs,  in  the  Highlands  of  Scotland,  they  are  of 
gigantic  dimensions,  and  appear  almost  isolated,  as  seen  from  many  points, 
yet  the  stern  and  severe  grandeur  of  the  scenery  which  they  adorn  is 
not  such  as  would  be  selected  by  a  poet  for  a  vale  of  enchantment.  The 
character  of  the  scene  would  accord  far  better  with  Milton's  picture  of 
the  infernal  world  ;  and  if  we  imagine  ourselves  to  behold  in  motions  in 
the  darkness  of  the  night,  one  of  those  fiery  currents  which  have  so  often 
traversed  the  great  valley,  we  may  well  recall 


"  yon  dreary  plain,  forlorn  and  wild, 


The  seat  of  desolation,  void  of  light, 

Save  what  the  glimmering  of  these  livid  flames 

Casts  pale  and  dreadful." 

The  face  of  the  precipices  already  mentioned  is  broken  in  the  most 
picturesque  manner  by  the  vertical  walls  of  lava  which  traverse  them. 
These  masses  usually  stand  out  in  relief,  are  exceedingly  diversified  in 
form,  and  of  immense  altitude.  In  the  autumn,  their  black  outline  may 
often  be  seen  relieved  by  clouds  of  fleecy  vapor  which  settle  behind 
them,  and  do  not  disperse  until  mid-day,  continuing  to  fill  the  valley 
while  the  sun  is  shining  on  every  other  part  of  Sicily,  and  on  the  higher 
regions  of  Etna. 

As  soon  as  the  vapors  begin  to  rise,  the  changes  of  scene  are  varied 
in  the  highest  degree,  different  rocks  being  unveiled  and  hidden  by  turns, 
and  the  summit  of  Etna  often  breaking  through  the  clouds  for  a  moment 
with  its  dazzling  snows,  and  being  then  as  suddenly  withdrawn  from 
the  view. 

An  unusual  silence  prevails ;  for  there  are  no  torrents  dashing  from 
the  rocks,  nor  any  movement  of  running  water  in  this  valley  such  as  may 
almost  invariably  be  heard  in  mountainous  regions.  Every  drop  of  water 
that  falls  from  the  heavens,  or  flows  from  the  melting  ice  and  snow,  is 
instantly  absorbed  by  the  porous  lava ;  and  such  is  the  dearth  of  springs, 


406 


ETNA. DIKES. 


[Cn.  XXV. 


that  the  herdsman  is  compelled  to  supply  his  flocks,  during  the  hot  season, 
from  stores  of  snow  laid  up  in  hollows  of  the  mountain  during  winter. 

The  strips  of  green  herbage  and  forest  land,  which  have  here  and  there 
escaped  the  burning  lavas,  serve,  by  contrast,  to  heighten  the  desolation 
of  the  scene.  When  I  visited  the  valley,  nine  years  after  the  eruption  of 
1819,  I  saw  hundreds  of  trees,  or  rather  the  white  skeletons  of  trees,  on 
the  borders  of  the  black  lava,  the  trunks  and  branches  being  all  leafless, 
and  deprived  of  their  bark  by  the  scorching  heat  emitted  from  the  melt- 
ed rock ;  an  image  recalling  those  beautiful  lines  : — 

"  As  when  heaven's  fire 

Hath  scath'd  the  forest  oaks,  or  mountain  pines, 
With  singed  top  their  stately  growth,  though  bare, 
Stands  on  the  blasted  heath." 

Form,  composition,  and  origin  of  the  dikes. — But  without  indulging 
the  imagination  any  longer  in  descriptions  of  scenery,  I  may  observe  that 
the  dikes  before  mentioned  form  unquestionably  the  most  interesting 
geological  phenomenon  in  the  Val  del  Bove.  Some  of  these  are  composed 
of  trachyte,  others  of  compact  blue  basalt  with  olivine.  They  vary  in 
breadth  from  two  to  twenty  feet  and  upwards,  and  usually  project  from 
the  face  of  the  cliffs,  as  represented  in  the  annexed  drawing  (fig.  49). 

Fig.  49. 


Dikes  at  the  base  of  the  Serre  del  Solflzio,  Etna. 

They  consist  of  harder  materials  than  the  strata  which  they  traverse,  and 
therefore  waste  away  less  rapidly  under  the  influence  of  that  repeated 


Cn.  XXV.] 


DIKES    OF    ETNA. 


407 


congelation  and  thawing  to  which  the  rocks  in  this  zone  of  Etna  are  ex- 
posed. The  dikes  are  for  the  most  part  vertical,  but  sometimes  they 
run  in  a  tortuous  course  through  the  tuffs  and  breccias,  as  represented 
in  fig.  50.  In  the  escarpment  of  Somma,  where  similar  walls  of  lava  cut 
through  alternating  beds  of  sand  and  scoriae,  a  coating  of  coal-black  rock, 
approaching  in  its  nature  and  appearance  to  pitchstone,  is  seen  at  the 
contact  of  the  dike  with  the  intersected  beds.  I  did  not  observe  such 
parting  layers  at  the  junction  of  the  Etnean  dikes  which  I  examined,  but 
they  may  perhaps  be  discoverable. 


Tortuous  veins  of  lava  at  Punto  di  Giumento,  Etna. 

The  geographical  position  of  these  dikes  is  most  interesting,  as  they 
are  very  numerous  near  the  head  of  the  Val  del  Bove,  where  the  cones 
of  1811  and  1819  were  thrown  up,  as  also  in  that  zone  of  the  mountain 
where  lateral  eruptions  are  frequent ;  whereas  in  the  valley  of  Calanna, 
which  is  below  that  parallel,  and  in  a  region  where  lateral  eruptions  are 
extremely  rare,  scarcely  any  dikes  are  seen,  and  none  whatever  still  lower 
in  the  valley  of  St.  Giacomo.  This  is  precisely  what  we  might  have 
expected,  if  we  consider  the  vertical  fissures  now  filled  with  rock  to  have 
been  the  feeders  of  lateral  cones,  or,  in  other  words,  the  channels  which 
gave  passage  to  the  lava-currents  and  scoriae  that  have  issued  from  vents 
in  the  forest  zone.  In  other  parts  of  Etna  there  may  be  numerous  dikes 
at  as  low  a  level  as  the  Valley  of  Calanna,  because  the  line  of  lateral 
eruptions  is  not  everywhere  at  the  same  height  above  the  sea ;  but  in 
the  section  above  alluded  to,  there  appeared  to  me  an  obvious  connec- 
tion between  the  frequency  of  dikes  and  of  lateral  eruptions. 

Some  fissures  may  have  been  filled  from  above,  but  I  did  not  see  any 
which,  by  terminating  downwards,  gave  proof  of  such  an  origin.  Almost 
all  the  isolated  masses  in  the  Val  del  Bove,  such  as  Capra,  Musara,  and 
others,  are  traversed  by  dikes,  and  may,  perhaps,  have  partly  owed  their 
preservation  to  that  circumstance,  if  at  least  the  action  of  occasional 
floods  has  been  one  of  the  destroying  causes  in  the  Val  del  Bove ;  for 
there  is  nothing  which  affords  so  much  protection  to  a  mass  of  strata 
against  the  undermining  action  of  running  water  as  a  perpendicular  dike 
of  hard  rock. 


408 


ERUPTION    OF    1811. ETNA. 


[On.  XXV. 


In  the  accompanying  drawing  (fig.  51),  the  flowing  of  the  lavas  of 
1811  and  1819,  between  the  rocks  Finochio,  Capra,  and  Musara,  is  rep- 
resented. The  h'-ight  of  the  two  last-mentioned  isolated  masses  has 
been  much  diminished  by  the  elevation  of  their  base,  caused  by  these 
currents.  They  may,  perhaps,  be  the  remnants  of  lateral  cones  which 
existed  before  the  Val  del  Bove  was  formed,  and  may  hereafter  be  once 
more  buried  by  the  lavas  that  are  now  accumulating  in  the  valley. 


Fig.  51. 


Yiew  of  the  rocks  Finochio,  Capra,  and  Musara,  Yal  del  Bove. 


From  no  point  of  view  are  the  dikes  more  conspicuous  than  from  the 
summit  of  the  highest  cone  of  Etna  ;  a  view  of  some  of  them  is  given  in 
the  annexed  drawing.  (Fig.  52.) 

Eruption  of  1811.  —  I  have  alluded  to  the  streams  of  lava  which  were 
poured  forth  in  1811  and  1819.  Gemmellaro,  who  witnessed  these 
eruptions,  informs  us  that  the  great  crater  in  1811  first  testified  by  its 
loud  detonations  that  a  column  of  lava  had  ascended  to  near  the  summit 
of  the  mountain.  A  violent  shock  was  then  felt,  and  a  stream  broke  out 
from  the  side  of  the  cone,  at  no  great  distance  from  its  apex.  Shortly 
after  this  had  ceased  to  flow,  a  second  stream  burst  forth  at  another 
opening,  considerably  below  the  first  ;  then  a  third  still  lower,  and  so  on 
till  seven  different  issues  had  been  thus  successively  formed,  all  lying 
upon  the  same  straight  line.  It  has  been  supposed  that  this  line  was  a 
perpendicular  rent  in  the  internal  framework  of  the  mountain,  which  rent 
was  probably  not  produced  at  one  shock,  but  prolonged  successively 
downwards,  by  the  lateral  pressure  and  intense  heat  of  the  internal  col- 
umn of  lava,  as  it  subsided  by  gradual  discharge  through  each  vent.* 

Eruption  of  1819.  —  In  1819  three  large  mouths  or  caverns  opened 
very  near  those  which  were  formed  in  the  eruptions  of  1811,  from  which 
flames,  red-hot  cinders,  and  sand  were  thrown  up  with  loud  explosions. 
A  few  minutes  afterwards  another  mouth  opened  below,  from  which 

*  Scrope  on  Volcanoes,  p.  153. 


CH.  XXV.] 


ERUPTION    OF    1819. — ETNA. 

Fig.  52. 


409 


View  from  the  summit  of  Etna  into  the  Val  del  Bove  * 

flames  and  smoke  issued ;  and  finally  a  fifth,  lower  still,  whence  a  tor- 
rent of  lava  flowed,  which  spread  itself  with  great  velocity  over  the 
deep  and  broad  valley  called  "  Val  del  Bove."  This  stream  flowed  two 
miles  in  the  first  twenty-four  hours,  and  nearly  as  far  in  the  succeeding 
day  arid  night.  The  three  original  mouths  at  length  united  into  one 
large  crater,  and  sent  forth  lava,  as  did  the  inferior  apertures,  so  that  an 
enormous  torrent  poured  down  the  "  Val  del  Bove."  When  it  arrived 
at  a  vast  and  almost  perpendicular  precipice,  at  the  head  of  the  Valley 
of  Calanna,  it  poured  over  in  a  cascade,  and,  being  hardened  in  its  de- 
scent, made  an  inconceivable  crash  as  it  was  dashed  against  the  bottom. 
So  immense  was  the  column  of  dust  raised  by  the  abrasion  of  the  tufa- 
ceous  hill  over  which  the  hardened  mass  descended,  that  the  Gatanians 
were  in  great  alarm,  supposing  a  new  eruption  to  have  burst  out  in  the 
woody  region,  exceeding  in  violence  that  near  the  summit  of  Etna. 

Mode  of  advance  of  the  lava. — Of  the  cones  thrown  up  during  this 
eruption,  not  more  than  two  are  of  sufficient  magnitude  to  be  num- 
bered among  those  eighty  which  were  before  described  as  adorning  the 
flanks  of  Etna.  The  surface  of  the  lava  which  deluged  the  "  Val  del 
Bove,"  consists  of  rocky  and  angular  blocks,  tossed  together  in  the 

*  This  drawing  is  part  of  a  panoramic  sketch  which  I  made  from  the  summit, 
of  the  cone,  December  1,  1828,  when  every  part  of  Etna  was  free  from  clouds 
except  the  Val  del  Bove.  The  small  cone,  and  the  crater  nearest  the  foreground, 
were  among  those  formed  during  the  eruptions  of  1810  and  1811. 


410  MODE  OF  ADVANCE  OF  LAVA.         [Ca  XXV. 

utmost  disorder.  Nothing  can  be  more  rugged,  or  more  unlike  the 
smooth  and  even  superficies,  which  those  who  are  unacquainted  with 
volcanic  countries  may  have  pictured  to  themselves,  in  a  mass  of  mat- 
ter which  had  consolidated  from  a  liquid  state.  Mr.  Scrope  observed 
this  current  in  the  year  1819,  slowly  advancing  down  a  considerable 
slope,  at  the  rate  of  about  a  yard  an  hour,  nine  months  after  its  emis- 
sion. The  lower  stratum  being  arrested  by  the  resistance  of  the  ground, 
the  upper  or  central  part  gradually  protruded  itself,  and,  being  unsup- 
ported, fell  down.  This  in  its  turn  was  covered  by  a  mass  of  more 
liquid  lava,  which  swelled  over  it  from  above.  The  current  had  all  the 
appearance  of  a  huge  heap  of  rough  and  large  cinders  rolling  over  and 
over  upon  itself  by  the  effect  of  an  extremely  slow  propulsion  from 
behind.  The  contraction  of  the  erust  as  it  solidified,  and  the  friction 
of  the  scoriform  cakes  against  one  another,  produced  a  crackling  sound. 
Within  the  crevices  a  dull  red  heat  might  be  seen  by  night,  and  vapor 
issuing  in  considerable  quantity  was  visible  by  day.* 

It  was  stated  that  when  the  lava  of  1819  arrived  at  the  head  of  the 
Valley  of  Calanna,  after  flowing  down  the  Val  del  Bove,  it  descended 
in  a  cascade.  This  stream,  in  fact,  like  many  previous  currents  of 
lava  which  have  flowed  down  successively  from  the  higher  regions  of 
Etna,  was  turned  by  a  great  promontory  projecting  from  the  southern 
side  of  the  Val  del  Bove.  This  promontory  consists  of  the  hills  called 
Zocolaro  and  Calanna,  and  of  a  ridge  of  inferior  height  which  connects 
them.  (See  fig.  53.) 

Fig.  53. 


A,  Zocolaro.  B,  Monte  di  Calanna. 

C,  Plain  at  the  head  of  the  Valley  of  Calanna. 

«,  Lava  of  1819  descending  the  precipice  and  flowing  through  the  valley. 
ft,  Lavas  of  1811  and  1819  flowing  round  the  hill  of  Calanna. 

.l-j  i'r.     •  ;:':•''*. t- ' 

It  happened  in  1811  and  1819  that  the  flows  of  lava  overtopped  the 
ridge  intervening  between  the  hills  of  Zocolaro  and  Calanna,  so  that 
they  fell  in  a  cascade  over  a  lofty  precipice,  and  began  to  fill  up  the 
valley  of  Calanna  (a,  fig.  53).  Other  portions  of  the  same  lava-current 
(6)  flowed  round  the  promontory,  and  they  exhibit  one  of  the  peculiar 

*  Scrope  on  Volcanoes,  p.  102. 


Gil.  XXV.]  LAVAS    AND    BRECCIAS. ETNA.  413 

characteristics  of  such  streams,  namely  that  of  becoming  solid  externally, 
even  while  yet  in  motion.  Instead  of  thinning  out  gradually  at  their 
edges,  their  sides  may  often  be  compared  to  two  rocky  walls  which  are 
sometimes  inclined  at  an  angle  of  between  thirty  and  forty  degrees. 
When  such  streams  are  turned  from  their  course  by  a  projecting  rock, 
they  move  right  onwards  in  a  new  direction  ;  and  in  the  Valley  of 
Calanna  a  considerable  space  has  thus  been  left  between  the  steep  sides 
of  the  lavas  b  b,  so  deflected,  and  the  precipitous  escarpment  of  Zoco- 
laro,  A,  which  bounds  the  plain  C. 

Lavas  and  breccias. — In  regard  to  the  volcanic  masses  which  are  in- 
tersected by  dikes  in  the  Val  del  Bove,  they  consist  in  great  part  of 
graystone  lavas,  of  an  intermediate  character  between  basalt  and 
trachyte,  and  partly  of  porphyritic  lava  resembling  trachyte,  but  to 
which  that  name  cannot,  according  to  Von  Buch  and  G.  Rose,  be  in 
strictness  applied,  because  the  felspar  belongs  to  the  variety  called 
Labradorite.  There  is  great  similarity  in  the  composition  of  the  ancient 
and  modern  lavas  of  Etna,  both  consisting  of  felspar,  augite,  olivine, 
and  titaniferous  iron.  The  alternating  breccias  are  made  up  of  scoriae, 
sand,  and  angular  blocks  of  lava.  Many  of  these  fragments  may  have 
been  thrown  out  by  volcanic  explosions,  which,  falling  on  the  hardened 
surface  of  moving  lava- currents,  may  have  been  carried  to  a  consider- 
able distance.  It  may  also  happen  that  when  lava  advances  very 
slowly,  in  the  manner  of  the  flow  of  1819,  the  angular  masses  re- 
sulting from  the  frequent  breaking  of  the  mass  as  it  rolls  over  upon 
itself,  may  produce  these  breccias.  It  is  at  least  certain  that  the  upper 
portion  of  the  lava-currents  of  1811  and  1819  now  consist  of  angular 
masses  to  the  depth  of  many  yards.  D'Aubuisson  has  compared  the 
surface  of  one  of  the  ancient  lavas  of  Auvergne  to  that  of  a  river  sud- 
denly frozen  over  by  the  stoppage  of  immense  fragments  of  drift-ice,  a 
description  perfectly  applicable  to  these  modern  Etnean  flows.  The 
thickness  of  the  separate  beds  of  conglomerate  or  breccia  which  are  seen 
in  the  same  vertical  section,  is  often  extremely  different,  varying  from 
3  to  nearly  50  feet,  as  I  observed  in  the  hill  of  Calanna. 

Flood  produced  by  the.  melting  of  snow  by  lava. — It  is  possible  that 
some  of  the  breccias  or  conglomerates  may  be  referred  to  aqueous 
causes,  as  great  floods  occasionally  sweep  down  the  flanks  of  Etna, 
when  eruptions  take  place  in  winter,  and  when  the  snows  are  melted 
by  lava.  It  is  true  that  running  water  in  general  exerts  no  power  on 
Etna,  the  rain  which  falls  being  immediately  imbibed  by  the  porous 
lavas  \  so  that,  vast  as  is  the  extent  of  the  mountain,  it  feeds  only  a  few 
small  rivulets,  and  these,  even,  are  dry  throughout  the  greater  portion 
of  the  year.  The  enormous  rounded  boulders,  therefore,  of  felspar- 
porphyry  and  basalt,  a  line  of  which  can  be  traced  from  the  sea,  from 
near  Giardini,  by  Mascali,  and  Zafarana,  to  the  "  Val  del  Bove,"  would 
offer  a  perplexing  problem  to  the  geologist,  if  history  had  not  preserved 
the  memorials  of  a  tremendous  flood  which  happened  in  this  district  in 
in  the  year  1755.  It  appears  that  two  streams  of  lava  flowed  in  that 


412  GLACIER   COVERED   BY    LAVA. ETNA.  [On.  XXV. 

year,  on  the  2d  of  March,  from  the  highest  crater ;  they  were  imme- 
diately precipitated  upon  an  enormous  mass  of  snow  which  then  covered 
the  whole  mountain,  and  was  extremely  deep  near  the  summit.  The 
sudden  melting  of  this  frozen  mass,  by  a  fiery  torrent  three  miles  in 
length,  produced  a  frightful  inundation,  which  devastated  the  sides  of 
the  mountain  for  eight  miles  in  length,  and  afterwards  covered  the  lower 
flanks  of  Etna,  where  they  were  less  steep,  together  with  the  plains  near 
the  sea,  with  great  deposits  of  sand,  scoriae,  and  blocks  of  lava. 

Many  absurd  stories  circulated  in  Sicily  respecting  this  event ;  such  as 
that  the  water  was  boiling,  and  that  it  was  vomited  from  the  highest 
crater ;  that  it  was  as  salt  as  the  sea,  and  full  of  marine  shells ;  but 
these  were  mere  inventions,  to  which  Recupero,  although  he  relates 
them  as  tales  of  the  mountaineers,  seems  to  have  attached  rather  too 
much  importance. 

Floods  of  considerable  violence  have  also  been  produced  on  Etna  by 
the  fall  of  heavy  rains,  aided,  probably,  by  the  melting  of  snow.  By 
this  cause  alone,  in  1761,  sixty  of  the  inhabitants  of  Acicatena  were 
killed,  and  many  of  their  houses  swept  away.* 

Glacier  covered  by  a  lava-stream  — A  remarkable  discovery  was  made 
on  Etna  in  1828  of  a  great  mass  of  ice,  preserved  for  many  years,  per- 
haps for  centuries,  from  melting,  by  the  singular  accident  of  a  current 
of  red-hot  lava  having  flowed  over  it.  The  following  are  the  facts  in 
attestation  of  a  phenomenon  which  must  at  first  sight  appear  of  so  para- 
doxical a  character.  The  extraordinary  heat  experienced  in  the  South 
of  Europe,  during  the  summer  and  autumn  of  1828,  caused  the  sup- 
plies of  snow  and  ice  which  had  been  preserved  in  the  spring  of  that 
year,  for  the  use  of  Catania  and  the  adjoining  parts  of  Sicily  and  the 
island  of  Malta,  to  fail  entirely.  Great  distress  was  consequently  felt 
for  want  of  a  commodity  regarded  in  those  countries  as  one  of  the  ne- 
cessaries of  life  rather  than  an  article  of  luxury,  and  the  abundance  of 
which  contributes  in  some  of  the  larger  cities  to  the  salubrity  of  the 
water  and  the  general  health  of  the  community.  The  magistrates  of 
Catania  applied  to  Signor  M.  Gemmellaro,  in  the  hope  that  his  local 
knowledge  of  Etna  might  enable  him  to  point  out  some  crevice  or  nat- 
ural grotto  on  the  mountain,  where  drift-snow  was  still  preserved. 
Nor  were  they  disappointed  ;  for  he  had  long  suspected  that  a  small 
mass  of  perennial  ice  at  the  foot  of  the  highest  cone  was  part  of  a  large 
and  continuous  glacier  covered  by  a  lava-current.  Having  procured  a 
large  body  of  workmen,  he  quarried  into  this  ice,  and  proved  the  super- 
position of  the  lava  for  several  hundred  yards,  so  fts  completely  to 
satisfy  himself  that  nothing  but  the  subsequent  flowing  of  the  lava  over 
the  ice  could  account  for  the  position  of  the  glacier.  Unfortunately  for 
the  geologist,  the  ice  was  so  extremely  hard,  and  the  excavation  so  ex- 
pensive, that  there  is  no  probability  of  the  operations  being  renewed. 

On  the  first  of  December,  1828,  I  visited  this  spot,  which  is  on  the 

*  Ferara,  DeScriz.  dell'  Etna,  p.  116. 


CH.  XXV.]  GLACIEK   COVERED   BY    LAVA.  413 

southeast  side  of  the  cone,  and  not  far  above  the  Casa  Inglese  ;  but  the 
fresh  snow  had  already  nearly  filled  up  the  new  opening,  so  that  it  had 
only  the  appearance  of  the  mouth  of  a  grotto.  I  do  not,  however, 
question  the  accuracy  of  the  conclusion  of  Signor  Gemmellaro,  who, 
being  well  acquainted  with  all  the  appearances  of  drift-snow  in  the  fissures 
and  cavities  of  Etna,  had  recognized,  even  before  the  late  excavations, 
the  peculiarity  of  the  position  of  the  ice  in  this  locality.  We  may  sup- 
pose that,  at  the  commencement  of  the  eruption,  a  deep  mass  of  drift- 
snow  had  been  covered  by  volcanic  sand  showered  down  upon  it  before" 
the  descent  of  the  lava.  A  dense  stratum  of  this  fine  dust  mixed  with 
scoriae  is  well  known  to  be  an  extremely  bad  conductor  of  heat ;  and 
the  shepherds  in  the  higher  regions  of  Etna  are  accustomed  to  provide 
water  for  their  flocks  during  summer,  by  strewing  a  layer  of  volcanic 
sand  a  few  inches  thick  over  the  snow,  which  effectually  prevents  the 
heat  of  the  sun  from  penetrating. 

Suppose  the  mass  of  snow  to  have  been  preserved  from  liquefaction 
until  the  lower  part  of  the  lava  had  consolidated,  we  may  then  readily 
conceive  that  a  glacier  thus  protected,  at  the  height  of  ten  thousand 
feet  above  the  level  of  the  sea,  would  endure  as  long  as  the  snows  of 
Mont  Blanc,  unless  melted  by  volcanic,  heat  from  below.  When  I 
visited  the  great  crater  in  the  beginning  of  winter  (December  1st,  1828), 
I  found  the  crevices  in  the  interior  incrusted  with  thick  ice,  and  in 
some  cases  hot  vapors  were  actually  streaming  out  between  masses  of 
ice  and  the  rugged  and  steep  walls  of  the  crater.* 

After  the  discovery  of  Signor  Gemmellaro,  it  would  not  be  surprising 
to  find  in  the  cones  of  the  Icelandic  volcanoes,  which  are  covered  for 
the  most  part  with  perpetual  snow,  repeated  alternations  of  lava-streams 
and  glaciers.  We  have,  indeed,  Lieutenant  Kendall's  authority  for  the 
fact  that  Deception  Island,  in  New  South  Shetland,  lat.  62°  55'  S.,  is 
principally  composed  of  alternate  layers  of  volcanic  ashes  and  ice.f 

Origin  of  the  Val  del  Bove. — It  is  recorded,  as  will  be  stated  in  the 
history  of  earthquakes  (ch.  29),  that  in  the  year  1772  a  great  subsi- 
dence took  place  on  Ptipandaynng,  the  largest  volcano  in  the  island  of 
Java ;  an  extent  of  ground  fifteen  miles  in  length,  and  six  in  breadth, 
covered  by  no  less  than  forty  villages,  was  engulphed,  and  the  cone 
lost  4000  feet  of  its  height.  In  like  manner  the  summit  of  Carguairazo, 
one  of  the  loftiest  of  the  Andes  of  Quito,  fell  in  on  the  19th  July,  1698 ; 
and  another  mountain  of  still  greater  altitude  in  the  same  chain,  called 
Capac  Urcu,  a  short  time  before  the  conquest  of  America  by  the  Spaniards. 

*  Mr.  Nasmyth,  the  inventor  of  the  steam-hammer,  has  lately  illustrated,  by 
a  very  striking  experiment,  the  non-conductibility  of  a  thin  layer  of  dry  sand  and 
clay.  Into  a  caldron  of  iron  one-fourth  of  an  inch  thick,  lined  with  sand  and 
clay  five-eighths  of  an  inch  thick,  he  poured  eight  tons  of  melted  iron  at  a  white 
heat.  After  the  fused  metal  had  been  twenty  minutes  in  the  caldron  the  palm 
of  the  hand  could  be  applied  to  the  outside  without  inconvenience,  and  after  forty 
minutes  there  was  not  heat  enough  to  singe  writing-paper.  This  fact  may  help 
us  to  explain  how  strata  in  contact  with  dikes,  or  beds  of  fused  matter,  havo 
sometimes  escaped  without  perceptible  alteration  by  heat. 

f  Journ.  of  Roy.  Geograph.  Soc.  vol.  i.  p.  64. 


414  ORIGIN    OF  THE   VAL   DEL   BOVE.  [On.  XXV. 

It  will  also  be  seen  in  the  next  chapter  that,  so  late  as  the  year  1822, 
during  a  violent  earthquake  and  volcanic  eruption  in  Java,  one  side  of 
the  mountain  called  Galongoon,  which  was  covered  by  a  dense  forest, 
became  an  enormous  gulf  in  the  form  of  a  semicircle.  The  new  cavity 
was  about  midway  between  the  summit  and  the  plain,  and  surrounded 
by  steep  rocks. 

Now  we  might  imagine  a  similar  event,  or  a  series  of  subsidences  to 
have  formerly  occurred  on  the  eastern  side  of  Etna,  although  such 
catastrophes  have  not  been  witnessed  in  modern  times,  or  only  on  a 
very  trifling  scale.  A  narrow  ravine,  about  a  mile  long,  twenty  feet 
wide,  and  from  twenty  to  thirty-six  in  depth,  has  been  formed,  within 
the  historical  era,  on  the  flanks  of  the  volcano,  near  the  town  of  Masca- 
lucia ;  and  a  small  circular  tract,  called  the  Cisterna,  near  the  summit, 
sank  down  in  the  year  1792,  to  the  depth  of  about  forty  feet,  and  left 
on  all  sides  of  the  chasm  a  vertical  section  of  the  beds,  exactly  resem- 
bling those  which  are  seen  in  the  precipices  of  the  Val  del  Bove.  At 
some  remote  periods,  therefore,  we  might  suppose  more  extensive  por- 
tions of  the  mountain  to  have  fallen  in  during  great  earthquakes. 

But  we  ought  not  to  exclude  entirely  from  our  speculations  another 
possible  agency,  by  which  the  great  cavity  may  in  part  at  least  have 
been  excavated,  namely,  the  denuding  action  of  the  sea.  Whether  its 
waves  may  once  have  had  access  to  the  great  valley  before  the  ancient 
portion  of  Etna  was  upheaved  to  its  present  elevation,  is  a  question 
which  will  naturally  present  itself  to  every  geologist.  Marine  shells 
have  been  traced  to  a  height  of  800  feet  above  the  base  of  Etna,  and 
would  doubtless  be  seen  to  ascend  much  higher,  were  not  the  structure 
of  the  lower  region  of  the  mountain  concealed  by  floods  of  lava.  We 
cannot  ascertain  to  what  extent  a  change  in  the  relative  level  of  land 
and  sea  may  have  been  carried  in  this  spot,  but  we  know  that  some  of 
the  tertiary  strata  in  Sicily  of  no  ancient  date  reach  a  height  of  3000 
feet,  and  the  marine  deposits  on  the  flanks  of  Etna,  full  of  recent  species 
of  shells,  may  ascend  to  equal  or  greater  heights.  The  narrow  Valley 
of  Calanna  leading  out  of  the  Val  del  Bove,  and  that  of  San  Giacomo 
lower  down,  have  much  the  appearance  of  ravines  swept  out  by  aqueous 
action. 

Structure  and  origin  of  the  cone  of  Etna. — Our  data  for  framing  a 
correct  theory  of  the  manner  in  which  the  cone  of  Etna  has  acquired  its 
present  dimensions  and  internal  structure  are  very  imperfect,  because  it 
is  on  its  eastern  side  only,  in  the  Val  del  Bove  above  described,  that  we 
see  a  deep  section  exposed.  Even  here  we  obtain  no  insight  into  the 
interior  composition  of  the  mountain  beyond  a  depth  of  between  three 
and  four  thousand  feet  below  the  base  of  that  highest  cone,  which  has 
been  several  times  destroyed  and  renewed.  The  precipices  seen  at  the 
head  of  the  Val  del  Bove,  in  the  escarpment  called  the  Serre  del  Sol- 
fizio,  exhibit  merely  the  same  series  of  alternating  lavas  and  breccias, 
which,  descending  with  a  general  dip  towards  the  sea,  form  the  bound- 
ary cliffs  of  all  other  parts  of  the  Val  del  Bove.  If  then  we  estimate 


Cn.  XXV.]       STRUCTURE  OF  THE  CONE  OF  ETNA.  415 

the  height  of  Etna  at  about  11,000  feet,  we  may  say  that  we  know 
from  actual  observation  less  than  one-half  of  its  component  materials, 
assuming  it  to  extend  downwards  to  the  level  of  the  sea ;  namely,  first, 
the  highest  cone,  which  is  about  1000  feet  above  its  base  ;  and,  second- 
ly, the  alternations  of  lava,  tuff,  and  volcanic  breccia,  which  constitute 
the  rocks  between  the  Cisterna,  near  the  base  of  the  upper  cone,  and 
the  foot  of  the  precipices  at  the  head  of  the  Val  del  Bove.  At  the 
lowest  point  to  which  the  vertical  section  extends,  there  are  no  signs  of 
any  approach  to  a  termination  of  the  purely  volcanic  mass,  which  may 
perhaps  penetrate  many  thousand  feet  farther  downwards.  There  is, 
indeed,  a  rock  called  Rocca  Gianicola,  near  the  foot  of  the  great  escarp- 
ment, which  consists  of  a  large  mass  between  150  and  200  feet  wide, 
not  divided  into  beds,  and  almost  resembling  granite  in  its  structure, 
although  agreeing  very  closely  in  mineral  composition  with  the  lavas  of 
Etna  in  general.*  This  mass  may  doubtless  be  taken  as  a  representa- 
tive of  those  crystalline  or  plutonic  formations  which  would  be  met  with 
in  abundance  if  we  could  descend  to  greater  depths  in  the  direction  of 
the  central  axis  of  the  mountain.  For  a  great  body  of  geological  evi- 
dence leads  us  to  conclude,  that  rocks  of  this  class  result  from  the  con- 
solidation, under  great  pressure,  of  melted  matter,  which  has  risen  up 
and  filled  rents  and  chasms,  such,  for  example,  as  may  communicate 
with  the  principal  and  minor  vents  of  eruption  in  a  volcano  like  Etna. 

But,  if  we  speculate  on  the  nature  of  the  formation  which  the  lava 
may  have  pierced  in  its  way  upwards,  we  may  fairly  presume  that  a 
portion  of  these  consist  of  marine  tertiary  rocks,  like  those  of  the  neigh- 
boring Val  di  Noto,  or  those  which  skirt  the  borders  of  the  Etnean  cone, 
on  its  southern  and  eastern  sides.  Etna  may,  in  fact,  have  been  at  first 
an  insular  volcano,  raising  its  summit  but  slightly  above  the  level  of  the 
sea  ;  but  we  have  no  grounds  for  concluding  that  any  of  the  beds  exposed 
in  the  deep  section  of  the  Val  del  Bove  have  formed  a  part  of  suck 
a  marine  accumulation.  On  the  contrary,  all  the  usual  signs  of  sub- 
aqueous origin  are  wanting  ;  and  even  if  we  believe  the  foundations  of 
the  mountain  to  have  been  laid  in  the  sea,  we  could  not  expect  this  por- 
tion to  be  made  visible  in  sections  which  only  proceed  downwards  from 
the  summit  through  one-half  the  thickness  of  the  mountain,  especially  as 
the  highest  points  attained  by  the  tertiary  strata  in  other  parts  of  Sicily 
very  rarely  exceed  3000  feet  above  the  sea. 

On  the  eastern  and  southern  base  of  Etna,  a  marine  deposit,  already 
alluded  to,  is  traced  up  to  the  height  of  800  or  1000  feet,  before  it  be- 
comes concealed  beneath  that  covering  of  modern  lavas  which  is  contin- 
ually extending  its  limits  during  successive  eruptions,  and  prevents  us 
from  ascertaining  how  much  higher  the  marine  strata  may  ascend.  As 
the  imbedded  shells  belong  almost  entirely  to  species  now  inhabiting 
the  Mediterranean,  it  is  evident  that  there  has  been  here  an  upheaval  of 
the  region  at  the  base  of  Etna  at  a  very  modern  period.  It  is  fair,  there- 

*  Hoffman,  Geognost.  Beobachtiuigen,  p.  701.     Berlin,  1839. 


416  OKIGIN    OF    THE    CONE    OF   ETNA.  [Cn.  XXV. 

fore,  to  infer  that  the  volcanic  nucleus  of  the  mountain,  partly  perhaps  of 
submarine,  and  partly  of  subaerial  origin,  participated  in  this  movement, 
and  was  carried  up  bodily.  Now,  in  proportion  as  a  cone  gains  height 
by  such  a  movement,  combined  with  the  cumulative  effects  of  eruptions, 
throwing  out  matter  successively  from  one  or  more  central  vents,  the 
hydrostatic  pressure  of  the  columns  of  lava  augments  with  their  increas- 
ing height,  until  the  time  arrives  when  the  flanks  of  the  cone  can  no 
longer  resist  the  increased  pressure ;  and  from  that  period  they  give 
way  more  readily,  lateral  outbursts  becoming  more  frequent.  Hence, 
independently  of  any  local  expansion  of  the  fractured  volcanic  mass, 
those  general  causes  by  which  the  modern  tertiary  strata  of  a  great  part 
of  Sicily  have  been  raised  to  the  height  of  several  thousand  feet  above 
their  original  level,  would  tend  naturally  to  render  the  discharge  of  lava 
and  scoriae  from  the  summit  of  Etna  less  copious,  and  the  lateral  dis- 
charge greater. 

If,  then,  a  conical  or  dome-shaped  mass  of  volcanic  materials  was 
accumulated  to  the  height  of  4000,  or  perhaps  7000  feet,  before  the  up 
ward  movement  began,  or,  what  is  much  more  probable,  during  the 
continuance  of  the  upward  movement,  that  ancient  mass  would  not  be 
buried  under  the  products  of  newer  eruptions,  because  these  last  would 
then  be  poured  out  chiefly  at  a  lower  level. 

Since  I  visited  Etna  in  1828,  M.  de  Beaumont  has  published  a  most 
valuable  memoir  on  the  structure  and  origin  of  that  mountain,  which  he 
examined  in  1834;*  and  an  excellent  description  of  it  has  also  appeared 
in  the  posthumous  work  of  Hoffmann,  f 

In  M.  de  Beaumont's  essay,  in  which  he  has  explained  his  views  with 
uncommon  perspicuity  and  talent,  he  maintains  that  all  the  alternating 
stony  and  fragmentary  beds,  more  than  3000  feet  thick,  which  are  ex- 
posed in  the  Val  del  Bove,  were  formed  originally  on  a  surface  so  nearly 
flat  that  the  slope  never  exceeded  three  degrees.  From  this  horizontal 
position  they  were  at  length  heaved  up  suddenly  (d'un  seul  coup)  into  a 
great  mountain,  to  which  no  important  additions  have  since  been  made. 
Prior  to  this  upthrow,  a  platform  is  supposed  to  have  existed  above  the 
level  of  the  sea,  in  which  various  fissures  opened ;  and  from  these  melt- 
ed matter  was  poured  forth  again  and  again,  which  spread  itself  around 
in  thin  sheets  of  uniform  thickness.  From  the  same  rents  issued  showers 
of  scoriae  and  fragmentary  matter,  which  were  spread  out  so  as  to  form 
equally  uniform  and  horizontal  beds,  intervening  between  the  sheets  of 
lava.  But  although,  by  the  continued  repetition  of  these  operations,  a 
vast  pile  of  volcanic  matter,  4000  feet  or  more  in  thickness,  was  built  up 
precisely  in  that  region  where  Etna  now  rises,  and  to  which  nothing 
similar  was  produced  elsewhere  in  Sicily,  still  we  are  told  that  Etna  was 
not  yet  a  mountain.  No  hypothetical  diagram  has  been  given  to  help 
us  to  conceive  how  this  great  mass  of  materials  of  supramarine  origin 


*  Mem.  pour  servir,  etc.,  torn.  iv.  Paris,  1838. 
f  Geognost.  Beobachtungen,  <fec.  Berlin,  1839. 


CH.  XXV.]  STRUCTURE    OF   THE   CONE   OF   ETNA.  417 

could  have  been  disposed  of  in  horizontal  beds,  so  as  not  to  constitute 
an  eminence  towering  far  above  the  rest  of  Sicily ;  but  it  is  assumed  that 
a  powerful  force  from  below  at  length  burst  suddenly  through  the  hori- 
zontal formation,  uplifted  it  to  a  considerable  height,  and  caused  the  beds 
to  be,  in  many  places,  highly  inclined.  This  elevatory  force  was  not  all 
expended  on  a  single  central  point  as  Von  Buch  has  imagined  in  the  case 
of  Palma,  Teneriffe,  or  Somma,  but  rather  followed  for  a  short  distance 
a  linear  direction.* 

Among  other  objections  that  may  be  advanced  against  the  theory 
above  proposed,  I  may  mention,  first,  that  the  increasing  number  of 
dikes  as  we  approach  the  head  of  the  Val  del  Bove,  or  the  middle  of 
Etna,  and  the  great  thickness  of  lava,  scoriae,  and  conglomerates  in  that 
region,  imply  that  the  great  centre  of  eruption  was  always  where  it  now 
is,  or  nearly  at  the  same  point,  and  there  must,  therefore,  have  been  a 
tendency,  from  the  beginning,  to  a  conical  or  dome-shaped  arrangement 
in  the  ejected  materials.  Secondly,  were  we  to  admit  a  great  number 
of  separate  points  of  eruption,  scattered  over  a  plain  or  platform,  there 
must  have  been  a  great  number  of  cones  thrown  up  over  these  different 
vents  ;  and  these  hills,  some  of  which  would  probably  be  as  lofty  as 
those  now  seen  on  the  flanks  of  Etna,  or  from  300  to  750  feet  in  height, 
would  break  the  continuity  of  the  sheets  of  lava,  while  they  would  be- 
come gradually  enveloped  by  them.  The  ejected  materials,  moreover, 
would  slope  at  a  high  angle  on  the  sides  of  these  cones,  and  where  they 
fell  on  the  surrounding  plain,  would  form  strata  thicker  near  the  base 
of  each  cone  than  at  a  distance. 

What  then  are  the  facts,  it  will  be  asked,  to  account  for  which  this 
hypothesis  of  original  horizontality,  followed  by  a  single  and  sudden 
effort  of  upheaval,  which  gave  to  the  beds  their  present  slope,  has  been 
invented  ?  M.  de  Beaumont  observes,  that  in  the  boundary  precipices 
of  the  Val  del  Bove,  sheets  of  lava  and  intercalated  beds  of  cinders, 
mixed  with  pulverulent  and  fragmentary  matter  evidently  cast  out 
during  eruptions,  are  sometimes  inclined  at  steep  angles,  varying  from 
15°  to  27°.  It  is  impossible,  he  says,  that  the  lavas  could  have  flowed 
originally  on  planes  so  steeply  inclined,  for  streams  which  descend  a 
slope  even  of  10°  from  narrow  stripes,  and  never  acquire  such  a  com- 
pact texture.  Their  thickness,  moreover,  always  inconsiderable,  varies 
with  every  variation  of  steepness,  in  the  declivity  down  which  they  flow ; 
whereas,  in  several  parts  of  the  Val  del  Bove,  the  sheets  of  lava  are 
continuous  for  great  distances,  in  spite  of  their  steep  inclination,  and  are 
often  compact,  and  perfectly  parallel  one  to  the  other,  even  where  there 
are  more  than  100  beds  of  interpolated  fragmentary  matter. 

The  intersecting  dikes  also  terminate  upwards  in  many  instances,  at 
different  elevations,  and  blend  (or,  as  M.  de  Beaumont  terms  it,  articu- 
late) with  sheets  of  lava,  which  they  meet  at  right  angles.  It  is  there- 
fore assumed  that  such  dikes  were  the  feeders  of  the  streams  of  lava 

*  De  Beaumont,  M6m.  pour  servir,  Ac.  torn.  iv.  pp.  187,  188. 
27 


418 


STKUCTURE   AND   ORIGIN 


[On.  XXV. 


with  which  they  unite,  and  they  are  supposed  to  prove  that  the  plat' 
form,  on  the  surface  of  which  the  melted  matter  was  poured  out,  was 
at  first  so  flat,  that  the  fluid  mass  spread  freely  and  equally  in  every 
direction,  and  not  towards  one  point  only  of  the  compass,  as  would 
happen  if  it  had  descended  the  sloping  sides  of  a  cone.  This  argument 
is  ingeniously  and  plainly  put  in  the  following  terms  : — "  Had  the 
melted  matter  poured  down  an  inclined  plane,  after  issuing  from  a  rent, 
the  sheet  of  lava  would,  after  consolidation,  have  formed  an  elbow  with 
the  dike,  like  the  upper  bar  of  the  letter  F,  instead  of  extending  itself 
on  both  sides  like  that  of  a  T."*  It  is  also  contended  that  a  series  of 
sheets  of  lava,  formed  on  a  conical  or  dome-shaped  mountain,  would 
have  been  more  numerous  at  points  farthest  from  the  central  axis,  since 
every  dike  which  had  been  the  source  of  a  lava-stream,  must  have  poured 
its  contents  downwards,  and  never  upwards. 

In  reference  to  the  facts  here  stated,  I  may  mention  that  the  dikes 
which  I  saw  in  the  Val  del  Bove  were  either  vertical,  or  made  almost 
all  of  them  a  near  approach  to  the  perpendicular,  which  could  not  have 
been  the  case  had  they  been  the  feeders  of  horizontal  beds  of  lava,  and 
had  they  consequently  joined  them  originally  at  right  angles,  for  then 
the  dikes,  as  at  a,  6,  c,  fig.  54,  ought  subsequently  to  have  acquired  a 

Fig.  54. 


Dikes  as  they  would  now  appear  had  they  been  originally  perpendicular. 

considerable  slope,  like  the  beds  which  they  intersect.  I  may  also  urge 
another  objection  to  the  views  above  set  forth,  namely,  that  had  the 
dikes  been  linear  vents,  or  orifices  of  eruption,  we  must  suppose  the 
inter-stratified  scoriae  and  lapilli,  as  well  as  the  lavas,  to  have  come 
out  of  them,  and  in  that  case  the  irregular  heaping  up  of  fragmentary 
matter  around  the  vents  would,  as  before  hinted,  have  disturbed  that 
uniform  thickness  and  parallelism  of  the  beds  which  M.  de  Beaumont 
describes. 

If,  however,  some  of  the  sheets  of  lava  join  the  dikes  in  such  a  man- 
ner, as  to  imply  that  they  were  in  a  melted  state  simultaneously  with 
the  contents  of  the  fissures, — a  point  not  easily  ascertained,  where  the 

*  Mem.  pour  servir,  torn.  iv.  p.  149. 


CH.  XXV.]  OF  THE   CONE   OF   ETNA.  419 

precipices  are  for  the  most  part  inaccessible, — the  fact  may  admit  of  a 
different  interpretation  from  that  proposed  by  the  French  geologists. 
Rents  like  those  before  alluded  to  (p.  399),  which  opened  in  the  plain 
of  S.  Lio  in  1669,  filled  below  with  incandescent  lava,  may  have  lain  in 
the  way  of  currents  of  melted  matter  descending  from  higher  openings. 
In  that  case,  the  matter  of  the  current  would  have  flowed  into  the 
fissure  and  mixed  with  the  lava  at  its  bottom.  Numerous  open  rents  of 
this  kind  are  described  by  Mr.  Dana  as  having  been  caused,  during  a  late 
eruption,  in  one  of  the  volcanic  domes  of  the  Sandwich  Islands.  They 
remained  open  at  various  heights  on  the  slopes  of  the  great  cone,  running 
in  different  directions,  and  demonstrate  the  possibility  of  future  junctions 
of  slightly  inclined  lava-streams  with  perpendicular  walls  of  lava. 

To  me,  therefore,  it  appears  far  more  easy  to  explain  the  uniform 
thickness  and  parallelism  of  so  many  lavas  and  beds  of  fragmentary 
matter  seen  in  the  Val  del  Bove,  by  supposing  them  to  have  issued 
successively  out  of  one  or  more  higher  vents  near  the  summit  of  a  great 
dome,  than  to  imagine  them  to  have  proceeded  from  lateral  dikes  or 
rents  opening  in  a  level  plain.  In  the  Sandwich  Islands,  we  have  ex- 
amples of  volcanic  domes  15,000  feet  high,  produced  by  successive  out- 
pourings from  vents  at  or  near  the  summit.  One  of  these,  Mount  Loa, 
has  a  slope  in  all  directions  of  6°  30';  another,  Mount  Kea,  a  mean 
inclination  of  7°  46'.  That  their  lavas  may  occasionally  consolidate  on 
slopes  of  25°,  and  even  more,  and  still  preserve  considerable  solidity  of 
texture,  has  been  already  stated  ;  see  above,  p.  383. 

We  know  not  how  large  a  quantity  of  modern  lava  may  have  been 
poured  into  the  bottom  of  the  Val  del  Bove,  yet  we  perceive  that  erup- 
tions breaking  forth  near  the  centre  of  Etna  have  already  made  some 
progress  in  filling  up  this  great  hollow.  Even  within  the  memory  of 
persons  now  living,  the  rocks  of  Musara  and  Capra  have,  as  before 
stated,  lost  much  of  their  height  and  picturesque  grandeur  by  the  piling 
up  of  recent  lavas  round  their  base  (see  fig.  51,  p.  408),  and  the  great 
chasm  has  intercepted  many  streams  which  would  otherwise  have  del- 
uged the  fertile  region  below,  as  has  happened  on  the  side  of  Catania. 
The  volcanic  forces  are  now  laboring,  therefore,  to  repair  the  breach 
which  subsidence  has  caused  on  one  side  of  the  great  cone ;  and  unless 
their  energy  should  decline,  or  a  new  sinking  take  place,  they  may  in 
time  efface  this  inequality.  In  that  event,  the  restored  portion  will  al- 
ways be  unconformable  to  the  more  ancient  part,  yet  it  will  consist,  like 
it,  of  alternating  beds  of  lava,  scorise,  and  conglomerates,  which,  with 
all  their  irregularities,  will  have  a  general  slope  from  the  centre  and 
summit  of  Etna  towards  the  sea. 

I  shall  conclude,  then,  by  remarking  that  I  conceive  the  general  incli- 
nation of  the  alternating  stony  and  fragmentary  beds  of  the  Val  del 
Bove,  from  the  axis  of  Etna  towards  its  circumference  or  base,  and  the 
greater  thickness  of  the  volcanic  pile  as  we  approach  the  central  parts  of 
the  mountain,  to  be  due  to  the  preponderance  of  eruptions  from  that 
centre.  These  gave  rise,  from  the  first,  to  a  dome-shaped  mass,  which 


420 


ANTIQUITY   OF   THE   CONE   OF   ETNA. 


[CH.  XXV. 


has  ever  since  been  increasing  in  height  and  area,  being  fractured  again 
and  again  by  the  expansive  force  of  vapors,  and  the  several  parts  made 
to  cohere  together  more  firmly  after  the  solidification  of  the  lava  with 
which  every  open  fissure  and  chasm  has  been  filled.  At  the  same  time 
the  cone  may  have  gained  a  portion  of  its  height  by  the  elevatory  effect 
of  such  dislocating  movements,  and  the  sheets  of  lava  may  have  acquired 
in  some  places  a  greater,  in  others  a  less,  inclination  than  that  which  at 
first  belonged  to  them. 

But  had  the  mountain  been  due  solely,  or  even  principally,  to  up- 
heaval, its  structure  would  have  resembled  that  which  geologists  have  so 
often  recognized  in  dome-shaped  hills,  or  certain  elevated  regions,  which 
all  consider  as  having  been  thrust  up  by  a  force  from  below.  In  this  case 
there  is  often  an  elliptical  cavity  at  the  summit,  due  partly  to  the  frac- 
ture of  the  upraised  rocks,  but  still  more  to  aqueous  denudation,  <is  they 
rose  out  of  the  sea.  The  central  cavity,  or  valley,  exposes  to  view  the 
subjacent  formation  c,  fig.  55,  and  the  incumbent  mass  dips  away  on  all 

Fig.  55. 


Non- volcanic  protuberance  and  valley  of  elevation. 

sides  from  the  axis,  but  has  no  tendency  to  thin  out  near  the  base  of  the 
dome,  or  at  x,  x ;  whereas  at  this  point  the  volcanic  mass  terminates 
(see  fig.  56)  and  allows  the  fundamental  rock  c  to  appear  at  the  surface. 
In  the  last  diagram,  the  more  ordinary  case  is  represented  of  a  great 
hollow  or  crater  at  the  summit  of  the  volcanic  cone;  but  instead  of 

Fig.  56. 


Volcanic  mountain  and  crater. 

this,  we  have  seen  that  in  the  case  of  Etna  there  is  a  deep  lateral  de- 
pression, called  the  Val  del  Bove,  the  upper  part  of  which  approaches 
near  to  the  central  axis,  and  the  origin  of  which  we  have  attributed  to 
subsidence. 

Antiquity  of  the  cone  of  Etna. — It  was  before  remarked  that  confined 
notions  in  regard  to  the  quantity  of  past  time  have  tended,  more  than 
any  other  prepossessions,  to  retard  the  progress  of  sound  theoretical 
views  in  geology  ;*  the  inadequacy  of  our  conceptions  of  the  earth's 
antiquity  having  cramped  the  freedom  of  our  speculations  in  this  science, 
very  much  in  the  same  way  as  a  belief  in  the  existence  of  a  vaulted  fir- 
mament once  retarded  the  progress  of  astronomy.  It  was  not  until 
Descartes  assumed  the  indefinite  extent  of  the  celestial  spaces,  and  re- 
moved the  supposed  boundaries  of  the  universe,  that  just  opinions  began 

*  P.  62,  supra. 


CH.  XXV.]  MODE   OF   INCREASE   OF   VOLCANOES.  421 

to  be  entertained  of  the  relative  distances  of  the  heavenly  bodies ;  and 
until  we  habituate  ourselves  to  contemplate  the  possibility  of  an  indefi- 
nite lapse  of  ages  having  been  comprised  within  each  of  the  modern 
periods  of  the  earth's  history,  we  shall  be  in  danger  of  forming  most 
erroneous  and  partial  views  in  geology. 

If  history  had  bequeathed  to  us  a  faithful  record  of  the  eruptions  of 
Etna,  and  a  hundred  other  of  the  principal  active  volcanoes  of  the  globe, 
during  the  last  three  thousand  years, — if  we  had  an  exact  account  of  the 
volume  of  lava  and  matter  ejected  during  that  period,  and  the  times 
of  their  production, — we  might,  perhaps,  be  able  to  form  a  correct  esti- 
mate of  the  average  rate  of  the  growth  of  a  volcanic  cone.  For  we 
might  obtain  a  mean  result  from  the  comparison  of  the  eruptions  of  so 
great  a  number  of  vents,  however  irregular  might  be  the  development 
of  the  igneous  action  in  any  one  of  them,  if  contemplated  singly  during 
a  brief  period. 

It  would  be  necessary  to  balance  protracted  periods  of  inaction  against 
the  occasional  outburst  of  paroxysmal  explosions.  Sometimes  we  should 
have  evidence  of  a  repose  of  seventeen  centuries,  like  that  which  was 
interposed  in  Ischia,  between  the  end  of  the  fourth  century  B.  c.,  and  the 
beginning  of  the  fourteenth  century  of  our  era.*  Occasionally  a  tre- 
mendous eruption,  like  that  of  Jorullo,  would  be  recorded,  giving  rise, 
at  once,  to  a  considerable  mountain. 

If  we  desire  to  approximate  to  the  age  of  a  cone  such  as  Etna,  we 
ought  first  to  obtain  some  data  in  regard  to  the  thickness  of  matter 
which  has  been  added  during  the  historical  era,  and  then  endeavor  to 
estimate  the  time  required  for  the  accumulation  of  such  alternating  lavas 
and  beds  of  sand  and  scoria3  as  are  superimposed  upon  each  other  in  the 
Val  del  Bove  ;  afterwards  we  should  try  to  deduce,  from  observations 
on  other  volcanoes,  the  more  or  less  rapid  increase  of  burning  mountains 
in  all  the  different  stages  of  their  growth. 

There  is  a  considerable  analogy  between  the  mode  of  increase  of  a 
volcanic  cone  and  that  of  trees  of  exogenous  growth.  These  trees  aug- 
ment, both  in  height  and  diameter,  by  the  successive  application  exter- 
nally of  cone  upon  cone  of  new  ligneous  matter ;  so  that  if  we  make  a 
transverse  section  near  the  base  of  the  trunk,  we  intersect  a  much  greater 
number  of  layers  than  nearer  to  the  summit.  When  branches  occasion- 
ally shoot  out  from  the  trunk,  they  first  pierce  the  bark,  and  then,  after 
growing  to  a  certain  size,  if  they  chance  to  be  broken  off,  they  may  be- 
come inclosed  in  the  body  of  the  tree,  as  it  augments  in  size,  forming 
knots  in  the  wood,  which  are  themselves  composed  of  layers  of  ligneous 
matter,  cone  within  cone. 

In  like  manner,  a  volcanic  mountain,  as  we  have  seen,  consists  of  a 
succession  of  conical  masses  enveloping  others,  while  lateral  cones,  having 
a  similar  internal  structure,  often  project,  in  the  first  instance,  like 
branches  from  the  surface  of  the  main  cone,  and  then  becoming  buried 
again,  are  hidden  like  the  knots  of  a  tree. 

*  See  p.  366 


4:22  MODE  OF  INCREASE  OF  VOLCANOES.       [Cn.  XXV. 

We  can  ascertain  the  age  of  an  oak  or  pine  by  counting  the  number 
of  concentric  rings  of  annual  growth  seen  in  a  transverse  section  near 
the  base,  so  that  we  may  know  the  date  at  which  the  seedling  began  to 
vegetate.  The  Baobab-tree  of  Senegal  (Adansonia  digitata)  is  supposed 
to  exceed  almost  any  other  in  longevity.  Adanson  inferred  that  one 
which  he  measured,  and  found  to  be  thirty  feet  in  diameter,  had  attained 
the  age  of  5150  years.  Having  made  an  incision  to  a  certain  depth,  he 
first  counted  three  hundred  rings  of  annual  growth,  and  observed  what 
thickness  the  tree  had  gained  in  that  period.  The  average  rate  of  growth 
of  younger  trees,  of  the  same  species,  was  then  ascertained,  and  the 
calculation  made  according  to  a  supposed  mean  rate  of  increase.  De 
Candolle  considers  it  not  improbable  that  the  celebrated  Taxodium  of 
Chapultepec,  in  Mexico  (Cupressus  disticha,  Linn.),  which  is  117  feet  in 
circumference,  may  be  still  more  aged.* 

It  is,  however,  impossible,  until  more  data  are  collected  respecting 
the  average  intensity  of  the  volcanic  action,  to  make  any  thing  like  an 
approximation  to  the  age  of  a  cone  like  Etna  ;  because,  in  this  case,  the 
successive  envelopes  of  lava  and  scoriae  are  not  continuous,  like  the  layers 
of  wood  in  a  tree,  and  afford  us  no  definite  measure  of  time.  Each  con- 
ical envelope  is  made  up  of  a  great  number  of  distinct  lava-currents  and 
showers  of  sand  and  scoriae,  differing  in  quantity,  and  which  may  have 
been  accumulated  in  unequal  periods  of  time.  Yet  we  cannot  fail  to 
form  the  most  exalted  conception  of  the  antiquity  of  this  mountain,  when 
we  consider  that  its  base  is  about  ninety  miles  in  circumference  ;  so  that 
it  would  require  ninety  flows  of  lava,  each  a  mile  in  breadth  at  their 
termination,  to  raise  the  present  foot  of  the  volcano  as  much  as  the 
average  height  of  one  lava-current. 

There  are  no  records  within  the  historical  era  which  lead  to  the  opin- 
ion that  the  altitude  of  Etna  has  materially  varied  within  the  last  two 
thousand  years.  Of  the  eighty  most  conspicuous  minor  cones  which 
adorn  its  flanks,  only  one  of  the  largest,  Monti  Rossi,  has  been  produced 
within  the  times  of  authentic  history.  Even  this  hill,  thrown  up  in  the 
year  1669,  although  450  feet  in  height,  only  ranks  as  a  cone  of  second 
magnitude.  Monte  Minardo,  near  Bronte,  rises,  even  now,  to  the  height 
of  750  feet,  although  its  base  has  been  elevated  by  more  modern  lavas 
and  ejections.  The  dimensions  of  these  larger  cones  appear  to  bear 
testimony  to  paroxysms  of  volcanic  activity,  after  which  we  may  con- 
clude, from  analogy,  that  the  fires  of  Etna  remained  dormant  for  many 
years — since  nearly  a  century  of  rest  has  sometimes  followed  a  violent 
eruption  in  the  historical  era.  It  must  also  be  remembered,  that  of  the 
small  number  of  eruptions  which  occur  in  a  century,  one  only  is  esti- 
mated to  issue  from  the  summit  of  Etna  for  every  two  that  proceed  from 
the  sides.  Nor  do  all  the  lateral  eruptions  give  rise  to  such  cones  as 
would  be  reckoned  amongst  the  smallest  of  the  eighty  hills  above  enu- 
merated ;  some  of  them  produce  merely  insignificant  monticules,  which 
are  soon  afterwards  buried  by  showers  of  ashes. 

*  On  the  Longevity  of  Trees,  Bibliot.  Univ.,  May,  1831. 


CH.  XXV.]  DILUVIAL   WAVES.  423 

How  many  years  then  must  we  not  suppose  to  have  been  expended 
in  the  formation  of  the  eighty  cones  ?  It  is  difficult  to  imagine  that  a 
fourth  part  of  them  have  originated  during  the  last  thirty  centuries. 
But  if  we  conjecture  the  whole  of  them  to  have  been  formed  in  twelve 
thousand  years,  how  inconsiderable  an  era  would  this  portion  of  time 
constitute  in  the  history  of  the  volcano  !  If  we  could  strip  oft  from 
Etna  all  the  lateral  monticules  now  visible,  together  with  the  lavas  and 
scoriae  that  have  been  poured  out  from  them,  and  from  the  highest 
crater,  during  the  period  of  their  growth,  the  diminution  of  the  entire 
mass  would  be  extremely  slight:  Etna  might  lose,  perhaps,  several 
miles  in  diameter  at  its  base,  and  some  hundreds  of  feet  in  elevation ; 
but  it  would  still  be  the  loftiest  of  Sicilian  mountains,  studded  with 
other  cones,  which  would  be  recalled,  as  it  were,  into  existence  by  the 
removal  of  the  rocks  under  which  they  are  now  buried. 

There  seems  nothing  in  the  deep  sections  of  the  Val  del  Bove  to  in- 
dicate that  the  lava-currents  of  remote  periods  were  greater  in  volume 
than  those  of  modern  times  ;  and  there  are  abundant  proofs  that  the 
countless  beds  of  solid  rock  and  scoriae  were  accumulated,  as  now,  in 
succession.  On  the  grounds,  therefore,  already  explained,  we  must 
infer  that  a  mass  so  many  thousand  feet  in  thickness  must  have  required 
an  immense  series  of  ages  anterior  to  our  historical  periods  for  its  growth  ; 
yet  the  whole  must  be  regarded  as  the  product  of  a  modern  portion  of 
the  tertiary  epoch.  Such,  at  least,  is  the  conclusion  that  seems  to  fol- 
low from  geological  data,  which  show  that  the  oldest  parts  of  the  moun- 
tain, if  not  of  posterior  date  to  the  marine  strata  around  its  base,  were 
at  least  of  coeval  origin. 

Some  geologists  contend,  that  the  sudden  elevation  of  large  continents 
from  beneath  the  waters  of  the  sea  have  again  and  again  produced 
waves  which  have  swept  Over  vast  regions  of  the  earth.*  But  it  is 
clear  that  no  devastating  wave  has  passed  over  the  forest  zone  of  Etna 
since  any  of  the  lateral  cones  before  mentioned  were  thrown  up ;  for 
none  of  these  heaps  of  loose  sand  and  scorise  could  have  resisted  for  a 
moment  the  denuding  action  of  a  violent  flood.  To  some,  perhaps,  it 
may  appear  that  hills  of  such  incoherent  materials  cannot  be  of  very 
great  antiquity,  because  the  mere  action  of  the  atmosphere  must,  in  the 
course  of  several  thousand  years,  have  obliterated  their  original  forms. 
But  there  is  no  weight  in  this  objection  ;  for  the  older  hills  are  covered 
with  trees  and  herbage,  which  protect  them  from  waste  ;  and,  in  regard 
to  the  newer  ones,  such  is  the  porosity  of  their  compoaent  materials, 
that  the  rain  which  falls  upon  them  is  instantly  absorbed  ;  and  for  the 
same  reason  that  the  rivers  on  Etna  have  a  subterranean  course,  there 
are  none  descending  the  sides  of  the  minor  cones. 

No  sensible  alteration  has  been  observed  in  the  form  of  these  cones 
since  the  earliest  periods  of  which  there  are  memorials ;  and  there 
seems  no  reason  for  anticipating  that  in  the  course  of  the  next  ten 

*  Sedgwick,  Anniv.  Address  to  Geol.  Soc.  p.  35.     Feb.  1831. 


424  VOLCANIC   ERUPTIONS   IN   ICELAND.  [Car.  XXVI 

thousand  or  twenty  thousand  years  they  will  undergo  any  great  altera- 
tion in  their  appearance,  unless  they  should  be  shattered  by  earthquakes 
or  covered  by  volcanic  ejections. 

In  other  parts  of  Europe,  as  in  Auvergne  and  Velay,  in  France, 
similar  loose  cones  of  scoriae,  probably  of  as  high  antiquity  as  the  whole 
mass  of  Etna,  stand  uninjured  at  inferior  elevations  above  the  level  of 
the  sea. 


CHAPTER  XXVI. 

Volcanic  eruption  in  Iceland  in  1783 — New  island  thrown  up — Lava  currents  of 
Skaptar  Jokul,  in  same  year — their  immense  volume — Eruption  of  Jorullo  in 
Mexico — Humboldt's  theory  of  the  convexity  of  the  plain  of  Malpais — Erup- 
tion of  Galongoon  in  Java — Submarine  volcanoes — Graham  island,  formed  in 
1831 — Volcanic  archipelagoes  —  Submarine  eruptions  in  mid-Atlantic  —  The 
Canaries — Teneriffe — Cones  thrown  up  in  Lancerote,  1730-36 — Santorin  and 
its  contiguous  isles — Barren  island  in  the  Bay  of  Bengal — Mud  volcanoes — 
Mineral  composition  of  volcanic  products. 

Volcanic  eruptions  in  Iceland. — WITH  the  exception  of  Etna  and  Ve- 
suvius, the  most  complete  chronological  records  of  a  series  of  eruptions 
are  those  of  Iceland,  for  their  history  reaches  as  far  back  as  the  ninth 
century  of  our  era ;  and,  from  the  beginning  of  the  twelfth  century, 
there  is  clear  evidence  that,  during  the  whole  period,  there  has  never 
been  an  interval  of  more  than  forty,  and  very  rarely  one  of  twenty  years, 
without  either  an  eruption  or  a  great  earthquake.  So  intense  is  the 
energy  of  the  volcanic  action  in  this  region,  that  some  eruptions  of 
Hecla  have  lasted  six  years  without  ceasing.  Earthquakes  have  often 
shaken  the  whole  island  at  once,  causing  great  changes  in  the  interior, 
such  as  the  sinking  down  of  hills,  the  rending  of  mountains,  the  deser- 
tion by  rivers  of  their  channels,  and  the  appearance  of  new  lakes.* 
New  islands  have  often  been  thrown  up  near  the  coast,  some  of  which 
still  exist ;  while  others  have  disappeared,  either  by  subsidence  or  the 
action  of  the  waves. 

In  the  interval  between  eruptions,  innumerable  hot  springs  afford 
vent  to  subterranean  heat,  and  solfataras  discharge  copious  streams  of 
inflammable  matter.  The  volcanoes  in  different  parts  of  this  island  are 
observed,  like  those  of  the  Phlegrsean  Fields,  to  be  in  activity  by  turns, 
one  vent  often  serving  for  a  time  as  a  safety-valve  to  the  rest.  Many 
cones  are  often  thrown  up  in  one  eruption,  and  in  this  case  they  take  a 
linear  direction,  running  generally  from  northeast  to  southwest,  from 
the  northeastern  part  of  the  island,  where  the  volcano  Krabla  lies,  to 
the  promontory  Reykianas. 

*  Von  Hoff,  vol.  ii.  p.  393. 


CH.  XX VI]  ERUPTION   OF  SKAPTAB  JOKUL.  425 

New  island  thrown  up  in  1783. — The  convulsions  of  the  year  1783 
appear  to  have  been  more  tremendous  than  any  recorded  in  the  modern 
annals  of  Iceland  ;  and  the  original  Danish  narrative  of  the  catastrophe, 
drawn  up  in  great  detail,  has  since  been  substantiated  by  several  English 
travellers,  particularly  in  regard  to  the  prodigious  extent  of  country  laid 
waste,  and  the  volume  of  lava  produced.*  About  a  month  previous  to 
the  eruption  on  the  mainland,  a  submarine  volcano  burst  forth  in  the  sea 
in  lat.  63°  25'  N.,  long.  23°  44'  W.,  at  a  distance  of  thirty  miles  in  a 
southwest  direction  from  Cape  Reykianas,  and  ejected  so  much  pumice, 
that  the  oceao  was  covered  with  that  substance  to  the  distance  of  150 
miles,  and  ships  were  considerably  impeded  in  their  course.  A  new 
island  was  thrown  up,  consisting  of  high  cliffs,  within  which  fire,  smoke, 
and  pumice  were  emitted  from  two  or  three  different  points.  This  island 
was  claimed  by  his  Danish  Majesty,  who  denominated  it  Nyoe,  or  the 
New  Island ;  but  before  a  year  had  elapsed,  the  sea  resumed  its  ancient 
domain,  and  nothing  was  left  but  a  reef  of  rocks  from  five  to  thirty 
fathoms  under  water. 

Great  eruption  of  Skaptdr  Jokul. — Earthquakes  which  had  long  been 
felt  in  Iceland,  became  violent  on  the  llth  of  June,  1783,  when  Skaptar 
Jokul,  distant  nearly  200  miles  from  Nyoe,  threw  out  a  torrent  of  lava 
which  flowed  down  into  the  river  Skapta,  and  completely  dried  it  up. 
The  channel  of  the  river  was  between  high  rocks,  in  many  places  from 
four  hundred  to  six  hundred  feet  in  depth,  and  near  two  hundred  in 
breadth.  Not  only  did  the  lava  fill  up  this  great  defile  to  the  brink,  but 
it  overflowed  the  adjacent  fields  to  a  considerable  extent.  The  burning 
flood,  on  issuing  from  the  confined  rocky  gorge,  was  then  arrested  for 
some  time  by  a  deep  lake,  which  formerly  existed  in  the  course  of  the 
river,  between  Skaptardal  and  Aa,  which  it  entirely  filled.  The  current 
then  advanced  again,  and  reaching  some  ancient  lava  full  of  subterra- 
neous caverns,  penetrated  and  melted  down  part  of  it ;  and  in  some 
places,  where  the  steam  could  not  gain  vent,  it  blew  up  the  rock, 
throwing  fragments  to  the  height  of  more  than  150  feet.  On  the  18th 
of  June  another  ejection  of  liquid  lava  rushed  from  the  volcano,  which 
flowed  down  with  amazing  velocity  over  the  surface  of  the  first  stream. 
By  the  damming  up  of  the  mouths  of  some  of  the  tributaries  of  the 
Skapta,  many  villages  were  completely  overflowed  with  water,  and  thus 
great  destruction  of  property  was  caused.  The  lava,  after  flowing  for 
several  days,  was  precipitated  down  a  tremendous  cataract  called  Stap- 
afoss,  where  it  filled  a  profound  abyss,  which  that  great  waterfall  had 

*  The  first  narrative  of  the  eruption  was  drawn  up  by  Stephenson,  then 
Chief  Justice  in  Iceland,  appointed  Commissioner  by  the  King  of  Denmark  for 
estimating  the  damage  done  to  the  country,  that  relief  might  be  afforded  to  the 
sufferers.  Henderson  was  enabled  to  correct  some  of  the  measurements  given 
by  Stephenson,  of  the  depth,  width,  and  length  of  the  lava  currents,  by  refer- 
ence to  the  MS.  of  Mr.  Paulson,  who  visited  the  tract,  in  1794,  and  examined  the 
lava  with  attention.  (Journal  of  a  Residence  in  Iceland,  &c.  p.  229.)  Some  of 
the  principal  facts  are  also  corroborated  by  Sir  William  Hooker,  in  his  "  Tour  in 
Iceland,"  voL  ii.  p.  128. 


426  IMMENSE   VOLUME  OF  THE   LAVA.  [Cn.  XXVI. 

been  hollowing  out  for  ages,  and  after  this,  the  fiery  current  again  con- 
tinued its  course. 

On  the  third  of  August,  fresh  floods  of  lava  still  pouring  from  the 
volcano,  a  new  branch  was  sent  off  in  a  different  direction ;  for  the 
channel  of  the  Skapta  was  now  so  entirely  choked  up,  and  every  open- 
ing to  the  west  and  north  so  obstructed,  that  the  melted  matter  was 
forced  to  take  a  new  course,  so  that  it  ran  in  a  southeast  direction,  and 
discharged  itself  into  the  bed  of  the  river  Hverfisfliot,  where  a  scene  of 
destruction  scarcely  inferior  to  the  former  was  occasioned.  These  Ice- 
landic lavas  (like  the  ancient  streams  which  are  met  with  in  Auvergne, 
and  other  provinces  of  Central  France),  are  stated  by  Stephenson  to 
have  accumulated  to  a  prodigious  depth  in  narrow  rocky  gorges ;  but 
when  they  came  to  wide  alluvial  plains,  they  spread  themselves  out  into 
broad  burning  lakes,  sometimes  from  twelve  to  fifteen  miles  wide,  and 
one  hundred  feet  deep.  When  the  "fiery  lake"  which  filled  up  the 
lower  portion  of  the  valley  of  the  Skapta  had  been  augmented  by  new 
supplies,  the  lava  flowed  up  the  course  of  the  river  to  the  foot  of  the 
hills  from  whence  the  Skapta  takes  its  rise.  This  affords  a  parallel  case 
to  one  which  can  be  shown  to  have  happened  at  a  remote  era  in  the 
volcanic  region  of  the  Vivarais  in  France,  where  lava  issued  from  the 
cone  of  Thueyts,  and  while  one  branch  ran  down,  another  more  powerful 
stream  flowed  up  the  channel  of  the  river  Ardeche. 

The  sides  of  the  valley  of  the  Skapta  present  superb  ranges  of  basaltic 
columns  of  older  lava;  resembling  those  which  are  laid  open  in  the  val- 
leys descending  from  Mont  Dor,  in  Auvergne,  where  more  modern  lava- 
currents,  on  a  scale  very  inferior  in  magnitude  to  those  of  Iceland,  have 
also  usurped  the  beds  of  the  existing  rivers.  The  eruption  of  Skaptar 
Jokul  did  not  entirely  cease  till  the  end  of  two  years ;  and  when  Mr. 
Paulson  visited  the  tract  eleven  years  afterwards,  in  1794,  he  found 
columns  of  smoke  still  rising  from  parts  of  the  lava,  and  several  rents 
filled  with  hot  water.* 

Although  the  population  of  Iceland  was  very  much  scattered,  and  did 
not  exceed  fifty  thousand,  no  less  than  twenty  villages  were  destroyed, 
besides  those  inundated  by  water ;  and  more  than  nine  thousand  human 
beings  perished,  together  with  an  immense  number  of  cattle,  partly  by 
the  depredations  of  the  lava,  partly  by  the  noxious  vapors  which  impreg- 
nated the  air,  and,  in  part,  by  the  famine  caused  by  showers  of  ashes 
throughout  the  island,  and  the  desertion  of  the  coasts  by  the  fish. 

Immense  volume  of  the  lava. — But  the  extraordinary  volume  of  melted 
matter  produced  in  this  eruption  deserves  the  particular  attention  of  the 
geologist.  Of  the  two  brandies,  which  flowed  in  nearly  opposite  direc- 
tions, the  greatest  was  fifty,  and  the  lesser  forty  miles  in  length.  The 
extreme  breadth  which  the  Skapta  branch  attained  in  the  low  countries 
was  from  twelve  to  fifteen  miles,  that  of  the  other  about  seven.  The 
ordinary  height  of  both  currents  was  one  hundred  feet,  but  in  narrow 

*  Henderson's  Journal,  <fec.  p.  228. 


CH.  XXVI.]        ANCIENT   AND    MODERN    LAVAS    COMPARED.  427 

defiles  it  sometimes  amounted  to  six  hundred.  Professor  Bischoff  has 
calculated  that  the  mass  of  lava  brought  up  from  the  subterranean 
regions  by  this  single  eruption  "  surpassed  in  magnitude  the  bulk  of 
Mont  Blanc."*  But  a  more  distinct  idea  will  be  formed  of  the  dimen- 
sions of  the  two  streams,  if  we  consider  how  striking  a  feature  they 
would  now  form  in  the  geology  of  England,  had  they  been  poured  out 
on  the  bottom  of  the  sea  after  the  deposition  and  before  the  elevation  of 
our  secondary  and  tertiary  rocks.  The  same  causes  which  have  exca- 
vated valleys  through  parts  of  our  marine  strata,  once  continuous,  might 
have  acted  with  equal  force  on  the  igneous  rocks,  leaving,  at  the  same 
time,  a  sufficient  portion  undestroyed  to  enable  us  to  discover  their  for- 
mer extent.  Let  us,  then,  imagine  the  termination  of  the  Skapta  branch 
of  lava  to  rest  on  the  escarpment  of  the  inferior  and  middle  oolite,  where 
it  commands  the  vale  of  Gloucester.  The  great  platform  might  be  one 
hundred  feet  thick,  and  from  ten  to  fifteen  miles  broad,  exceeding  any 
which  can  be  found  in  Central  France.  We  may  also  suppose  great 
tabular  masses  to  occur  at  intervals,  capping  the  summit  of  the  Cotswold 
Hills  between  Gloucester  and  Oxford,  by  Northleach,  Burford,  and 
other  towns.  The  wide  valley  of  the  Oxford  clay  would  then  occasion 
an  interruption  for  many  miles ;  but  the  same  rocks  might  recur  on  the 
summit  of  Cumnor  and  Shotover  Hills,  and  all  the  other  oolitic  emi- 
nences of  that  district.  On  the  chalk  of  Berkshire,  extensive  plateaus, 
six  or  seven  miles  wide,  would  again  be  formed ;  and  lastly,  crowning 
the  highest  sands  of  Highgate  and  Hampstead,  we  might  behold  some 
remnants  of  the  current  five  or  six  hundred  feet  in  thickness,  causing 
those  hills  to  rival,  or  even  to  surpass,  in  height,  Salisbury  Craigs  and 
Arthur's  Seat. 

The  distance  between  the  extreme  points  here  indicated  would  not 
exceed  ninety  miles  in  a  direct  line ;  and  we  might  then  add,  at  the  dis- 
tance of  nearly  two  hundred  miles  from  London,  along  the  coast  of 
Dorsetshire  and  Devonshire,  for  example,  a  great  mass  of  igneous  rocks, 
to  represent  those  of  contemporary  origin,  which  were  produced  beneath 
the  level  of  the  sea,  where  the  island  of  Nyoe  rose  up. 

Volume  of  ancient  and  modern  flows  of  lava  compared. — Yet,  gigantic 
as  must  appear  the  scale  of  these  modern  volcanic  operations,  we  must 
be  content  to  regard  them  as  perfectly  insignificant  in  comparison  to 
currents  of  the  primeval  ages,  if  we  embrace  the  theoretical  views  of 
many  geologists,  which  were  not  inaccurately  expressed  by  the  late  Pro- 
fessor Alexander  Brongniart,  when  he  declared  that  "aux  epoques 
geognostiques  anciennes,  tous  les  phenomenes  geologiques  se  passoicnt 
dans  des  dimensions  centuples  de  celles  qu'ils  presentent  aujourd'hui."f 
Had  Skaptar  Jokul,  therefore,  been  a  volcano  of  the  olden  time,  it  would 
have  poured  forth  lavas  at  a  single  eruption  a  hundred  times  more  volu- 
minous than  those  which  were  witnessed  by  the  present  generation  in 

*  Jameson's  Phil.  Journ.  vol.  xxvi.  p.  291. 

f  Tableau  des  Terrains  qui  composent  1'Ecorce  du  Globe,  p.  52.     Paris,  1829. 


428  ERUPTION   OF  JORULLO,  A.  D.  1759.  [On.  XXVI. 

1783.  But  it  may,  on  the  contraiy,  be  affirmed  that,  among  the  older 
formations,  no  igneous  rock  of  such  colossal  magnitude  has  yet  been  met 
with ;  nay,  it  would  be  most  difficult  to  point  out  a  mass  of  ancient  date 
(distinctly  referable  to  a  single  eruption)  which  would  even  rival  in 
volume  the  matter  poured  out  from  Skaptar  Jokul  in  1783. 

Eruption  of  Jorullo  in  1759. — As  another  example  of  the  stupendous 
scale  of  modern  volcanic  eruptions,  I  may  mention  that  of  Jorullo  in 
Mexico,  in  1759.  The  great  region  to  which  this  mountain  belongs  has 
already  been  described.  The  plain  of  MaJpais  forms  part  of  an  elevated 
platform,  between  two  and  three  thousand  feet  above  the  level  of  the 
sea,  and  is  bounded  by  hills  composed  of  basalt,  trachyte,  and  volcanic 
tuff,  clearly  indicating  that  the  country  had  previously,  though  probably 
at  a  remote  period,  been  the  theatre  of  igneous  action.  From  the  era 
of  the  discovery  of  the  New  World  to  the  middle  of  the  last  century,  the 
district  had  remained  undisturbed,  and  the  space,  now  the  site  of  the 
volcano,  which  is  thirty-six  leagues  distant  from  the  nearest  sea,  was 
occupied  by  fertile  fields  of  sugar-cane  and  indigo,  and  watered  by  the 
two  brooks  Cuitimba  and  San  Pedro.  In  the  month  of  June,  1759, 
hollow  sounds  of  an  alarming  nature  were  heard,  and  earthquakes  suc- 
ceeded each  other  for  two  months,  until,  at  the  end  of  September,  flames 
issued  from  the  ground,  and  fragments  of  burning  rocks  were  thrown  to 
prodigious  heights.  Six  volcanic  cones,  composed  of  scoriae  and  frag- 
mentary lava,  were  formed  on  the  line  of  a  chasm  which  ran  in  the  direc- 
tion from  N.  N.  E.  to  S.  S.  W.  The  least  of  these  cones  was  300  feet  in 
height;  and  Jorullo,  the  central  volcano,  was  elevated  1600  feet  above 
the  level  of  the  plain.  It  sent  forth  great  streams  of  basaltic  lava,  con- 
taining included  fragments  of  granitic  rocks,  and  its  ejections  did  not 
cease  till  the  month  of  February,  1760.* 

Humboldt  visited  the  country  more  than  forty  years  after  this  occur- 
rence, and  was  informed  by  the  Indians,  that  when  they  returned,  long 
after  the  catastrophe,  to  the  plain,  they  found  the  ground  uninhabitable 
from  the  excessive  heat.  When  he  himself  visited  the  place,  there 
appeared,  around  the  base  of  the  cones,  and  spreading  from  them,  as 
from  a  centre,  over  an  extent  of  four  square  miles,  a  mass  of  matter  of 
a  convex  form,  about  550  feet  high  at  its  junction  with  the  cones,  and 
gradually  sloping  from  them  in  all  directions  towards  the  plain.  This 
mass  was  still  in  a  heated  state,  the  temperature  in  the  fissures  being  on 


o,  Summit  of  Jorullo.    &,  c,  Inclined  plane  sloping  at  an  angle  of  6°  from  the  base  of  the  cones. 

the  decrease  from  year  to  year,  but  in  1780  it  was  still  sufficient  to  light 
a  cigar  at  the  depth  of  a  few  inches.     On  this  slightly  convex  protuber- 

*  Daubeny  on  Volcanoes,  p.  337. 


CH.  XXVI.]         CONVEXITY   OF  THE   PLAIN   OF  MALPAIS.  429 

ance,  the  slope  of  which  must  form  an  angle  of  about  6°  with  the  hori- 
zon, were  thousands  of  flattish  conical  mounds,  from  six  to  nine  feet  high, 
which,  as  well  as  large  fissures  traversing  the  plain,  acted  as  fumeroles, 
giving  out  clouds  of  sulphurous  acid  and  hot  aqueous  vapor.  The  two 
small  rivers  before  mentioned  disappeared  during  the  eruption,  losing 
themselves  below  the  eastern  extremity  of  the  plain,  and  reappearing  as 
hot  springs  at  its  western  limit. 

Cause  of  the  convexity  of  the  plain  of  Malpais. — Humboldt  attributed 
the  convexity  of  the  plain  to  inflation  from  below ;  supposing  the  ground, 
for  four  square  miles  in  extent,  to  have  risen  up  in  the  shape  of  a  blad- 
der to  the  elevation  of  550  feet  above  the  plain  in  the  highest  part. 
But  Mr.  Scrope  has  suggested  that  the  phenomena  may  be  accounted 
for  far  more  naturally,  by  supposing  that  lava  flowing  simultane- 
ously from  the  different  orifices,  and  principally  from  Jorullo,  united 
into  a  sort  of  pool  or  lake.  As  they  were  poured  forth  on  a  surface 
previously  flat,  they  would,  if  their  liquidity  was  not  very  great,  remain 
thickest  and  deepest  near  their  source,  and  diminish  in  bulk  from  thence 
towards  the  limits  of  the  space  which  they  covered.  Fresh  supplies 
were  probably  emitted  successively  during  the  course  of  an  eruption 
which  lasted  more  than  half  a  year  ;  and  some  of  these,  resting  on  those 
first  emitted,  might  only  spread  to  a  small  distance  from  the  foot  of  the 
cone,  where  they  would  necessarily  accumulate  to  a  great  height.  The 
average  slope  of  the  great  dome-shaped  volcanoes  of  the  Sandwich 
Islands,  formed  almost  exclusively  of  lava,  with  scarce  any  scoriae,  is 
between  6°  30'  and  7°  46',  so  that  the  inclination  of  the  convex  mass 
around  Jorullo,  if  we  adopt  Mr.  Scrope's  explanation  (see  fig.  57),  is 
quite  in  accordance  with  the  known  laws  which  govern  the  flow  of  lava. 

The  showers,  also,  of  loose  and  pulverulent  matter  from  the  six  cra- 
ters, and  principally  from  Jorullo,  would  be  composed  of  heavier  and 
more  bulky  particles  near  the  cones,  and  would  raise  the  ground  at 
their  base,  where,  mixing  with  rain,  they  might  have  given  rise  to  the 
stratum  of  black  clay,  which  is  described  as  covering  the  lava.  The 
small  conical  mounds  (called  "  hornitos,"  or  little  ovens)  may  resemble 
those  five  or  six  small  hillocks  which  existed  in  1823  on  the  Vesuvian 
lava,  and  sent  forth  columns  of  vapor,  having  been  produced  by  the 
disengagement  of  elastic  fluids  heaping  up  small  dome-shaped  masses 
of  lava.  The  fissures  mentioned  by  Humboldt  as  of  frequent  occurrence, 
are  such  as  might  naturally  accompany  the  consolidation  of  a  thick  bed 
of  lava,  contracting  as  it  congeals  ;  and  the  disappearance  of  rivers  is 
the  usual  result  of  the  occupation  of  the  lower  part  of  a  valley  or  plain 
by  lava,  of  which  there  are  many  beautiful  examples  in  the  old  lava- 
currents  of  Auvergne.  The  heat  of  the  "  hornitos"  is  stated  to  have 
diminished  from  the  first ;  and  Mr.  Bullock,  who  visited  the  spot  many 
years  after  Humboldt,  found  the  temperature  of  the  hot  spring  very 
low, — a  fact  which  seems  clearly  to  indicate  the  gradual  congelation  of 
a  subjacent  bed  of  lava,  which  from  its  immense  thickness  may  have 
been  enabled  to  retain  its  heat  for  half  a  century.  The  reader  may  be 


430  VOLCANIC   ERUPTIONS    IN   JAVA.  [Cfi.  XXVL 

reminded,  that  when  we  thus  suppose  the  lava  near  the  volcano  to  have 
been,  together  with  the  ejected  ashes,  more  than  five  hundred  feet  in 
depth,  we  merely  assign  a  thickness  which  the  current  of  Skaptar  Jokul 
attained  in  some  places  in  1*783. 

Hollow  sound  of  the  plain  when  struck. — Another  argument  adduced 
in  support  of  the  theory  of  inflation  from  below,  'was,  the  hollow  sound 
made  by  the  steps  of  a  horse  upon  the  plain  ;  which,  however,  proves 
nothing  more  than  that  the  materials  of  which  the  convex  mass  is  com- 
posed are  light  and  porous.  The  sound  called  "  rimbombo"  by  the 
Italians  is  very  commonly  returned  by  made  ground  when  struck  sharply ; 
and  has  been  observed  not  only  on  the  sides  of  Vesuvius  and  other  vol- 
canic cones  where  there  is  a  cavity  below,  but  in  such  regions  as  the 
Campagna  di  Roma,  composed  in  a  great  measure  of  tuff  and  porous 
volcanic  rocks.  The  reverberation,  however,  may  perhaps  be  assisted 
by  grottoes  and  caverns,  for  these  may  be  as  numerous  in  the  lavas  of 
Jorullo  as  in  many  of  those  of  Etna ;  but  their  existence  would  lend  no 
countenance  to  the  hypothesis  of  a  great  arched  cavity,  four  square 
miles  in  extent,  and  in  the  centre  550  feet  high.* 

No  recent  eruptions  of  Jorullo. — In  a  former  edition  I  stated  that  I 
had  been  informed  by  Captain  Vetch,  that  in  1819  a  tower  at  Guada- 
laxara  was  thrown  down  by  an  earthquake,  and  that  ashes,  supposed  to 
have  come  from  Jorullo,  fell  at  the  same  time  at  Guanaxuato,  a  town 
situated  140  English  miles  from  the  volcano.  But  Mr.  Burkhardt,  a 
German  director  of  mines,  who  examined  Jorullo  in  1827,  ascertained 
that  there  had  been  no  eruption  there  since  Humboldt's  visit  in  1803. 
He  went  to  the  bottom  of  the  crater,  and  observed  a  slight  evolution  of 
sulphurous  acid  vapors,  but  the  "  hornitos"  had  entirely  ceased  to  send 
forth  steam.  During  the  twenty-four  years  intervening  between  his 
visit  and  that  of  Humboldt,  vegetation  had  made  great  progress  on  the 
flanks  of  the  new  hills ;  the  rich  soil  of  the  surrounding  country  was 
once  more  covered  with  luxuriant  crops  of  sugar-cane  and  indigo,  and 
there  was  an  abundant  growth  of  natural  underwood  on  all  the  uncul- 
tivated tracts. f 

Galongoon,  Java,  1822. — The  mountain  of  Galongoon  (or  Galung 
Gung)  was  in  1822  covered  by  a  dense  forest,  and  situated  in  a  fruitful 
and  thickly-peopled  part  of  Java.  There  was  a  circular  hollow  at  its 
summit,  but  no  tradition  existed  of  any  former  eruption.  In  July,  1822, 
the  waters  of  the  river  Kunir,  one  of  those  which  flowed  from  its  flanks, 
became  for  a  time  hot  and  turbid.  On  the  8th  of  October  following  a 
loud  explosion  was  heard,  the  earth  shook,  and  immense  columns  of  hot 
water  and  boiling  mud,  mixed  with  burning  brimstone,  ashes,  and  lapilli, 
of  the  size  of  nuts,  were  projected  from  the  mountain  like  a  waterspout, 
with  such  prodigious  violence  that  large  quantities  fell  beyond  the  river 
Tandoi,  which  is  forty  miles  distant.  Every  valley  within  the  range  of 

*  See  Scrope  on  Volcanoes,  p.  267. 

f  Leonhard  and  Bronn's  Neues  Jahrbucb,  1835,  p.  36. 


CH.  XXVL]  SUBMARINE   VOLCANOES.  431 

this  eruption  became  filled  with  a  burning  torrent,  and  the  rivers,  swol- 
len with  hot  water  and  mud,  overflowed  their  banks,  and  carried  away 
great  numbers  of  the  people,  who  were  endeavoring  to  escape,  and  the 
bodies  of  cattle,  wild  beasts,  and  birds.  A  space  of  twenty-four  miles 
between  the  mountain  and  the  river  Tandoi  was  covered  to  such  a 
depth  with  bluish  mud  that  people  were  buried  in  their  houses,  and 
not  a  trace  of  the  numerous  villages  and  plantations  throughout  that 
extent  was  visible.  Within  this  space  the  bodies  of  those  who  perished 
were  buried  in  mud  and  concealed,  but  near  the  limits  of  the  volcanic 
action  they  were  exposed,  and  strewed  over  the  ground  in  great  num- 
bers, partly  boiled  and  partly  burnt. 

It  was  remarked,  that  the  boiling  mud  and  cinders  were  projected 
with  such  violence  from  the  mountain,  that  while  many  remote  villages 
were  utterly  destroyed  and  buried,  others  much  nearer  the  volcano 
were  scarcely  injured. 

The  first  eruption  lasted  nearly  five  hours,  and  on  the  following  days 
the  rain  fell  in  torrents,  and  the  rivers,  densely  charged  with  mud, 
deluged  the  country  far  and  wide.  At  the  end  of  four  days  (October 
12th)  a  second  eruption  occurred  more  violent  than  the  first,  in  which 
hot  water  and  mud  were  again  vomited,  and  great  blocks  of  basalt  were 
thrown  to  the  distance  of  seven  miles  from  the  volcano.  There  was  at 
the  same  time  a  violent  earthquake,  and  in  one  account  it  is  stated  that/the 
face  of  the  mountain  was  utterly  changed,  its  summits  broken  down,  and 
one  side,  which  had  been  covered  with  trees,  became  an  enormous  gulf 
in  the  form  of  a  semicircle.  This  cavity  was  about  midway  between  the 
summit  and  the  plain,  and  surrounded  by  steep  rocks,  said  to  be  newly 
heaped  up  during  the  eruption.  New  hills  and  valleys  are  said  to  have 
been  formed,  and  the  rivers  Banjarang  and  Wulan  changed  their  course, 
and  in  one  night  (October  12th)  2000  persons  were  killed. 

The  first  intimation  which  the  inhabitants  of  Bandong  received  of  this 
calamity  on  the  8th  of  October,  was  the  news  that  the  river  Wulna  was 
bearing  down  into  the  sea  the  dead  bodies  of  men,  and  the  carcasses  of 
stags,  rhinoceroses,  tigers,  and  other  animals.  The  Dutch  painter  Payen 
determined  to  travel  from  thence  to  the  volcano,  and  he  found  that  the 
quantity  of  the  ashes  diminished  as  he  approached  the  base  of  the  moun- 
tain. He  alludes  to  the  altered  form  of  the  mountain  after  the  12th, 
but  does  not  describe  the  new  semicircular  gulf  on  its  side. 

The  official  accounts  state  that  114  villages  were  destroyed,  and  above 
4000  persons  killed.* 

Submarine  volcanoes.— Although  we  have  every  reason  to  believe  that 
volcanic  eruptions  as  well  as  earthquakes  are  common  in  the  bed  of  the 
sea,  it  was  not  to  be  expected  that  many  opportunities  would  occur  to 
scientific  observers  of  witnessing  the  phenomena.  The  crews  of  vessels 
have  sometimes  reported  that  they  have  seen  in  different  places  sulphur- 

*  Van  der  Boon  Mesch,  de  Incendiis  Mont. him  Java>,  &c.  Lugd.  Bat.  1826 ; 
and  Official  Report  of  the  President,  Baron  Van  der  Capellen ;  also,  Von  Buch, 
lies  Canar.  p.  424. 


432  GRAHAM   ISLAND.  [On.  XXVi. 

ous  smoke,  flame,  jets  of  water,  and  steam,  rising  up  from  the  sea,  or 
they  have  observed  the  waters  greatly  discolored,  and  in  a  state  of  vio- 
lent agitation  as  if  boiling.  New  shoals  have  also  been  encountered,  or 
a  reef  of  rocks  just  emerging  above  the  surface,  where  previously  there 
was  always  supposed  to  have  been  deep  water.  On  some  few  occasions 
the  gradual  formation  of  an  island  by  a  submarine  eruption  has  been  ob- 
served, as  that  of  Sabrina,  in  the  year  1811,  off  St.  Michael's  in  the 
Azores.  The  throwing  up  of  ashes  in  that  case,  and  the  formation  of 
a  cone  about  three  hundred  feet  in  height,  with  a  crater  in  the  centre, 
closely  resembled  the  phenomena  usually  accompanying  a  volcanic  erup- 
tion on  land.  Sabrina  was  soon  washed  away  by  the  waves.  Previous 
eruptions  in  the  same  part  of  the  sea  were  recorded  to  have  happened 
in  1691  and  1720.  The  rise  of  Nyoe,  also,  a  small  island  off  the  coast 
of  Iceland,  in  1783,  has  already  been  alluded  to  ;  and  another  volcanic 
isle  was  produced  by  an  eruption  near  Reikiavig,  on  the  same  coast,  in 
June,  1830.* 

Graham  Island\,  1831. — We  have  still  more  recent  and  minute  infor- 
mation respecting  the  appearance,  in  1831,  of  a  new  volcanic  island  in 
the  Mediterranean,  between  the  S.  W.  coast  of  Sicily  and  that  projecting 
part  of  the  African  coast  where  ancient  Carthage  stood.  The  site  of  the 
island  was  not  any  part  of  the  great  shoal,  or  bank,  called  "  Nerita,"  as 
was  first  asserted,  but  a  spot  where  Captain  W.  H.  Smyth  had  found, 
in  his  survey  a  few  years  before,  a  depth  of  more  than  one  hundred 
fathoms  water.J 

The  position  of  the  island  (lat.  37°  8'  30"  N.,  long.  12°  42'  15"  E.) 
was  about  thirty  miles  S.  W.  of  Sciacca,  in  Sicily,  and  thirty-three  miles 
N.  E.  of  Pantellaria.§  On  the  28th  of  June,  about  a  fortnight  before 
the  eruption  was  visible,  Sir  Pulteney  Malcolm,  in  passing  over  the  spot 
in  his  ship,  felt  the  shocks  of  an  earthquake,  as  if  he  had  struck  on  a 
sand-bank  ;  and  the  same  shocks  were  felt  on  the  west  coast  of  Sicily, 
in  a  direction  from  S.  W.  to  K  E.  About  the  10th  of  July,  John 
Corrao,  the  captain  of  a  Sicilian  vessel,  reported  that,  as  he  passed  near 
the  place,  he  saw  a  column  of  water  like  a  water-spout,  sixty  feet  high, 
and  800  yards  in  circumference,  rising  from  the  sea,  and  soon  afterwards 
a  dense  steam  in  its  place,  which  ascended  to  the  height  of  1800  feet- 
The  same  Corrao,  on  his  return  from  Girgenti,  on  the  18th  of  July, 
found  a  small  island,  twelve  feet  high  with  a  crater  in  its  centre,  eject- 
ing volcanic  matter,  and  immense  columns  of  vapor  ;  the  sea  around  being 

*  Journ.  de  Geol.  tome  i. 

f  In  a  former  edition,  I  selected  the  name  of  Sciacca  out  of  seven  which  had 
been  proposed  ;  but  the  Royal  and  Geographical  Societies  have  now  adopted 
Graham  Island  ;  a  name  given  by  Capt.  Senlionse,  R.  N.,  the  first  who  succeeded 
in  landing  on  it.  The  seven  rival  names  are  Nerita,  Ferdinanda,  Hotham,  Graham, 
Corrao,  Sciacca,  Julia.  As  the  isle  was  visible  for  only  about  three  months,  this 
is  an  instance  of  a  wanton  multiplication  of  synonyms  which  has  scarcely  ever  been 
outdone  even  in  the  jiriiia's  of  zoology  and  botany. 

±  Phil.  Trans.  1832,  p.  -2uo. 

§  Journ.  of  Roy.  Geograph.  Soc.  1830-31. 


Ou  XXVI] 


GRAHAM   ISLAND. 


433 


Form  of  the  cliffs  of  Graham  Island,  as  seen  from  S.  S.  E.,  distant  one  mile,  7th  August,.  1831.* 

covered  with  floating  cinders  and  dead  fish.     The  scoriae  were  of  a 
chocolate  color,  and  the  water  which  boiled  in  the  circular  basin  was  of 

Fig.  59. 


View  of  the  interior  of  Graham  Island,  29th  Sept.,  1831. 


a  dingy  red.     The  eruption  continued  with  great  violence  to  the  end  of 
the  same  month ;  at  which  time  the  island  was  visited  by  several  per- 


Fig. 


Graham  Island,  29th  Sept,  1831.t 

*  Phil.  Trans,  part.  ii.  1832,  reduced  from  drawings  by  Capt.  Wodehouse,  R.  N. 

f  In  the  annexed  sketch  (fig.  60),  drawn  by  M.  Joiuville,  who  accompanied 
M.  C.  Prevost,  the  beds  seem  to  slope  towards  the  centre  of  the  crater ;  but  I  am 
informed  by  M.  Prevost  that  these  lines  were  not  intended  by  the  artist  to  repre- 
sent the  dip  of  the  beds. 

28 


4:34.  GRAHAM   ISLAND.  [On.  XXVI. 

sons,  and  among  others  by  Capt.  Swinburne,  R.  K,  and  M.  Hoffmann, 
the  Prussian  geologist.  It  was  then  from  fifty  to  ninety  feet  in  height, 
and  three-quarters  of  a  mile  in  circumference.  By  the  4th  of  August 
it  became,  according  to  some  accounts,  above  200  feet  high,  and  three 
miles  in  circumference  ;  after  which  it  began  to  diminish  in  size  by  the 
action  of  the  waves,  and  it  was  only  two  miles  round  on  the  25th  of 
August ;  and  on  the  3d  of  September,  when  it  was  carefully  examined 
by  Captain  Wodehouse,  only  three-fifths  of  a  mile  in  circumference  ;  its 
greatest  height  being  then  107  feet.  At  this  time  the  crater  was  about  780 
feet  in  circumference.  On  the  29th  of  September,  when  it  was  visited 
byMons.  C.  Prevost,  its  circumference  was  reduced  to  about  700  yards. 
It  was  composed  entirely  of  incoherent  ejected  matter,  scoriae,  pumice, 
and  lapilli,  forming  regular  strata,  some  of  which  are  described  as  hav- 
ing been  parallel  to  the  steep  inward  slope  of  the  crater,  while  the  rest 
were  inclined  outwards,  like  those  of  Vesuvius.*  When  the  arrangement 
of  the  ejected  materials  has  been  determined  by  their  falling  continually 
on  two  steep  slopes,  that  of  the  external  cone  and  that  of  the  crater, 
which  is  always  a  hollow  inverted  cone,  a  transverse  section  would 

Fig.  61. 


probably  resemble  that  given  in  the  annexed  figure  (61).  But  when  I 
visited  Vesuvius,  in  1828,  I  saw  no  beds  of  scoriae  inclined  towards  the 
axis  of  the  cone.  (See  fig.  45,  p.  381.)  Such  may  have  once  existed ; 
but  the  explosions  or  subsidences,  or  whatever  causes  produced  the 
great  crater  of  1822,  had  possibly  destroyed  them. 

Few  of  the  pieces  of  stone  thrown  out  from  Graham  Island  exceeded 
a  foot  in  diameter.  Some  fragments  of  dolomitic  limestone  were  inter- 
mixed ;  but  these  were  the  only  non- volcanic  substances.  During  the 
month  of  August,  there  occurred  on  the  S.  W.  side  of  the  new  island 
a  violent  ebullition  and  agitation  of  the  sea,  accompanied  by  the  con- 
stant ascension  of  a  column  of  dense  white  steam,  indicating  the  exist- 
ence of  a  second  vent  at  no  great  depth  from  the  surface.  Towards 
the  close  of  October,  no  vestige  of  the  crater  remained,  and  the  island 
was  nearly  levelled  with  the  surface  of  the  ocean,  with  the  exception, 
at  one  point,  of  a  small  monticule  of  sand  and  scoriae.  It  was  reported 
that,  at  the  commencement  of  the  year  following  (1832),  there  was  a 
depth  of  150  feet  where  the  island  had  been:  but  this  account  was 
quite  erroneous ;  for  in  the  early  part  of  that  year  Captain  Swinburne 
found  a  shoal  and  discolored  water  there,  and  towards  the  end  of  1833 
a  dangerous  reef  existed  of  an  oval  figure,  about  three-fifths  of  a  mile 
in  extent.  In  the  centre  was  a  black  rock,  of  the  diameter  of  about 

*  See  Memoir  by  M.  C.  Prevost,  Ann.  des  Sci.  Nat.  torn.  xxiv. 


OH.  XXVI.] 


NEW   VOLCANIC    ISLAND. 


435 


twenty-six  fathoms,  from  nine  to  eleven  feet  under  water ;  and  round 
this  rock  are  banks  of  black  volcanic  stones  and  loose  sand.  At  the 
distance  of  sixty  fathoms  from  this  central  mass,  the  depth  increased 
rapidly.  There  was  also  a  second  shoal  at  the  distance  of  450  feet 
S.  W.  of  the  great  reef,  with  fifteen  feet  water  over  it,  also  composed 
of  rock,  surrounded  by  deep  sea.  We  can  scarcely  doubt  that  the  rock 
in  the  middle  of  the  larger  reef  is  solid  lava,  which  rose  up  in  the  princi- 
pal crater,  and  that  the  second  shoal  marks  the  site  of  the  submarine 
eruption  observed  in  August,  1831,  to  the  S.  W.  of  the  island. 

From  the  whole  of  the  facts  above  detailed,  it  appears  that  a  hill 
eight  hundred  feet  or  more  in  height  was  formed  by  a  submarine  vol- 
canic vent,  of  which  the  upper  part  (only  about  two  hundred  feet  high) 
emerged  above  the  waters,  so  as  to  form  an  island.  This  cone  must 
have  been  equal  in  size  to  one  of  the  largest  of  the  lateral  volcanoes  on 
the  flanks  of  Etna,  and  about  half  the  height  of  the  mountain  Jorullo 
in  Mexico,  which  was  formed  in  the  course  of  nine  months,  in  1759.  In 
the  centre  of  the  new  volcano  a  large  cavity  was  kept  open  by  gaseous 
discharges,  which  threw  out  scoriae ;  and  fluid  lava  probably  rose  up 
in  this  cavity.  It  is  not  uncommon  for  small  subsidiary  craters  to  open 
near  the  summit  of  a  cone,  and  one  of  these  may  have  been  formed  in 
the  case  of  Graham  Island ;  a  vent,  perhaps,  connected  with  the  main 
channel  of  discharge  which  gave  passage  in  that  direction  to  elastic 
fluids,  scoriae,  and  melted  lava.  It  does  not  appear  that,  either  from 
this  duct,  or  from  the  principal  vent,  there  was  any  overflowing  of  lava ; 
but  melted  rock  may  have  flowed  from  the  flanks  or  base  of  the  cone 
(a  common  occurrence  on  land),  and  may  have  spread  in  a  broad  sheet 
over  the  bottom  of  the  aea. 

The  dotted  lines  in  the  annexed  figure  are  an  imaginary  restoration 
of  the  upper  part  of  the  cone,  now  removed  by  the  waves  :  the  strong 
lines  represent  the  part  of  the  volcano  which  is  still  under  water:  in 
the  centre  is  a  great  column,  or  dike,  of  solid  lava,  two  hundred  feet  in 
diameter,  supposed  to  fill  the  space  by  which  the  gaseous  fluids  rose ; 
and  on  each  side  of  the  dike  is  a  stratified  mass  of  scoriae  and  fragmen- 

Fig.  62. 


Supposed  section  of  Graham  Island.    (C.  Maclaren.*) 

tary  lava.  The  solid  nucleus  of  the  reef,  where  the  black  rock  is  now 
found,  withstands  the  movements  of  the  sea;  while  the  surrounding 
loose  tuffs  are  cut  away  to  a  somewhat  lower  level.  In  this  manner  the 

*  Geol.  of  Fife  and  the  Lothians,  p.  41.     Edin.  1839. 


436  CANARY    ISLANDS.  [Cfl.  XXVI 

lava,  which  was  the  lowest  part  of  the  island,  or,  to  speak  more  cor- 
rectly, which  scarcely  ever  rose  above  the  level  of  the  sea  when  the 
island  existed,  has  now  become  the  highest  point  in  the  reef. 

No  appearances  observed,  either  during  the  eruption  or  since  the 
island  disappeared,  gave  the  least  support  to  the  opinion  promulgated 
by  some  writers,  that  part  of  the  ancient  bed  of  the  sea  had  been  lifted 
up  bodily. 

The  solid  products,  says  Dr.  John  Davy,  whether  they  consisted  of 
sand,  light  cinders,  or  vesicular  lava,  differed  more  in  form  than  in 
composition.  The  lava  contained  augite  ;  and  the  specific  gravity  was 
2*07  and  2*70.  When  the  light  spongy  cinder,  which  floated  on  the 
sea,  was  reduced  to  fine  powder  by  trituration,  and  the  greater  part  of 
the  entangled  air  got  rid  of,  it  was  found  to  be  of  the  specific  gravity 
2'64  ;  and  that  of  some  of  the  sand  which  fell  in'  the  eruption  was 
2'75  ;*  so  that  the  materials  equalled  ordinary  granites  in  weight  and 
solidity.  The  only  gas  evolved  in  any  considerable  quantity  was  car- 
bonic acid.f 

Submarine  eruptions  in  mid- Atlantic. — In  the  Nautical  Magazine  for 
1835,  p.  642,  and  for  1838,  p.  361,  and  in  the  Comptes  Rendus,  April, 
1838,  accounts  are  given  of  a  series  of  volcanic  phenomena,  earthquakes, 
troubled  water,  floating  scoriae  and  columns  of  smoke,  which  have  been 
observed  at  intervals  since  the  middle  of  the  last  century,  in  a  space  of 
open  sea  between  longitudes  20°  and  22°  west,  about  half  a  degree 
south  of  the  equator.  These  facts,  says  Mr.  Darwin,  seem  to  show, 
that  an  island  or  an  archipelago  is  in  process  of  formation  in  the  middle 
of  the  Atlantic  ;  a  line  joining  St.  Helena  and  Ascension  would,  if  pro- 
longed, intersect  this  slowly  nascent  focus  of  volcanic  action.];  Should 
land  be  eventually  formed  here,  it  will  not  be  the  first  that  has  been 
produced  by  igneous  action  in  this  ocean  since  it  was  inhabited  by  the 
existing  species  of  testacea.  At  Porto  Praya  in.  St.  Jago,  one  of  the 
Azores,  a  horizontal,  calcareous  stratum  occurs,  containing  shells  of 
recent  marine  species,  covered  by  a  great  sheet  of  basalt  eighty  feet 
thick. §  It  would  be  difficult  to  estimate  too  highly  the  commercial 
and  political  importance  which  a  group  of  islands  might  acquire,  if  in 
the  next  two  or  three  thousand  years  they  should  rise  in  mid-ocean 
between  St.  Helena  and  Ascension. 

CANARY    ISLANDS. 

Eruption  in  Lancerote,  1*730  to  1736. — The  effects  of  an  eruption 
which  happened  in  Lancerote,  one  of  the  Canary  Islands,  between  the 
years  1730  and  1736,  were  very  remarkable;  and  a  detailed  descrip- 
tion has  been  published  by  Von  Buch,  who  had  an  opportunity,  when 
he  visited  that  island  in  1815,  of  comparing  the  accounts  transmitted  to 
us  of  the  event,  with  the  present  state  and  geological  appearances  of  the 

*  Phil.  Trans.  1832,  p.  243.  ,      f  Ibid.  p.  249 

|  Darwin's  Volcanic  Islands,  p.  92.  §  Ibid.  p.  6. 


CH.  XXVI.  1         ERUPTION  >IN   LANCEEOTE,    1730 — 1736.  437 

country.*  On  the  1st  of  September,  1730,  the  earth  split  open  on  a 
sudden  two  leagues  from  Yaira.  In  one  night  a  considerable  hill  of 
ejected  matter  was  thrown  up ;  and,  a  few  days  later,  another  vent 
opened,  and  gave  out  a  lava-stream,  which  overran  Chinanfaya  and 
other  villages.  It  flowed  first  rapidly,  like  water,  but  became  after- 
wards heavy  and  slow,  like  honey.  On  the  7th  of  September  an  im- 
mense rock  was  protruded  from  the  bottom  of  the  lava  with  a  noise  like 
thunder,  and  the  stream  was  forced  to  change  its  course  from  N.  to 
N.  W.,  so  that  St.  Catalina  and  other  villages  were  overflowed. 

Whether  this  mass  was  protruded  by  an  earthquake,  or  was  a  mass 
of  ancient  lava,  blown  up  like  that  before  mentioned  in  1783  in  Iceland, 
is  not  explained. 

On  the  llth  of  September  more  lava  flowed  out,  and  covered  the 
village  of  Maso  entirely,  and  for  the  space  of  eight  days  precipitated 
itself  with  a  horrible  roar  into  the  sea.  Dead  fish  floated  on  the  waters 
in  indescribable  multitudes,  or  were  thrown  dying  on  the  shore.  After 
a  brief  interval  of  repose,  three  new  openings  broke  forth  immediately 
from  the  site  of  the  consumed  St.  Catalina,  and  sent  out  an  enormous 
quantity  of  lapilli,  sand,  and  ashes.  On  the  28th  of  October  the  cattle 
throughout  the  whole  country  dropped  lifeless  to  the  ground,  suffocated 
by  putrid  vapors,  which  condensed  and  fell  down  in  drops.  On  the 
1st  of  December  a  lava-stream  reached  the  sea,  and  formed  an  island, 
round  which  dead  fish  were  strewed. 

Number  of  cones  thrown  up. — It  is  unnecessary  here  to  give  the 
details  of  the  overwhelming  of  other  places  by  fiery  torrents,  or  of  a 
storm  which  was  equally  new  and  terrifying  to  the  inhabitants,  as  they 
had  never  known  one  in  their  country  before.  On  the  10th  of  January, 
1731,  a  high  hill  was  thrown  up,  which,  on  the  same  day,  precipitated 
itself  back  again  into  its  own  crater ;  fiery  brooks  of  lava  flowed  from  it 
to  the  sea.  On  the  3d  of  February  a  new  cone  arose.  Others  were 
thrown  up  in  March,  and  poured  forth  lava-streams.  Numerous  other 
volcanic  cones  were  subsequently  formed  in  succession,  till  at  last  their 
number  amounted  to  about  thirty.  In  June,  1731,  during  a  renewal  of 
the  eruptions,  all  the  banks  and  shores  in  the  western  part  of  the  island 
were  covered  with  dying  fish,  of  different  species,  some  of  which  had 
never  before  been  seen.  Smoke  and  flame  arose  from  the  sea,  with 
loud  detonations.  These  dreadful  commotions  lasted  without  interrup- 
tion for  Jive  successive  years,  so  that  a  great  emigration  of  the  inhabitants 
became  necessary. 

Their  linear  direction. — As  to  the  height  of  the  new  cones,  Von  Buch 
was  assured  that  the  formerly  great  and  flourishing  St.  Catalina  lay 
buried  under  hills  400  feet  in  height ;  and  he  observes  that  the  most 
elevated  cone  of  the  series  rose  600  feet  above  its  base,  and  1378  feet 
above  the  sea,  and  that  several  others  were  nearly  as  high.  The  new 

*  This  account  was  principally  derived  by  Von  Buch  from  the  MS.  of  Don 
Andrea  Lorenzo  Curbeto,  curate  of  Yaira,  the  point  where  the  eruption  began. 
— Ueber  einen  vulcanischen  Ausbruch  auf  der  Insel  Lanzerote. 


4:38  ANCIENT   AND   MODERN   LAVAS.  [Ca  XXVI. 

vents  were  all  arranged  in  one  line,  about  two  geographical  miles  long, 
and  in  a  direction  nearly  east  and  west.  If  we  admit  the  probability  of 
Von  Buch's  conjecture,  that  these  vents  opened  along  the  line  of  a  cleft, 
it  seems  necessary  to  suppose  that  this  subterranean  fissure  was  only 
prolonged  upwards  to  the  surface  by  degrees,  and  that  the  rent  was 
narrow  at  first,  as  is  usually  the  case  with  fissures  caused  by  earth- 
quakes. Lava  and  elastic  fluids  might  escape  from  some  point  on  the 
rent  where  there  was  least  resistance,  till,  the  first  aperture  becoming 
obstructed  by  ejections  and  the  consolidation  of  lava,  other  orifices  burst 
open  in  succession  along  the  line  of  the  original  fissure.  Von  Buch 
found  that  each  crater  was  lowest  on  that  side  on  which  lava  had 
issued  ;  but  some  craters  were  not  breached,  and  were  without  any  lava 
streams.  In  one  of  these  were  open  fissures,  out  of  which  hot  vapors 
rose,  which  in  1815  raised  the  thermometer  to  145°  Fahrenheit,  and 
was  probably  at  the  boiling  point  lower  down.  The  exhalations 
seemed  to  consist  of  aqueous  vapor  ;  yet  they  could  not  be  pure  steam, 
for  the  crevices  were  incrusted  on  either  side  by  siliceous  sinter  (an 
opal-like  hydrate  of  silica  of  a  white  color),  which  extended  almost  to 
the  middle.  This  important  fact  attests  the  length  of  time  during 
which  chemical  processes  continue  after  eruptions,  and  how  open  fissures 
may  be  filled  up  laterally  by  mineral  matter,  sublimed  from  volcanic 
exhalations.  The  lavas  of  this  eruption  covered  nearly  a  third  of  the 
whole  island,  often  forming  on  slightly  inclined  planes  great  horizontal 
sheets  several  square  leagues  in  area,  resembling  very  much  the  basaltic 
platforms  of  Auvergne. 

Pretended  distinction  between  ancient  and  modern  lavas. — One  of  the 
new  lavas  was  observed  to  contain  masses  of  olivine  of  an  olive-green 
color,  resembling  those  which  occur  in  one  of  the  lavas  of  the  Vivarais. 
Von  Buch  supposes  the  great  crystals  of  olivine  to  have  been  derived 
from  a  previously  existing  basalt  melted  up  by  the  new  volcanoes ;  but 
we  have  scarcely  sufficient  data  to  bear  out  such  a  conjecture.  The 
older  rocks  of  the  island  consist,  in  a  great  measure,  of  that  kind 
of  basaltic  lava  called  dolerite,  sometimes  columnar,  and  partly  of  com- 
mon basalt  and  amygdaloid.  Some  recent  lavas  assumed,  on  entering 
the  sea,  a  prismatic  form,  and  so  much  resembled  the  older  lavas  of 
the  Canaries,  that  the  only  geological  distinction  which  Von  Buch 
appears  to  have  been  able  to  draw  between  them  was,  that  they  did 
not  alternate  with  conglomerates,  like  the  ancient  basalts.  Some 
modern  writers  have  endeavored  to  discover,  in  the  abundance  of  these 
conglomerates,  a  proof  of  the  dissimilarity  of  the  volcanic  action  in 
ancient  and  modern  times  ;  but  this  character  is  more  probably  attribu- 
table to  the  difference  between  submarine  operations  and  those  on  the 
land.  All  the  blocks  and  imperfectly  rounded  fragments  of  lava,  trans- 
ported during  the  intervals  of  eruption,  by  rivers  and  torrents,  into  the 
adjoining  sea,  or  torn  by  the  continued  action  of  the  waves  from  cliffs 
which  are  undermined,  must  accumulate  in  stratified  breccias  and  con- 
glomerates, and  be  covered  again  and  again  by  other  lavas.  This  is 


On.  XXVL]  TENERIFFE.  4:39 

now  taking  place  on  the  shores  of  Sicily,  between  Catania  and  Trezza, 
where  the  sea  breaks  down  and  covers  the  shore  with  blocks  and  peb- 
bles of  the  modern  lavas  of  Etna ;  and  on  parts  of  the  coast  of  Ischia, 
where  numerous  currents  of  trachyte  are  in  like  manner  undermined  in 
lofty  precipices.  So  often,  then,  as  an  island  is  raised  in  a  volcanic 
archipelago  by  earthquakes  from  the  deep,  the  fundamental  and  (rela- 
tively to  all  above)  the  oldest  lava  will  often  be  distinguishable  from 
those  formed  by  subsequent  eruptions  on  dry  land,  by  their  alternation 
with  beds  of  sandstone  and  fragmentary  rocks. 

The  supposed  want  of  identity,  then,  between  the  volcanic  phenomena 
of  different  epochs  resolves  itself  partly  at  least  into  the  marked  differ- 
ence between  the  operations  simultaneously  in  progress,  above  and  below 
the  waters.  Such,  indeed,  is  the  source,  as  was  before  stated  in  the  First 
Book  (Chap.  V.),  of  many  of  our  strongest  theoretical  prejudices  in  ge- 
ology. No  sooner  do  we  study  and  endeavor  to  explain  submarine  ap- 
pearances, than  we  feel,  to  use  a  common  expression,  out  of  our  element ; 
and  unwilling  to  concede  that  our  extreme  ignorance  of  processes  now 
continually  going  on  can  be  the  cause  of  our  perplexity,  we  take  refuge 
in  a  "  pre-existent  order  of  nature." 

Recent  formation  of  oolitic  travertin  in  Lancer ote. — Throughout  a  con- 
siderable part  of  Lancerote,  the  old  lavas  are  covered  by  a  thin  stratum 
of  limestone,  from  an  inch  to  two  feet  in  thickness.  It  is  of  a  hard  sta- 
lactitic  nature,  sometimes  oolitic,  like  the  Jura  limestone,  and  contains  frag- 
ments of  lava  and  terrestrial  shells,  chiefly  helices  and  spiral  bulimi.  It 
sometimes  rises  to  the  height  of  800  feet  above  the  level  of  the  sea.  Von 
Buch  imagines  that  this  remarkable  superstratum  has  been  produced  by 
the  furious  northwest  storms,  which  in  winter  drive  the  spray  of  the  sea 
in  clouds  over  the  whole  island ;  from  whence  calcareous  particles  may 
be  deposited  stalactitically.  Mr.  Darwin  informs  me  that  he  found  a 
limestone  in  St.  Helena,  the  harder  parts  of  which  correspond  precisely  to 
the  stone  of  Lancerote.  He  attributes  the  origin  of  this  rock  in  St.  Helena 
not  to  the  spray  of  the  sea,  but  to  drifting  by  violent  winds  of  the  finer 
particles  of  shells  from  the  sea-beach.  Some  parts  of  this  drift  are  sub- 
sequently dissolved  by  atmospheric  moisture,  and  redeposited,  so  as  to 
convert  calcareous  sand  into  oolite. 

Recent  eruption  in  Lancerote. — From  the  year  1736  to  1815,  when  Von 
Buch  visited  Lancerote,  there  had  been  no  eruption ;  but,  in  August,  1824, 
a  crater  opened  near  the  port  of  Rescif,  and  formed  by  its  ejections,  in 
the  space  of  twenty-four  hours,  a  considerable  hill.  Violent  earthquakes 
preceded  and  accompanied  this  eruption.* 

Teneri/e. — The  Peak  of  Teneriffe  is  about  12,000  feet  high,  and  stands, 
says  Von  Buch,  like  a  tower  encircled  by  its  fosse  and  bastion.  The  bas- 
tion consists,  like  the  semicircular  escarpment  of  Somma  turned  towards 
Vesuvius,  of  precipitous  cliffs,  composed  of  trachyte,  basalt,  coarse  con- 
glomerates, and  tuffs,  traversed  by  volcanic  dikes,  mostly  vertical,  and  of 

*  Ferussac,  Bulletiu  des  Sci.  Nat.  tome  v.  p.  45  :  1825. 


440  TENEEIFFE.  [On.  XXVI. 

basalt.  These  cliffs  vary  in  height  from  1000  to  1800  feet,  and  are  sup- 
posed by  Von  Buch  to  have  been  heaved  up  into  their  present  position 
by  a  force  exerted  from  below,  in  accordance  with  the  theory  proposed 
by  the  same  author  for  the  origin  of  the  cones  of  Vesuvius  and  Etna. 
According  to  the  observations  of  M.  Deville  in  1839*,  the  trachytes  are 
often  granitoid  in  their  aspect,  and  contain  instead  of  glassy  felspar  the 
allied  mineral  called  oligoclase,  which  had  been  previously  considered  as 
characteristic  of  more  ancient  igneous  rocks.  The  same  traveller  sup- 
poses, although  he  found  no  limestone  or  trace  of  fossils  in  any  of  the 
rocks  of  Teneriffe,  that  the  alternating  trachytes  and  trachytic  conglom- 
erates originated  beneath  the  sea.  If  this  opinion  be  correct,  and  it  is 
at  least  very  probable,  geologists  may  still  speculate  on  two  modes  in 
which  the  mass  of  the  island  acquired  its  present  form  and  elevation 
above  the  sea.  1st,  The  advocates  of  Von  Buch's  crater- of- elevation 
hypothesis  may  imagine  that  a  succession  of  horizontally  superimposed 
beds  were  upheaved  by  a  sudden  movement,  and  tilted  so  as  to  dip  in 
all  directions  outwards  from  the  centre  of  a  new  dome-shaped  eminence, 
in  the  middle  of  which  a  large  opening  or  bowl-shaped  cavity  was  pro- 
duced. 2dly,  Or  according  to  the  theory  which  to  me  appears  prefer- 
able, a  submarine  hill  in  the  form  of  a  flattened  dome  may  have  gradu- 
ally accumulated,  partly  below  the  waters  and  partly  above  by  the  con- 
tinued outpourings  of  sheets  of  lava  and  the  ejection  of  ashes  from  a 
central  orifice.  In  this  case  the  dikes  would  represent  the  fissures,  which 
were  filled  during  successive  eruptions,  and  the  original  inclination  of  the 
beds  may  have  been  increased  by  the  distension  and  upheaval  of  the  mass 
during  reiterated  convulsions,  acting  most  forcibly  at  or  near  the  channel 
of  discharge,  which  would  become  partially  sealed  up  with  lava  from  time 
to  time,  and  then  be  burst  open  again  during  eruptions.  At  length  the 
whole-  island  may  have  been  raised  bodily  out  of  the  sea  by  a  gradual 
upward  movement. 

Whatever  theory  we  adopt,  we  must  always  explain  the  abrupt  termi- 
nation of  the  dikes  and  layers  of  trachyte  and  basalt  in  the  steep  walls  of 
the  escarpments  surrounding  the  great  crater  by  supposing  the  removal 
of  part  of  the  materials  once  prolonged  farther  inward  towards  the  centre. 
If,  according  to  the  elevation- crater  hypothesis,  a  series  of  sheets  of  lava 
and  ashes  originally  spread  over  a  level  and  even  surface  have  been  vio- 
lently broken  and  uplifted,  why  do  not  the  opposite  walls  of  the  chasm 
correspond  in  such  a  manner  as  to  imply  by  their  present  outline  that 
they  were  formerly  united  ?  It  is  evident  that  the  precipices  on  opposite 
sides  of  the  crateriform  hollow  would  not  fit  if  brought  together,  there 
being  no  projecting  masses  in-  one  wall  to  enter  into  indentations  in  the 
other,  as  would  happen  with  the  sides  of  many  mineral  veins,  trap-dikes, 
and  faults,  could  we  extract  the  intrusive  matter  now  separating  them, 
and  reunite  the  rocks  which  have  been  fractured  and  disjoined. 

The  highest  crater  of  the  peak  has  merely  disengaged  sulphureous 

*  Comptes  Rendus  Acad.  Sci.     Paris,  Juin,  1846. 


CH.  XXVI.]  SANTOEIN.  441 

vapors  ever  since  it  has  been  known  to  Europeans ;  but  an  eruption 
happened  in  June,  1798,  not  far  from  the  summit,  and  others  are  re- 
corded, which  poured  out  streams  of  lava  from  great  heights,  besides 
man}'  which  have  broken  out  nearer  the  level  of  the  sea.  All  these,  how- 
ever, seem  to  be  dependent  on  one  great  centre  of  eruption,  or  on  that 
open  channel  communicating  between  the  interior  of  the  earth  and  the 
atmosphere,  which  terminates  in  the  highest  crater  of  the  peak. 

We  may  consider  Teneriffe,  then,  as  having  been  from  a  remote  period 
the  principal  and  habitual  vent  of  the  volcanic  archipelago  of  the 
Canaries.  The  discharges  which  have  taken  place  in  the  contiguous 
isles  of  Palma,  Lancerote,  and  the  rest,  may  be  of  a  subsidiary  kind,  and 
have  probably  been  most  frequent  and  violent  when  the  greater  crater 
has  been  partially  sealed  up,  just  as  the  violent  eruptions  of  Ischia  or 
that  of  Monte  Nuovo  coincided  with  the  dormant  state  of  Vesuvius. 

SANTORIN. 

The  Gulf  of  Santorin,  in  the  Grecian  Archipelago,  has  been  for  two 
thousand  years  a  ecene  of  active  volcanic  operations.  The  largest  of  the 
three  outer  islands  of  the  group  (to  which  the  general  name  of  Santorin 
is  given)  is  called  Thera  (or  sometimes  Santorin),  and  forms  more  than 
two-thirds  of  the  circuit  of  the  gulf  (see  Map,  fig.  63,  p.  442).  The 
length  of  the  exterior  coast-line  of  this  and  the  other  two  islands  named 
Therasia  and  Aspronisi,  taken  together,  amounts  to  about  thirty  miles, 
and  that  of  the  inner  coast-line  of  the  same  islands  to  about  eighteen 
miles.  In  the  middle  of  the  gulf  are  three  other  islands,  called  the 
Little,  the  New,  and  the  Old  "  Kaimenis,"  or  "  Burnt  Islands."  The 
accompanying  map  has  been  reduced  from  a  recent  survey  executed  in 
1848  by  Captain  Graves,  R.  N.,  and  shortly  to  be  published  by  the 
Admiralty. 

Pliny  informs  us  that  the  year  186,  B.  c.,  gave  birth  to  the  Old  Kai- 
meni,  also  called  Hiera,  or  the  "Sacred  Isle,"  and  in  the  year  19  of  our 
era  "  Thia"  (the  Divine)  made  its  appearance  above  water,  and  was  soon 
joined  by  subsequent  eruptions  to  the  older  island,  from  which  it  was 
only  250  paces  distant.  The  Old  Kaimeni  also  increased  successively  in 
size  in  726  and  in  1427.  A  century  and  a  half  later,  in  1573,  another 
eruption  produced  the  cone  and  crater  called  Micra-Kaimeni,  or  "  the 
Small  Burnt  Island."  The  next  great  event  which  we  find  recorded 
occurred  in  1650,  when  a  submarine  outbreak  violently  agitated  the  sea, 
at  a  point  three  and  a  half  miles  to  the  N.  E.  of  Thera,  and  which  gave 
rise  to  a  shoal  (see  A  in  the  map)  carefully  examined  during  the  late 
survey  in  1848  by  Captain  Graves,  and  found  to  have  ten  fathoms  water 
over  it,  the  sea  deepening  around  it  in  all  directions.  This  eruption 
lasted  three  months,  covering  the  sea  with  floating  pumice.  At  the  same 
time  an  earthquake  destroyed  many  houses  in  Thera,  while  the  sea  broke 
upon  the  coast  and  overthrew  two  churches,  exposing  to  view  two  vil- 
lages, one  on  each  side  of  the  mountain  of  St.  Stephen,  both  of  which 


442 


SANTORIN, 

Fig.  68. 


[On.  XXVI. 


Map  of  Santorin  in  the  Grecian  Archipelago,  from  a  Survey  in  1848,  by  Captain  Graves,  E.  N. 
7%e  soundings  are  given  in  fathoms. 

A,  Shoal  formed  by  submarine  volcanic  eruption  in  1650. 

B,  Northern  entrance.  C,  Mansell's  Eock. 
D,  Mount  St  Elias,  1887  feet  high. 


Sea          Aspronisi 


Fig.  64. 
The  three  Kaimenis 


Thera 


Section  of  Santorin,  in  a  N.  E.  and  S.  W.  direction,  from  Thera  through  the  Kaimenis  to  Aspronisi. 


Aspronisi 


Sea 


Fig.  65. 

The  three  Kaimenis 
Old  New     Little 


Th-ra 


Part  of  the  section,  fig.  64,  enlarged. 


OH.  XXVI]  SANTORIN.  443 

must  have  been  overwhelmed  by  showers  of  volcanic  matter  during  some 
previous  eruptions  of  unknown  date.*  The  accompanying  evolution  of 
sulphur  and  hydrogen  issuing  from  the  sea  killed  more  than  fifty  persons, 
and  above  1000  domestic  animals.  A  wave,  also,  50  feet  high,  broke 
upon  the  rocks  of  the  Isle  of  Nia,  about  four  leagues  distant,  and  advanced 
450  yards  into  the  interior  of  the  Island  of  Sikino.  Lastly,  in  1707  and 
1709,  Nea-Kaimeni,  or  the  New  Burnt  Island,  was  formed  between  the 
two  others,  Palaia  and  Micra,  the  Old  and  Little  isles.  This  isle  was 
composed  originally  of  two  distinct  parts ;  the  first  which  rose  was  called 
the  White  Island,  composed  of  a  mass  of  pumice,  extremely  porous. 
Goree,  the  Jesuit,  who  was  then  in  Santorin,  says  that  the  rock  "  cut 
like  bread,"  and  that,  when  the  inhabitants  landed  on  it,  they  found  a 
multitude  of  full-grown  fresh  oysters  adhering  to  it,  which  they  ate.f 
This  mass  was  afterwards  covered,  in  great  part,  by  the  matter  ejected 
from  the  crater  of  a  twin-island  formed  simultaneously,  and  called  Black 
Island,  consisting  of  brown  trachyte.  The  trachytic  lava  which  rose  on 
this  spot  appears  to  have  been  a  long  time  in  an  intumescent  state,  for 
the  New  Kaimeni  was  sometimes  lowered  on  one  side  while  it  gained 
height  on  the  other,  and  rocks  rose  up  in  the  sea  at  different  distances 
from  the  shore  and  then  disappeared  again.  The  eruption  was  renewed 
at  intervals  during  the  years  1711  and  1712,  and  at  length  a  cone  was 
piled  up  to  the  height  of  330  feet  above  the  level  of  the  sea,  its  exterior 
slope  forming  an  angle  of  33°  with  the  horizon,  and  the  crater  on  its 
summit  being  80  yards  in  diameter.  In  addition  to  the  two  points  of 
subaerial  eruption  on  the  New  and  Little  Kaimenis,  two  other  cones, 
indicating  the  sites  of  submarine  outbursts  of  unknown  date,  were  dis- 
covered under  water  near  the  Kaimenis  during  the  late  survey. 

In  regard  to  the  "  White  Island,"  which  was  described  and  visited  by 
Goree  in  1707,  we  are  indebted  to  Mr.  Edward  Forbes  for  having,  in 
1842,  carefully  investigated  the  layer  of  pumiceous  ash  of  which  it  is 
constituted.  He  obtained  from  it  many  shells  of  marine  genera,  Pectun- 
culus,  Area,  Cardita,  Trochus,  and  others,  both  univalve  and  bivalve,  all 
of  recent  Mediterranean  species.  They  were  in  a  fine  state  of  preserva- 
tion, the  bivalves  with  the  epidermis  remaining,  and  valves  closed, 
showing  that  they  had  been  suddenly  destroyed.  Mr.  Forbes,  from  his 
study  of  the  habits  of  the  mollusca  living  at  different  depths  in  the 
Mediterranean,  was  able  to  decide  that  such  an  assemblage  of  species 
could  not  have  lived  at  a  less  depth  than  220  feet,  so  that  a  bodily  up- 
heaval of  the  mass  to  that  amount  must  have  taken  place  in  order  to 
bring  up  this  bed  of  ashes  and  shells  to  the  level  of  the  sea,  and  they 
now  rise  five  or  six  feet  above  that  level.J 

We  may  compare  this  partial  elevation  of  solid  matter  to  the  rise  of  a 
hardened  crust  of  scorise,  such  as  is  usually  formed  on  the  surface  of 
lava-currents,  even  while  they  are  in  motion,  and  which,  although  stony 
and  capable  of  supporting  heavy  weights,  may  be  upraised  without 

*  Virlet,  Bull,  de  la  Soc.  Geol.  de  France,  torn.  iii.  p.  103. 

f  Phil.  Trans.  No.  332.  \  E.  Forbes,  Brit.  Association,  Report  for  1843 


444  SANTOEIN.  [On.  XXVI 

bursting  by  the  intumescence  of  the  melted  matter  below.  That  the 
upheaval  was  merely  local  is  proved  by  the  fact  that  the  neighboring 
Kaimenis  did  not  participate  in  the  movement,  still  less  the  three  more 
distant  or  outer  islands  before  mentioned.  The  history,  therefore,  of 
the  Kaimenis  shows  that  they  have  been  the  result  of  intermittent  action, 
and  it  lends  no  support  to  the  hypothesis  of  the  sudden  distension  of 
horizontal  beds  blown  up  like  a  bladder  by  a  single  paroxysmal  effort  of 
expansive  gases. 

It  will  be  seen  by  the  accompanying  map  and  sections,  that  the  Kai- 
menis are  arranged  in  a  linear  direction,  running  N.  E.  and  S.  W.,  in  a 
manner  different  from  that  represented  in  the  older  charts.  In  their 
longest  diameter  they  form  at  their  base  a  ridge  nearly  bisecting  the  gulf 
or  crater  (see  sections,  figs.  64,  65). 

On  considering  these  facts  we  are  naturally  led  to  compare  the  smaller 
and  newer  islands  in  the  centre  of  the  gulf  to  the  modern  cone  of  Vesu- 
vius, surrounded  by  the  older  semicircular  escarpment  of  Somma,  or  to 
liken  them  to  the  Peak  of  Teneriffe  before  described,  as  surrounded  by 
its  "  fosse  and  bastion."  This  idea  will  appear  to  be  still  more  fully 
confirmed  when  we  study  the  soundings  taken  during  the  late  hydro- 
graphical  survey.  Thera,  which  constitutes  alone  more  than  two-thirds 
of  the  outer  circuit,  presents  everywhere  towards  the  gulf,  high  and 
steep  precipices  composed  of  rocks  of  volcanic  origin.  In  all  places 
near  the  base  of  its  cliffs,  a  depth  of  from  800  to  1000  feet  of  water  was 
found,  and  Lieut.  Leycester  informs  us*  that  if  the  gulf,  which  is  six 
miles  in  diameter,  could  be  drained,  a  bowl-shaped  cavity  would  appear 
with  walls  2449  feet  high  in  some  places,  and  even  on  the  southwest 
side,  where  it  is  lowest,  nowhere  less  than  1200  feet  high  ;  while  the 
Kaimenis  would  be  seen  to  form  in  the  centre  a  huge  mountain  five  and 
a  half  miles  in  circumference  at  its  base,  with  three  principal  summits 
(the  Old,  the  New,  and  the  Little  Burnt  Islands)  rising  severally  to  the 
heights  of  1251,  1629,  and  1158  feet  above  the  bottom  of  the  abyss. 
The  rim  of  the  great  caldron  thus  exposed  would  be  observed  to  be 
in  all  parts  perfect  and  unbroken,  except  at  one  point  where  there  is  a 
deep  and  long  chasm  or  channel,  known  by  mariners  as  "  the  northern 
entrance"  (B,  fig.  63)  between  Thera  and  Therasia,  and  called  by  Lieut. 
Leycester  "the  door  into  the  crater."  It  is  no  less  than  11 70  feet 
deep,  and  constitutes,  us  will  appear  by  the  soundings  (see  map),  a  re- 
markable feature  in  the  bed  of  the  sea.  There  is  no  corresponding 
channel  passing  out  from  the  gulf  into  the  Mediterranean  at  any  other 
point  in  the  circuit  between  the  outer  islands,  the  greatest  depth  there 
ranging  from  7  to  66  feet.  * 

We  may  conceive,  therefore,  if  at  some  former  time  the  whole  mass 
of  Santorin  stood  at  a  higher  level  by  1200  feet,  that  this  single  ravine 
or  narrow  valley  now  forming  "  the  northern  entrance,"  was  the  passage 
by  which  the  sea  entered  a  circular  bay  and  swept  out  in  the  form  of 

*  See  a  paper  read  to  the  Geographical  Society  in  1849. 


Cir.  XXVI.]  SANTORIN.  445 

mud  and  pebbles,  the  materials  derived  by  denudation  from  wasting 
cliffs.  In  this  manner  the  original  crater  may  have  been  slowly  widened 
and  deepened,  after  which  the  whole  archipelago  may  have  been  partially 
submerged  to  its  present  depth. 

That  such  oscillations  of  level  may  in  the  course  of  ages  have  taken 
place,  will  be  the  more  readily  admitted  when  we  state  that  part  of 
Thera  has  actually  sunk  down  in  modern  times,  as,  for  example,  during 
the  great  earthquake  before  alluded  to,  which  happened  in  1650.  The 
subsidence  alluded  to  is  proved  not  only  by  tradition,  but  by  the  fact 
that  a  road  which  formerly  led  between  two  places  on  the  east  coast  of 
Thera  is  now  twelve  fathoms  under  water. 

MM.  Boblaye  and  Virlet  mention,*  that  the  waves  are  constantly  un- 
dermining and  encroaching  on  the  cliffs  of  Therasia  and  Aspronisi,  and 
shoals  or  submarine  ledges  were  found,  during  the  late  survey,  to  occur 
round  a  great  part  of  these  islands,  attesting  the  recent  progress  of 
denudation.  M.  Virlet  also  remarks,  in  regard  to  the  separation  of  the 
three  islands  forming  the  walls  of  the  crater,  that  the  channels  be- 
tween them  are  all  to  the  W.  and  N.  W.,  the  quarter  most  exposed  to 
the  waves  and  currents. 

Mr.  Darwin,  in  his  work  on  volcanic  islands,  has  shown  that  in  the 
Mauritius  and  in  Santiago,  there  is  an  external  circle  of  basaltic  rocks 
of  vast  diameter,  in  the  interior  of  which  more  modern  eruptions  have 
taken  place,  the  older  rocks  dipping  away  from  the  central  space  in 
every  direction,  as  in  the  outer  islands  of  Santorin.  He  refers  the  nu- 
merous breaches,  some  of  them  very  wide  in  the  external  ramparts  of 
those  islands,  to  the  denuding  action  of  the  sea.  Every  geologist,  there-' 
fore,  will  be  prepared  to  call  in  the  aid  of  the  same  powerful  cause,  to 
account  for  the  removal  of  a  large  part  of  the  rocks  which  must  once 
have,  occupied  the  interior  space,  in  the  same  manner  as  they  attribute 
the  abstraction  of  matter  from  elliptical  "  valleys  of  elevation,"  such  as 
those  of  Woolhope  and  the  Wealden  in  England,  to  the  waves  and  cur- 
rents of  the  sea. 

Thera,  Therasia,  and  Aspronisi  are  all  composed  of  volcanic  matter, 
except  the  southern  part  of  Thera,  where  Mount  St.  Elias  rises  to  three 
times  the  height  of  the  loftiest  of  the  igneous  rocks,  reaching  an  ele- 
vation of  1887  feet  above  the  sea.f  This  mountain  is  formed  of 
granular  limestone  and  argillaceous  schist,  and  must  have  been  origi- 
nally a  submarine  eminence  in  the  bed  of  the  Mediterranean,  before 
the  volcanic  cone,  one  side  of  the  base  of  which  now  abuts  against 
it,  was  foiyned.  The  inclination,  strike,  and  fractures  of  the  calcareous 
and  argillaceous  strata  of  St.  Elias  have  no  relation  to  the  great  cone, 
but,  according  to  M.  Bory  St.  Vincent,  have  the  same  direction  as  those 
of  the  other  isles  of  the  Grecian  Archipelago,  namely,  from  N.  N.  W. 
to  S.  S.  E.  Each  of  the  three  islands,  Thera,  Therasia,  and  Aspronisi, 

*  Bull,  de  la  Soc.  Geol.  de  France,  tome  iii. 

f  Virlet,  Bull  de  la  Soc.  Geol.  de  France,  tome  iii.  p.  103. 


446  BARKEN   ISLAND.  [Cn.  XXVI. 

is  capped  by  an  enormous  mass  of  white  tufaceous  conglomerate,  from 
forty  to  fifty  feet  thick,  beneath  which  are  beds  of  trachytic  lava  and 
tuff,  having  a  gentle  inclination  of  only  3°  or  4°.  Each  bed  is  usually 
very  narrow  and  discontinuous,  the  successive  layers  being  moulded  or 
dove-tailed,  as  M.  Virlet  expresses  it,  into  the  inequalities  of  the  pre- 
viously existing  surface,  on  which  showers  of  cinders  or  streams  of 
melted  matter  have  been  poured.  Nothing,  therefore,  seems  more 
evident  than  that  we  have  in  Santorin  the  basal  remains  of  a  great 
ruined  cone,  or  flattened  dome  ;  and  the  absence  of  dikes  in  the  cliffs 
surrounding  the  gulf  would  indicate  that  the  eruptions  took  place  origi- 
nally, as  they  have  done  in  the  last  two  thousand  years,  not  near  the 
margin  but  in  the  centre  of  the  space  now  occupied  by  the  gulf.  The 
central  portions  of  the  dome  have  since  been  removed  by  engulfment, 
or  denudation,  or  by  both  these  causes. 

An  important  fact  is  adduced  by  M.  Yirlet,  to  show  that  the  gentle 
dip  of  the  lava-streams  in  the  three  outer  islands  towards  all  points  of 
the  compass,  away  from  the  centre  of  the  gulf,  has  not  been  due  to 
the  upheaval  of  horizontal  beds,  as  conjectured  by  Von  Buch,  who 
had  not  visited  Santorin.*  The  French  geologist  found  that  the  vesi- 
cles or  pores  of  the  trachytic  masses  were  lengthened  out  in  the  sev- 
eral directions  in  which  they  would  have  flowed  if  they  had  descended 
from  the  axis  of  a  cone  once  occupying  the  centre  of  the  crater.  For 
it  is  well  known  that  the  bubbles  of  confined  gas  in  a  fluid  in  mo- 
tion assume  an  oval  form,  and  the  direction  of  their  longer  axis  coincides 
always  with  that  of  the  stream. 

On  a  review,  therefore,  of  all  the  facts  now  brought  to  light  respect-' 
ing  Santorin,  I  attribute  the  moderate  slope  of  the  beds  in  Thera  and 
the  other  external  islands  to  their  having  originally  descended  the 
inclined  flanks  of  a  large  volcanic  cone,  the  principal  orifice  or  vents  of 
eruption  having  been  always  situated  where  they  are  now,  in  or  near 
the  centre  of  the  space  occupied  by  the  gulf  or  crater — in  other  words, 
where  the  outburst  of  the  Kaimenis  has  been  witnessed  in  historical 
times.  The  single  long  and  deep  opening  into  the  crater  is  a  feature 
common  to  all  those  remnants  of  ancient  volcanoes,  the  central  portions 
of  which  have  been  removed,  and  is  probably  connected  with  aqueous 
denudation.  This  denuding  process  has  been  the  work  of  ages  when 
the  sea  was  admitted  into  an  original  crater,  and  has  taken  place  during 
the  gradual  emergence  of  the  island  from  the  sea,  or  during  various 
oscillations  in  its  level. 

The  volcanic  island  of  St.  Paul  in  the  midst  of  the  Indian  Ocean,  lat. 
38°  44'  S.,  long.  77°  37'  E.,  surveyed  by  Capt.  Blackwood  in  1842, 
seems  to  exemplify  the  first  stage  in  the  formation  of  such  an  archipelago 
as  that  of  Santorin.  We  have  there  a  crater  one  mile  in  diameter,  sur- 
rounded by  steep  and  lofty  cliffs  on  every  side  save  one,  where  the  sea 
enters  by  a  single  passage  nearly  dry  at  low  water.  In  the  interior  of 

*  Poggendorf's  Annalen,  1836,  p.  183. 


CH.  XXVL] 


MUD   VOLCANOES. 


4:4:7 


the  small  circular 'bay  or  crater  there  is  a  depth  of  30  fathoms,  or  180 
feet.  The  surface  of  the  island  slopes  away  on  all  sides  from  the  crest 
of  the  rocks  encircling  the  crater.* 

Barren  Island. — There  is  great  analogy  between  the  structure  of 
Barren  Island  in  the  Bay  of  Bengal,  lat.  12°  15',  and  that  of  Santorin 


Fig.  66. 


Cone  and  crater  of  Barren  Island,  in  the  Bay  of  Bengal.    Height  of  the  central  cone  (according 
to  Capt.  Miller,  in  1834),  500  feet 

last  described.  When  seen  from  the  ocean,  this  island  presents,  on  al- 
most all  sides,  a  surface  of  bare  rocks,  rising,  with  a  moderate  acclivity, 
towards  the  interior  ;  but  at  one  point  there  is  a  cleft  by  which  we  can 
penetrate  into  the  centre,  and  there  discover  that  it  is  occupied  by  a 
great  circular  basin,  filled  by  the  waters  of  the  sea,  and  bordered  all 
around  by  steep  rocks,  in  the  midst  of  which  rises  a  volcanic  cone,  very 
frequently  in  eruption.  The  summit  of  this  cone  is  about  500  feet  in 
height,  corresponding  to  that  of  the  circular  border  which  incloses  the 
basin ;  so  that  it  can  be  seen  from  the  sea  only  through  the  ravine. 
It  is  most  probable  that  the  exterior  inclosure  of  Barren  Island  (c,  d, 
fig.  67)  is  nothing  more  than  the  remains  of  a  truncated  cone  c,  a,  b,  d, 


Sea 


Supposed  section  of  Barren  Island,  in  the  Bay  of  Bengal. 

a  great  portion  of  which  has  been  removed  by  engulfment,  explosion, 
or  denudation,  which  may  have  preceded  the  formation  of  the  new  in- 
terior cone  /,  e,  g.\ 

MUD    VOLCANOES. 

Iceland. — Mr.  R.  Bunsen,  in  his  account  of  the  pseudo- volcanic  phe- 
nomena of  Iceland,  describes  many  valleys  where  sulphurous  and 
aqueous  vapors  burst  forth  with  a  hissing  sound,  from  the  hot  soil 

*  See  Admiralty  Chart,  with  views  and  sections,  1842. 

f  For  height  of  cone  and  references,  see  Buist,  Volcanoes  of  India,  Trans.  Bom- 
bay Geol.  Soc.  vol.  x.  p.  143. 


448 


MUD   VOLCANOES. 


[Ca.  XXVL 


formed  of  volcanic  tuff.  In  such  spots  a  pool  of  boiling  water  is  seen, 
in  which  a  bluish-black  argillaceous  paste  rises  in  huge  bubbles.  These 
bubbles  on  bursting  throw  the  boiling  mud  to  a  height  of  fifteen  feet  and 
upwards,  accumulating  it  in  ledges  round  the  crater  or  basin  of  the  spring. 

Baku  on  the  Caspian. — The  formation  of  a  new  mud  volcano  was  wit- 
nessed on  the  27th  of  November,  1827,  at  Tokmali,  on  the  peninsula 
of  Abscheron,  east  of  Baku.  Flames  blazed  up  to  an  extraordinary 
height  for  a  space  of  three  hours,  and  continued  for  twenty  hours  to 
rise  about  three  feet  above  a  crater,  from  which  mud  was  ejected.  At 
another  point  in  the  same  district  where  flames  issued,  fragments  of 
rock  of  large  size  were  hurled  up  into  the  air,  and  scattered  around.* 

Sicily. — At  a  place  called  Macaluba,  near  Girgenti  in  Sicily,  are 
several  conical  mounds  from  ten  to  thirty  feet  in  height,  with  small 
craters  at  their  summits,  from  which  cold  water,  mixed  with  mud  and 
bitumen,  is  cast  out.  Bubbles  of  carbonic  acid  and  carburetted  hydro- 
gen gas  are  also  disengaged  from  these  springs,  and  at  certain  periods 
with  such  violence,  as  to  throw  the  mud  to  the  height  of  200  feet. 
These  "  air  volcanoes,"  as  they  are  sometimes  termed,  are  known  to 
have  been  in  the  same  state  of  activity  for  the  last  fifteen  centuries  ;  and 
Dr.  Daubeny  imagines  that  the  gasss  which  escape  may  be  generated 

Fig.  68. 


Mud  cones  and  craters  of  Hinglaj  near  Beila,  district  of  Lus,120  miles  northwest  of  inouth 
of  Indus.    From  original  drawing  by  Capt.  Eobertson.    (See  Map,  p.  460.) 

*  Humboldt's  Cosmos. 


CH.  XXVI.]  COMPOSITION    OF    VOLCANIC    PRODUCTS.  449 

by  the  slow  combustion  of  beds  of  sulphur,  which  is  actually  in  pro- 
gress in  the  blue  clay,  out  of  which  the  springs  rise.*  But  as  the  gases 
are  similar  to  those  disengaged  in  volcanic  eruptions,  and  as  they  have 
continued  to  stream  out  for  so  long  a  period,  they  may  perhaps  be 
derived  from  a  more  deep-seated  source. 

Bella  in  India. — In  the  district  of  Luss  or  Lus,  south  of  Beila,  about 
120  miles  1ST.  W.  of  Cutch  and  the  mouths  of  the  Indus  (see  Map,  fig. 
71,  p.  460),  numerous  mud  volcanoes  are  scattered  over  an  area  of  prob- 
ably not  less  than  1000  square  miles.  Some  of  these  have  been  well 
described  by  Captain  Hart,  and  subsequently  by  Captain  Robertson,  who 
has  paid  a  visit  to  that  region,  and  made  sketches  of  them,  which  he  has 
kindly  placed  at  my  disposal.  From  one  of  these  the  annexed  view  has 
been  selected.  These  conical  hills  occur  to  the  westward  of  the  Hara 
mountains  and  the  river  Hubb.  (See  Map,  p.  460.)  One  of  the  cones 
is  400  feet  high,  composed  of  light-colored  earth,  and  having  at  its  sum- 
mit a  crater  thirty  yards  in  diameter.  The  liquid  mud  which  fills  the 
crater  is  continually  disturbed  by  air-bubbles,  and  here  and  there  is  cast 
up  in  small  jets.f 

Mineral  composition  of  volcanic  products. — The  mineral  called  felspar 
forms  in  general  more  than  half  of  the  mass  of  modern  lavas.  When  it 
is  in  great  excess,  lavas  are  called  trachytic :  they  consist  generally  of  a 
base  of  compact  felspar,  in  which  crystals  of  glassy  felspar  are  dissemi- 
nated^ When  augite  (or  pyroxene)  predominates,  lavas  are  termed  ba- 
saltic. They  contain  about  50  per  cent,  of  silica,  or  much  less  than  the 
trachytes,  in  which  there  is  usually  about  75  per  cent,  of  that  mineral. 
They  also  contain  about  11  per  cent,  of  protoxide  of  iron,  and  as  much 
of  lime,  both  of  which  are  wanting,  or  only  in  insignificant  quantities  in 
the  trachytic  rocks.  J  But  lavas  occur  of  an  intermediate  composition 
between  the  trachytic  and  basaltic,  which  from  their  color  have  been 
called  graystones.  The  abundance  of  quartz,  forming  distinct  crystals  or 
concretions,  characterizes  the  granitic  and  other  ancient  rocks,  now  gen- 
erally considered  by  geologists  as  of  igneous  origin  ;  whereas  that  min- 
eral is  rarely  exhibited  in  a  separate  form  in  recent  lavas,  although  silica 
enters  so  largely  into  their  composition.  Hornblende,  so  common  in  hy- 
pbgene  rocks,  or  those  commonly  called  "  primary,"  is  rare  in  modern 
lava ;  nor  does  it  enter  largely  into  rocks  of  any  age  in  which  augite 
abounds.  It  should,  however,  be  stated,  that  the  experiments  of  Mr. 
Gustav  Rose  have  made  it  very  questionable,  whether  the  minerals  called 
hornblende  and  augite  can  be  separated  as  distinct  species,  as  their  dif- 
ferent varieties  seem  to  pass  into  each  other,  whether  we  consider  the 
characters  derived  from  their  angles  of  crystallization,  their  chemical 
composition,  or  their  specific  gravity.  The  difference  in  form  of  the  two 
substances  may  be  explained  by  the  different  circumstances  under  which 

*  Daubeny,  Volcanoes,  p.  267. 

f  See  Buist,  Volcanoes  of  India,  Trans.  Bombay  GeoL  Soc.  vol.  x.  p.  154,  and 
Captain  Robertson,  Journ.  of  Roy.  Asiat.  Soc.  1850. 

I  See  Glossary.  §  Bunsen,  Volcanic  Rocks  of  Iceland. 

29 


450  SUBTERRANEAN    VOLCANIC    KOCKS.  [Cfl.  XXVI. 

they  have  been  produced,  the  form  of  hornblende  being  the  result  of 
slower  cooling.  Crystals  of  augite  have  been  met  with  in  the  scoriae  of 
furnaces,  but  never  those  of  hornblende ;  and  crystals  of  augite  have 
been  obtained  by  melting  hornblende  in  a  platina  crucible ;  but  horn- 
blende itself  has  not  been  formed  artificially.*  Mica  occurs  plentifully  in 
some  recent  trachytes,  but  is  rarely  present  where  augite  is  in  excess. 

Frequency  of  eruptions,  and  nature  of  subterranean  igneous  rocks. — 
When  we  speak  of  the  igneous  rocks  of  our  own  times,  we  mean  that 
small  portion  which,  in  violent  eruptions,  is  forced  up  by  elastic  fluids  to 
the  surface  of  the  earth, — the  sand,  scoriae,  and  lava,  which  cool  in  the 
open  air.  But  we  cannot  obtain  access  to  that  which  is  congealed  far 
beneath  the  surface  under  great  pressure,  equal  to  that  of  many  hun- 
dred, or  many  thousand  atmospheres. 

During  the  last  century,  about  fifty  eruptions  are  recorded  of  the  five 
European  volcanic  districts,  of  Vesuvius,  Etna,  Volcano,  Santorin,  and 
Iceland  ;  but  many  beneath  the  sea  in  the  Grecian  archipelago  and  near 
Iceland  may  doubtless  have  passed  unnoticed.  If  some  of  them  pro- 
duced no  lava,  others,  on  the  contrary,  like  that  of  Skaptar  Jokul,  in  1783, 
poured  out  melted  matter  for  five  or  six  years  consecutively ;  which  cases, 
being  reckoned  as  single  eruptions,  will  compensate  for  those  of  inferior 
strength.  Now,  if  we  consider  the  active  volcanoes  of  Europe  to  consti- 
tute about  a  fortieth  part  of  those  already  known  on  the  globe,  and  cal- 
culate that,  one  with  another,  they  are  about  equal  in  activity  to  the  burn- 
ing mountains  in  other  districts,  we  may  then  compute  that  there  happen 
on  the  earth  about  2000  eruptions  in  the  course  of  a  century,  or  about 
twenty  every  year. 

However  inconsiderable,  therefore,  may  be  the  superficial  rocks  which 
the  operations  of  fire  produce  on  the  surface,  we  must  suppose  the  sub- 
terranean changes  now  constantly  in  progress  to  be  on  the  grandest  scale. 
The  loftiest  volcanic  cones  must  be  as  insignificant,  when  contrasted  to  the 
products  of  fire  in  the  nether  regions,  as  are  the  deposits  formed  in  shal- 
low estuaries  when  compared  to  submarine  formations  accumulating  in 
the  abysses  of  the  ocean.  In  regard  to  the  characters  of  these  volcanic 
rocks,  formed  in  our  own  times  in  the  bowels  of  the  earth,  whether  in  rents 
and  caverns,  or  by  the  cooling  of  lakes  of  melted  lava,  we  may  safely  in- 
fer that  the  rocks  are  heavier  and  less  porous  than  ordinary  lavas,  and 
more  crystalline,  although  composed  of  the  same  mineral  ingredients.  As 
the  hardest  crystals  produced  artificially  in  the  laboratory  require  the 
longest  time  for  their  formation,  so  we  must  suppose  that  where  the  cool- 
ing down  of  melted  matter  takes  place  by  insensible  degrees,  in  the  course 
of  ages,  a  variety  of  minerals  will  be  produced  far  harder  than  any  formed 
by  natural  processes  within  the  short  period  of  human  observation. 

These  subterranean  volcanic  rocks,  moreover,  cannot  be  stratified  in 
the  same  manner  as  sedimentary  deposits  from  water,  although  it  is  evi- 
dent that  when  great  masses  consolidate  from  a  state  of  fusion,  they  may 

*  Bulletin  de  la  Soc.  Geol.  de  France,  torn.  ii.  p.  206. 


CH.  XXVIL]  EARTHQUAKES    AND   THEIR   EFFECTS.  451 

separate  into  natural  divisions ;  for  this  is  seen  to  be  the  case  in  many 
lava-currents.  We  may  also  expect  that  the  rocks  in  question  will  often 
be  rent  by  earthquakes,  since  these  are  common  in  volcanic  regions ;  and 
the  fissures  will  be  often  injected  with  similar  matter,  so  that  dikes  of 
crystalline  rock  will  traverse  masses  of  similar  composition.  It  is  also 
clear,  that  no  organic  remains  can  be  included  in  such  masses,  as  also 
that  these  deep-seated  igneous  formations  considered  in  mass  must  under- 
lie all  the  strata  containing  organic  remains,  because  the  heat  proceeds 
from  below  upwards,  and  the  intensity  required  to  reduce  the  mineral 
ingredients  to  a  fluid  state  must  destroy  all  organic  bodies  in  rocks  in- 
cluded in  the  midst  of  them. 

If  by  a  continued  series  of  elevatory  movements,  such  masses  shall 
hereafter  be  brought  up  to  the  surface,  in  the  same  manner  as  sedimen- 
tary marine  strata  have,  in  the  course  of  ages,  been  upheaved  to  the 
summit  of  the  loftiest  mountains,  it  is  not  difficult  to  foresee  what 
perplexing  problems  may  be  presented  to  the  geologist.  He  may  then, 
perhaps,  study  in  some  mountain-chain  the  very  rocks  produced  at  the 
depth  of  several  miles  beneath  the  Andes,  Iceland,  or  Java,  in  the  time 
of  Leibnitz,  and  draw  from  them  the  same  conclusion  which  that  philos- 
opher derived  from  certain  igneous  products  of  high  antiquity  ;  for  he 
conceived  our  globe  to  have  been,  for  an  indefinite  period,  in  the  state 
of  a  comet,  without  an  ocean,  and  uninhabitable  alike  by  aquatic  or 
terrestrial  animals. 


CHAPTER  XXVII. 

EARTHQUAKES    AND    THEIR    EFFECTS. 

Earthquakes  and  their  effects — Deficiency  of  ancient  accounts — Ordinary  atmo- 
spheric phenomena — Changes  produced  by  earthquakes  in  modern  times  consid- 
ered in  chronological  order — Earthquake  in  Syria,  1837 — Earthquakes  in  Chili 
in  1837  and  1835— Isle  of  Santa  Maria  raised  ten  feet— Chili,  1822— Extent  of 
country  elevated — Aleppo  and  Ionian  Isles — Earthquake  of  Cutch  in  1819 — 
Subsidence  in  the  Delta  of  the  Indus— Island  of  Sumbawa  in  1815 — Earthquake 
of  Caraccas  in  1812 — Shocks  at  New  Madrid  in  1811  in  the  valley  of  the  Mis- 
sissippi— Aleutian  Islands  in  1806 — Reflections  on  the  earthquakes  of  the  nine- 
teenth century — Earthquake  in  Quito,  Quebec,  &c. — Java,  1786 — Sinking  down 
of  large  tracts. 

IN  the  sketch  before  given  of  the  geographical  boundaries  of  volcanic 
regions,  I  stated,  that  although  the  points  of  eruption  are  but  thinly 
scattered,  constituting  mere  spots  on  the  surface  of  those  vast  districts, 
yet  the  subterranean  movements  extend  simultaneously  over  immense 
areas.  We  may  now  proceed  to  consider  the  changes  which  these 
movements  produce  on  the  surface,  and  in  the  internal  structure  of  the 
earth's  crust. 


452  PHENOMENA    ATTENDING    EARTHQUAKES.        [Cfl.  XXVII, 

Deficiency  of  ancient  accounts. — It  is  only  within  the  last  century  and 
a  half,  since  Hooke  first  promulgated,  in  1688,  his  views  respecting  the 
connection  between  geological  phenomena  and  earthquakes,  that  the 
permanent  changes  affected  by  these  convulsions  have  excited  attention. 
Before  that  time,  the  narrative  of  the  historian  was  almost  exclusively 
confined  to  the  number  of  human  beings  who  perished,  the  number  of 
cities  laid  in  ruins,  the  value  of  property  destroyed,  or  certain  atmo- 
spheric appearances  which  dazzled  or  terrified  the  observers.  The  crea- 
tion of  a  new  lake,  the  engulfing  of  a  new  city,  or  the  raising  of  a  new 
island,  are  sometimes,  it  is  true,  adverted  to,  as  being  too  obvious,  or  of 
too  much  geographical  or  political  interest  to  be  passed  over  in  silence. 
But  no  researches  were  made  expressly  with  a  view  of  ascertaining  the 
amount  of  depression  or  elevation  of  the  ground,  or  any  particular  alter- 
ations in  the  relative  position  of  sea  and  land  ;  and  very  little  distinction 
was  made  between  the  raising  of  soil  by  volcanic  ejections,  and  the  up- 
heaving of  it  by  forces  acting  from  below.  The  same  remark  applies  to 
a  very  large  proportion  of  modern  accounts  :  and  how  much  reason  we 
have  to  regret  this  deficiency  of  information  appears  from  this,  that  in 
every  instance  where  a  spirit  of  scientific  inquiry  has  animated  the  eye- 
witnesses of  these  events,  facts  calculated  to  throw  light  on  former  modi- 
fications of  the  earth's  structure  are  recorded. 

Phenomena  attending  earthquakes. — As  I  shall  confine  myself  almost 
entirely,  in  the  following  notice  of  earthquakes,  to  the  changes  brought 
about  by  them  in  the  configuration  of  the  earth's  crust,  I  may  mention, 
generally,  some  accompaniments  of  these  terrible  events  which  are 
almost  uniformly  commemorated  in  history,  that  it  may  be  unnecessary 
to  advert  to  them  again.  Irregularities  in  the  seasons  preceding  or  fol- 
lowing the  shocks ;  sudden  gusts  of  wind,  interrupted  by  dead  calms  ; 
violent  rains  at  unusual  seasons,  or  in  countries  where  such  phenomena 
are  almost  unknown ;  a  reddening  of  the  sun's  disk,  and  a  haziness  in 
the  air,  often  continued  for  months ;  an  evolution  of  electric  matter,  or 
of  inflammable  gas  from  the  soil,  with  sulphurous  and  mephitic  vapors ; 
noises  underground,  like  the  running  of  carriages,  or  the  discharge  of 
artillery,  or  distant  thunder;  animals  uttering  cries  of  distress,  and 
evincing  extraordinary  alarm,  being  more  sensitive  than  men  of  the 
slightest  movement ;  a  sensation  like  sea-sickness,  and  a  dizziness  in  the 
head,  experienced  by  men  : — these,  and  other  phenomena,  less  con- 
nected with  our  present  subject  as  geologists,  have  recurred  again  and 
again  at  distant  ages,  and  in  all  parts  of  the  globe. 

I  shall  now  begin  the  enumeration  of  earthquakes  with  the  latest 
authentic  narratives,  and  so  carry  back  the  survey  retrospectively,  that 
I  may  bring  before  the  reader,  in  the  first  place,  the  minute  and  circum- 
stantial details  of  modern  times,  and  thus  enable  him,  by  observing  the 
extraordinary  amount  of  change  within  the  last  150  years,  to  perceive 
how  great  must  be  the  deficiency  in  the  meager  annals  of  earlier  eras. 


Oil.  XXVIL]  EARTHQUAKES   IN    CHILI.  453 

EARTHQUAKES    OP    THE    NINETEENTH    CENTURY.* 

Syria,  January,  1837. — It  has  been  remarked  that  earthquakes 
affect  elongated  areas.  The  violent  shock  which  devastated  Syria  in 
1837  was  felt  on  a  line  500  miles  in  length  by  90  in  breadth  :f  more 
than  6000  persons  perished  ;  deep  rents  were  caused  in  solid  rocks,  and 
new  hot  springs  burst  out  at  Tabereah. 

Chili — Valdivia,  1837. — One  of  the  latest  earthquakes  by  which  the 
position  of  solid  land  is  known  to  have  been  permanently  altered  is  that 
which  occurred  in  Chili,  on  November  7th,  1837.  On  that  day  Valdivia 
was  destroyed  by  an  earthquake,  and  a  whaler,  commanded  by  Captain 
Coste,  was  violently  shaken  at  sea,  and  lost  her  masts,  in  lat.  43°  38'  S. 
in  sight  of  the  land.  The  captain  went  on  the  llth  of  December  follow- 
ing to  a  spot  near  the  island  of  Lemus,  one  of  the  Chonos  archipelago, 
where  he  had  anchored  two  years  before,  and  found  that  the  bottom  of 
the  sea  had  been  raised  more  than  eight  feet.  Some  rocks  formerly 
covered  at  all  times  by  the  sea  were  now  constantly  exposed,  and  an 
enormous  quantity  of  shells  and  fish  in  a  decaying  state,  which  had  been 
thrown  there  by  the  waves,  or  suddenly  laid  dry  during  the  earthquake, 
attested  the  recent  date  of  the  occurrence.  The  whole  coast  was  strewed 
with  uprooted  trees.J 

Chili — Conception,  1835. — Fortunately  we  have  a  still  more  detailed 
account  of  the  geographical  changes  produced  in  the  same  country  on 
the  20th  of  February,  1835.  An  earthquake  was  then  felt  at  all  places 
between  Copiapo  and  Chiloe,  from  north  to  south,  and  from  Mendoza 
to  Juan  Fernandez,  from  east  to  west.  "  Vessels,"  says  Mr.  Caldcleugh, 
"  navigating  the  Pacific,  within  100  miles  of  the  coast,  experienced  the 
shock  with  considerable  force."§  Conception,  Talcahuano,  Chilian,  and 
other  towns  were  thrown  down.  From  the  account  of  Captain  Fitz  Roy, 
R.  N.,  who  was  then  employed  in  surveying  the  coast,  we  learn  that  after 
the  shock  the  sea  retired  in  the  Bay  of  Conception,  and  the  vessels 
grounded,  even  those  which  had  been  lying  in  seven  fathoms  water :  all 
the  shoals  were  visible,  and  soon  afterwards  a  wave  rushed  in  and  then 
retreated,  and  was  followed  by  two  other  waves.  The  vertical  height  of 
these  waves  does  not  appear  to  have  been  much  greater  than  from  six- 
teen to  twenty  feet,  although  they  rose  to  much  greater  heights  when 
they  broke  upon  a  sloping  beach. 

According  to  Mr.  Caldcleugh  and  Mr.  Darwin,  the  whole  volcanic 

*  Since  the  publication  of  the  first  edition  of  this  work,  numerous  accounts  of 
recent  earthquakes  have  been  published ;  but  as  they  do  not  illustrate  any  new 
principle,  I  cannot  insert  them,  as  they  would  enlarge  too  much  the  size  of  my 
work.  The  late  Von  Hoff  published  from  time  to  time,  in  Poggendorf 's  Annalen, 
lists  of  earthquakes  which  happened  between  1821  and  1836  ;  and,  by  consulting 
these,  the  reader  will  perceive  that  every  month  is  signalized  by  one  or  many 
convulsions  in  some  part  of  the  globe.  See  also  Mallet's  Dynamics  of  Earth- 
quakes, Trans.  Roy.  Irish  Acad.  1 846  ;  and  "  Earthquakes,"  Admiralty  Manual, 
1849  ;  also  Hopkins'  Report,  Brit.  Assoc.  1847-8. 

f  Darwin,  Geol.  Proceedings,  vol.  ii.  p.  658. 

I  Dumoulin,  Comptes  Rendus  de  1'Acad.  des  Scl  Oct.  1838,  p.  706. 

§  Phil.  Trans.  1836,  p.  21. 


454: 


Fig.  69. 


EARTHQUAKES   IN   CHILI. 

70 


[CH.  XXVIL 


chain  of  the  Chilian  Andes,  a  range  150  miles  in  length,  was  in  a  state 
of  unusual  activity,  both  during  the  shocks  and  for  some  time  preceding 
and  after  the  convulsion,  and  lava  was  seen  to  flow  from  the  crater  of 
Osorno.  (See  Map,  fig.  69.)  The  island  of  Juan  Fernandez,  distant 
365  geographical  miles  from  Chili,  was  violently  shaken  at  the  same 
time,  and  devastated  by  a  great  wave.  A  submarine  volcano  broke  out 


CH.  XXVIL] 


EARTHQUAKE    IN    CHILI,    1835. 


455 


there  near  Bacalao  Head,  about  a  mile  from  the  shore,  in  sixty-nine 
fathoms  water,  and  illumined  the  whole  island  during  the  night.* 

"At  Conception,"  says  Captain  Fitz  Roy,  "the  earth  opened  and 
closed  rapidly  in  numerous  places.  The  direction  of  the  cracks  was  not 
uniform,  though  generally  from  southeast  to  northwest.  The  earth  was 
not  quiet  for  three  days  after  the  great  shock,  and  more  than  300 
shocks  were  counted  between  the  20th  February  and  the  4th  of  March. 
The  loose  earth  of  the  valley  of  the  Biobio  was  everywhere  parted  from 
the  solid  rocks  which  bound  the  plain,  there  being  an  opening  between 
them  from  an  inch  to  a  foot  in  width. 


Fig.  70. 


"  For  some  days  after  the  20th  of  February,  the  sea  at  Talcahuano," 
says  Captain  Fitz  Roy,  "  did  not  rise  to  the  usual  marks  by  four  or  five 
feet  vertically.  When  walking  on  the  shore,  even  at  high  water,  beds 
of  dead  mussels,  numerous  chitons,  and  limpets,  and  withered  sea- 
weed, still  adhering,  though  lifeless,  to  the  rocks  on  which  they  had 
lived,  everywhere  met  the  eye."  But  this  difference  in  the  relative  level 
of  the  land  and  sea  gradually  diminished,  till  in  the  middle  of  April  the 
water  rose  again  to  within  two  feet  of  the  former  high-water  mark.  It 
might  be  supposed  that  these  changes  of  level  merely  indicated  a  tem- 
porary disturbance  in  the  set  of  the  currents  or  in  the  height  of  the  tides 
at  Talcahuano ;  but,  on  considering  what  occurred  in  the  neighboring 
island  of  Santa  Maria,  Captain  Fitz  Roy  concluded  that  the  land  had 

*  Phil.  Trans.  1826. 


4:56  EARTHQUAKE   IN   ISCHIA,    1828.  [On.  XXVII. 

been  raised  four  or  five  feet  in  February,  and  that  it  had  returned  in 
April  to  within  two  or  three  feet  of  its  former  level. 

Santa  Maria,  the  island  just  alluded  to,  is  about  seven  miles  long  and 
two  broad,  and  about  twenty-five  miles  southwest  of  Conception.  (See 
Map,  fig.  70.)  The  phenomena  observed  there  are  most  important.  "  It 
appeared,"  says  Captain  Fitz  Roy,  who  visited  Santa  Maria  twice,  the 
first  time  at  the  end  of  March,  and  afterwards  in  the  beginning  of  April, 
"  that  the  southern  extremity  of  the  island  had  been  raised  eight  feet, 
the  middle  nine,  and  the  northern  end  upwards  of  ten  feet.  On  steep 
rocks,  where  vertical  measures  could  be  correctly  taken,  beds  of  dead 
mussels  were  found  ten  feet  above  high-water  mark.  One  foot  lower 
than  the  highest  bed  of  mussels,  a  few  limpets  and  chitons  were  seen 
adhering  to  the  rock  where  they  had  grown.  Two  feet  lower  than  the 
same,  dead  mussels,  chitons,  and  limpets  were  abundant. 

"  An  extensive  rocky  flat  lies  around  the  northern  parts  of  Santa 
Maria.  Before  the  earthquake  this  flat  was  covered  by  the  sea,  some 
projecting  rocks  only  showing  themselves.  Now,  the  whole  flat  is  ex- 
posed, and  square  acres  of  it  are  covered  with  dead  shell-fish,  the  stench 
arising  from  which  is  abominable.  By  this  elevation  of  the  land  the 
southern  port  of  Santa  Maria  has  been  almost  destroyed ;  little  shelter 
remaining  there,  and  very  bad  landing."  The  surrounding  sea  is  also 
stated  to  have  become  shallower  in  exactly  the  same  proportion  as  the 
land  had  risen  ;  the  soundings  having  diminished  a  fathom  and  a  half 
everywhere  around  the  island. 

At  Tubal,  also,  to  the  southeast  of  Santa  Maria,  the  land  was  raised  six 
feet,  at  Mocha  two  feet,  but  no  elevation  could  be  ascertained  at  Valdivia. 

Among  other  effects  of  the  catastrophe,  it  is  stated  that  cattle  stand- 
ing on  a  steep  slope,  near  the  shore,  were  rolled  down  into  the  sea,  and 
many  others  were  washed  off  by  the  great  wave  from  low  land  and 
drowned.* 

In  November  of  the  same  year  (1835),  Conception  was  shaken  by 
a  severe  earthquake,  and  on  the  same  day  Osorno,  at  the  distance  of 
400  miles,  renewed  its  activity.  These  facts  prove  not  only  the  connec- 
tion of  earthquakes  with  volcanic  eruptions  in  this  region,  but  also  the 
vast  extent  of  the  subterranean  areas  over  which  the  disturbing  cause 
acts  simultaneously. 

Ischia,  1828. — On  the  2d  of  February  the  whole  island  of  Ischia 
was  shaken  by  an  earthquake,  and  in  the  October  following  I  found  all 
the  houses  in  Casamicciol  still  without  their  roofs.  On  the  sides  of  a 
ravine  between  that  town  and  Forio,  I  saw  masses  of  greenish  tuff 
which  had  been  thrown  down.  The  hot-spring  of  Rita,  which  was 
nearest  the  centre  of  the  movement,  was  ascertained  by  M.  Covelli  to 
have  increased  in  temperature,  showing,  as  he  observes,  that  the  ex- 
plosion took  place  below  the  reservoirs  which  heat  the  thermal  waters.^ 

*  Darwin's  Journ.  of  Travels  in  South  America,  Voyage  of  Beagle,  p.  372. 
f  Biblioth.  Univ.  Oct.  1828,  p.  157. 


CH.  XXV IL]  EARTHQUAKE   IN   CHILI,    1822.  457 

Bogota,  1827. — On  the  16th  of  November,  1827,  the  plain  of  Bogota, 
in  New  Granada,  or  Colombia,  was  convulsed  by  an  earthquake,  and  a 
great  number  of  towns  were  thrown  down.  Torrents  of  rain  swelled 
the  Magdalena,  sweeping  along  vast  quantities  of  mud  and  other  sub- 
stances, which  emitted  a  sulphurous  vapor  and  destroyed  the  fish. 
Popayan,  which  is  distant  200  geographical  miles  S.  S.  W.  of  Bogota, 
suffered  greatly.  Wide  crevices  appeared  in  the  road  of  Guanacas, 
leaving  no  doubt  that  the  whole  of  the  Cordilleras  sustained  a  powerful 
shock.  Other  fissures  opened  near  Costa,  in  the  plains  of  Bogota,  into 
which  the  river  Tunza  immediately  began  to  flow.*  It  is  worthy  of 
remark,  that  in  all  such  cases  the  ancient  gravel  bed  of  a  river  is  de- 
serted and  a  new  one  formed  at  a  lower  level ;  so  that  a  want  of  rela- 
tion in  the  position  of  alluvial  beds  of  the  existing  water- courses  may 
be  no  test  of  the  high  antiquity  of  such  deposits,  at  least  in  countries 
habitually  convulsed  by  earthquakes.  Extraordinary  rains  accompanied 
the  shocks  before  mentioned ;  and  two  volcanoes  are  said  to  have  been 
in  eruption  in  the  mountain-chain  nearest  to  Bogota. 

Chili,  1822.— On  the  19th  of  November,  1822,  the  coast  of  Chili 
was  visited  by  a  most  destructive  earthquake.  The  shock  was  felt  si- 
multaneously throughout  a  space  of  1200  miles  from  north  to  south. 
St.  Jago,  Valparaiso,  and  some  other  places,  were  greatly  injured. 
When  the  district  round  Valparaiso  was  examined  on  the  morning  after 
the  shock,  it  was  found  that  the  coast  for  a  considerable  distance  was 
raised  above  its  former  level. f  At  Valparaiso  the  elevation  was  three 
feet,  and  at  Quintero  about  four  feet.  Part  of  the  bed  of  the  sea,  says 
Mrs.  Graham,  remained  bare  and  dry  at  high  water,  "with  beds  of 
oysters,  mussels,  and  other  shells  adhering  to  the  rocks  on  which  they 
grew,  the  fish  being  all  dead,  and  exhaling  most  offensive  effluvia. J 

An  old  wreck  of  a  ship,  which  before  could  not  be  approached, 
became  accessible  from  the  land,  although  its  distance  from  the  original 
sea-shore  had  not  altered.  It  was  observed  that  the  water-course  of  a 
mill,  at  the  distance  of  about  a  mile  from  the  sea,  gained  a  fall  of  four- 
teen inches,  in  little  more  than  one  hundred  yards  ;  and  from  this  fact 
it  is  inferred  that  the  rise  in  some  parts  of  the  inland  country  was  far 
more  considerable  than  on  the  borders  of  the  ocean. §  Part  of  the  coast 
thus  elevated  consisted  of  granite,  in  which  parallel  fissures  were  caused, 
some  of  which  were  traced  for  a  mile  and  a  half  inland.  Cones  of  earth 
about  four  feet  high  were  thrown  up  in  several  districts,  by  the  forcing 
up  of  water  mixed  with  sand  through  funnel-shaped  hollows, — a  phenom- 
enon very  common  in  Calabria,  and  the  explanation  of  which  will  here- 
after be  considered.  Those  houses  in  Chili  of  which  the  foundations 
were  on  rock  were  less  damaged  than  such  as  were  built  on  alluvial 
soil. 

Mr.  Cruickshanks,  an  English  botanist,  who  resided  in  the  country 

*  Phil.  Mag.  July  1828,  p.  37 

f  Geol.  Tnins.  vol.  i.  2d  ser.,  and  Journ.  of  Sci.  1824,  vol.  xvii.  p.  40. 

\  Geol.  Trans,  vol.  i.  2d  ser.  p.  415.  §  Journ.  of  Sci.  vol.  xvii.  p.  42. 


458  COAST   OF   CHILI   ELEVATED.  [On.  XXVII- 

during  the  earthquake,  has  informed  me  that  some  rocks  of  greenstone 
at  Quintero,  a  few  hundred  yards  from  the  beach,  which  had  always 
been  under  water  till  the  shock  of  1822,  have  since  been  uncovered 
when  the  tide  is  at  half-ebb :  and  he  states  that,  after  the  earthquake, 
it  wras  the  general  belief  of  the  fishermen  and  inhabitants  of  the  Chilian 
coast,  not  that  the  land  had  risen,  but  that  the  ocean  had  permanently 
retreated. 

Dr.  Meyen,  a  Prussian  traveller,  who  visited  Valparaiso  in  1831,  says 
that  on  examining  the  rocks  both  north  and  south  of  the  town,  nine  years 
after  the  event,  he  found,  in  corroboration  of  Mrs.  Graham's  account, 
that  remains  of  animals  and  sea- weed,  the  Lessonia  of  Bory  de  St.  Vin- 
cent, which  has  a  firm  ligneous  stem,  still  adhered  to  those  rocks  which 
in  1822  had  been  elevated  above  high-water  mark.*  According  to  the 
same  author,  the  whole  coast  of  Central  Chili  was  raised  about  four  feet, 
and  banks  of  marine  shells  were  laid  dry  on  many  parts  of  the  coast. 
He  observed  similar  banks,  elevated  at  unknown  periods,  in  several 
places,  especially  at  Copiapo,  where  the  species  all  agree  with  those  now 
living  in  the  ocean.  Mr.  Freyer  also,  who  resided  some  years  in  South 
America,  has  confirmed  these  statements  ;f  and  Mr.  Darwin  obtained 
evidence  that  the  remains  of  an  ancient  wall,  formerly  washed  by  the 
sea,  and  now  11^  feet  above  high-water  mark,  acquired  several  feet  of 
this  additional  elevation  during  the  earthquake  of  1822.J 

The  shocks  continued  up  to  the  end  of  September,  1823  ;  even  then, 
forty-eight  hours  seldom  passed  without  one,  and  sometimes  two  or 
three  were  felt  during  twenty-four  hours.  Mrs.  Graham  observed,  after 
the  earthquake  of  1822,  that  besides  a  beach  newly  raised  above  high- 
water  mark,  there  were  several  older  elevated  lines  of  beach,  one  above 
the  other,  consisting  of  shingle  mixed  with  shells  extending  in  a  parallel 
direction  to  the  shore,  to  the  height  of  fifty  feet  above  the  sea.§ 

JZxtent  of  country  elevated. — By  some  observers  it  has  been  supposed 
that  the  whole  country  from  the  foot  of  the  Andes  to  a  great  distance 
under  the  sea  was  upraised  in  1822,  the  greatest  rise  being  at  the  dis- 
tance of  about  two  miles  from  the  shore.  "  The  rise  upon  the  coast  was 
from  two  to  four  feet : — at  the  distance  of  a  mile  inland  it  must  have 
been  from  five  to  six  or  seven  feet."||  It  has  also  been  conjectured  by 
the  same  eye-witnesses  to  the  convulsion,  that  the  area  over  which  this 
permanent  alteration  of  level  extended  may  have  been  equal  to  100,000 
square  miles.  Although  the  increased  fall  of  certain  water-courses  may 
have  afforded  some  ground  for  this  conjecture,  it  must  be  considered  as 
very  hypothetical,  and  the  estimate  may  have  exceeded  or  greatly  fallen 
short  of  the  truth.  It  may  nevertheless  be  useful  to  reflect  on  the  enor- 
mous amount  of  change  which  this  single  convulsion  occasioned,  if  the 

*  Reise  um  die  Erde  ;  and  see  Dr.  Meyen's  letter  cited  Foreign  Quart.  Kev 
No.  33,  p.  13,  1836. 

f  Geol.  Soc.  Proceedings,  No.  xl.  p.  179,  Feb.  1835. 

±  Proceed.  Geol.  Soc.  vol.  ii.  p.  447. 

§  Geol.  Trans,  vol.  i  2d  ser.  p.  415. 

|  Journal  of  Science,  vol.  xvii.  pp.  40,  45. 


CH.  XXVII.]  COAST    OF    CHILI   ELEVATED.  459 

extent  of  country  moved  upward  really  amounted  to  100,000  square 
miles, — an  extent  just  equal  to  half  the  area  of  France,  or  about  five- 
sixths  of  the  area  of  Great  Britain  and  Ireland.  If  we  suppose  the 
elevation  to  have  been  only  three  feet  on  an  average,  it  will  be  seen  that 
the  mass  of  rock  added  to  the  continent  of  America  by  the  movement, 
or,  in  other  words,  the  mass  previously  below  the  level  of  the  sea,  and 
after  the  shocks  permanently  above  it,  must  have  contained  fifty-seven 
cubic  miles  in  bulk ;  which  would  be  sufficient  to  form  a  conical  moun- 
tain two  miles  high  (or  about  as  high  as  Etna),  with  a  circumference  at 
the  base  of  nearly  thirty-three  miles.  We  may  take  the  mean  specific 
gravity  of  the  rock  at  2'655, — a  fair  average,  and  a  convenient  one  in 
such  computations,  because  at  such  a  rate  a  cubic  yard  weighs  two  tons. 
Then,  assuming  the  great  pyramid  of  Egypt,  if  solid,  to  weigh,  in  accord- 
ance with  an  estimate  before  given,  six  million  tons,  we  may  state  the 
rock  added  to  the  continent  by  the  Chilian  earthquake  to  have  more  than 
equalled  100,000  pyramids. 

But  it  must  always  be  borne  in  mind  that  the  weight  of  rock  here  al- 
luded to  constituted  but  an  insignificant  part  of  the  whole  amount  which 
the  volcanic  forces  had  to  overcome.  The  whole  thickness  of  rock  be- 
tween the  surface  of  Chili  and  the  subterranean  foci  of  volcanic  action 
may  be  many  miles  or  leagues  deep.  Say  that  the  thickness  was  only 
two  miles,  even  then  the  mass  which  changed  place  and  rose  three  feet 
being  200,000  cubic  miles  in  volume,  must  have  exceeded  in  weight 
363  million  pyramids. 

It  may  be  instructing  to  consider  these  results  in  connection  with 
others  already  obtained  from  a  different  source,  and  to  compare  the 
working  of  two  antagonistic  forces — the  levelling  power  of  running 
water,  and  the  expansive  energy  of  subterranean  heat.  How  long,  it 
may  be  asked,  would  the  Ganges  require,  according  to  data  before  ex- 
plained (p.  283),  to  transport  to  the  sea  a  quantity  of  solid  matter  equal 
to  that  which  may  have  been  added  to  the  land  by  the  Chilian  earth- 
quake ?  The  discharge  of  mud  in  one  year  by  the  Ganges  was  estima- 
ted at  20,000  million  cubic  feet.  According  to  that  estimate  it  would 
require  about  four  centuries  (or  418  years)  before  the  river  could  bear 
down  from  the  continent  into  the  sea  a  mass  equal  to  that  gained  by  the 
Chilian  earthquake.  In  about  half  that  time,  perhaps,  the  united  waters 
of  the  Ganges  and  Burrampooter  might  accomplish  the  operation. 

Cutch,  1819. — A  violent  earthquake  occurred  at  Cutch,  in  the  delta 
of  the  Indus,  on  the  16th  of  June,  1819.  (See  Map,  fig.  71.)  The 
principal  town,  Bhooj,  was  converted  into  a  heap  of  ruins,  and  its  stone 
buildings  were  thrown  down.  The  movement  was  felt  over  an  area 
having  a  radius  of  1000  miles  from  Bhooj,  and  extending  to  Khatman- 
doo,  Calcutta,  and  Pondicherry.*  The  vibrations  were  felt  in  North- 
west India,  at  a  distance  of  800  miles,  after  an  interval  of  about  fifteen 
minutes  after  the  earthquake  at  Bhooj.  At  Ahmedabad  the  great 

*  See  Asiatic  Journal,  vol.  i. 


460 


FORT   OF    CUTCH    SUBMERGED. 

71. 


[On.  XXVII. 


MAP 

of 

THE    COITXTIUKS 

at 

THE  MOUTH  OF  THE 
INDUS. 


Areas  submerged  during 
earthquak 


i   The  Kunn,  alternately  land 
and  water. 


mosque,  erected  by  Sultan  Ahmed  nearly  450  years  before,  fell  to  the 
ground,  attesting  how  long  a  period  had  elapsed  since  a  shock  of  simi- 
lar violence  had  visited  that  point.  At  Anjar,  the  fort,  with  its  tower 
and  guns,  was  hurled  to  the  ground  in  one  common  mass  of  ruin.  The 
shocks  continued  until  the  20th  ;  when,  thirty  miles  northwest  from 
Bhooj,  the  volcano  called  Denodur  is  said  by  some  to  have  sent  forth 
flames,  but  Capt.  Grant  was  unable  to  authenticate  this  statement. 

Subsidence  in  the  delta  of  the  Indus. — Although  the  ruin  of  towns  was 
great,  the  face  of  nature  in  the  inland  country,  says  Captain  Macmurdo, 
was  not  visibly  altered.  In  the  hills  some  large  masses  only  of  rock 
and  soil  were  detached  from  the  precipices  ;  but  the  eastern  and  almost 
deserted  channel  of  the  Indus,  which  bounds  the  province  of  Cutch,  was 
greatly  changed.  This  estuary,  or  inlet  of  the  sea,  was,  before  the 
earthquake,  fordable  at  Luckput,  being  only  about  a  foot  deep  when 
the  tide  was  at  ebb,  and  at  flood-tide  never  more  than  six  feet ;  but  it 
was  deepened  at  the  fort  of  Luckput,  after  the  shock,  to  more  than 
eighteen  feet  at  low  water*  "On  sounding  other  parts  of  the  channel,  it 
was  found,  that  where  previously  the  depth  of  the  water  at  flood  never 
exceeded  one  or  two  feet,  it  had  become  from  four  to  ten  feet  deep. 
By  these  and  other  remarkable  changes  of  level,  a  part  of  the  inland 
navigation  of  that  country,  which  had  been  closed  for  centuries,  became 
again  practicable. 

*  Macmurdo  Ed.  Phil.  Journ.  iv.  106. 


Cri.  XXVII. 


FORT  OF  CUTCH  SUBMERGED. 

Fig.  72. 


461 


Fort  of  Sindrce,  on  the  eastern  branch  of  the  Indus,  before  it  was  submerged  by  the  earthquake 
of  1819,  from  a  sketch  of  Capt.  Grindlay,  made  in  1808. 

Fort  and  village  submerged.* — The  fort  and  village  of  Sindree,  on  the 
eastern  arm  of  the  Indus,  above  Luckput,  are  stated  by  the  same  writer 
to  have  been  overflowed ;  and,  after  the  shock,  the  tops  of  the  houses 
and  wall  were  alone  to  be  seen  above  the  water,  for  the  houses,  although 
submerged,  were  not  cast  down.  Had  they  been  situated,  therefore,  in 
the  interior,  where  so  many  forts  were  levelled  to  the  ground,  their  site 
would,  perhaps,  have  been  regarded  as  having  remained  comparatively 
unmoved.  Hence  we  may  suspect  that  great  permanent  upheavings 
and  depressions  of  soil  may  be  the  result  of  earthquakes,  without  the 
inhabitants  being  in  the  least  degree  conscious  of  any  change  of  level. 

A  more  recent  survey  of  Cutch,  by  Sir  A.  Burnes,  who  was  not  in 
communication  with  Capt.  Macmurdo,  confirms  the  facts  above  enumera- 
ted, and  adds  many  important  details. f  That  officer  examined  the 
delta  of  the  Indus  in  1826  and  1828,  and  from  his  account  it  appears 
that,  when  Sindree  subsided  in  June,  1819,  the  sea  flowed  in  by  the 
eastern  mouth  of  the  Indus,  and  in  a  few  hours  converted  a  tract  of 
land,  2000  square  miles  in  area,  into  an  inland  sea,  or  lagoon.  Neither 
the  rush  of  the  sea  into  this  new  depression,  nor  the  movement  of  the 
earthquake,  threw  down  entirely  the  small  fort  of  Sindree,  one  of  the 
four  towers,  the  northwestern,  still  continuing  to  stand  ;  and,  the  day  after 
the  earthquake,  the  inhabitants  who  had  ascended  to  the  top  of  this 
tower,  saved  themselves  in  boats. J 

*  I  was  indebted  to  mv  friend  the  late  Sir  Alexander  Burnes  for  the  accom- 
panying sketch  (fig.  72)  o*f  the  fort  of  Sindree,  as  it  appeared  eleven  years  before 
the  earthquake. 

f  This  Memoir  is  now  in  the  Library  of  the  Royal  Asiatic  Society  of  London. 

\  Several  particulars  not-  given  in  the  earlier  edition  were  afterwards  obtained 
by  me  from  personal  communication  with  Sir  A.  Burnes  in  London. 


462  ELEVATION   OF   THE   ULLAH   BUND.  [On.  XXVIL 

Elevation  of  the  Ullah  Bund. — Immediately  after  the  shock,  the  in- 
habitants of  Sindree  saw,  at  the  distance  of  five  miles  and  a  half  from 
their  village,  a  long  elevated  mound,  where  previously  there  had  been  a 
low  and  perfectly  level  plain.  (See  Map,  fig.  71.)  To  this  uplifted 
tract  they  gave  the  name  of  "  Ullah  Bund,"  or  the  "  Mound  of  God," 
to  distinguish  it  from  several  artificial  dams  previously  thrown  across 
the  eastern  arm  of  the  Indus. 

Extent  of  country  raised. — It  has  been  ascertained  that  this  new- 
raised  country  is  upwards  of  fifty  miles  in  length  from  east  to  west, 
running  parallel  to  that  line  of  subsidence  before  mentioned,  which 
caused  the  grounds  around  Sindree  to  be  flooded.  The  range  of  this 
elevation  extends  from  Puchum  Island  towards  Gharee;  its  breadth 
from  north  to,south  is  conjectured  to  be  in  some  parts  sixteen  miles,  and 
its  greatest  ascertained  height  above  the  original  level  of  the  delta  is 
ten  feet, — an  elevation  which  appears  to  the  eye  to  be  very  uniform 
throughout. 

For  several  years  after  the  convulsion  of  1819,  the  course  of  the  In- 
dus was  very  unsettled,  and  at  length,  in  1826,  the  river  threw  a  vast 
body  of  water  into  its  eastern  arm,  that  called  the  Phurraun,  above 
Sindree  ;  and  forcing  its  way  in  a  more  direct  course  to  the  sea,  burst 
through  all  the  artificial  dams  which  had  been  thrown  across  its  chan- 
nel, and  at  length  cut  right  through  the  "  Ullah  Bund,"  whereby  a 
natural  section  was  obtained.  In  the  perpendicular  cliffs  thus  laid  open 
Sir  A.  Burnes  found  that  the  upraised  lands  consisted  of  clay  filled  with 
shells.  The  new  channel  of  the  river  where  it  intersected  the  "  bund" 
was  eighteen  feet  deep,  and  forty  yards  in  width;  but  in  1828  the 
channel  was  still  farther  enlarged.  The  Indus,  when  it  first  opened  this 
new  passage,  threw  such  a  body  of  water  into  the  new  mere,  or  salt 
lagoon,  of  Sindree,  that  it  became  fresh  for  many  months ;  but  it  had 
recovered  its  saltness  in  1828,  when  the  supply  of  river- water  was  less 
copious,  and  finally  it  became  more  salt  than  the  sea,  in  consequence,  as 
the  natives  suggested  to  Sir  A.  Burnes,  of  the  saline  particles  with 
which  the  "  Runn  of  Cutch"  is  impregnated. 

In  1828  Sir  A.  Burnes  went  in  a  boat  to  the  ruins  of  Sindree,  where 
a  single  remaining  tower  was  seen  in  the  midst  of  a  wide  expanse  of  sea. 
The  tops  of  the  ruined  walls  still  rose  two  or  three  feet  above  the  level 
of  the  water  ;  and  standing  on  one  of  these,  he  could  behold  nothing  in 
the  horizon  but  water,  except  in  one  direction,  where  a  blue  streak  of 
land  to  the  north  indicated  the  Ullah  Bund.  This  scene  presents  to  the 
imagination  a  lively  picture  of  the  revolutions  now  in  progress  on  the 
earth — a  waste  of  waters  "where  a  few  years  before  all  was  land,  and 
the  only  land  visible  consisting  of  ground  uplifted  by  a  recent  earth- 
quake. 

Ten  years  after  the  visit  of  Sir  A.  Burnes  above  alluded  to,  my  friend, 
Captain  Grant,  F.  G.  S.,  of  the  Bombay  Engineers,  had  the  kindness 
to  send  at  my  request  a  native  surveyor  to  make  a  plan  of  Sindree  and 
Ullah  Bund,  in  March,  1838.  From  his  description  it  appears  that,  at 


CH.  XXVIL]  EARTHQUAKE  OF    CUTCH.  463 

that  season,  the  driest  of  the  whole  year,  he  found  the  channel  travers- 
ing the  Bund  to  be  100  yards  wide,  without  water,  and  incrusted  with 
salt.  He  was  told  that  it  has  now  only  four  or  five  feet  of  water  in  it 
after  rains.  The  sides  or  banks  were  nearly  perpendicular,  and  nine 
feet  in  height.  The  lagoon  has  diminished  both  in  area  and  depth,  and 
part  near  the  fort  was  dry  land.  The  annexed  drawing,  made  by  Cap- 
Fig.  73. 


View  of  the  Tort  of  Sindrec,  from  the  west,  in  March,  1888. 

tain  Grant  from  the  surveyor's  plan,  shows  the  appearance  of  the  fort 
in  the  midst  of  the  lake,  as  seen  in  1838  from  the  west,  or  from  the 
same  point  as  that  from  which  Captain  Grindlay's  sketch  (see  fig.  72) 
was  taken  in  1808,  before  the  earthquake. 

The  Runn  of  Cutch  is  a  flat  region  of  a  very  peculiar  character,  and  no 
less  than  7000  square  miles  in  area :  a  greater  superficial  extent  than 
Yorkshire,  or  about  one-fourth  the  area  of  Ireland.  It  is  not  a  desert 
of  moving  sand,  nor  a  marsh,  but  evidently  the  dried-up  bed  of  an  in- 
land sea,  which  for  a  great  part  of  every  year  has  a  hard  and  dry  bot- 
tom uncovered  by  weeds  or  grass,  and  only  supporting  here  and  there  a 
few  tamarisks.  But  during  the  monsoons,  when  the  sea  runs  high,  the 
salt-water  driven  up  from  the  Gulf  of  Cutch  and  the  creeks  at  Luckput 
overflows  a  large  part  of  the  Runn,  especially  after  rains,  when  the  soaked 
ground  permits  the  sea-water  to  spread  rapidly.  The  Runn  is  also  liable 
to  be  overflowed  occasionally  in  some  parts  by  river- water :  and  it  is  re- 
markable that  the  only  portion  which  was  ever  highly  cultivated  (that 
anciently  called  Sayra)  is  now  permanently  submerged.  The  surface  of 
the  Runn  is  sometimes  incrusted  with  salt  about  an  inch  in  depth,  in  conse- 
quence of  the  evaporation  of  the  sea- water.  Islands  rise  up  in  some  parts 
of  the  waste,  and  the  boundary  lands  form  bays  and  promontories.  The 
natives  have  various  traditions  respecting  the  former  separation  of  Cutch 
and  Sinde  by  a  bay  of  the  sea,  and  the  drying  up  of  the  district  called 
the  Runn.  But  these  tales,  besides  the  usual  uncertainty  of  oral  tradi- 
tion, are  farther  obscured  by  mythological  fictions.  The  conversion  of 
the  Runn  into  land  is  chiefly  ascribed  to  the  miraculous  powers  of  a  Hin- 
doo saint,  by  name  Damorath  (or  Dhoorunnath),  who  had  previously'done 
penance  for  twelve  years  on  the  summit  of  Denodur  hill.  Captain  Grant 
infers,  on  various  grounds,  that  this  saint  flourished  about  the  eleventh 


464:  VOLCANIC   ERUPTION   IN   SUMBAWA,  1815.       [On.  XXVII 

or  twelfth  century  of  our  era.  In  proof  of  the  drying  up  of  the  Runn. 
some  towns  far  inland  are  still  pointed  out  as  having  once  been  ancient 
ports.  It  has,  moreover,  been  always  said  that  ships  were  wrecked  and 
engulphed  by  the  great  catastrophe ;  and  in  the  jets  of  black  muddy 
water  thrown  out  of  fissures  in  that  region,  in  1819,  there  were  cast  up 
numerous  pieces  of  wrought-iron  and  ship  nails.*  Cones  of  sand  six  or 
eight  feet  in  height  were  at  the  same  time  thrown  up  on  these  lands.f 

We  must  not  conclude  without  alluding  to  a  moral  phenomenon 
connected  with  this  tremendous  catastrophe,  which  we  regard  as  highly 
deserving  the  attention  of  geologists.  It  is  stated  by  Sir  A.  Burnes,  that 
"  these  wonderful  events  passed  unheeded  by  the  inhabitants  of  Cutch ;" 
for  the  region  convulsed,  though  once  fertile,  had  for  a  long  period  been 
reduced  to  sterility  by  want  of  irrigation,  so  that  the  natives  were  indif- 
ferent as  to  its  fate.  Now  it  is  to  this  profound  apathy  which  all  but 
highly  civilized  nations  feel,  in  regard  to  physical  events  not  having  an 
immediate  influence  on  their  worldly  fortunes,  that  we  must  ascribe  the 
extraordinary  dearth  of  historical  information  concerning  changes  of  the 
earth's  surface,  which  modern  observations  show  to  be  by  no  means  of 
rare  occurrence  in  the  ordinary  course  of  nature. 

Since  the  above  account  was  written,  a  description  has  been  published 
of  more  recent  geographical  changes  in  the  district  of  Cutch,  near  the 
mouth  of  the  Koree,  or  eastern  branch  of  the  Indus,  which  happened 
in  June,  1845.  A  large  area  seems  to  have  subsided,  and  the  Sindree 
lake  had  become  a  salt  marsh. J 

Island  of  Sumbawa,  1815. — In  April,  1815,  one  of  the  most  frightful 
eruptions  recorded  in  history  occurred  in  the  province  of  Tomboro,  in  the 
island  of  Sumbawa  (see  Map,  fig.  39,  p.  351),  about  200  miles  from 
the  eastern  extremity  of  Java.  In  April  of  the  year  preceding  the 
volcano  had  been  observed  in  a  state  of  considerable  activity,  ashes  hav- 
ing fallen  upon  the  decks  of  vessels  which  sailed  past  the  coast. §  The 
eruption  of  1815  began  on  the  5th  of  April,  but  was  most  violent  on  the 
llth  and  12th,  and  did  not  entirely  cease  till  July.  The  sound  of  the 
explosions  was  heard  in  Sumatra,  at  the  distance  of  970  geographical 
miles  in  a  direct  line ;  and  at  Ternate,  in  an  opposite  direction,  at  the 
distance  of  720  miles.  Out  of  a  population  of  12,000,  in  the  province 
of  Tomboro,  only  twenty-six  individuals  survived.  Violent  whirlwinds 
carried  up  men,  horses,  cattle,  and  whatever  else  came  within  their  influ- 
ence into  the  air ;  tore  up  the  largest  trees  by  the  roots,  and  covered  the 
whole  sea  with  floating  timber.  |  Great  tracts  of  land  were  covered  by 
lava,  several  streams  of  which,  issuing  from  the  crater  of  the  Tomboro 
mountain,  reached  the  sea-.  So  heavy  was  the  fall  of  ashes,  that  they 
broke  into  the  Resident's  house  at  Bima,  forty  miles  east  of  the  volcano, 
and  rendered  it  as  well  as  many  other  dwellings  in  the  town  uninhabit- 
able. On  the  side  of  Java  the  ashes  were  carried  to  the  distance  of  300 

*  Capt.  Burnes'  Account.  f  Capt.  Macmurdo's  Memoir,  Ed.  Phil.  Journ. 
vol.  iv.  p.  106.  I  Quart.  Geol.  Journ.  vol.  ii.  p.  103. 

§  MS.  of  J.  Crawfurd,  Esq.        |   Raffles'  Java,  vol.  i.  p.  28. 


CH.  XXVIL]  TOWN   OF   TOMBORO   SUBMEEGED.  465 

miles,  and  217  towards  Celebes,  in  sufficient  quantity  to  darken  the  air. 
The  floating  cinders  to  the  westward  of  Sumatra  formed,  on  the  12th  of 
April,  a  mass  two  feet  thick,  and  several  miles  in  extent,  through  which 
ships  with  difficulty  forced  their  way. 

The  darkness  occasioned  in  the  daytime  by  the  ashes  in  Java  was  so 
profound,  that  nothing  equal  to  it  was  ever  witnessed  in  the  darkest 
night.  Although  this  volcanic  dust  when  it  fell  was  an  impalpable 
powder,  it  was  of  considerable  weight  when  compressed,  a  pint  of  it 
weighing  twelve  ounces  and  three  quarters.  "  Some  of  the  finest  parti- 
cles," says  Mr.  Crawfurd,  "  were  transported  to  the  islands  of  Amboyna 
and  Banda,  which  last  is  about  800  miles  east  from  the  site  of  the  vol- 
cano, although  the  southeast  monsoon  was  then  at  its  height."  They 
must  have  been  projected,  therefore,  into  the  upper  regions  of  the 
atmosphere,  where  a  counter-current  prevailed. 

Along  the  sea-coast  of  Sumbawa  and  the  adjacent  isles,  the  sea  rose 
suddenly  to  the  height  of  from  two  to  twelve  feet,  a  great  wave  rushing 
up  the  estuaries,  and  then  suddenly  subsiding.  Although  the  wind  at 
Bima  was  still  during  the  whole  time,  the  sea  rolled  in  upon  the  shore, 
and  filled  the  lower  parts  of  the  houses  with  water  a  foot  deep.  Every 
prow  and  boat  was  forced  from  the  anchorage,  and  driven  on  shore. 

The  town  called  Tomboro,  on  the  west  side  of  Sumbawa,  was  over- 
flowed by  the  sea,  which  encroached  upon  the  shore  so  that  the  water 
remained  permanently  eighteen  feet  deep  in  places  where  there  was  land 
before.  Here  we  may  qbserve,  that  the  amount  of  subsidence  of  land 
was  apparent,  in  spite  of  the  ashes,  which  would  naturally  have  caused 
the  limits  of  the  coast  to  be  extended. 

The  area  over  which  tremulous  noises  and  other  volcanic  effects  ex- 
tended, was  1000  English  miles  in  circumference,  including  the  whole 
of  the  Molucca  Islands,  Java,  a  considerable  portion  of  Celebes,  Suma- 
tra, and  Borneo.  In  the  island  of  Amboyna,  in  the  same  month  and 
year,  the  ground  opened,  threw  out  water,  and  then  closed  again.* 

In  conclusion,  I  may  remind  the  reader,  that  but  for  the  accidental 
presence  of  Sir  Stamford  Raffles,  then  Governor  of  Java,  we  should 
scarcely  have  heard  in  Europe  of  this  tremendous  catastrophe.  He 
required  all  the  residents  in  the  various  districts  under  his  authority  to 
send  in  a  statement  of  the  circumstances  which  occurred  within  their  own 
knowledge  ;  but,  valuable  as  were  their  communications,  they  are  often 
calculated  to  excite  rather  than  to  satisfy  the  curiosity  of  the  geologist. 
They  mention  that  similar  effects,  though  in  a  less  degree,  had,  about 
seven  years  before,  accompanied  an  eruption  of  Carang  Assam,  a  volcano 
in  the  island  of  Bali,  west  of  Sumatra;  but  no  particulars  of  that  great 
catastrophe  are  recorded. f 

Caraccas,  1812. — On  the  26th  of  March,  1812,  several  violent  shocks 
of  an  earthquake  were  felt  in  Caraccas.  The  surface  undulated  like  a 
boiling  liquid,  and  terrific  sounds  were  heard  underground.  The  whole 

*  Raffles'  Hist,  of  Java,  vol.  i.  p.  25.     Ed.  Phil.  Journ.  vol.  iii.  p.  389. 
f  Life  and  Services  of  Sir  Stamford  Raffles,  p.  241.     London,  1830. 

30 


466  EARTHQUAKE  OF   NEW   MADRID,  1811.  [On.  XXVII 

city  with  its  splendid  churches  was  in  an  instant  a  heap  of  ruins,  under 
which  10,000  of  the  inhabitants  were  buried.  On  the  5th  of  April, 
enormous  rocks  were  detached  from  the  mountains.  It  was  believed 
that  the  mountain  Silla  lost  from  300  to  360  feet  of  its  height  by  subsi- 
dence ;  but  this  was  an  opinion  not  founded  on  any  measurement.  On 
the  27th  of  April,  a  volcano  in  St.  Vincent's  threw  out  ashes ;  and,  on 
the  30th,  lava  flowed  from  its  crater  into  the  sea,  while  its  explosions 
were  heard  at  a  distance  equal  to  that  between  Vesuvius  and  Switzer- 
land, the  sound  being  transmitted,  as  Humboldt  supposes,  through  the 
ground.  During  the  earthquake  which  destroyed  Caraccas,  an  immense 
quantity  of  water  was  thrown  out  at  Valecillo,  near  Valencia,  as  also  at 
Porto  Cabello,  through  openings  in  the  earth ;  and  in  the  Lake  Mara- 
caybo  the  water  sank.  Humboldt  observed  that  the  Cordilleras,  com- 
posed of  gneiss  and  mica  slate,  and  the  country  immediately  at  their  feet, 
were  more  violently  shaken  than  the  plains.* 

South  Carolina  and  New  Madrid,  Missouri,  1811-12. — Previous  to 
the  destruction  of  La  Guayra  and  Caraccas,  in  1812,  earthquakes  were 
felt  in  South  Carolina ;  and  the  shocks  continued  till  those  cities  were 
destroyed.  The  valley  also  of  the  Mississippi,  from  the  village  of  New 
Madrid  to  the  mouth  of  the  Ohio  in  one  direction,  and  to  the  St.  Francis 
in  another,  was  convulsed  in  such  a  degree  as  to  create  new  lakes  and 
islands.  It  has  been  remarked  by  Humboldt  in  his  Cosmos,  that  the 
earthquake  of  New  Madrid  presents  one  of  the  few  examples  on  record 
of  the  incessant  quaking  of  the  ground  for  several  successive  months  far 
from  any  volcano.  Flint,  the  geographer,  who  visited  the  country  seven 
years  after  the  event,  informs  us,  that  a  tract  of  many  miles  in  extent, 
near  the  Little  Prairie,  became  covered  with  water  three  or  four  feet 
deep  ;  and  when  the  water  disappeared  a  stratum  of  sand  was  left  in  its 
place.  Large  lakes  of  twenty  miles  in  extent  were  formed  in  the  course 
of  an  hour,  and  others  were  drained.  The  grave-yard  at  New  Madrid 
was  precipitated  into  the  bed  of  the  Mississippi ;  and  it  is  stated  that  the 
ground  whereon  the  town  is  built,  and  the  river-bank  for  fifteen  miles 
above,  sank  eight  feet  below  their  former  level.f  The  neighboring  forest 
presented  for  some  years  afterwards  "  a  singular  scene  of  confusion ;  the 
trees  standing  inclined  in  every  direction,  and  many  having  their  trunks 
and  branches  broken."]; 

The  inhabitants  relate  that  the  earth  rose  in  great  undulations ;  and 
when  these  reached  a  certain  fearful  height,  the  soil  burst,  and  vast  vol- 
umes of  water,  sand,  and  pit- coal  were  discharged  as  high  as  the  tops 
of  the  trees.  Flint  saw  hundreds  of  these  deep  chasms  remaining  in  an 
alluvial  soil,  seven  years  after.  The  people  in  the  country,  although 
inexperienced  in  such  convulsions,  had  remarked  that  the  chasms  in  the 
earth  were  in  a  direction  from  S.  W.  to  N.  E. ;  and  they  accordingly 
felled  the  tallest  trees,  and  laying  them  at  right  angles  to  the  chasms, 

*  Humboldt's  Pera.  Nar.  vol.  iv.  p.  12  ;  and  Ed.  Phil.  Journ.  vol.  i.  p.  272 :  1819 

f  Cramer's  Navigator,  p.  243.     Pittsburgh,  1821. 

\  Long's  Exped.  to  the  Rocky  Mountains,  vol.  iii.  p.  184. 


CH.  XXVII.]  EARTHQUAKE   OF   NEW  MADRID,  1811.  467 

stationed  themselves  upon  them.  By  this  invention,  when  chasms  open- 
ed more  than  once  under  these  trees,  several  persons  were  prevented 
from  being  swallowed  up.*  At  one  period  during  this  earthquake,  the 
ground  not  far  below  New  Madrid  swelled  up  so  as  to  arrest  the  Missis- 
sippi in  its  course,  and  to  cause  a  temporary  reflux  of  its  waves.  The 
motion  of  some  of  the  shocks  is  described  as  having  been  horizontal,  and 
of  others  perpendicular  ;  and  the  vertical  movement  is  said  to  have  been 
much  less  desolating  than  the  horizontal. 

The  above  account  has  been  reprinted  exactly  as  it  appeared  in 
former  editions  of  this  work,  compiled  from  the  authorities  which  I  have 
cited;  but  having  more  recently  (March,  1846)  had  an  opportunity 
myself  of  visiting  the  disturbed  region  of  the  Mississippi,  and  convers- 
ing with  many  eye-witnesses  of  the  catastrophe,  I  am  able  to  confirm 
the  truth  of  those  statements,  and  to  add  some  remarks  on  the  present 
face  and  features  of  the  country.  I  skirted,  as  was  before  related  (p. 
270),  part  of  the  territory  immediately  west  of  New  Madrid,  called 
"  the  sunk  country,"  which  was  for  the  first  time  permanently  sub- 
merged during  the  earthquake  of  1811-12.  It  is  said  to  extend  along 
the  course  of  the  White  Water  and  its  tributaries  for  a  distance  of  be- 
tween 70  and  80  miles  north  and  south,  and  30  miles  east  and  west.  I 
saw  on  its  borders  many  full-grown  trees  still  standing  leafless,  the  bot- 
toms of  their  trunks  several  feet  under  water,  and  a  still  greater  num- 
ber lying  prostrate.  An  active  vegetation  of  aquatic  plants  is  already 
beginning  to  fill  up  some  of  the  shallows,  and  the  sediment  washed  in 
by  occasional  floods  when  the  Mississippi  rises  to  an  extraordinary 
height  contributes  to  convert  the  sunk  region  into  marsh  and  forest 
land.  Even  on  the  dry  ground  along  the  confines  of  the  submerged 
area,  I  observed  in  some  places  that  all  the  trees  of  prior  date  to  1811 
were  dead  and  leafless,  though  standing  erect  and  entire.  They  are 
supposed  to  have  been  killed  by  the  loosening  of  their  roots  during  the 
repeated  undulations  which  passed  through  the  ground  for  three  months 
in  succession. 

Mr.  Bringier,  an  experienced  engineer  of  New  Orleans,  who  was  on 
horseback  near  New  Madrid  when  some  of  the  severest  shocks  were  ex- 
perienced, related  to  me  (in  1846),  that  "as  the  waves  advanced  the 
trees  bent  down,  and  the  instant  afterwards,  while  recovering  their  posi- 
tion, they  often  met  those  of  other  trees  similarly  inclined,  so  that  their 
branches  becoming  interlocked,  they  were  prevented  from  righting  them- 
selves again.  The  transit  of  the  wave  through  the  woods  was  marked 
by  the  crashing  noise  of  countless  boughs,  first  heard  on  one  side  and 
then  on  the  other.  At  the  same  time  powerful  jets  of  water,  mixed 
with  sand,  mud,  and  fragments  of  coaly  matter,  were  cast  up,  endanger- 
ing the  lives  of  both  horse  and  rider." 

I  was  curious,  to  ascertain  whether  any  vestiges  still  remained  of 
these  fountains  of  mud  and  water,  and  carefully  examined  between  New 

*  Sillinian's  Journ.  Jan.  1829. 


468  ALEUTIAN   ISLANDS.  [Cu.  XXVII. 

Madrid  and  the  Little  Prairie  several  "  sink  holes,"  as  they  are  termed. 
They  consist  of  cavities  from  10  to  30  yards  in  width,  and  20  feet  or 
more  in  depth,  and  are  very  conspicuous,  interrupting  the  level  surface 
of  a  flat  alluvial  plain.  I  saw  abundance  of  sand,  which  some  of  the 
present  inhabitants  saw  spouting  from  these  deep  holes,  also  fragments 
of  decayed  wood  and  black  bituminous  shale,  probably  drifted  down  at 
some  former  period  in  the  main  channel  of  the  Mississippi,  from  the 
coal-fields  farther  north.  I  also  found  numerous  rents  in  the  soil  left 
by  the  earthquake,  some  of  them  still  several  feet  wide,  and  a  yard  or 
two  in  depth,  although  the  action  of  rains,  frost,  and  occasional  inunda- 
tions, and  especially  the  leaves  of  trees  blown  into  them  in  countless 
numbers  every  autumn,  have  done  much  to  fill  them  up.  I  measured 
the  direction  of  some  of  the  fissures,  which  usually  varied  from  10  to 
45  degrees  W.  of  north,  and  were  often  parallel  to  each  other ;  I  found, 
however,  a  considerable  diversity  in  their  direction.  Many  of  them  are 
traceable  for  half  a  mile  and  upwards,  but  they  might  easily  be  mis- 
taken for  artificial  trenches  if  resident  settlers  were  not  there  to  assure 
us  that  within  their  recollection  they  were  "  as  deep  as  wells."  Frag- 
ments of  coaly  shale  were  strewed  along  the  edges  of  some  of  these 
open  fissures,  together  with  white  sand,  in  the  same  manner  as  round 
the  "sinkholes."* 

Among  other  monuments  of  the  changes  wrought  in  1811-12,  I  ex- 
plored the  bed  of  the  lake  called  Eulalie,  near  New  Madrid,  300  yards 
long  by  100  yards  in  width,  which  was  suddenly  drained  during  the 
earthquake.  The  parallel  fissures  by  wThich  the  waters  escaped  are  not 
yet  entirely  closed,  and  all  the  trees  growing  on  its  bottom  were  at  the 
time  of  my  visit  less  than  34  years  old.  They  consisted  of  cotton- wood, 
willows,  and  honey-locust,  and  other  species,  differing  from  those  cloth- 
ing the  surrounding  higher  grounds,  which  are  more  elevated  by  12  or 
15  feet.  On  them  the  hickory,  the  black  and  white  oak,  the  gum  and 
other  trees,  many  of  them  of  ancient  date,  were  flourishing. 

Aleutian  Islands,  1806. — In  the  year  1806,  a  new  island,  in  the  form 
of  a  peak,  with  some  low  conical  hills  upon  it,  is  said  to  have  risen  from 
the  sea  among  the  Aleutian  Islands,  east  of  Kamtschatka.  According  to 
Langsdorf,f  it  was  four  geographical  miles  in  circumference ;  and  Von 
Buch  infers  from  its  magnitude,  and  from  its  not  having  again  subsided 
below  the  level  of  the  sea,  that  it  did  not  consist  merely  of  ejected  mat- 
ter, but  of  a  solid  rock  of  trachyte  upheaved.^  Another  extraordinary 
eruption  happened  in  the  spring  of  the  year  1814,  in  the  sea  near  Una- 
laschka,  in  the  same  archipelago.  A  new  isle  was  then  produced  of 
considerable  size,  and  with  a- peak  three  thousand  feet  high,  which  re- 
mained standing  for  a  year  afterwards,  though  with  somewhat  dimin- 
ished height. 

Although  it  is  not  improbable  that  earthquakes  accompanying  these 

*  See  Lyell's  Second  Visit  to  the  United  States,  ch.  xxxiii. 
f  Bemerkungen  auf  einer  Reise  um  die  Welt.  bd.  ii.  s.  209. 
\  Neue  Allgem.  Geogr.  Ephemer.  bd.  iii.  s.  348. 


CH.  XX VI I]  EARTHQUAKE   OF   QUITO.  469 

tremendous  eruptions  may  have  heaved  up  part  of  the  bed  of  the  sea, 
yet  the  circumstance  of  the  islands  not  having  disappeared  like  Sabrina 
(see  p.  416),  may  have  arisen  from  the  emission  of  lava.  If  Jorullo,  for 
example,  in  1759,  had  risen  from  a  shallow  sea  to  the  height  of  1600 
feet,  instead  of  attaining  that  elevation  above  the  Mexican  plateau,  the 
massive  current  of  basaltic  lava  which  poured  out  from  its  crater  would 
have  enabled  it  to  withstand,  for  a  long  period,  the  action*  of  a  turbu- 
lent sea. 

Reflections  on  the  earthquakes  of  the  nineteenth  century. — We  are  now 
about  to  pass  on  to  the  events  of  the  eighteenth  century  ;  but  before  we 
leave  the  consideration  of  those  already  enumerated,  let  us  pause  for  a 
moment,  and  reflect  how  many  remarkable  facts  of  geological  interest 
are  afforded  by  the  earthquakes  above  described,  though  they  constitute 
but  a  small  part  of  the  convulsions  even  of  the  last  forty  years.  New 
rocks  have  risen  from  the  waters ;  new  hot  springs  have  burst  out,  and 
the  temperature  of  others  has  been  raised ;  the  coast  of  Chili  has  been 
thrice  permanently  elevated ;  a  considerable  tract  in  the  delta  of  the 
Indus  has  sunk  down,  and  some  of  its  shallow  channels  have  become 
navigable  ;  an  adjoining  part  of  the  same  district,  upwards  of  fifty  miles 
in  length  and  sixteen  in  breadth,  has  been  raised  about  ten  feet  above  its 
former  level ;  part  of  the  great  plain  of  the  Mississippi,  for  a  distance  of 
eighty  miles  in  length  by  thirty  in  breadth,  has  sunk  down  several  feet ; 
the  town  of  Tomboro  has  been  submerged,  and  twelve  thousand  of  the 
inhabitants  of  Sumbawa  have  been  destroyed.  Yet,  with  a  knowledge 
of  these  terrific  catastrophes,  witnessed  during  so  brief  a  period  by  the 
present  generation,  will  the  geologist  declare  with  perfect  composure 
that  the  earth  has  at  length  settled  into  a  state  of  repose  ?  Will  he 
continue  to  assert  that  the  changes  of  relative  level  of  land  and  sea,  so 
common  in  former  ages  of  the  world,  have  now  ceased  ?  If,  in  the  face 
of  so  many  striking  facts,  he  persists  in  maintaining  this  favorite  dogma, 
it  is  in  vain  to  hope  that,  by  accumulating  the  proofs  of  similar  convul- 
sions during  a  series  of  antecedent  ages,  we  shall  shake  his  tenacity  of 
purpose : — 

Si  fractus  illabatur  orbis 
Impavidum  ferient  ruinae. 

EARTHQUAKES    OF    THE    EIGHTEENTH    CENTURY. 

Quito,  1797. — On  the  morning  of  February  4th,  1797,  the  volcano 
of  Tunguragua  in  Quito,  and  the  surrounding  district,  for  forty  leagues 
from  south  to  north,  and  twenty  leagues  from  west  to  east,  experienced 
an  undulating  movement,  which  lasted  four  minutes.  The  same  shock 
was  felt  over  a  tract  of  170  leagues  from  south  to  north,  from  Piura  to 
Popayan ;  and  140  from  west  to  east,  from  the  sea  to  the  river  Napo. 
In  the  smaller  district  first  mentioned,  where  the  movement  was  more 
intense,  every  town  was  levelled  to  the  ground ;  and  Riobamba,  Quero, 
and  other  places,  were  buried  under  masses  detached  from  the  moun- 


470  EARTHQUAKES   OF   CUMANA,  QUEBEC,  ETC.      [On.  XXVII 

tains.  At  the  foot  of  Tunguragua  the  earth  was  rent  open  in  several 
places  ;  and  streams  of  water  and  fetid  mud,  called  "  moya,"  poured 
out,  overflowing  and  wasting  every  thing.  In  valleys  1000  feet  broad, 
the  water  of  these  floods  reached  to  the  height  of  600  feet ;  and  the 
mud  deposit  barred  up  the  course  of  the  river,  so  as  to  form  lakes, 
which  in  some  places  continued  for  more  than  eighty  days.  Flames  and 
suffocating  Vapors  escaped  from  the  lake  Quilotoa,  and  killed  all  the 
cattle  on  its  shores.  The  shocks  continued  all  February  and  March  ; 
and  on  the  5th  of  April  they  recurred  with  almost  as  much  violence  as 
at  first.  We  are  told  that  the  form  of  the  surface  in  the  district  most 
shaken  was  entirely  altered,  but  no  exact  measurements  are  given 
whereby  we  may  estimate  the  degree  of  elevation  or  subsidence.*  In- 
deed it  would  be  difficult,  except  in  the  immediate  neighborhood  of  the 
sea,  to  obtain  any  certain  standard  of  comparison  if  the  levels  were  really 
as  much  altered  as  the  narrations  imply. 

Cumana,  1797. — In  the  same  year,  on  the  14th  of  December,  the 
small  Antilles  experienced  subterranean  movements,  and  four-fifths  of 
the  town  of  Cumana  was  shaken  down  by  a  vertical  shock.  The  form 
of  the  shoal  of  Mornerouge,  at  the  mouth  of  the  river  Bourdones,  was 
changed  by  an  upheaving  of  the  ground. f 

Canada — Quebec,  1791. — We  learn  from  Captain  Bayfield's  memoirs, 
that  earthquakes  are  very  frequent  on  the  shore  of  the  estuary  of  the 
St.  Lawrence,  of  force  sufficient  at  times  to  split  walls  and  throw  down 
chimneys.  Such  were  the  effects  experienced  in  December,  1721,  in  St. 
Paul's  Bay,  about  fifty  miles  N.  E.  from  Quebec ;  and  the  inhabitants 
say,  that  about  every  twenty-five  years  a  violent  earthquake  returns, 
which  lasts  forty  days.  In  the  History  of  Canada,  it  is  stated  that,  in 
1663,  a  tremendous  convulsion  lasted  six  months,  extending  from  Que- 
bec to  Tadeausac, — a  distance  of  about  130  miles.  The  ice  on  the 
river  was  broken  up,  and  many  landslips  caused. J 

Caraccas,  1790. — In  the  Caraccas,  near  where  the  Caura  joins  the 
Orinoco,  between  the  towns  San  Pedro  de  Alcantara  and  San  Francisco 
de  Aripao,  an  earthquake,  on  St.  Matthew's  day  1790,  caused  a  sinking 
in  of  the  granitic  soil,  and  left  a  lake  800  yards  in  diameter,  and  from 
eighty  to  one  hundred  in  depth.  It  was  a  portion  of  the  forest  of  Ari- 
pao which  subsided,  and  the  trees  remained  green  for  several  months 
under  water. § 

Sicily,  1790. — On  the  18th  of  March  in  the  same  year,  at  S.  Maria 
di  Niscemi,  some  miles  from  Terranuova,  near  the  south  coast  of  Sicily, 
the  ground  gradually  sunk  down  for  a  circumference  of  three  Italian 
miles,  during  seven  shocks ;  and,  in  one  place,  to  the  depth  of  thirty 
feet.  It  continued  to  subside  to  the  end  of  the  month.  Several  fissures 
sent  forth  sulphur,  petroleum,  steam,  and  hot  water,  and  a  stream  of 

*  Cavanilles,  Journ.  de  Phys.  tome  xlix.  p.  230.  Gilbert's  Annalen,  bcL  vi. 
Humboldt's  Voy.  p.  317. 

f  Humboldt's  Voy.,  Relat.  Hist.,  part.  i.  p.  309. 

1  Macgregor's  Travels  in  America. 

§  Humboldt's  Voy.,  Relat.  Hist.,  part.  ii.  p.  632, 


CH.  XXVIIL]          EARTHQUAKES    IN    JAVA   AND   CALABKIA.  471 

mud,  which  flowed  for  two  hours,  and  covered  a  space  sixty  feet  long 
and  thirty  broad.  This  happened  far  from  both  the  ancient  and  modern 
volcanic  district,  in  a  group  of  strata  consisting  chiefly  of  blue  clay.* 

Java,  1786. — About  the  year  1786,  an  earthquake  was  felt  at  inter- 
vals, for  the  period  of  four  months,  in  the  neighborhood  of  Batur,  in 
Java,  and  an  eruption  followed.  Various  rents  were  formed,  which 
emitted  a  sulphurous  vapor ;  separate  tracts  sunk  away,  and  were 
swallowed  by  the  earth.  Into  one  of  these  the  rivulet  Dotog  entered, 
and  afterwards  continued  to  follow  a  subterraneous  course.  The  village 
of  Jampang  was  buried  in  the  ground,  with  thirty-eight  of  its  inhabit- 
ants, who  had  not  time  to  escape.  We  are  indebted  to  Dr.  Horsfield 
for  having  verified  the  above-mentioned  facts.f 


CHAPTER  XXVIIL 

EARTHQUAKE  IN  CALABRIA,  1783. 

Earthquake  in  Calabria,  February  5,  1783— Shocks  continued  to  the  end  of  the 
year  1786 — Authorities — Area  convulsed — Geological  structure  of  the  district 
— Difficulty  of  ascertaining  changes  of  level — Subsidence  of  the  quay  at  Messi- 
na— Movement  in  the  stones  of  two  obelisks — Shift  or  fault  in  the  Round  Tower 
of  Terranuova — Opening  and  closing  of  fissures — Large  edifices  engulfed — 
Dimensions  of  new  caverns  and  fissures — Gradual  closing  in  of  rents — Bounding 
of  detached  masses  into  the  air — Landslips — Buildings  transported  entire  to 
great  distances — New  lakes — Funnel-shaped  hollows  in  alluvial  plains — Cur- 
rents of  mud — Fall  of  cliffs,  and  shore  near  Scilla  inundated — State  of  Strom- 
boli  and  Etna  during  the  shocks — Ho\v  earthquakes  contribute  to  the  formation 
of  valleys — Concluding  remarks. 

Calabria,  1783. — OF  the  numerous  earthquakes  which  have  occurred 
in  different  parts  of  the  globe,  during  the  last  100  years,  that  of  Cala- 
bria, in  1783,  is  almost  the  only  one  of  which  the  geologist  can  be  said 
to  have  such  a  circumstantial  account  as  to  enable  him  fully  to  appre- 
ciate the  changes  which  this  cause  is  capable  of  producing  in  the  lapse 
of  ages.  The  shocks  began  in  February,  1783,  and  lasted  for  nearly 
four  years,  to  the  end  of  1786.  Neither  in  duration,  nor  in  violence, 
nor  in  the  extent  of  territory  moved,  was  this  convulsion  remarkable, 
when  contrasted  with  many  experienced  in  other  countries,  both  during 
the  last  and  present  century  ;  nor  were  the  alterations  which  it  occa- 
sioned in  the  relative  level  of  hill  and  valley,  land  and  sea,  so  great  as 
those  effected  by  some  subterranean  movements  in  South  America,  in 
later  times.  The  importance  of  the  earthquake  in  question  arises  from 
the  circumstance,  that  Calabria  is  the  only  spot  hitherto  visited,  both 

*  Ferrara,  Camp,  fl.,  p.  51.  f  Batav.  Trans,  vol.  viii.  p.  141. 


472 


EARTHQUAKE   IN    CALABRIA. 


[On.  XXVIII. 


during  and  after  the  convulsions,  by  men  possessing  sufficient  leisure, 
zeal,  and  scientific  information,  to  enable  them  to  collect  and  describe 
with  accuracy  the  physical  facts  which  throw  light  on  geological  ques- 
tions. 

Authorities. — Among  the  numerous  authorities,  Vivenzio,  physician 
to  the  king  of  Naples,  transmitted  to  the  court  a  regular  statement  of 
his  observations  during  the  continuance  of  the  shocks  ;  and  his  narra- 
tive is  drawn  up  with  care  and  clearness.*  Francesco  Antonio  Gri- 
maldi,  then  secretary  of  war,  visited  the  different  provinces  at  the  king's 
command,  and  published  a  most  detailed  description  of  the  permanent 
changes  in  the  surface.f  He  measured  the  length,  breadth,  and  depth 


16 


Fig.  42. 


of  the  different  fissures  and  gulfs  which  opened,  and  ascertained  their 
number  in  many  provinces.  His  comments,  moreover,  on  the  reports  of 
the  inhabitants,  and  his  explanations  of  their  relations,  are  judicious  and 
instructive.  Pignataro,  a  physician  residing  at  Monteleone,  a  town 
placed  in  the  very  centre  of  the  convulsions,  kept  a  register  of  the 
shocks,  distinguishing  them  into  four  classes,  according  to  their  degree 
of  violence.  From  his  work,  it  appears  that,  in  the  year  1783,  the 
number  was  949,  of  which  501  were  shocks  of  the  first  degree  of  force  ; 

*  Istoria  de'  Tremuoti  della  Calabria  del  1783. 

f  Descriz.  de'  Tremuoti  Accad.  nelle  Calabria  nel  1783.     Napoli,  1784. 


CH.  XXVIII. ]  EARTHQUAKE   IN   CALABRIA,    1783.  473 

and  in  the  following  year  there  were  151,  of  which  98  were  of  the  first 
magnitude. 

Count  Ippolito,  also,  and  many  others,  wrote  descriptions  of  the 
earthquake  ;  and  the  Royal  Academy  of  Naples,  not  satisfied  with  these 
and  other  observations,  sent  a  deputation  from  their  own  body  into  Cala- 
bria, before  the  shocks  had  ceased,  who  were  accompanied  by  artists  in- 
structed to  illustrate  by  drawings  the  physical  changes  of  the  district, 
and  the  state  of  ruined  towns  and  edifices.  Unfortunately  these  artists 
were  not  very  successful  in  their  representations  of  the  condition  of  the 
country,  particularly  when  they  attempted  to  express,  on  a  large  scale, 
the  extraordinary  revolutions  which  many  of  the  great  and  minor  river- 
courses  underwent.  But  many  of  the  plates  published  by  the  Academy 
are  valuable  ;  and  as  they  are  little  known,  I  sjiall  frequently  avail  my- 
self of  them  to  illustrate  the  facts  about  to  be  described.* 

In  addition  to  these  Neapolitan  sources  of  information,  our  country- 
man, Sir  William  Hamilton,  surveyed  the  district,  not  without  some 
personal  risk,  before  the  shocks  had  ceased  ;  and  his  sketch,  published 
in  the  Philosophical  Transactions,  supplies  many  facts  that  would  other- 
wise have  been  lost.  He  has  explained,  in  a  rational  manner,  many 
events  which,  as  related  in  the  language  of  some  eye-witnesses,  appeared 
marvellous  and  incredible.  Dolomieu  also  examined  Calabria  during 
the  catastrophe,  and  wrote  an  account  of  the  earthquake,  correcting  a 
mistake  into  which  Hamilton  had  fallen,  who  supposed  that  a  part  of 
the  tract  shaken  had  consisted  of  volcanic  tuff.  It  is,  indeed,  a  circum- 
stance which  enhances  the  geological  interest  of  the  commotions  which 
so  often  modify  the  surface  of  Calabria,  that  they  are  confined  to  a 
country  where  there  are  neither  ancient  nor  modern  rocks  of  volcanic 
or  trappean  origin ;  so  that  at  some  future  time,  when  the  era  of  dis- 
turbance shall  have  passed  by,  the  cause  of  former  revolutions  will  be 
as  latent  as  in  parts  of  Great  Britain  now  occupied  exclusively  by  ancient 
marine  formations. 

Extent  of  the  area  convulsed. — The  convulsion  of  the  earth,  sea,  and 
air  extended  over  the  whole  of  Calabria  Ultra,  the  southeast  part  of 
Calabria  Citra,  and  across  the  sea  to  Messina  and  its  environs ;  a  district 
lying  between  the  38th  and  39th  degrees  of  latitude.  The  concussion 
was  perceptible  over  a  great  part  of  Sicily,  and  as  far  north  as  Naples ; 
but  the  surface  over  which  the  shocks  acted  so  forcibly  as  to  excite 
intense  alarm  did  not  generally  exceed  500  square  miles  in  area.  The 
soil  of  that  part  of  Calabria  is  composed  chiefly,  like  the  southern  part 
of  Sicily,  of  calcareo- argillaceous  strata  of  great  thickness,  containing 
marine  shells.  This  clay  is  sometimes  associated  with  beds  of  sand  and 
limestone.  For  the  most  part  these  formations  resemble  in  appearance 
and  consistency  the  Subapennine  marls,  with  their  accompanying  sands 
and  sandstones  ;  and  the  whole  group  bears  considerable  resemblance, 

*  Istoria  de'  Fenomeni  del  Tremoto,  (fee.,  nell'  An.  1783,  posta  in  luce  dalla  Real. 
Accad.,  Ac.  di  Nap.  Napoli,  1783,  foL 


474  EXTENT   OF   THE   AREA   CONVULSED.  [On.  XXVIII. 

in  the  yielding  nature  of  its  materials,  to  most  of  our  tertiary  deposits 
in  France  and  England.  Chronologically  considered,  however,  the  Cala- 
brian  formations  are  comparatively  of  modern  date,  often  abounding  in 
fossil  shells  referable  to  species  now  living  in  the  Mediterranean. 

We  learn  from  Vivencio,  that  on  the  20th  and  26th  of  March,  1783, 
earthquakes  occurred  in  the  islands  of  Zante,  Cephalonia,  and  St.  Maura  ; 
and  in  the  last- mentioned  island  several  public  edifices  and  private 
houses  were  overthrown,  and  many  people  destroyed. 

If  the  city  of  Oppido,  in  Calabria  Ultra,  be  taken  as  a  centre,  and 
round  that  centre  a  circle  be  described,  with  a  radius  of  twenty-two 
miles,  this  space  will  comprehend  the  surface  of  the  country  which 
suffered  the  greatest  alteration,  and  where  all  the  towns  and  villages 
were  destroyed.  The  first  shock,  of  February  5th,  1783,  threw  down, 
in  two  minutes,  the  greater  part  of  the  houses  in  all  the  cities,  towns, 
and  villages,  from  the  western  flanks  of  the  Apennines  in  Calabria  Ultra 
to  Messina  in  Sicily,  and  convulsed  the  whole  surface  of  the  country. 
Another  occurred  on  the  28th  of  March,  with  almost  equal  violence. 
The  granitic  chain  which  passes  through  Calabria  from  north  to  south, 
and  attains  the  height  of  many  thousand  feet,  was  shaken  but  slightly 
by  the  first  shock,  but  more  rudely  by  some  which  followed. 

Some  writers  have  asserted  that  the  wave-like  movements  which 
were  propagated  through  the  recent  strata,  from  west  to  east,  became 
very  violent  when  they  reached  the  point  of  junction  with  the  granite, 
as  if  a  reaction  was  produced  where  the  undulatory  movement  of  the 
soft .  strata  was  suddenly  arrested  by  the  more  solid  rocks.  But  the 
statement  of  Dolomieu  on  this  subject  is  most  interesting,  and  perhaps, 
in  a  geological  point  of  view,  the  most  important  of  all  the  observations 
which  are  recorded.*  The  Apennines,  he  says,  which  consist  in  great 
part  of  hard  and  solid  granite,  with  some  micaceous  and  argillaceous 
schists,  form  bare  mountains  with  steep  sides,  and  exhibit  marks  of 
great  degradation.  At  their  base  newer  strata  are  seen  of  sand  and 
clay,  mingled  with  shells ;  a  marine  deposit  containing  such  ingredients 
as  would  result  from  the  decomposition  of  granite.  The  surface  of  this 
newer  (tertiary]  formation  constitutes  what  is  called  the  plain  of  Cala- 
bria— a  platform  which  is  flat  and  level,  except  where  intersected  by 
narrow  valleys  or  ravines,  which  rivers  and  torrents  have  excavated 
sometimes  to  the  depth  of  six  hundred  feet.  The  sides  of  these  ravines 
are  almost  perpendicular;  for  the  superior  stratum,  being  bound  to- 
gether by  the  roots  of  trees,  prevents  the  formation  of  a  sloping  bank. 
The  usual  effect  of  the  earthquake,  he  continues,  was  to  disconnect  all 
those  masses  which  either  "had  not  sufficient  bases  for  their  bulk,  or 
which  was  supported  only  by  lateral  adherence.  Hence  it  follows  that 
throughout  almost  the  whole  length  of  the  chain,  the  soil  which  adhered 
to  the  granite  at  the  base  of  the  mountains  Caulone,  Esope,  Sagra,  and 


*  Dissertation  on  the  Calabrian  Earthquake,  (fee.,  translated  in  Pinkerton's 
Voyages  and  Travels,  vol.  v. 


CH.  XXVIII.]  EARTHQUAKE    IN    CALABKIA.  475 

Aspramonte,  slid  over  the  solid  and  steeply  inclined  nucleus,  and  de- 
scended somewhat  lower,  leaving  almost  uninterruptedly  from  St. 
George  to  beyond  St.  Christina,  a  distance  of  from  nine  to  ten  miles,  a 
chasm  between  the  solid  granitic  nucleus  and  the  sandy  soil.  Many 
lands  slipping  thus  were  carried  to  a  considerable  distance  from  their 
former  position,  so  as  entirely  to  cover  others ;  and  disputes  arose  as  to 
whom  the  property  which  had  thus  shifted  its  place  should  belong. 

From  this  account  of  Dolomieu  we  might  anticipate,  as  the  result  of  a 
continuance  of  such  earthquakes,  first,  a  longitudinal  valley  following  the 
line  of  junction  of  the  older  and  newer  rocks  ;  secondly,  greater  disturb- 
ance in  the  newer  strata  near  the  point  of  contact  than  at  a  greater  dis- 
tance from  the  mountains ;  phenomena  very  common  in  other  parts  of 
Italy  at  the  junction  of  the  Apennine  and  Subapennine  formations. 

Mr.  Mallet,  in  his  valuable  essay  on  the  Dynamics  of  Earthquakes,* 
offers  the  following  explanation  of  the  fact  to  which  Dolomieu  has  called 
attention.  When  a  wave  of  elastic  compression,  of  which  he  considers 
the  earth-wave  to  consist,  passes  abruptly  from  a  body  having  an  ex- 
tremely low  elasticity,  such  as  clay  and  gravel,  into  another  like  granite, 
whose  elasticity  is  remarkably  high,  it  changes  not  cnly  its  velocity  but 
in  part  also  its  course,  a  portion  being  reflected  and  a  portion  refracted. 
The  wave  being  thus  sent  back  again  produces  a  shock  in  the  opposite 
direction,  doing  great  damage  to  buildings  on  the  surface  by  thus  re- 
turning upon  itself.  At  the  same  time,  the  shocks  are  at  once  eased 
when  they  get  into  the  more  elastic  materials  of  the  granitic  mountains. 

The  surface  of  the  country  during  the  Calabrian  earthquakes  often 
heaved  like  the  billows  of  a  swelling  sea,  which  produced  a  swimming 
in  the  head,  like  sea-sickness.  It  is  particularly  stated,  in  almost  all  the 
accounts,  that  just  before  each  shock  the  clouds  appeared  motionless ; 
and,  although  no  explanation  is  offered  of  this  phenomenon,  it  is  obvi- 
ously the  same  as  that  observed  in  a  ship  at  sea  when  it  pitches  violently. 
The  clouds  seem  arrested  in  their  career  as  often  as  the  vessel  rises  in  a 
direction  contrary  to  their  course  ;  so  that  the  Calabrians  must  have  ex- 
perienced precisely  the  same  motion  on  the  land. 

Trees,  supported  by  their  trunks,  sometimes  bent  during  the  shocks 
to  the  earth,  and  touched  it  with  their  tops.  This  is  mentioned  as  a 
well-known  fact  by  Dolomieu ;  and  he  assures  us  that  he  was  always 
on  his  guard  against  the  spirit  of  exaggeration  in  which  the  vulgar  are 
ever  ready  to  indulge  when  relating  these  wonderful  occurrences. 

It  is  impossible  to  suppose  that  these  waves,  which  are  described  in 
Italy  and  other  regions  of  earthquakes  as  passing  along  the  solid  surface 
of  the  earth  in  a  given  direction  like  a  billow  on  the  sea,  have  any  strict 
analogy  with  the  undulations  of  a  fluid.  They  are  doubtless  the  effects 
of  vibrations,  radiating  from  some  deep-seated  point,  each  of  which  on 
reaching  the  surface  lifts  up  the  ground,  and  then  allows  it  again  to  sub- 
side. As  the  distance  between  the  source  of  the  subterranean  move- 

*  Proceed.  Roy.  Irish  Acad.  1846,  p.  26. 


476  EARTHQUAKE   IN    CALABRIA,  1783.  [Cn.  XXVIII. 

ment  and  the  surface  must  vary  according  to  the  outline  of  the  country, 
so  the  vibratory  jar  will  reach  different  points  in  succession. 

The  Academicians  relate  that  in  some  of  the  cities  of  Calabria  effects 
were  produced  seeming  to  indicate  a  whirling  or  vorticose  movement. 
Thus,  for  example,  two  obelisks  (fig.  75 )  placed  at  the  extremities  of  a 

Fig.  75. 


Shifts  in  the  stones  of  two  obelisks  in  the  Convent  of  St  Bruno. 

magnificent  fagade  in  the  convent  of  S.  Bruno,  in  a  small  town  called 
Stefano  del  Bosco,  were  observed  to  have  undergone  a  movement  of  a 
singular  kind.  The  shock  which  agitated  the  building  is  described  as 
having  been  horizontal  and  vorticose.  The  pedestal  of  each  obelisk 
remained  in  its  original  place ;  but  the  separate  stones  above  were 
turned  partially  round,  and  removed  sometimes  nine  inches  from  their 
position  without  falling. 

It  has  been  suggested  by  Mr.  Darwin  that  this  kind  of  displacement 
may  be  due  to  a  vibratory  rather  than  a  whirling  motion  ;*  and  more 
lately  Mr.  Mallet,  in  the  paper  already  cited,  has  offered  a  very  inge- 
nious solution  of  the  problem.  He  refers  the  twisting  simply  to  an  elastic 
wave,  which  has  moved  the  pedestal  forwards  and  back  again,  by  an 
alternate  horizontal  motion  within  narrow  limits,  and  he  has  succeeded 
in  showing  that  a  rectilinear  movement  in  the  ground  may  have  sufficed 
to  cause  an  incumbent  body  to  turn  partially  round  upon  its  bed,  pro- 
vided a  certain  relation  exist  between  the  position  of  the  centre  of  gravity 
of  the  body  and  its  centre  of  adherence. f 

I  shall  now  consider,  in  the  first  place,  that  class  of  physical  changes 
produced  by  the  earthquake  which  are  connected  with  alterations  in  the 
relative  level  of  the  different:  parts  of  the  land  ;  and  afterwards  describe 
those  which  are  more  immediately  connected  with  the  derangement  of 
the  regular  drainage  of  the  country,  and  where  the  force  of  running  water 
co-operated  with  that  of  the  earthquake. 

Difficulty  of  ascertaining  changes  of  level. — In  regard  to  alterations  of 

*  Journal  of  a  Naturalist,  p.  376,  and  ii.  ib.  308. 
f  Proceedings  Roy.  Irish  Acad.  1846,  pp.  14-16. 


CH.  XXVIII.]  CHANGES    OF    RELATIVE    LEVEL.  477 

relative  level,  none  of  the  accounts  establish  that  they  were  on  a  con- 
siderable scale ;  but  it  must  always  be  remembered  that,  in  proportion 
to  the  area  moved  is  the  difficulty  of  proving  that  the  general  level  has 
undergone  any  change,  unless  the  sea-coast  happens  to  have  participated 
in  the  principal  movement.  Even  then  it  is  often  impossible  to  deter- 
mine whether  an  elevation  or  depression  even  of  several  feet  has  occurred, 
because  there  is  nothing  to  attract  notice  in  a  band  of  shingle  and  sand 
of  unequal  breadth  above  the  level  of  the  sea  running  parallel  to  a  coast ; 
such  bands  generally  marking  the  point  reached  by  the  waves  during 
spring  tides,  or  the  most  violent  tempests.  The  scientific  investigator 
has  not  sufficient  topographical  knowledge  to  discover  whether  the  ex- 
tent of  beach  has  diminished  or  increased ;  and  he  who  has  the  necessary 
local  information,  scarcely  ever  feels  any  interest  in  ascertaining  the 
amount  of  the  rise  or  fall  of  the  ground.  Add  to  this  the  great  diffi- 
culty of  making  correct  observations,  in  consequence  of  the  enormous 
waves  which  roll  in  upon  a  coast  during  an  earthquake,  and  efface  every 
landmark  near  the  shore. 

Subsidence  of  the  quay  at  Messina. — It  is  evidently  in  seaports  alone 
that  we  can  look  for  very  accurate  indications  of  slight  changes  of  level ; 
and  when  we  find  them,  we  may  presume  that  they  would  not  be  rare 
at  other  points,  if  equal  facilities  of  comparing  relative  altitudes  were 
afforded.  Grimaldi  states  (and  his  account  is  confirmed  by  Hamilton  and 
others),  that  at  Messina,  in  Sicily,  the  shore  was  rent ;  and  the  soil  along 
the  port,  which  before  the  shock  was  perfectly  level,  was  found  afterwards 
to  be  inclined  towards  the  sea, — the  sea  itself  near  the  "  Banchina"  be- 
coming deeper,  and  its  bottom  in  several  places  disordered.  The  quay 
also  sunk  down  about  fourteen  inches  below  the  level  of  the  sea,  and  the 
houses  in  its  vicinity  were  much  fissured.  (Phil.  Trans.  1783.) 

Among  various  proofs  of  partial  elevation  and  depression  in  the  inte- 
rior, the  Academicians  mention,  in  their  Survey,  that  the  ground  was 
sometimes  on  the  same  level  on  both  sides  of  new  ravines  and  fissures, 
but  sometimes  there  had  been  a  considerable  shifting,  either  by  the  up- 
heaving of  one  side,  or  the  subsidence  of  the  other.  Thus,  on  the  sides 
of  long  rents  in  the  territory  of  Soriano,  the  stratified  masses  had  altered 
their  relative  position  to  the  extent  of  from  eight  to  fourteen  palms  (six 
to  ten  and  a  half  feet).  , 

Polistena. — Similar  shifts  in  the  strata  are  alluded  to  in  the  territory 
of  Polistena,  where  there  appeared  innumerable  fissures  in  the  earth. 
One  of  these  was  of  great  length  and  depth ;  and  in  parts  the  level  of 
the  corresponding  sides  was  greatly  changed.  (See  fig.  76.) 

Terranuova. — In  the  town  of  Terranuova  some  houses  were  seen  up- 
lifted above  the  common  level,  and  others  adjoining  sunk  down  into  the 
earth.  In  several  streets  the  soil  appeared  thrust  up,  and  abutted 
against  the  walls  of  houses :  a  large  circular  tower  of  solid  masonry, 
part  of  which  had  withstood  the  general  destruction,  was  divided  by  a 
vertical  rent,  and  one  side  was  upraised,  and  the  foundations  heaved  out 
of  the  ground.  It  was  compared  by  the  Academicians  to  a  great  tooth 


4Y8 


EARTHQUAKE    IN    CALABEIA,  1783.  [On.  XXVIII. 

Fig.  76. 


Deep  fissure,  near  Polistena,  caused  by  the  earthquake  of  1783. 


half  extracted  from  the  alveolus,  with  the  upper  part  of  the  fangs  ex- 
posed.    (See  fig.  77.) 

Along  the  line  of  this  shift,  or  "  fault,"  as  it  would  be  termed  techni- 
cally by  miners,  the  walls  were  found  to  adhere  firmly  to  each  other,  and 
to  fit  so  well,  that  the  only  signs  of  their  having  been  disunited  was  the 
want  of  correspondence  in  the  courses  of  stone  on  either  side  of  the  rent. 

Fig.  7T. 


IS-,. 


Shift  or  "fault"  in  the  Bound  Tower  of  Terranuova  in  Calabria,  occasioned  by  the  earthquake  of 

Dolomieu  saw  a  stone  well  in  the  convent  of  the  Augustins  at  Terra- 
nuova, which  had  the  appearance  of  having  been  driven  out  of  the  earth. 
It  resembled  a  small  tower  eight  or  nine  feet  in  height,  and  a  little  in- 
clined. This  effect,  he  says,  was  produced  by  the  consolidation  and 
consequent  sinking  of  the  sandy  soil  in  which  the  well  was  dug. 


CH.  XXVIII.]          EARTHQUAKE   IN    CALABKIA,  1783.  479 

In  some  walls  which  had  been  thrown  down,  or  violently  shaken,  in 
Monteleone,  the  separate  stones  were  parted  from  the  mortar,  so  as  to 
leave  an  exact  mould  where  they  had  rested ;  whereas  in  other  cases 
the  mortar  was  ground  to  dust  between  the  stones. 

It  appears  that  the  wave-like  motions  often  produced  effects  of  the 
most  capricious  kind.  Thus,  in  some  streets  of  Monteleone,  every  house 
was  thrown  down  but  one ;  in  others,  all  but  two  ;  and  the  buildings 
which  were  spared  were  often  scarcely  in  the  least  degree  injured.  In 
m'any  cities  of  Calabria,  all  the  most  solid  buildings  were  thrown  down, 
while  those  which  were  slightly  built  escaped  ;  but  at  Rosarno,  as  also 
at  Messina  in  Sicily,  it  was  precisely  the  reverse,  the  massive  edifices 
being  the  only  ones  that  stood. 

Fissures. — It  appears  evident  that  a  great  part  of  the  rending  and 
fissuring  of  the  ground  was  the  effect  of  a  violent  motion  from  below 
upwards ;  and  in  a  multitude  of  cases  where  the  rents  and  chasms 
opened  and  closed  alternately,  we  must  suppose  that  the  earth  was  by 
turns  heaved  up,  and  then  let  fall  again.*  We  may  conceive  the  same 
effect  to  be  produced  on  a  small  scale,  if,  by  some  mechanical  force,  a 
pavement  composed  of  large  flags  of  stone  should  be  raised  up,  and 
then  allowed  to  fall  suddenly,  so  as  to  resume  its  original  position.  If 
any  small  pebbles  happened  to  be  lying  on  the  line  of  contact  of  two 
flags,  they  would  fall  into  the  opening  when  the  pavement  rose,  and  be 
swallowed  up,  so  that  no  trace  of  them  would  appear  after  the  subsi- 
dence of  the  stones.  In  the  same  manner,  when  the  earth  was  up- 
heaved, large  houses,  trees,  cattle,  and  men  were  engulfed  in  an  instant 
in  chasms  and  fissures ;  and  when  the  ground  sank  down  again,  the 
earth  closed  upon  them,  so  that  no  vestige  of  them  was  discoverable 
on  the  surface.  In  many  instances,  individuals  were  swallowed  up  by 
one  shock,  and  then  thrown  out  again  alive,  together  with  large  jets  of 
water,  by  the  shock  which  immediately  succeeded. 

Fig.  78. 


Fissures  near  Jerocarue,  in  Calabria,  caused  by  the  earihquake  of  17S3. 
*  See  Mr.  Mallet's  attempt  to  controvert  this  view,  p.  32  ibid. 


480 


EARTHQUAKE   IN   CALABKIA,    1783.  [Cfl.  XXVIII. 


At  Jerocarne,  a  country  which,  according  to  the  Academicians,  was 
lacerated  in  a  most  extraordinary  manner,  the  fissures  ran  in  every  direc- 
tion, "like  cracks  on  a  broken  pane  of  glass"  (see  fig.  78);  and  as  a 
great  portion  of  them  remained  open  after  the  shocks,  it  is  very  possible 
that  this  country  was  permanently  upraised.  It  was  usual,  as  we  learn 
from  Dolomieu,  for  the  chasms  and  fissures  throughout  Calabria,  to  run 
parallel  to  the  course  of  some  pre-existing  gorges  in  their  neighborhood. 

Houses  engulfed. — In  the  vicinity  of  Oppido,  the  central  point  from 
which  the  earthquake  diffused  its  violent  movements,  many  houses  were 
swallowed  up  by  the  yawning  earth,  which  closed  immediately  over 
them.  In  the  adjacent  district,  also,  -of  Cannamaria  four  farm-houses, 
several  oil-stores,  and  some  spacious  dwelling-houses  were  so  completely 
engulfed  in  one  chasm,  that  not  a  vestige  of  them  was  afterwards  dis- 
cernible. The  same  phenomena  occurred  at  Terranuova,  S.  Christina, 
and  Sinopoli.  The  Academicians  state  particularly,  that  when  deep 
abysses  had  opened  in  the  argillaceous  strata  of  Terranuova,  and  houses 
had  sunk  into  them,  the  sides  of  the  chasms  closed  with  such  violence, 
that,  on  excavating  afterwards  to  recover  articles  of  value,  the  workmen 
found  the  contents  and  detached  parts  of  the  buildings  jammed  together 
so  as  to  become  one  compact  mass.  It  is  unnecessary  to  accumulate  ex- 
amples of  similar  occurrences  ;  but  so  many  are  well  authenticated  during 
this  earthquake  in  Calabria,  that  we  may,  without  hesitation,  yield  assent 
to  the  accounts  of  catastrophes  of  the  same  kind  repeated  again  and 
again  in  history,  where  whole  towns  are  declared  to  have  been  engulfed, 
and  nothing  but  a  pool  of  water  or  tract  of  sand  left  in  their  place. 

Chasm  formed  near  Oppido. — On  the  sloping  side  of  a  hill  near 
Oppido  a  great  chasm  opened  ;  and,  although  a  large  quantity  of  soil 
was  precipitated  into  the  abyss,  together  with  a  considerable  number 
of  olive-trees  and  part  of  a  vineyard,  a  great  gulf  remained  after  the 
shock,  in  the  form  of  an  amphitheatre,  500  feet  long  and  200  feet  deep. 
(See  fig.  79.) 

Fig.  79. 


Chasm  formed  by  the  earthquake  of  1783,  near  Oppido  in  Calabria. 


CH.  XXVIII.]  EARTHQUAKE    IN    CALABRIA,    1783.  481 

Dimensions  of  new  fissures  and  chasms. — According  to  Grimaldi, 
many  fissures  and  chasms,  formed  by  the  first  shock  of  February  5th, 
were  greatly  widened,  lengthened,  and  deepened  by  the  violent  convul- 
sions of  March  28th.  In  the  territory  of  San  Fili  this  observer  found  a 
new  ravine,  half  a  mile  in  length,  two  feet  and  a  half  broad,  and  twenty- 
five  feet  deep  ;  and  another  of  similar  dimensions  in  the  territory  of 
Rosarno.  A  ravine  nearly  a  mile  long,  105  feet  broad  and  thirty  feet 
deep,  opened  in  the  district  of  Plaisano,  where,  also,  two  gulfs  were 
caused — one  in  a  place  called  Cerzulle,  three-quarters  of  a  mile  long, 
150  feet  broad,  and  above  one  hundred  feet  deep  ;  and  another  at  La 
Fortuna,  nearly  a  quarter  of  a  mile  long,  above  thirty  feet  in  breadth, 
and  no  less  than  225  feet  deep. 

In  the  district  of  Fosolano  three  gulfs  opened  :  one  of  these  meas- 
ured 300  feet  square,  and  above  thirty  feet  deep ;  another  was  nearly 
half  a  mile  long,  fifteen  feet  broad,  and  above  thirty-feet  deep  ;  the 
third  was  750  feet  square.  Lastly,  a  calcareous  mountain,  called 
Zefirio,  at  the  southern  extremity  of  the  Italian  peninsula,  was  cleft  in 
two  for  the  length  of  nearly  half  a  mile,  and  an  irregular  breadth  of 
many  feet.  Some  of  these  chasms  were  in  the  form  of  a  crescent. 
The  annexed  cut  (fig.  80)  represents  one  by  no  means  remarkable  for 

Fig.  SO. 


Chasm  in  the  hill  of  St  Angel o,  near  Soriano,  in  Calabria,  caused  by  the  earthquake  of  1733. 

its  dimensions,  which  remained  open  by  the.  side  of  a  small  pass  over 
the  hill  of  St.  Angelo,  near  Soriano.  The  small  river  Mesima  is  seen 
in  the  foreground. 

Formation  of  circular  hollows  and  new  lakes. — In  the  report  of  the 
Academy,  we. find  that  some  plains  were  covered  with  circular  hollows, 
for  the  most  part  about  the  size  of  carriage- wheels,  but  often  somewhat 
larger  or  smaller.  When  filled  with  water  to  within  a  foot  or  two  of 
the  surface,  they  appeared  like  wells  ;  but,  in  general,  they  were  filled 
with  dry  sand,  sometimes  with  a  concave  surface,  and  at  other  times 
convex.  (See  fig.  81.)  On  digging  down,  they  found  them  to  be  funnel- 

31 


482 


EARTHQUAKE   IN    CALABRIA,    1783.  [On.  XXVIIL 

Fig.  81. 


Circular  hollows  in  the  plain  of  Ilosan 


1  by  the  earthquake  of  1783. 


bhaped,  and  the  moist  loose  sand  in  the  centre  marked  the  tube  up 
which  the  water  spouted.  The  annexed  cut  (fig.  82)  represents  a  sec- 
tion of  one  of  these  inverted  cones  when  the  water  had  disappeared,  and 
nothing  but  dry  micaceous  sand  remained. 

Fig.  82. 


Section  of  one  of  the  circular  hollows  formed  in  the  plain  of  Eosarno. 

A  small  circular  pond  of  similar  character  was  formed  not  far  from 
Polistena  (see  fig.  83) ;  and  in  the  vicinity  of  Seminara,  a  lake  was  sud- 
denly caused  by  the  opening  of  a  great  chasm,  from  the  bottom  of  which 
water  issued.  This  lake  was  called  Lago  del  Tolfilo.  It  extended  1785 
feet  in  length,  by  937  in  breadth,  and  52  in  depth.  The  inhabitants, 
dreading  the  miasma  of  this  stagnant  pool,  endeavored,  at  great  cost,  to 
drain  it  by  canals,  but  without  success,  as  it  was  fed  by  springs  issuing 
from  the  bottom  of  the  deep  chasm. 

Vivenzio  states,  that  near  Sitizzano  a  valley  was  nearly  filled  up  to  a 
level  with  the  high  grounds  on  each  side,  by  the  enormous  masses  de- 


OH.  XXVIII.]  CLOSENG   OF   FISSURES.  4:83 

Fig.  83. 


Circular  pond  near  Polistena,  in  Calabria,  caused  by  the  earthquake  in  1783. 

tached  from  the  boundary  hills,  and  cast  down  into  the  course  of  two 
streams.  By  this  barrier  a  lake  was  formed  of  great  depth,  about  two 
miles  long  and  a  mile  broad.  The  same  author  mentions  that,  upon  the 
whole,  there  were  fifty  lakes  occasioned  during  the  convulsions  :  and  he 
assigns  localities  to  all  of  these.  The  government  surveyors  enumerated 
215  lakes  ;  but  they  included  in  this  number  many  small  ponds. 

Cones  of  sand  thrown  up. — Many  of  the  appearances  exhibited  in  the 
alluvial  plains,  such  as  springs  spouting  up  their  water  like,  fountains  at 
the  moment  of  the  shock,  have  been  supposed  to  indicate  the  alternate 
rising  and  sinking  of  the  ground.  The  first  effect  of  the  more  violent 
shocks  was  usually  to  dry  up  the  rivers,  but  they  immediately  afterwards 
overflowed  their  banks.  In  marshy  places,  an  immense  number  of  cones 
of  sand  were  thrown  up.  These  appearances  Hamilton  explains,  by 
supposing  that  the  first  movement  raised  the  fissured  plain  from  below 
upwards,  so  that  the  rivers  and  stagnant  waters  in  bogs  sank  down,  or 
at  least  were  not  upraised  with  the  soil.  But  when  the  ground  returned 
with  violence  to  its  former  position,  the  water  was  thrown  up  in  jets 
through  fissures.* 

The  phenomenon,  according  to  Mr.  Mallet,  may  be  simply  an  accident 
contingent  on  the  principal  cause  of  disturbance,  the  rapid  transit  of  the 
earth-wave.  "  The  sources,"  he  says,  "  of  copious  springs  usually  lie  in 
flat  plates  or  fissures  filled  with  water,  whether  issuing  from  solid  rock, 
or  from  loose  materials  ;  now,  if  a  vein,  or  thin  flat  cavity  filled  with 
water,  be  in  such  a  position  that  the  plane  of  the  plate  of  water  or  fis- 
sure be  transverse  to  the  line  of  transit  of  the  earth-wave,  the  effect  of 
the  arrival  of  the  earth-wave  at  the  watery  fissure  will  be,  at  the  instant, 
to  compress  its  walls  more  or  less  together,  and  so  squeeze  out  the  water, 
which  will,  for  a  moment,  gush  up  at  the  spring-head  like  a  fountain,  and 
again  remain  in  repose  after  the  transit  of  the  wave." 

Gradual  closing  in  of  fissures. — Sir  W.  Hamilton  was  shown  several 

*  Phil.  Trans,  vol.  Iwdii.  p.  180. 


484:  EARTHQUAKE   IN   CALABRIA,  1783.  [On.  XXVIII. 

deep  fissures  in  the  vicinity  of  Mileto,  which,  although  not  one  of  them 
was  above  a  foot  in  breadth,  had  opened  so  wide  during  the  earthquake 
as  to  swallow  an  ox  and  nearly  one  hundred  goats.  The  Academicians 
also  found,  on  their  return  through  districts  which  they  had  passed  at 
the  commencement  of  their  tour,  that  many  rents  had,  in  that  short 
interval,  gradually  closed  in,  so  that  their  width  had  diminished  several 
feet,  and  the  opposite  walls  had  sometimes  nearly  met.  It  is  natural 
that  this  should  happen  in  argillaceous  strata,  while,  in  more  solid  rocks, 
we  may  expect  that  fissures  will  remain  open  for  ages.  Should  this  be 
ascertained  to  be  a  general  fact  in  countries  convulsed  by  earthquakes, 
it  may  afford  a  satisfactory  explanation  of  a  common  phenomenon  in 
mineral  veins.  Such  veins  often  retain  their  full  size  so  long  as  the  rocks 
consist  of  limestone,  granite,  or  other  indurated  materials  ;  but  they  con- 
tract their  dimensions,  become  mere  threads,  or  are  even  entirely  cut  off, 
where  masses  of  an  argillaceous  nature  are  interposed.  If  we  suppose 
the  filling  up  of  fissures  with  metallic  and  other  ingredients  to  be  a  pro- 
cess requiring  ages  for  its  completion,  it  is  obvious  that  the  opposite  walls 
of  rents,  where  strata  consist  of  yielding  materials,  must  collapse  or 
approach  very  near  to  each  other  before  sufficient  time  is  allowed  for  the 
accretion  of  a  large  quantity  of  veinstone. 

Thermal  waters  augmented. — It  is  stated  by  Grimaldi,  that  the  ther- 
mal waters  of  St.  Eufemia,  in  Terra  di  Amato,  which  first  burst  out  dur- 
ing the  earthquake  of  1638,  acquired,  in  February,  1783,  an  augmen- 
tation both  in  quantity  and  degree  of  heat.  This  fact  appears  to  indicate 
a  connection  between  the  heat  of  the  interior  and  the  fissures  caused  by 
the  Calabrian  earthquakes,  notwithstanding  the  absence  of  volcanic  rocks, 
either  ancient  or  modern,  in  that  district. 

Bounding  of  detached  masses  into  the  air. — The  violence  of  the  move- 
ment of  the  ground  upwards  was  singularly  illustrated  by  what  the 
Academicians  call  the  "  sbalzo,"  or  bounding  into  the  air,  to  the  height 
of  several  yards,  of  masses  slightly  adhering  to  the  surface.  In  some 
towns  a  great  part  of  the  pavement  stones  were  thrown  up,  and  found 
lying  with  their  lower  sides  uppermost.  In  these  cases,  we  must  sup- 
pose that  they  were  propelled  upwards  by  the  momentum  which  they 
had  acquired  ;  and  that  the  adhesion  of  one  end  of  the  mass  being  greater 
than  that  of  the  other,  a  rotatory  motion  had  been  communicated  to  them. 
When  the  stone  was  projected  to  a  sufficient  height  to  perform  some- 
what more  than  a  quarter  of  a  revolution  in  the  air,  it  pitched  down  on 
its  edge,  and  fell  with  its  lower  side  uppermost. 

Effects  of  earthquakes  on  the  excavations  of  valleys. — The  next  class 
of  effects  to  be  considered,  are  those  more  immediately  connected  with 
the  formation  of  valleys,  in  which  the  action  of  water  was  often  combined 
with  that  of  the  earthquake.  The  country  agitated  was  composed,  as 
before  stated,  chiefly  of  argillaceous  strata,  intersected  by  deep  narrow 
valleys,  sometimes  from  500  to  600  feet  deep.  As  the  boundary  cliffs 
were  in  great  part  vertical,  it  will  readily  be  conceived  that,  amidsi  the 
various  movements  of  the  earth,  the  precipices  overhanging  rivers,  being 


CH.  XXVIII.]  LANDSLIPS.  485 

without  support  on  one  side,  were  often  thrown  down.  We  find,  indeed, 
that  inundations  produced  by  obstructions  in  river-courses  are  among 
the  most  disastrous  consequences  of  great  earthquakes  in  all  parts  of  the 
world,  for  the  alluvial  plains  in  the  bottoms  of  valleys  are  usually  the 
most  fertile  and  well-peopled  parts  of  the  whole  country ;  and  whether 
the  site  of  a  town  is  above  or  below  a  temporary  barrier  in  the  channel 
of  a  river,  it  is  exposed  to  injury  by  the  waters  either  of  a  lake  or  flood. 

Landslips. — From  each  side  of  the  deep  valley  or  ravine  of  Terra- 
nuova  enormous  masses  of  the  adjoining  flat  country  were  detached,  and 
cast  down  into  the  course  of  the  river,  so  as  to  give  rise  to  great  lakes. 
Oaks,  olive-trees,  vineyards,  and  corn,  were  often  seen  growing  at  the 
bottom  of  the  ravine,  as  little  injured  as  their  former  companions,  which 
still  continued  to  flourish  in  the  plain  above,  at  least  500  feet  higher, 
and  at  the  distance  of  about  three-quarters  of  a  mile.  Jn  one  part  of 
this  ravine  was  an  enormous  mass,  200  feet  high  and  about  400  feet  at 
its  base,  which  had  been  detached  by  some  former  earthquake.  It  is 
well  attested,  that  this  mass  travelled  down  the  ravine  nearly  four  miles, 
having  been  put  in  motion  by  the  earthquake  of  the  5th  of  February. 
Hamilton,  after  examining  the  spot,  declared  that  this  phenomenon 
might  be  accounted  for  by  the  declivity  of  the  valley,  the  great  abun- 
dance of  rain  which  fell,  and  the  great  weight  of  the  alluvial  matter 
which  pressed  behind  it.  Dolomieu  also  alludes  to  the  fresh  impulse 
derived  from  other  masses  falling,  and  pressing  upon  the  rear  of  those 
first  set  in  motion. 

The  first  account  sent  to  Naples  of  the  two  great  slides  or  landslips 
above  alluded  to,  which  caused  a  great  lake  near  Terranuova,  was 
couched  in  these  words  : — "  Two  mountains  on  the  opposite  sides  of  a 
valley  walked  from  their  original  position  until  they  met  in  the  middle 
of  the  plain,  and  there  joining  together,  they  intercepted  the  course  of 
a  river,"  &c.  The  expressions  here  used  resemble  singularly  those 
applied  to  phenomena,  probably  very  analogous,  which  are  said  to  have 
occurred  at  Fez,  during  the  great  Lisbon  earthquake,  as  also  in  Jamaica 
and  Java  at  other  periods. 

Not  far  from  Soriano,  which  was  levelled  to  the  ground  by  the  great 
shock  of  February,  a  small  valley,  containing  a  beautiful  olive-grove, 
called  Fra  Ramondo,  underwent  a  most  extraordinary  revolution.  In- 
numerable fissures  first  traversed  the  river-plain  in  all  directions,  and 
absorbed  the  water  until  the  argillaceous  substratum  became  soaked,  so 
that  a  great  part  of  it  was  reduced  to  a  state  of  fluid  paste.  Strange 
alterations  in  the  outline  of  the  ground  were  the  consequence,  as  the 
soil  to  a  great  depth  was  easily  moulded  into  any  form.  In  addition  to 
this  change,  the  ruins  of  the  neighboring  hills  were  precipitated  into 
the  hollow  ;  and  while  many  olives  were  uprooted,  others  remained 
growing  on  the  fallen  masses,  and  inclined  at  various  angles  (see  fig.  84). 
The  small  river  Caridi  was  entirely  concealed  for  many  days;  and  when 
at  length  it  reappeared,  it  had  shaped  for  itself  an  entirely  new  channel. 

Buildings  transported  entire  to  great  distances. — Near  Seminara  an 


486 


EARTHQUAKE    IN1  CALABRIA,    1783.  [On.  XXVIII. 

Fig.  84. 


Changes  of  the  surface  at  Fra  Eamondo,  near  Soriano,  in  Calabria. 


1,  Portion  of  a  hill  covered  with  olives  thrown  down. 

2,  New  bed  of  the  river  Caridi. 


3,  Town  of  Soriano. 


extensive  olive-ground  and  orchard  were  hurled  to  a  distance  of  two 
hundred  feet,  into  a  valley  sixty  feet  in  depth.  At  the  same  time  a 
deep  chasm  was  riven  in  another  part  of  the  high  platform  from  which 
the  orchard  had  been  detached,  and  the  river  immediately  entered  the 
fissure,  leaving  its  former  bed  completely  dry.  A  small  inhabited 
house,  standing  on  the  mass  of  earth  carried  down  into  the  valley,  went 
along  with  it  entire,  and  without  injury  to  the  inhabitants.  The  olive- 
trees,  also,  continued  to  grow  on  the  land  which  had  slid  into  the  valley, 
and  bore  the  same  year  an  abundant  crop  of  fruit. 

Two  tracts  of  land  on  which  a  great  part  of  the  town  of  Polistena 
stood,  consisting  of  some  hundreds  of  houses,  were  detached  into  a  con- 
tiguous ravine,  and  nearly  across  it,  about  half  a  mile  from  their  original 
site  ;  and  what  is  most  extraordinary,  several  of  the  inhabitants  were 
dug  out  from  the  ruins  alive  and  unhurt. 

Two  tenements,  near  Mileto,  called  the  Macini  and  Vaticano,  occu- 
pying an  extent  of  ground  about  a  mile  long  and  half  a  mile  broad, 
were  carried  for  a  mile  down  a  valley.  A  thatched  cottage,  together 
with  large  olive  and  mulberry  trees,  most  of  which  remained  erect,  were 
carried  uninjured  to  this  extraordinary  distance.  According  to  Hamil- 
ton, the  surface  removed  had  been  long  undermined  by  rivulets,  which 
were  afterwards  in  full  view  on  the  bare  spot  deserted  by  the  tenements. 
The  earthquake  seems  to  have  opened  a  passage  in  the  adjoining  argil- 
laceous hills,  which  admitted  water  charged  with  loose  soil  into  the 
subterranean  channels  of  the  rivulets  immediately  under  the  tenements, 
so  that  the  foundations  of  the  ground  set  in  motion  by  the  earthquake 
were  loosened.  Another  example  of  subsidence,  where  the  edifices 


CH.  XXVIII] 


CURRENTS   OF   MUD. 


487 


were  not  destroyed,  is  mentioned  by  Grimaldi,  as  having  taken  place  in 
the  city  of  Catanzaro,  the  capital  of  the  province  of  that  name.  The 
houses  in  the  quarter  called  Sari  Giuseppe  subsided  with  the  ground  to 
various  depths  from  two  to  four  feet,  but  the  buildings  remained  unin- 
jured. 

It  would  be  tedious,  and  our  space  would  not  permit  us,  to  follow  the 
different  authors  through  their  local  details  of  landslips  produced  in 
minor  valleys ;  but  they  are  highly  interesting,  as  showing  to  how  great 
an  extent  the  power  of  rivers  to  widen  valleys,  and  to  carry  away  large 
portions  of  soil  towards  the  sea,  is  increased  where  earthquakes  arc  of 
periodical  occurrence.  Among  other  territories,  that  of  Cinquefrondi, 
was  greatly  convulsed,  various  portions  of  soil  being  raised  or  sunk,  and 
innumerable  fissures  traversing  the  country  in  all  directions  (see  fig.  85). 

Fig.  85. 


Landslips  near  Cinquefrondi,  caused  by  the  earthquake  of  1783. 

Along  the  flanks  of  a  small  valley  in  this  district  there  appears  to  have 
been  an  almost  uninterrupted  line  of  landslips. 

Currents  of  mud. — Near  S.  Lucido,  among  other  places,  the  soil  is 
described  as  having  been  "  dissolved,"  so  that  large  torrents  of  mud  in- 
undated all  the  low  grounds,  like  lava.  Just  emerging  from  this  mud, 
the  tops  only  of  trees  and  of  the  ruins  of  farm-houses  were  seen.  Two 
miles  from  Laureana,  the  swampy  soil  in  two  ravines  became  filled  with 
calcareous  matter,  which  oozed  out  from  the  ground  immediately  before 
the  first  great  shock.  This  mud,  rapidly  accumulating,  began,  ere  long, 
to  roll  onward,  like  a  flood  of  lava,  into  the  valley,  where  the  two  streams 
uniting,  moved  forward  with  increased  impetus  from  east  to  west.  It 
now  presented  a  breadth  of  225  feet  by  15  in  depth,  and,  before  it  ceased 
to  move,  covered  a  surface  equal  in  length  to  an  Italian  mile.  In  its 
progress  it  overwhelmed  a  flock  of  thirty  goats,  and  tore  up  by  the  roots 
many  olive  and  mulberry  trees,  which  floated  like  ships  upon  its  surface. 
When  this  calcareous  lava  had  ceased  to  move,  it  gradually  became  dry 
and  hard,  during  which  process  the  mass  was  lowered  seven  feet  and  a 


488  EARTHQUAKE    IN    CALABRIA,  1783.  [CiL  XXVIII. 

half.  It  contained  fragments  of  earth  of  a  ferruginous  color,  and  emit- 
ting a  sulphureous  smell. 

Fall  of  the  sea-cliffs. — Along  the  sea-coast  of  the  Straits  of  Messina, 
near  the  celebrated  rock  of  Scilla,  the  fall  of  huge  masses  detached  from 
the  bold  and  lofty  cliffs  overwhelmed  many  villas  and  gardens.  At  Gian 
Greco,  a  continuous  line  of  cliff,  for  a  mile  in  length,  was  thrown  down. 
Great  agitation  was  frequently  observed  in  the  bed  of  the  sea  during 
the  shocks,  and,  on  those  parts  of  the  coast  where  the  movement  was 
most  violent,  all  kinds  of  fish  were  taken  in  abundance,  and  with  unusual 
facility.  Some  rare  species,  as  that  called  Cicirelli,  which  usually  lie 
buried  in  the  sand,  were  taken  on  the  surface  of  the  waters  in  great 
quantity.  The  sea  is  said  to  have  boiled  up  near  Messina,  and  to  have 
been  agitated  as  if  by  a  copious  discharge  of  vapors  from  its  bottom. 

Shore  near  Scilla  inundated. — The  prince  of  Scilla  had  persuaded  a 
great  part  of  his  vassals  to  betake  themselves  to  their  fishing-boats  for 
safety,  and  he  himself  had  gone  on  board.  On  the  night  of  the  5th  of 
February,  when  some  of  the  people  were  sleeping  in  the  boats,  and  others 
on  a  level  plain  slightly  elevated  above  the  sea,  the  earth  rocked,  and 
suddenly  a  great  mass  was  torn  from  the  contiguous  Mount  Jaci,  and 
thrown  down  with  a  dreadful  crash  upon  the  plain.  Immediately  after- 
wards, the  sea,  rising  more  than  twenty  feet  above  the  level  of  this  low 
tract,  rolled  foaming  over  it,  and  swept  away  the  multitude.  It  then 
retreated,  but  soon  rushed  back  again  with  greater  violence,  bringing 
with  it  some  of  the  people  and  animals  it  had  carried  away.  At  the  same 
time  every  boat  was  sunk  or  dashed  against  the  beach,  and  some  of  them 
were  swept  far  inland.  The  aged  prince,  with  1430  of  his  people,  was 
destroyed. 

State  of  Stromboli  and  Etna  during  the  shocks. — The  inhabitants  of 
Pizzo  remarked  that  on  the  5th  of  February,  1*783,  when  the  first  great 
shock  afflicted  Calabria,  the  volcano  of  Stromboli,  which  is  in  full  view 
of  that  town,  and  at  the  distance  of  about  fifty  miles,  smoked  less,  and 
threw  up  a  less  quantity  of  inflamed  matter  than  it  had  done  for  some 
years  previously.  On  the  other  hand,  the  great  crater  of  Etna  is  said 
to  have  given  out  a  considerable  quantity  of  vapor  towards  the  begin- 
ning, and  Stromboli  towards  the  close,  of  the  commotions.  But  as  no 
eruption  happened  from  either  of  these  great  vents  during  the  whole 
earthquake,  the  sources  of  the  Calabrian  convulsions,  and  of  the  volcanic 
fires  of  Etna  and  Stromboli,  appear  to  be  very  independent  of  each  other ; 
unless,  indeed,  they  have  the  same  mutual  relation  as  Vesuvius  and  the 
volcanoes  of  the  Phlegrsean  Fields  and  Ischia,  a  violent  disturbance  in 
one  district  serving  as  a  safety-valve  to  the  other,  and  both  never  being 
in  full  activity  at  once. 

Excavation  of  valleys. — It  is  impossible  for  the  geologist  to  consider 
attentively  the  effect  of  this  single  earthquake  of  1783,  and  to  look  for- 
ward to  the  alterations  in  the  physical  condition  of  the  country  to  which 
a  continued  series  of  such  movements  will  hereafter  give  rise,  without 
perceiving  that  the  formation  of  valleys  by  running  water  can  never  be 


On.  XXVIIL]  EXCAVATION   OF  VALLEYS.  489 

understood,  if  we  consider  the  question  independently  of  the  agency  of 
earthquakes.  It  must  not  be  imagined  that  rivers  only  begin  to  act  when 
a  country  is  already  elevated  far  above  the  level  of  the  sea,  for  their 
action  must  of  necessity  be  most  powerful  while  land  is  rising  and  sink- 
ing by  successive  movements.  Whether  Calabria  is  now  undergoing 
any  considerable  change  of  relative  level,  in  regard  to  the  sea,  or  is,  upon 
the  whole,  nearly  stationary,  is  a  question  which  our  observations,  con- 
fined almost  entirely  to  the  last  half  century,  cannot  possibly  enable  us 
to  determine.  But  we  know  that  strata,  containing  species  of  shells 
identical  with  those  now  living  in  the  contiguous  parts  of  the  Mediter- 
ranean, have  been  raised  in  that  country,  as  they  have  in  Sicily,  to  the 
height  of  several  thousand  feet. 

Now,  those  geologists  who  grant  that  the  present  course  of  Nature 
in  the  inanimate  world  has  continued  the  same  since  the  existing  species 
of  animals  were  in  being,  will  not  feel  surprised  that  the  Calabrian  streams 
and  rivers  have  cut  out  of  such  comparatively  modern  strata  a  great  sys- 
tem of  valleys,  varying  in  depth  from  fifty  to  six  hundred  feet,  and  often 
several  miles  wide,  if  they  consider  how  numerous  may  have  been  the 
shocks  which  accompanied  the  uplifting  of  those  recent  marine  strata  to 
so  prodigious  a  height.  Some  speculators,  indeed,  who  disregard  the 
analogy  of  existing  nature,  and  who  are  always  ready  to  assume  that  her 
forces  were  more  energetic  in  by-gone  ages,  may  dispense  with  a  long 
series  of  movements,  and  suppose  that  Calabria  "  rose  like  an  exhalation" 
from  the  deep,  after  the  manner  of  Milton's  Pandemonium.  But  such 
an  hypothesis  would  deprive  them  of  that  peculiar  removing  force  re- 
quired to  form  a  regular  system  of  deep  and  wide  valleys ;  for  time, 
which  they  are  so  unwilling  to  assume,  is  essential  to  the  operation. 
Time  must  be  allowed  in  the  intervals  between  distinct  convulsions,  for 
running  water  to  clear  away  the  ruins  caused  by  landslips,  otherwise  the 
fallen  masses  will  serve  as  buttresses,  and  prevent  the  succeeding  earth- 
quake from  exerting  its  full  power.  The  sides  of  the  valley  must  be 
again  cut  away  by  the  stream,  and  made  to  form  precipices  and  over- 
hanging cliffs,  before  the  next  shock  can  take  effect  in  the  same  manner. 

Possibly  the  direction  of  the  succeeding  shock  may  not  coincide  with 
that  of  the  valley,  a  great  extent  of  adjacent  country  being  equally 
shaken.  Still  it  will  usually  happen  that  no  permanent  geographical 
change  will  be  produced  except  in  valleys.  In  them  alone  will  occur 
landslips  from  the  boundary  cliffs,  and  these  will  frequently  divert  the 
stream  from  its  accustomed  course,  causing  the  original  ravine  to  become 
both  wider  and  more  tortuous  in  its  direction. 

If  a  single  convulsion  of  extreme  violence  should  agitate  at  once  an 
entire  hydrographical  basin,  or  if  the  shocks  should  follow  each  other 
too  rapidly,  the  previously  existing  valleys  would  be  annihilated,  instead 
of  being  modified  and  enlarged.  Every  stream  might  in  that  case  be 
compelled  to  begin  its  operations  anew,  and  to  shape  out  new  channels, 
instead  of  continuing  to  deepen  and  widen  those  already  excavated.  But 
if  the  subterranean  movements  have  been  intermittent,  and  if  sufficient 


490  EARTHQUAKE    IN    CALABRIA,  1783.  [On.  XXVIH. 

periods  have  always  intervened  between  the  severer  shocks  to  allow  the 
drainage  of  the  country  to  be  nearly  restored  to  its  original  state,  then 
are  both  the  kind  and  degree  of  force  supplied  by  which  running  water 
may  hollow  out  valleys  of  any  depth  or  size  consistent  with  the  elevation 
above  the  sea  which  the  districts  drained  by  them  may  have  attained. 

When  we  read  of  the  drying  up  and  desertion  of  the  channels  of 
rivers,  the  accounts  most  frequently  refer  to  their  deflection  into  some 
other  part  of  the  same  alluvial  plain,  perhaps  several  miles  distant.  Under 
certain  circumstances  a  change  of  level  may  undoubtedly  force  the  water 
to  flow  over  into  some  distinct  hydrographical  basin ;  but  even  then  it 
will  fall  immediately  into  some  other  system  of  valleys  already  formed. 

We  learn  from  history  that,  ever  since  the  first  Greek  colonists  settled 
in  Calabria,  that  region  has  been  subject  to  devastation  by  earthquakes ; 
and,  for  the  last  century  and  a  half,  ten  years  have  seldom  elapsed  with- 
out a  shock ;  but  the  severer  convulsions  have  not  only  been  separated 
by  intervals  of  twenty,  fifty,  or  one  hundred  years,  but  have  not  affected 
precisely  the  same  points  when  they  recurred.  Thus  the  earthquake  of 
1783,  although  confined  within  the  same  geographical  limits  as  that  of 
1638,  and  not  very  inferior  in  violence,  visited,  according  to  Grimaldi, 
very  different  districts.  The  points  where  the  local  intensity  of  the 
force  is  developed  being  thus  perpetually  varied,  more  time  is  allowed 
for  the  removal  of  separate  mountain  masses  thrown  into  river- channels 
by  each  shock. 

Number  of  persons  who  perished  during  the  earthquake. — The  number 
of  persons  who  perished  during  the  earthquake  in  the  two  Calabrias  and 
Sicily,  is  estimated  by  Hamilton  at  about  forty  thousand ;  and  about 
twenty  thousand  more  died  by  epidemics,  which  were  caused  by  insuf- 
ficient nourishment,  exposure  to  the  atmosphere,  and  malaria,  arising 
from  the  new  stagnant  lakes  and  pools. 

By  far  the  greater  number  were  buried  under  the  ruins  of  their  houses ; 
but  many  were  burnt  to  death  in  the  conflagrations  which  almost  in- 
variably followed  the  shocks.  These  fires  raged  the  more  violently  in 
some  cities,  such  as  Oppido,  from  the  immense  magazines  of  oil  which 
were  consumed. 

Many  persons  were  engulfed  in  deep  fissures,  especially  the  peasants 
when  flying  across  the  open  country,  and  their  skeletons  may  perhaps 
be  buried  in  the  earth  to  this  day,  at  the  depth  of  several  hundred  feet. 

When  Dolomieu  visited  Messina  after  the  shock  of  Feb.  5th,  he  de- 
scribes the  city  as  still  presenting,  at  least  at  a  distance,  an  imperfect 
image  of  its  ancient  splendor.  Every  house  was  injured,  but  the  walls 
were  standing ;  the  whole  population  had  taken  refuge  in  wooden  huts 
in  the  neighborhood,  and  all  was  solitude  and  silence  in  the  streets  :  it 
seemed  as  if  the  city  had  been  desolated  by  the  plague,  and  the  impres- 
sion made  upon  his  feelings  was  that  of  melancholy  and  sadness.  "  But 
when  I  passed  over  to  Calabria,  and  first  beheld  Polistena,  the  scene  of 
horror  almost  deprived  me  of  my  faculties ;  my  mind  was  filled  with 
mingled  compassion  and  terror ;  nothing  had  escaped ;  all  was  levelled 


CH.  XX VIII.]          NUMBER    OF    PERSONS    WHO    PERISHED.  491 

with  the  dust ;  not  a  single  house  or  piece  of  wall  remained  ;  on  all  sides 
were  heaps  of  stone  so  destitute  of  form,  that  they  gave  no  conception 
of  there  ever  having  been  a  town  on  the  spot.  The  stench  of  the  dead 
bodies  still  rose  from  the  ruins.  I  conversed  with  many  persons  who 
had  been  buried  for  three,  four,  and  even  for  five  days ;  I  questioned 
them  respecting  their  sensations  in  so  dreadful  a  situation,  and  they 
agreed  that  of  all  the  physical  evils  they  endured,  thirst  was  the  most 
intolerable;  and  that  their  mental  agony  was  increased  by  the  idea  that 
they  were  abandoned  by  their  friends,  who  might  have  rendered  them 
assistance."* 

It  is  supposed  that  about  a  fourth  part  of  the  inhabitants  of  Polistena, 
and  of  some  other  towns,  were  buried  alive,  and  might  have  been  saved 
had  there  been  no  want  of  hands  ;  but  in  so  general  a  calamity,  where 
each  was  occupied  with  his  own  misfortunes  or  those  of  his  family,  aid 
could  rarely  be  obtained.  Neither  tears,  nor  supplications,  nor  promises 
of  high  rewards  were  listened  to.  Many  acts  of  self-devotion,  prompted 
by  parental  and  conjugal  tenderness,  or  by  friendship,  or  the  gratitude 
of  faithful  servants,  are  recorded ;  but  individual  exertions  were,  for  the 
most  part,  ineffectual.  It  frequently  happened,  that  persons  in  search 
of  those  most  dear  to  them  could  hear  their  moans, — could  recognize 
their  voices — were  certain  of  the  exact  spot  where  they  lay  buried  be- 
neath their  feet,  yet  could  afford  them  no  succor.  The  piled  mass 
resisted  all  their  strength,  and  rendered  their  efforts  of  no  avail. 

At  Terranuova,  four  Augustin  monks,  who  had  taken  refuge  in  a 
vaulted  sacristy,  the  arch  of  which  continued  to  support  an  immense  pile 
of  ruins,  made  their  cries  heard  for  the  space  of  four  days.  One  only  of 
the  brethren  of  the  whole  convent  was  saved,  and  "  of  what  avail  was 
his  strength  to  remove  the  enormous  weight  of  rubbish  which  had  over- 
whelmed his  companions  ?"  He  heard  their  voices  die  away  gradually  ; 
and  when  afterwards  their  four  corpses  were  disinterred,  they  were  found 
clasped  in  each  other's  arms.  Affecting  narratives  are  preserved  of 
mothers  saved  after  the  fifth,  sixth,  and  even  seventh  day  of  their  inter- 
ment, when  their  infants  or  children  had  perished  with  hunger. 

It  might  have  been  imagined  that  the  sight  of  sufferings  such  as  these 
would  have  been  sufficient  to  awaken  sentiments  of  humanity  and  pity  in 
the  most  savage  breasts  ;  but  while  some  acts  of  heroism  are  related, 
nothing  could  exceed  the  general  atrocity  of  conduct  displayed  by  the 
Calabrian  peasants :  they  abandoned  the  farms,  and  flocked  in  great 
numbers  into  the  towns — not  to  rescue  their  countrymen  from  a  linger- 
ing death,  but  to  plunder.  They  dashed  through  the  streets,  fearless  of 
danger,  amid  tottering  walls  and  clouds  of  dust,  trampling  beneath  their 
feet  the  bodies  of  the  wounded  and  half-buried,  and  often  stripping  them, 
while  yet  living,  of  their  clothes. f 

Concluding  remarks. — But  to  enter  more  fully  into  these  details  would 
be  foreign  to  the  purpose  of  the  present  work,  and  several  volumes 

*  Pinkerton's  Voyages  and  Travels,  vol.  v.  as  cited  above,  p.  455,  note. 
\  Doloraieu,  ibid. 


492  EARTHQUAKE   IN   CALABRIA,    1783.  [Cn.  XXVIIL 

would  be  required  to  give  the  reader  a  just  idea  of  the  sufferings  which 
the  inhabitants  of  many  populous  districts  have  undergone  during  the 
earthquakes  of  the  last  loO  years.  A  bare  mention  of  the  loss  of  life — 
as  that  fifty  or  a  hundred  thousand  souls  perished  in  one  catastrophe — 
conveys  to  the  reader  no  idea  of  the  extent  of  misery  inflicted  :  we  must 
learn,  from  the  narratives  of  eye-witnesses,  the  various  forms  in  which 
death  was  encountered,  the  numbers  who  escaped  with  loss  of  limbs  or 
serious  bodily  injuries,  and  the  multitude  who  were  suddenly  reduced  to 
penury  and  want.  It  has  been  often  remarked,  that  the  dread  of  earth- 
quakes is  strongest  in  the  minds  of  those  who  have  experienced  them 
most  frequently ;  whereas,  in  the  case  of  almost  every  other  danger, 
familiarity  with  peril  renders  men  intrepid.  The  reason  is  obvious — 
scarcely  any  part  of  the  mischief  apprehended  in  this  instance  is  imagin- 
ary ;  the  first  shock  is  often  the  most  destructive  ;  and,  as  it  may  occur 
in  the  dead  of  the  night,  or  if  by  day,  without  giving  the  least  warning 
of  its  approach,  no  forethought  can  guard  against  it  ;  and  when  the  con- 
vulsion has  begun,  no  skill,  or  courage,  or  presence  of  mind,  can  point 
out  the  path  of  safety.  During  the  intervals,  of  uncertain  duration, 
between  the  more  fatal  shocks,  slight  tremors  of  the  soil  are  not  unfre- 
quent ;  and  as  these  sometimes  precede  more  violent  convulsions,  they 
become  a  source  of  anxiety  and  alarm.  The  terror  arising  from  this 
cause  alone  is  of  itself  no  inconsiderable  evil. 

Although  sentiments  of  pure  religion  are  frequently  awakened  by  these 
awful  visitations,  yet  we  more  commonly  find  that  an  habitual  state  of 
fear,  a  sense  of  helplessness,  and  a  belief  in  the  futility  of  all  human  exer- 
tions, prepare  the  minds  of  the  vulgar  for  the  influence  of  a  demoralizing 
superstition. 

Where  earthquakes  are  frequent,  there  can  never  be  perfect  security 
of  property  under  the  best  government ;  industry  cannot  be  assured  of 
reaping  the  fruits  of  its  labor ;  and  the  most  daring  acts  of  outrage  may 
occasionally  be  perpetrated  with  impunity,  when  the  arm  of  the  law  is 
paralyzed  by  the  general  consternation.  It  is  hardly  necessary  to  add, 
that  the  progress  of  civilization  and  national  wealth  must  be  retarded  by 
convulsions  which  level  cities  to  the  ground,  destroy  harbors,  render 
roads  impassable,  and  cause  the  most  cultivated  valley-plains  to  be 
covered  with  lakes,  or  the  ruins  of  adjoining  hills. 

Those  geologists  who  imagine  that,  at  remote  periods  ere  man  became 
a  sojourner  on  earth,  the  volcanic  agency  was  more  energetic  than  now, 
should  be  careful  to  found  their  opinion  on  strict  geological  evidence,  and 
not  permit  themselves  to  Jbe  biased,  as  they  have  often  been,  by  a 
notion,  that  the  disturbing  force  would  probably  be  mitigated  for  the 
sake  of  man. 

I  shall  endeavor  to  point  out  in  the  sequel,  that  the  general  tendency 
of  subterranean  movements,  when  their  effects  are  considered  for  a  suffi- 
cient lapse  of  ages,  is  eminently  beneficial,  and  that  they  constitute  an 
essential  part  of  that  mechanism  by  which  the  integrity  of  the  habitable 
surface  is  preserved,  and  the  very  existence  and  perpetuation  of  dry  land 


CH.  XXIX.]  EARTHQUAKE    OF   JAVA.  493 

secured.  Why  the  working  of  this  same  machinery  should  be  attended 
with  so  much  evil,  is  a  mystery  far  beyon«ji  the  reach  of  our  philosophy, 
and  must  probably  remain  so  until  we  are  permitted  to  investigate,  not 
our  planet  alone  and  its  inhabitants,  but  other  parts  of  the  moral  and 
material  universe  with  which  they  may  be  connected.  Could  our  sur- 
vey embrace  other  worlds,  and  the  events,  not  of  a  few  centuries  only, 
but  of  periods  as  indefinite  as  those  with  which  geology  renders  us 
familiar,  some  apparent  contradictions  might  be  reconciled,  and  some 
difficulties  would  doubtless  be  cleared  up.  But  even  then,  as  our  capa- 
cities are  finite,  while  the  scheme  of  the  universe  may  be  infinite,  both 
in  time  and  space,  it  is  presumptuous  to  suppose  that  all  sources  of  doubt 
and  perplexity  would  ever  be  removed.  On  the  contrary,  they  might, 
perhaps,  go  on  augmenting  in  number,  although  our  confidence  in  the 
wisdom  of  the  plan  of  Nature  should  increase  at  the  same  time ;  for  it 
has  been  justly  said,  that  the  greater  the  circle  of  light,  the  greater  the 
boundary  of  darkness  by  which  it  is  surrounded.* 


CHAPTER  XXIX. 

EARTHQUAKES — continued. 

Earthquake  of  Java,  1772 — Truncation  of  a  lofty  cone — St.  Domingo,  1770 — Lis- 
bon, 1755 — Great  area  over  which  the  shocks  extended — Retreat  of  the  sea — 
Proposed  explanations — Conception  Bay,  1750 — Permanent  elevation — Peru, 
1746 — Java,  1699 — Rivers  obstructed  by  landslips — Subsidence  in  Sicily,  1693 
— Moluccas,  1693 — Jamaica,  1692 — Large  tracts  engulfed — Portion  of  Port 
Royal  sunk — Amount  of  change  in  the  last  150  years — Elevation  and  subsidence 
of  land  in  Bay  of  Baise — Evidence  of  the  same  afforded  by  the  Temple  of 
Serapis. 

IN  the  preceding  chapters  we  have  considered  a  small  part  only  of 
those  earthquakes  which  have  occurred  during  the  last  seventy  years, 
of  which  accurate  and  authentic  descriptions  happen  to  have  been  re- 
corded. In  examining  those  of  earlier  date,  we  find  their  number  so  great 
that  allusion  can  be  made  to  a  few  only  respecting  which  information 
of  peculiar  geological  interest  has  been  obtained. 

Java,  1772. —  Truncation  of  a  lofty  cone. — In  the  year  1772,  Papan- 
dayang,  formerly  one  of  the  loftiest  volcanoes  in  the  island  of  Java,  was 
in  eruption.  Before  all  the  inhabitants  on  the  declivities  of  the  moun- 
tain could  save  themselves  by  flight,  the  ground  began  to  give  way, 
and  a  great  part  of  the  volcano  fell  in  and  disappeared.  It  is  estimated 
that  an  extent  of  ground  of  the  mountain  itself  and  its  immediate  envi- 

*  Sir  H.  Davy's  Consolations  in  Travel,  p.  246. 


494:  EARTHQUAKE    OF    HINDOSTAN.  CH.  XXIX.] 

rons,  fifteen  miles  long  and  full  six  broad,  was  by  this  commotion  swal- 
lowed up  in  the  bowels  of  the  earth.  Forty  villages  were  destroyed, 
some  being  engulfed  and  some  covered  by  the  substances  thrown  out 
on  this  occasion,  and  2957  of  the  inhabitants  perished.  A  proportionate 
number  of  cattle  were  also  killed,  and  most  of  the  plantations  of  cotton, 
indigo,  and  coffee  in  the  adjacent  districts  were  buried  under  the  vol- 
canic matter.  This  catastrophe  appears  to  have  resembled,  although  on 
a  grander  scale,  that  of  the  ancient  Vesuvius  in  the  year  79.  The  cone 
was  reduced  in  height  from  9000  to  about  5000  feet ;  and,  as  vapors 
still  escape  from  the  crater  on  its  summit,  a  new  cone  may  one  day  rise 
out  of  the  ruins  of  the  ancient  mountain,  as  the  modern  Vesuvius  has 
risen  from  the  remains  of  Somma.* 

St.  Domingo,  1770. — During  a  tremendous  earthquake  which  de- 
stroyed a  great  part  of  St.  Domingo,  innumerable  fissures  were  caused 
throughout  the  island,  from  which  mephitic  vapors  emanated  and  pro- 
duced an  epidemic.  Hot  springs  burst  forth  in  many  places  where  there 
had  been  no  water  before  ;  but  after  a  time  they  ceased  to  flow.f 

In  a  previous  earthquake,  in  November,  1751,  a  violent  shock  de- 
stroyed the  capital,  Port  au  Prince,  and  part  of  the  coast,  twenty 
leagues  in  length,  sank  down,  and  has  ever  since  formed  a  bay  of  the 
sea.]; 

Hindostan,  1762. — The  town  of  phittagong,  in  Bengal,  was  violently 
shaken  by  an  earthquake,  on  the  2d  of  April,  1762,  the  earth  opening 
in  many  places,  and  throwing  up  water  and  mud  of  a  sulphureous  smell. 
At  a  place  called  Bardavan,  a  large  river  was  dried  up  ;  and  at  Bar 
Charra,  near  the  sea,  a  tract  of  ground  sunk  down,  and  200  people, 
with  all  their  cattle,  were  lost.  It  is  said,  that  sixty  square  miles  of  the 
Chittagong  coast  suddenly  and  permanently  subsided  during  this  earth- 
quake, and  that  Ces-lung-Toom,  one  of  the  Mug  mountains,  entirely  dis- 
appeared, and  another  sank  so  low,  that  its  summit  only  remained  visi- 
ble. Four  hills  are  also  described  as  having  been  variously  rent  asunder, 
leaving  open  chasms  from  thirty  to  sixty  feet  in  width.  Towns  which 
subsided  several  cubits,  were  overflowed  with  water ;  among  others, 
Deep  Gong,  which  was  submerged  to  the  depth  of  seven  cubits.  Two 
volcanoes  are  said  to  have  opened  in  the  Secta  Cunda  hills.  The  shock 
was  also  felt  at  Calcutta. §  While  the  Chittagong  coast  was  sinking,  a 
corresponding  rise  of  the  ground  took  place  at  the  island  of  Ramree, 
and  at  Cheduba  (see  Map,  fig.  39,  p.  351  ).| 

Lisbon,  1755. — In  no  part  of  the  volcanic  region  of  southern  Europe 

*  Dr.  Horsfield,  Batav.  Trans,  vol.  viii.  p.  26.  Dr.  H.  informs  me  that  he  has 
seen  this  truncated  mountain  ;  and,  though  he  did  not  ascend  it,  lie  has  conversed 
with  those  who  have  examined  it.  Raffles'  account  (History  of  Java,  voL  i.)  is 
derived  from  Horsfield. 

f  Essai  sur  1'Hist.  Nat.  de  1'Isle  de  St.  Domingue.     Paris,  1776. 

±  Hist,  de  1'Acad.  des  Sciences.     1752,  Paris. 

§  M'Clelland's  Report  on  Min.  Resources  of  India:  1838,  Calcutta.  For  other 
particulars,  see  Phil.  Trans,  vol.  liii. 

|  Journ.  Aeiat.  Soc.  Bengal,  voL  x.  pp.  351,  433. 


CH.  XXIX.]  EARTHQUAKE    OF   LISBON.  495 

has  so  tremendous  an  earthquake  occurred  in  modern  times,  as  that 
which  began  on  the  1st  of  November,  1755,  at  Lisbon.  A  sound  of 
thunder  was  heard  underground,  and  immediately  afterwards  a  violent 
shock  threw  down  the  greater  part  of  that  city.  In  the  course  of  about 
six  minutes,  sixty  thousand  persons  perished.  The  sea  first  retired  and 
laid  the  bar  dry;  it  then  rolled  in,  rising  fifty  feet  or  more  above  its 
ordinary  level.  The  mountains  of  Arrabida,  Estrella,  Julio,  Marvan, 
and  Cintra,  being  some  of  the  largest  in  Portugal,  were  impetuously 
shaken,  as  it  were,  from  their  very  foundations  ;  and  some  of  them 
opened  at  their  summits,  which  were  split  and  rent  in  a  wonderful  man- 
ner, huge  masses  of  thejn  being  thrown  down  into  the  subjacent  val- 
leys.* Flames  are  related  to  have  issued  from  these  mountains,  which 
are  supposed  to  have  been  electric  ;  they  are  also  said  to  have  smoked  ; 
but  vast  clouds  of  dust  may  have  given  rise  to  this  appearance. 

The  area  over  which  this  convulsion  extended  is  very  remarkable. 
It  has  been  computed,  says  Humboldt,f  that  on  the  1st  November, 
1755,  a  portion  of  the  earth's  surface  four  times  greater  than  the  ex- 
tent of  Europe  was  simultaneously  shaken.  The  shock  was  felt  in  the 
Alps,  and  on  the  coast  of  Sweden,  in  small  inland  lakes  on  the  shores 
of  the  Baltic,  in  Thuringia,  and  in  the  flat  country  of  northern  Germany. 
The  thermal  springs  of  Toplitz  dried  up,  and  again  returned,  inundating 
every  thing  with  water  discolored  by  ochre.  In  the  islands  of  Antigua, 
Barbadoes,  and  Martinique  in  the  West  Indies,  where  the  tide  usually 
rises  little  more  than  two  feet,  it  suddenly  rose  above  twenty  feet,  the 
water  being  discolored  and  of  an  inky  blackness.  The  movement  was 
also  sensible  in  the  great  lakes  of  Canada.  At  Algiers  and  Fez,  in  the 
north  of  Africa,  the  agitation  of  the  earth  was  as  violent  as  in  Spain 
and  Portugal ;  and  at  the  distance  of  eight  leagues  from  Morocco,  a 
village  with  the  inhabitants,  to  the  number  of  about  8000  or  10,000 
persons,  are  said  to  haVe  been  swallowed  up ;  the  earth  soon  after- 
wards closing  over  them. 

Subsidence  of  the  quay. — Among  other  extraordinary  events  related 
to  have  occurred  at  Lisbon  during  the  catastrophe  was  the  subsidence 
of  a  new  quay,  built  entirely  of  marble  at  an  immense  expense.  A 
great  concourse  of  people  had  collected  there  for  safety,  as  a  spot  where 
they  might  be  beyond  the  reach  of  falling  ruins ;  but  suddenly  the 
quay  sank  down  with  all  the  people  on  it,  and  not  one  of  the  dead 
bodies  ever  floated  to  the  surface.  A  great  number  of  boats  and  srrnll 
vessels  anchored  near  it,  all  full  of  people,  were  swallowed  up,  as  in 
a  whirlpool.];  No  fragments  of  these  wrecks  ever  rose  again  to  the  sur- 
face, and  the  water  in  the  place  where  the  quay  had  stood  is  stated,  in 
many  accounts,  to  be  unfathomable ;  but  Whitehurst  says  he  ascer- 
tained it  to  be  one  hundred  fathoms.§ 

*  Hist,  and  Philos.  of  Earthquakes,  p.  317.  f  Cosmos,  vol.  i. 

\  Rev.  C.  Davy's  Letters,  vol.  ii.  Letter  ii.  p.  12,  who  was  at  Lisbon  at  the  time, 
and  ascertained  that  the  boats  and  vessels  said  to  have  been  swallowed  were 
missing.  §  On  the  Formation  of  the  Earth,  p.  55. 


496  SHOCKS   AT   SEA.  [Cfl.  XXIX. 

Circumstantial  as  are  the  contemporary  narratives,  I  learn  from  a. 
correspondent,  Mr.  F.  Freeman,  in  1841,  that  no  part  of  the  Tagus  was 
then  more  than  thirty  feet  deep  at  high  tide,  and  an  examination  of  the 
position  of  the  new  quay,  and  the  memorials  preserved  of  the  time  and 
manner  in  which  it  was  built,  rendered  the  statement  of  so  great  a  sub- 
sidence in  1755  quite  unintelligible.  Perhaps  a  deep  narrow  chasm,  such 
as  was  before  described  in  Calabria  (p.  481),  opened  and  closed  again 
in  the  bed  of  the  Tagus,  after  swallowing  up  some  incumbent  buildings 
and  vessels.  We  have  already  seen  that  such  openings  may  collapse 
after  the  shock  suddenly,  or,  in  places  where  the  strata  are  of  soft  and 
yielding  materials,  very  gradually.  According  to  the  observations  made 
at  Lisbon,  in  1837,  by  Mr.  Sharpe,  the  destroying  effects  of  this  earth- 
quake were  confined  to  the  tertiary  strata,  and  were  most  violent  on  the 
blue  clay,  on  which  the  lower  part  of  the  city  is  constructed.  Not  a 
building,  he  says,  on  the  secondary  limestone  or  the  basalt  was  injured.* 

Shocks  felt  at  sea. — The  shock  was  felt  at  sea,  on  the  deck  of  a  ship 
to  the  west  of  Lisbon,  and  produced  very  much  the  same  sensation  as 
on  dry  land.  Off  St.  Lucar,  the  captain  of  the  ship  Nancy  felt  his 
vessel  so  violently  shaken,  that  he  thought  she  had  struck  the  ground  ; 
but,  on  heaving  the  lead,  found  a  great  depth  of  water.  Captain  Clark, 
from  Denia,  in  latitude  36°  24'  N.,  between  nine  and  ten  in  the  morn- 
ing, had  his  ship  shaken  and  strained  as  if  she  had  struck  upon  a  rock, 
so  that  the  seams  of  the  deck  opened,  and  the  compass  was  overturned 
in  the  binnacle.  Another  ship,  forty  leagues  west  of  St.  Vincent,  ex- 
perienced so  violent  a  concussion,  that  the  men  were  thrown  a  foot  and 
a  half  perpendicularly  up  from  the  deck. 

Rate  at  which  the  movement  travelled. — The  agitation  of  lakes,  rivers, 
and  springs,  in  Great  Britain,  was  remarkable.  At  Loch  Lomond,  in 
Scotland,  for  example,  the  water,  without  the  least  apparent  cause, 
rose  against  its  banks,  and  then  subsided  below  its  usual  level.  The 
greatest  perpendicular  height  of  this  swell  was  two  feet  four  inches.  It 
is  said  that  the  movement  of  this  earthquake  was  undulatory,  and  that 
it  travelled  at  the  rate  of  twenty  miles  a  minute,  its  velocity  being  cal- 
culated by  the  intervals  between  the  time  when  the  first  shock  was  felt 
at  Lisbon,  and  its  time  of  occurrence  at  other  distant  places. f 

Great  wave  and  retreat  of  the  sea. — A  great  wave  swept  over  the 
coast  of  Spain,  and  is  said  to  have  been  sixty  feet  high  at  Cadiz.  At 
Tangier,  in  Africa,  it  rose  and  fell  eighteen  times  on  the  coast.  At 
Funchal,  in  Madeira,  it  rose  full  fifteen  feet  perpendicular  above  high- 
water  mark,  although  the  tide,  which  ebbs  and  flows  there  seven  feet, 
was  then  at  half-ebb.  Besides  entering  the  city,  and  committing  great 
havoc,  it  overflowed  other  seaports  in  the  island.  At  Kinsale,  in  Ireland, 
a  body  of  water  rushed  into  the  harbor,  whirled  round  several  vessels, 
and  poured  into  the  market-place. 


f  GeoL  Soc.  Proceedings,  No.  60,  p.  36.     1838. 

i  Michell  on  Earthquakes,  Phil.  Trans,  vol.  li.  p.  666.     1760. 


CH.  XXIX.]  GREAT   WAVE   OF   THE   SEA.  497 

It  was  before  stated  that  the  sea  first  retired  at  Lisbon  ;  and  this  re- 
treat of  the  ocean  from  the  shore,  at  the  commencement  of  an  earthquake, 
and  its  subsequent  return  in  a  violent  wave,  is  a  common  occurrence. 
In  order  to  account  for  the  phenomenon,  Michell  imagined  a  subsidence 
at  the  bottom  of  the  sea,  from  the  giving  way  of  the  roof  of  some  cav- 
ity in  consequence  of  a  vacuum  produced  by  the  condensation  of  steam. 
Such  condensation,  he  observes,  might  be  the  first  effect  of  the  intro- 
duction of  a  large  body  of  water  into  fissures  and  cavities  already  filled 
with  steam,  before  there  has  been  sufficient  time  for  the  heat  of  the  in- 
candescent lava  to  turn  so  large  a  supply  of  water  into  steam,  which 
being  soon  accomplished  causes  a  greater  explosion. 

Another  proposed  explanation  is,  the  sudden  rise  of  the  land,  which 
would  cause  the  sea  to  abandon  immediately  the  ancient  line  of  coast ; 
and  if  the  shore,  after  being  thus  heaved  up,  should  fall  again  to  its 
original  level,  the  ocean  would  return.  This  theory,  however,  will  not 
account  for  the  facts  observed  during  the  Lisbon  earthquake  ;  for  the 
retreat  preceded  the  wave,  not  only  on  the  coast  of  Portugal,  but  also 
at  the  island  of  Madeira,  and  several  other  places.  If  the  upheaving  of 
the  coast  of  Portugal  had  caused  the  retreat,  the  motion  of  the  waters, 
when  propagated  to  Madeira,  would  have  produced  a  wave  previous  to 
the  retreat.  Nor  could  the  motion  of  the  waters  at  Madeira  have  been 
caused  by  a  different  local  earthquake  ;  for  the  shock  travelled  from 
Lisbon  to  Madeira  in  two  hours,  which  agrees  with  the  time  which  it 
required  to  reach  other  places  equally  distant.* 

The  following  is  another  solution  of  the  problem,  which  has  been 
offered : — Suppose  a  portion  of  the  bed  of  the  sea  to  be  suddenly  up- 
heaved ;  the  first  effect  will  be  to  raise  over  the  elevated  part  a  body 
of  water,  the  momentum  of  which  will  carry  it  much  above  the  level  it 
will  afterwards  assume,  causing  a  draught  or  receding  of  the  water  from 
the  neighboring  coasts,  followed  immediately  by  the  return  of  the  dis- 
placed water,  which  will  also  be  impelled  by  its  momentum  much  far- 
ther and  higher  on  the  coast  than  its  former  level.f 

Mr.  Darwin,  when  alluding  to  similar  waves  on  the  coast  of  Chili, 
states  his  opinion,  that  "  the  whole  phenomenon  is  due  to  a  common  un- 
dulation in  the  water,  proceeding  from  a  line  or  point  of  disturbance 
some  little  way  distant.  If  the  waves,"  he  says,  "  sent  off  from  the. 
paddles  of  a  steam-vessel  be  watched  breaking  on  the  sloping  shore  of 
a  still  river,  the  water  will  be  seen  first  to  retire  two  or  three  feet,  and 
then  to  return  in  little  breakers,  precisely  analogous  to  those  consequent 
on  an  earthquake."  He  also  adds,  that  "  the  earthquake- wave  occurs 
some  time  after  the  shock,  the  water  at  first  retiring  both  from  the 
shores  of  the  mainland  and  of  outlying  islands,  and  then  returning  in 
mountainous  breakers.  Their  size  is  modified  by  the  form  of  the  neigh- 
boring coast ;  for  it  is  ascertained  in  South  America,  that  places  situa- 


*  Michell,  Phil.  Trans,  vol.  li.  p.  614. 
f  Quarterly  Review,  No.  Ixxxvi.  p.  459. 
32 


498  GREAT  WAVE  OF  THE  SEA.         [On.  XXIX, 

ted  at  the  head  of  shoaling  bays  have  suffered  most,  whereas  towns  like 
Valparaiso,  seated  close  on  the  border  of  a  profound  ocean,  have  never 
been  inundated,  though  severely  shaken  by  earthquakes."* 

More  recently  (February,  1846),  Mr.  Mallet,  in  his  memoir  above 
cited  (p.  475),  has  endeavored  to  bring  to  bear  on  this  difficult  subject 
the  more  advanced  knowledge  obtained  of  late  years  respecting  the  true 
theory  of  waves.  He  conceives  that  when  the  origin  of  the  shock  is  be- 
neath the  deep  ocean,  one  wave  is  propagated  through  the  land,  and 
another  moving  with  inferior  velocity  is  formed  on  the  surface  of  the 
ocean.  This  last  rolls  in  upon  the  land  long  after  the  earth-wave  has 
arrived  and  spent  itself.  However  irreconcilable  it  may  be  to  our  com- 
mon notions  of  solid  bodies,  to  imagine  them  capable  of  transmitting, 
with  such  extreme  velocity,  motions  analogous  to  tidal  waves,  it  seems 
nevertheless  certain  that  such  undulations  are  produced,  and  it  is  sup- 
posed that  when  the  shock  passes  a  given  point,  each  particle  of  the  solid 
earth  describes  an  ellipse  in  space.  The  facility  with  which  all  the  par- 
ticles of  a  solid  mass  can  be  made  to  vibrate  may  be  illustrated,  says 
Gay  Lussac,  by  many  familiar  examples.  If  we  apply  the  ear  to  one 
end  of  a  long  wooden  beam,  and  listen  attentively  when  the  other  end 
is  struck  by  a  pin's  head,  we  hear  the  shock  distinctly  ;  which  shows 
that  every  fibre  throughout  the  whole  length  has  been  made  to  vibrate. 
The  rattling  of  carriages  on  the  pavement  shakes  the  largest  edifices ; 
and  in  the  quarries  underneath  some  quarters  in  Paris,  it  is  found  that 
the  movement  is  communicated  through  a  considerable  thickness  of 
rock.f 

The  great  sea-wave  originating  directly  over  the  centre  of  disturbance 
is  propagated,  as  Michel!  correctly  stated,  in  every  direction,  like  the 
circle  upon  a  pond  when  a  pebble  is  dropped  into  it,  the  different  rates 
at  which  it  moves  depending  (as  he  also  suggested)  on  variations  in  the 
depth  of  the  water.  This  wave  of  the  sea,  says  Mr.  Mallet,  is  raised  by 
the  impulse  of  the  shock  immediately  below  it,  which  in  great  earth- 
quakes lifts  up  the  ground  two  or  three  feet  perpendicularly.  The 
velocity  of  the  shock,  or  earth- wave,  is  greater  because  it  "  depends  upon 
a  function  of  the  elasticity  of  the  crust  of  the  earth,  whereas  the  velocity 
of  the  sea- wave  depends  upon  a  function  of  the  depth  of  the  sea." 

"  Although  the  shock  in  its  passage  under  the  deep  ocean  gives  no 
trace  of  its  progress,  it  no  sooner  gets  into  soundings  or  shallow  water, 
than  it  gives  rise  to  another  and  smaller  wave  of  the  sea.  It  carries,  as 
it  were,  upon  its  back,  this  lesser  aqueous  undulation  ;  a  long  narrow  ridge 
of  water  which  corresponds  in  form  and  velocity  to  itself,  being  pushed 
up  by  the  partial  elevation  of  the  bottom.  It  is  this  small  wave,  called 
technically  the  '  forced  sea- wave,'  which  communicates  the  earthquake- 
shock  to  ships  at  sea,  as  if  they  had  struck  upon  a  rock.  It  breaks 
upon  a  coast  at  the  same  moment  that  the  shock  reaches  it,  and  some- 

*  Darwin's  Travels  in  South  America,  <fec.,  1832  to  1836.  Voyage  of  H.  M.S. 
Beagle,  vol.  iii.  p.  377. 

f  Ann.  de  Ch.  et  de  Ph.,  torn.  xxii.  p.  428. 


CH.  XXIX.]  EARTHQUAKE  IN   CHILI,    1751.  499 

times  it  may  cause  an  apparent  slight  recession  from  the  shore,  followed 
by  its  flowing  up  somewhat  higher  than  the  usual  tide  mark  :  this  will 
happen  where  the  beach  is  very  sloping,  as  is  usual  where  the  sea  is 
shallow,  for  then  the  velocity  of  the  low  flat  earth-wave  is  such,  that  it 
slips  as  it  were,  from  under  the  undulation  in  the  fluid  above.  It  does 
this  at  the  moment  of  reaching  the  beach,  which  it  elevates  by  a  verti- 
cal height  equal  to  its  own,  and  as  instantly  lets  drop  again  to  its  former 
level." 

"  While  the  shock  propagated  through  the  solid  earth  has  thus  trav- 
elled with  extra  rapidity  to  the  land,  the  great  sea-wave  has  been  fol- 
lowing at  a  slower  pace,  though  advancing  at  the  rate  of  several  miles 
in  a  minute.  It  consists,  in  the  deep  ocean,  of  a  long  low  swell  of  enor- 
mous volume,  having  an  equal  slope  before  and  behind,  and  that  so 
gentle  that  it  might  pass  under  a  ship  without  being  noticed.  But  when 
it  reaches  the  edge  of  soundings,  its  front  slope,  like  that  of  a  tidal  wave 
under  similar  circumstances,  becomes  short  and  steep,  while  its  rear 
slope  is  long  and  gentle.  If  there  be  water  of  some  depth  close  into 
shore,  this  great  wave  may  roll  in  long  after  the  shock,  and  do  little 
damage  ;  but  if  the  shore  be  shelving,  there  will  be  first  a  retreat  of  the 
water,  and  then  the  wave  will  break  upon  the  beach  and  roll  in  far 
upon  the  land."* 

The  various  opinions  which  have  been  offered  by  Michell  and  later 
writers,  respecting  the  remote  causes  of  earthquake  shocks  in  the  in- 
terior of  the  earth,  will  more  properly  be  discussed  in  the  thirty-second 
chapter. 

Chili,  1751.— On  the  24th  of  May,  1751,  the  ancient  town  of  Con- 
ception, otherwise  called  Penco,  was  totally  destroyed  by  an  earthquake, 
and  the  sea  rolled  over  it.  (See  plan  of  the  bay,  fig.  70,  p.  455.)  The 
ancient  port  was  rendered  entirely  useless,  and  the  inhabitants  built 
another  town  about  ten  miles  from  the  sea-coast,  in  order  to  be  beyond 
the  reach  of  similar  inundations.  At  the  same  time,  a  colony  recently 
settled  on  the  sea-shore  of  Juan  Fernandez  was  almost  entirely  over- 
whelmed by  a  wave  which  broke  upon  the  shore. 

It  has  been  already  stated,  that  in  1835,  or  eighty-four  years  after 
the  destruction  of  Penco,  the  same  coast  was  overwhelmed  by  a  similar 
flood  from  the  sea  during  an  earthquake ;  and  it  is  also  known  that 
twenty-one  years  before  (or  in  1730),  a  like  wave  rolled  over  these 
fated  shores,  in  which  many  of  the  inhabitants  perished.  A  series  of 
similar  catastrophes  has  also  been  tracked  back  as  far  as  the  year  1590,f 
beyond  which  we  have  no  memorials  save  those  of  oral  tradition.  Molina, 
who  has  recorded  the  customs  and  legends  of  the  aborigines,  tells  us, 
that  the  Araucanian  Indians,  a  tribe  inhabiting  the  country  between  the 
Andes  and  the  Pacific,  including  the  part  now  called  Chili,  "  had  among 
them  a  tradition  of  a  great  deluge,  in  which  only  a  few  persons  were 

*  Mallet,  Proceed.  Roy.  Irish  Acad.  1846. 

f  See  Father  Acosta's  work ;  and  Sir  Woodbine  Parish,  GeoL  Soc.  Proceedings, 
voL  ii.  p.  215. 


500  ELEVATION   IN   CONCEPTION   BAY.  [Cn.  XXIX. 

saved,  who  took  refuge  upon  a  high  mountain  called  Thegtheg,  "  the 
thundering,"  which  had  three  points.  Whenever  a  violent  earthquake 
occurs,  these  people  fly  for  safety  to  the  mountains,  assigning  as  a  rea- 
son, that  they  are  fearful,  after  the  shock,  that  the  sea  will  again  return 
and  deluge  the  world.* 

Notwithstanding  the  tendency  of  writers  in  his  day  to  refer  all  tra- 
ditionary inundations  t<\  one  remote  period,  Molina  remarks  that  this 
flood  of  the  Araucanians  "  was  probably  very  different  from  that  of 
Noah."  We  have,  indeed,  no  means  of  conjecturing  how  long  this  same 
tribe  had  flourished  in  Chili,  but  we  can  scarcely  doubt,  that  if  its  ex- 
perience reached  back  even  for  three  or  four  centuries,  several  inroads 
of  the  ocean  must  have  occurred  within  that  period.  But  the  memory 
of  a  succession  of  physical  events,  similar  in  kind,  though  distinct  in 
time,  can  never  be  preserved  by  a  people  destitute  of  written  annals. 
Before  two  or  three  generations  have  passed  away  all  dates  are  forgot- 
ten, and  even  the  events  themselves,  unless  they  have  given  origin  to 
some  customs,  or  religious  rites  and  ceremonies.  Oftentimes  the  inci- 
dents of  many  different  earthquakes  and  floods  become  blended 
together  in  the  same  narrative ;  and  in  such  cases  the  single  ca- 
tastrophe is  described  in  terms  so  exaggerated,  or  is  so  disguised  by 
mythological  fictions,  as  to  be  utterly  valueless  to  the  antiquary  or  phi- 
losopher. 

Proofs  of  elevation  of  twenty -four  feet. — During  a  late  survey  of  Con- 
ception Bay,  Captain  Beechey  and  Sir  E.  Belcher  discovered  that  the 
ancient  harbor,  which  formerly  admitted  all  large  merchant  vessels 
which  went  round  the  Cape,  is  now  occupied  by  a  reef  of  sandstone, 
certain  points  of  which  project  above  the  sea  at  low  water,  the  greater 
part  being  very  shallow.  A  tract  of  a  mile  and  a  half  in  length,  where, 
according  to  the  report  of  the  inhabitants,  the  water  was  formerly  four 
or  five  fathoms  deep,  is  now  a  shoal ;  consisting,  as  our  hydrographers 
found,  of  hard  sandstone,  so  that  it  cannot  be  supposed  to  have  been 
formed  by  recent  deposits  of  the  river  Biobio,  an  arm  of  which  carries 
down  loose  micaceous  sand  into  the  same  bay. 

It  is  impossible  at  this  distance  of  time  to  affirm  that  the  bed  of  the 
sea  was  uplifted  at  once  to  the  height  of  twenty-four  feet,  during  the 
single  earthquake  of  1751,  because  other  movements  may  have  occurred 
subsequently;  but  it  is  said,  that  ever  since  the  shock  of  1751,  no  ves- 
sels have  been  able  to  approach  within  a  mile  and  a  half  of  the  ancient 
port  of  Penco.  (See  Map,  p.  455.)  In  proof  of  the  former  elevation 
of  the  coast  near  Penco  our  surveyors  found  above  high- water  mark  an 
enormous  bed  of  shells  of  the  same  species  as  those  now  living  in  the 
bay,  filled  with  micaceous  sand  like  that  which  the  Biobio  now  conveys 
to  the  bay.  These  shells,  as  well  as  others,  which  cover  the  adjoining 
hills  of  mica-schist  to  the  height  of  several  hundred  feet,  have  lately 
been  examined  by  experienced  conchologists  in  London,  and  identified 

*  Molina,  Hist,  of  Chili,  voL  it 


CH.  XXIX.]        EARTHQUAKE  IN  PERU,  1746.  501 

with  those  taken  at  the  same  time  in  a  living  state  from  the  bay  and  its 
neighborhood.* 

Ulloa,  therefore,  was  perfectly  correct  in  his  statement  that,  at  various 
heights  above  the  sea  between  Talcahuano  and  Conception,  "  mines 
were  found  of  various  sorts  of  shells  used  for  lime  of  the  very  same  kinds 
as  those  found  in  the  adjoining  sea."  Among  them  he  mentions  the 
great  mussel  called  Chores,  and  two  others  which  he  describes.  Some 
of  these,  he  says,  are  entire,  and  others  broken  ;  they  occur  at  the  bot- 
tom of  the  sea,  in  four,  six,  ten,  or  twelve  fathom  water,  where  they  ad- 
here to  a  sea-plant  called  Cochayuyo.  They  are  taken  in  dredges,  and 
have  no  resemblance  to  those  found  on  the  shore  or  in  shallow  water ; 
yet  beds  of  them  occur  at  various  heights  on  the  hills.  "  I  was  the 
more  pleased  with  the  sight,"  he  adds,  "  as  it  appeared  to  me  a  con- 
vincing proof  of  the  universality  of  the  deluge,  although  I  am  not  igno- 
rant that  some  have  attributed  their  position  to  other  causes."f  It  has, 
however,  been  ascertained  that  the  foundation  of  the  Castle  of  Penco 
was  so  low  in  1835,  or  at  so  inconsiderable  an  elevation  above  the  high- 
est spring  tides,  as  to  discountenance  the  idea  of  any  permanent  upheaval 
in  modern  times,  on  the  site  of  that  ancient  port ;  but  no  exact  measure- 
ments or  levellings  appear  as  yet  to  have  been  made  to  determine  this 
point,  which  is  the  more  worthy  of  investigation,  because  it  may  throw 
some  light  on  an  opinion  often  promulgated  of  late  years,  that  there 
is  a  tendency  in  the  Chilian  coast,  after  each  upheaval,  to  sink  gradually 
and  return  towards  its  former  position. 

Peru,  1746. — Peru  was  visited,  on  the  28th  of  October,  1746,  by  a 
tremendous  earthquake.  In  the  first  twenty-four  hours,  two  hundred 
shocks  were  experienced.  The  ocean  twice  retired  and  returned  impetu- 
ously upon  the  land :  Lima  was  destroyed,  and  part  of  the  coast  near 
Callao  was  converted  into  a  bay  :  four  other  harbors,  among  which  were 
Cavalla  and  Guanape,  shared  the  same  fate.  There  were  twenty-three 
ships  and  vessels,  great  and  small,  in  the  harbor  of  Callao,  of  which 
nineteen  were  sunk ;  and  the  other  four,  among  which  was  a  frigate 
called  St.  Fermin,  were  carried  by  the  force  of  the  waves  to  a  great  dis- 
tance up  the  country,  and  left  on  dry  ground  at  a  considerable  height 
above  the  sea.  The  number  of  inhabitants  in  this  city  amounted  to  four 
thousand.  Two  hundred  only  escaped,  twenty-two  of  whom  were  saved 
on  a  small  fragment  of  the  fort  of  Vera  Cruz,  which  remained  as  the  only 
memorial  of  the  town  after  this  dreadful  inundation.  Other  portions  of 
its  site  were  completely  covered  with  heaps  of  sand  and  gravel. 

A  volcano  in  Lucanas  burst  forth  the  same  night,  and  such  quanti- 
ties of  water  descended  from  the  cone  that  the  whole  country  was  over- 
flowed ;  and  in  the  mountain  near  Pataz,  called  Conversiones  de  Caxa- 
marquilla,  three  other  volcanoes  burst  out,  and  frightful  torrents  of  water 
swept  down  their  sides.]; 

*  Captain  Belcher  has  shown  me  these  shells,  and  the  collection  has  been 
examined  by  Mr.  Broderip. 

f  Ulloa's  Voyage  to  South  America,  vol.  ii.  book  viii.  ch.  vi 
\  Ibid.  vol.  ii.  book  vii.  ch.  vii 


502  EARTHQUAKE   IN   JAVA,   1699.  [On.  XXIX. 

There  are  several  records  of  prior  convulsions  in  Peru,  accompanied  by 
similar  inroads  in  the  sea,  one  of  which  happened  fifty-nine  years  before 
(in  1687),  when  the  ocean,  according  to  Ulloa,  first  retired  and  then  re- 
turned in  a  mountainous  wave,  overwhelming  Callao  and  its  environs, 
with  the  miserable  inhabitants.*  This  same  wave,  according  to  Lionel 
Wafer,  carried  ships  a  league  into  the  country,  and  drowned  man  and 
beast  for  fifty  leagues  along  the  shore. f  Inundations  of  still  earlier  dates 
are  carefully  recorded  by  Ulloa,  Wafer,  Acosta,  and  various  writers,  who 
describe  them  as  having  expended  their  chief  fury,  some  on  one  part  of 
the  coast  and  some  on  another. 

But  all  authentic  accounts  cease  when  we  ascend  to  the  era  of  the 
conquest  of  Peru  by  the  Spaniards.  The  ancient  Peruvians,  although 
far  removed  from  barbarism,  were  without  written  annals,  and  therefore 
unable  to  preserve  a  distinct  recollection  of  a  long  series  of  natural 
events.  They  had,  however,  according  to  Antonio  de  Herrera,  who,  in 
the  beginning  of  the  seventeenth  century,  investigated  their  antiqui- 
ties, a  tradition,  "  that  many  years  before  the  reign  of  the  Incas,  at  a 
time  when  the  country  was  very  populous,  there  happened  a  great  flood  ; 
the  sea  breaking  out  beyond  its  bounds,  so  that  the  land  was  covered 
with  water  and  all  the  people  perished.  To  this  the  Guacas,  inhabiting 
the  vale  of  Xausca,  and  the  natives  of  Chiquito,  in  the  province  of  Cal- 
lao, add  that  some  persons  remained  in  the  hollows  and  caves  of  the 
highest  mountains,  who  again  peopled  the  land.  Others  of  the  moun- 
tain people  affirm  that  all  perished  in  the  deluge,  only  six  persons  being 
saved  on  a  float,  from  whom  descended  all  the  inhabitants  of  that  coun- 
tty.'t 

On  the  mainland  near  Lima,  and  on  the  neighboring  island  of  San 
Lorenzo,  Mr.  Darwin  found  proofs  that  the  ancient  bed  of  the  sea  had 
been  raised  to  the  height  of  more  than  eighty  feet  above  water  within 
the  human  epoch,  strata  having  been  discovered  at  that  altitude,  con- 
taining pieces  of  cotton  thread  and  plaited  rush,  together  with  sea- weed 
and  marine  shells.§  The  same  author  learnt  from  Mr.  Gill,  a  civil 
engineer,  that  he  discovered  in  the  interior  near  Lima,  between  Casma 
and  Huaraz,  the  dried-up  channel  of  a  large  river,  sometimes  worn 
through  solid  rock,  which,  instead  of  continually  ascending  towards  its 
source,  has,  in  one  place,  a  steep  downward  slope  in  that  direction,  for  a 
ridge  or  line  of  hills  has  been  uplifted  directly  across  the  bed  of  the 
stream,  which  is  now  arched.  By  these  changes  the  water  has  been 
turned  into  some  other  course ;  and  a  district,  once  fertile,  and  still  cov- 
ered with  ruins,  and  bearing  the  marks  of  ancient  cultivation,  has  been 
converted  into  a  desert.  || 

Java,  1699. — On  the  5th  of  January,  1699,  a  terrible  earthquake 
visited  Java,  and  no  less  than  208  considerable  shocks  were  reckoned. 

*  Ulloa's  Voyage,  vol.  ii.  p.  82. 

f  Wafer,  cited  by  Sir  W.  Pariah,  Geol.  Soc.  Proceedings,  vol.  ii.  p.  215. 

\  Hist,  of  America,  decad.  iii.  book  xi.  ch.  i. 

§  Darwin's  Journal,  p.  451.  |  Ibid.  p.  41S. 


CH.  XXTX.]         EARTHQUAKE   IN    QUITO,  1698. SICILY,  1693.         503 

Many  houses  in  Batavia  were  overturned,  and  the  flame  and  noise  of  a 
volcanic  eruption  were  seen  and  heard  in  that  city,  which  were  after- 
wards found  to  proceed  from  Mount  Salek,*  a  volcano  six  days'  journey 
distant.  Next  morning  the  Batavian  river,  which  has  its  rise  from  that 
mountain,  became  very  high  and  muddy,  and  brought  down  abundance 
of  bushes  and  trees,  half  burnt.  The  channel  of  the  river  being  stopped 
up,  the  water  overflowed  the  country  round  the  gardens  about  the  town, 
and  some  of  the  streets,  so  that  fishes  lay  dead  in  them.  All  the  fish 
in  the  river,  except  the  carps,  were  killed  by  the  mud  and  turbid  water. 
A  great  number  of  drowned  buffaloes,  tigers,  rhinoceroses,  deer,  apes, 
and  other  wild  beasts,  were  brought  down  by  the  current ;  and,  "  not- 
withstanding," observes  one  of  the  writers,  "  that  a  crocodile  is  amphib- 
ious, several  of  them  were  found  dead  among  the  rest."f 

It  is  stated  that  seven  hills  bounding  the  river  sank  down ;  by  which 
is  merely  meant,  as  by  similar  expressions  in  the  description  of  the  Cala- 
brian  earthquakes,  seven  great  landslips.  These  hills,  descending  some 
from  one  side  of  the  valley  and  some  from  the  other,  filled  the  channel, 
and  the  waters  then  finding  their  way  under  the  mass,  flowed  out  thick 
and  muddy.  The  Tangaran  river  was  also  dammed  up  by  nine  hills, 
and  in  its  channel  were  large  quantities  of  drift  trees.  Seven  of  its 
tributaries  also  are  said  to  have  been  "  covered  up  with  earth."  A  high 
tract  of  forest  land,  between  the  two  great  rivers  before  mentioned,  is 
described  as  having  been  changed  into  an  open  country,  destitute  of 
trees,  the  surface  being  spread  over  with  fine  red  clay.  This  part  of 
the  account  may,  perhaps,  merely  refer  to  the  sliding  down  of  woody 
tracts  into  the  valleys,  as  happened  to  so  many  extensive  vineyards  and 
olive-grounds  in  Calabria,  in  1783.  The  close  packing  of  large  trees  in 
the  Batavian  river  is  represented  as  very  remarkable,  and  it  attests  in  a 
striking  manner  the  destruction  of  soil  bordering  the  valleys  which  had 
been  caused  by  floods  and  landslips.^ 

Quito,  1698. — In  Quito,  on  the  19th  of  July,  1698,  during  an  earth- 
quake, a  great  part  of  the  crater  and  summit  of  the  volcano  Carguairazo 
fell  in,  and  a  stream  of  water  and  mud  issued  from  the  broken  sides  of 
the  hill.§ 

Sicily,  1693. — Shocks  of  earthquakes  spread  over  all  Sicily  in  1693, 
and  on  the  llth  of  January  the  city  of  Catania  and  forty-nine  other 
places  were  levelled  to  the  ground,  and  about  one  hundred  thousand 
people  killed.  The  bottom  of  the  sea,  says  Vicentino  Bonajutus,  sank 
down  considerably,  both  in  ports,  inclosed  bays,  and  open  parts  of  the 
coast,  and  water  bubbled  up  along  the  shores.  Numerous  long  fissures 
of  various  breadths  were  caused,  which  threw  out  sulphurous  water; 
and  one  of  them,  in  the  plain  of  Catania  (the  delta  of  the  Simeto),  at 
the  distance  of  four  miles  from  the  sea,  sent  forth  water  as  salt  as  the 
sea.  The  stone  buildings  of  a  street  in  the  city  of  Noto,  for  the  length 

*  Misspelt  "  Sales"  iu  Hooke's  Account. 

f  Hooke's  Posthumous  Works,  p.  437.     1706.  \  Phil.  Trans.  1700. 

§  Humboldt,  Atl.  Pit.  p.  106. 


504:  MOLUCCAS,    1693.— JAMAICA,    1692.  [Ca  XXIX. 

of  half  a  mile,  sank  into  the  ground,  and  remained  hanging  on  one  side. 
In  another  street,  an  opening  large  enough  to  swallow  a  man  and  horse 
appeared.* 

Moluccas,  1693. — The  small  Isle  of  Sorea,  which  consists  of  one 
great  volcano,  was  in  eruption  in  the  year  1693.  Different  parts  of  the 
cone  fell,  one  after  the  other,  into  a  deep  crater,  until  almost  half  the 
space  of  the  island  was  converted  into  a  fiery  lake.  Most  of  the  inhab- 
itants fled  to  Banda ;  but  great  pieces  of  the  mountain  continued  to 
fall  down,  so  that  the  lake  of  lava  became  wider ;  and  finally  the  whole 
population  was  compelled  to  emigrate.  It  is  stated  that,  in  proportion 
as  the  burning  lake  increased  in  size,  the  earthquakes  were  less  ve- 
hement.f 

Jamaica,  1692. — In  the  year  1692,  the  island  of  Jamaica  was  visited 
by  a  violent  earthquake ;  the  ground  swelled  and  heaved  like  a  rolling 
sea,  and  was  traversed  by  numerous  cracks,  two  or  three  hundred  of 
which  were  often  seen  at  a  time,  opening  and  then  closing  rapidly 
again.  Many  people  were  swallowed  up  in  these  rents ;  some  the  earth 
caught  by  the  middle,  and  squeezed  to  death ;  the  heads  of  others  only 
appeared  above  ground ;  and  some  were  first  engulfed,  and  then  cast 
up  again  with  great  quantities  of  water.  Such  was  the  devastation, 
that  even  in  Port  Royal,  then  the  capital,  where  more  houses  are  said 
to  have  been  left  standing  than  in  the  whole  island  besides,  three-quar- 
ters of  the  buildings,  together  with  the  ground  they  stood  on,  sank  down 
with  their  inhabitants  entirely  under  water. 

Subsidence  in  the  harbor. — The  large  storehouses  on  the  harbor  side 
subsided,  so  as  to  be  twenty-four,  thirty-six,  and  forty-eight  feet  under 
water ;  yet  many  of  them  appear  to  have  remained  standing,  for  it  is 
stated  that,  after  the  earthquake,  the  mast-heads  of  several  ships 
wrecked  in  the  harbor,  together  with  the  chimney-tops  of  houses,  were 
just  seen  projecting  above  the  waves.  A  tract  of  land  round  the  town, 
about  a  thousand  acres  in  extent,  sank  down  in  less  than  one  minute, 
during  the  first  shock,  and  the  sea  immediately  rolled  in.  The  Swan 
frigate,  which  was  repairing  in  the  wharf,  was  driven  over  the  tops  of 
many  buildings,  and  then  thrown  upon  one  of  the  roofs,  through  which 
it  broke.  The  breadth  of  one  of  the  streets  is  said  to  have  been  doubled 
by  the  earthquake. 

According  to  Sir  H.  De  la  Beche,  the  part  of  Port  Royal  described 
as  having  sunk  was  built  upon  newly  formed  land,  consisting  of  sand, 
in  which  piles  had  been  driven ;  and  the  settlement  of  this  loose  sand, 
charged  with  the  weight  of  heavy  houses,  may,  he  suggests,  have  given 
rise  to  the  subsidence  alluded  to.J 

There  have  undoubtedly  been  instances  in  Calabria  and  elsewhere 
of  slides  of  land  on  which  the  houses  have  still  remained  standing ;  and 
it  is  possible  that  such  may  have  been  the  case  at  Port  Royal.  The 


*  Phil.  Trans.  1698-4.  f  Phil.  Trans.  1698. 

\  Manual  of  Geol.  p.  133,  second  edition. 


OH.  XXIX.]  CHANGES    CAUSED   BY   EARTHQUAKES.  505 

fact  at  least  of  submergence  is  unquestionable,  for  I  was  informed  by 
the  late  Admiral  Sir  Charles  Hamilton  that  he  frequently  saw  the  sub- 
merged houses  of  Port  Royal  in  the  year  1780,  in  that  part  of  the  har- 
bor which  lies  between  the  town  and  the  usual  anchorage  of  men-of- 
war.  Bryan  Edwards  also  says,  in  his  history  of  the  West  Indies,  that 
in  1793  the  ruins  were  visible  in  clear  weather  from  the  boats  which 
sailed  over  them.*  Lastly,  Lieutenant  B.  Jeffery,  R.  N.,  tells  me  that, 
being  engaged  in  a  survey  between  the  years  1824  and  1835,  he  re- 
peatedly visited  the  site  in  question,  where  the  depth  of  the  water  is 
from  four  to  six  fathoms,  and  whenever  there  was  but  little  wind  per- 
ceived distinct  traces  of  houses.  He  saw  these  more  clearly  when  he 
used  the  instrument  called  the  "  diver's  eye,"  which  is  let  down  below 
the  ripple  of  the  wave.f 

At  several  thousand  places  in  Jamaica  the  earth  is  related  to  have 
opened.  On  the  north  of  the  island  several  plantations,  with  their  in- 
habitants, were  swallowed  up,  and  a  lake  appeared  in  their  place,  cover- 
ing above  a  thousand  acres,  which  afterwards  dried  up,  leaving  nothing 
but  sand  and  gravel,  without  the  least  sign  that  there  had  ever  been  a 
house  or  a  tree  there.  Several  tenements  at  Yallows  were  buried  under 
land-slips  ;  and  one  plantation  was  removed  half  a  mile  from  its  place, 
the  crops  continuing  to  grow  upon  it  uninjured.  Between  Spanish  Town 
and  Sixteen-mile  Walk,  the  high  and  perpendicular  cliffs  bounding  the 
river  fell  in,  stopped  the  passage  of  the  river  and  flooded  the  latter  place 
for  nine  days,  so  that  the  people  "  concluded  it  had  been  sunk  as  Port 
Royal  was."  But  the  flood  at  length  subsided,  for  the  river  had  found 
some  new  passage  at  a  great  distance. 

Mountains  shattered. — The  Blue  and  other  of  the  highest  mountains 
are  declared  to  have  been  strangely  torn  and  rent.  They  appeared 
shattered  and  half-naked,  no  longer  affording  a  fine  green  prospect,  as 
before,  but  stripped  of  their  woods  and  natural  verdure.  The  rivers  on 
these  mountains  first  ceased  to  flow  for  about  twenty-four  hours,  and 
then  brought  down  into  the  sea,  at  Port  Royal  and  other  places,  several 
hundred  thousand  tons  of  timber,  which  looked  like  floating  islands  on 
the  ocean.  The  trees  were  in  general  barked,  most  of  their  branches 
having  been  torn  off  in  the  descent.  It  is  particularly  remarked  in  this, 
as  in  the  narratives  of  so  many  earthquakes,  that  fish  were  taken  in  great 
numbers  on  the  coast  during  the  shocks.  The  correspondents  of  Sir 
Hans  Sloane,  who  collected  with  care  the  accounts  of  eye-witnesses  of 
the  catastrophe,  refer  constantly  to  subsidences,  and  some  supposed  the 
whole  of  Jamaica  to  have  sunk  down.J 

Reflections  on  the  amount  of  change  in  the  last  one  hundred  and  sixty 
years. — I  have  now  only  enumerated  some  few  of  the  earthquakes  of  the 
last  160  years,  respecting  which  facts  illustrative  of  geological  inquiries 
are  on  record.  Even  if  my  limits  permitted,  it  would  be  an'unprofit- 

*  Vol.  i.  p.  236,  8vo  ed.  3  vols.  1801.         f  Letter  to  the  Author,  May,  1838. 
Phil.  Trans.  1694. 


506  DEFICIENCY   OF   HISTORICAL   EECOKDS.  [Cu.  XXIX 

able  task  to  examine  all  the  obscure  and  ambiguous  narratives  of  similar 
events  of  earlier  epochs ;  although,  if  the  places  were  now  examined  by 
geologists  well  practised  in  the  art  of  interpreting  the  monuments  of 
physical  changes,  many  events  which  have  happened  within  the  histor- 
ical era  might  doubtless  be  still  determined  with  precision.  It  must 
not  be  imagined  that,  in  the  above  sketch  of  the  occurrences  of  a  short 
period,  I  have  given  an  account  of  all,  or  even  the  greater  part,  of  the 
mutations  which  the  earth  has  undergone  by  the  agency  of  subterra- 
nean movements.  Thus,  for  example,  the  earthquake  of  Aleppo,  in  the 
present  century,  and  of  Syria,  in  the  middle  of  the  eighteenth,  would 
doubtless  have  afforded  numerous  phenomena,  of  great  geological  im- 
portance, had  those  catastrophes  been  described  by  scientific  observers. 
The  shocks  in  Syria  in  1759,  were  protracted  for  three  months,  through- 
out a  space  of  ten  thousand  square  leagues :  an  area  compared  to  which 
that  of  the  Calabrian  earthquake  in  1783  was  insignificant.  Accon, 
Saphat,  Balbeck,  Damascus,  Sidon,  Tripoli,  and  many  other  places,  were 
almost  entirely  levelled  to  the  ground.  Many  thousands  of  the  inhabit- 
ants perished  in  each  ;  and,  in  the  valley  of  Balbeck  alone,  20,000  men 
are  said  to  have  been  victims  to  the  convulsion.  In  the  absence  of 
scientific  accounts,  it  would  be  as  irrelevant  to  our  present  purpose  to 
enter  into  a  detailed  account  of  such  calamities,  as  to  follow  the  tract  of 
an  invading  army,  to  enumerate  the  cities  burnt  or  rased  to  the  ground, 
and  reckon  the  number  of  individuals  who  perished  by  famine  or  the 
sword. 

Deficiency  of  historical  records. — If  such,  then,  be  the  amount  of 
ascertained  changes  in  the  last  160  years,  notwithstanding  the  extreme 
deficiency  of  our  records  during  that  brief  period,  how  important  must 
we  presume  the  physical  revolutions  to  have  been  in  the  course  of  thirty 
or  forty  centuries,  during  which  some  countries  habitually  convulsed  by 
earthquakes  have  been  peopled  by  civilized  nations  !  Towns  engulfed 
during  one  earthquake  may,  by  repeated  shocks,  have  sunk  to  great 
depths  beneath  the  surface,  while  the  ruins  remain  as  imperishable  as 
the  hardest  rocks  in  which  they  are  inclosed.  Buildings  and  cities,  sub- 
merged, for  a  time,  beneath  seas  or  lakes,  and  covered  with  sedimentary 
deposits,  must,  in  some  places,  have  been  re-elevated  to  considerable 
heights  above  the  level  of  the  ocean.  The  signs  of  these  events  have, 
probably,  been  rendered  visible  by  subsequent  mutations,  as  by  the  en- 
croachments of  the  sea  upon  the  coast,  by  deep  excavations  made  by 
torrents  and  rivers,  by  the  opening  of  new  ravines,  and  chasms,  and  other 
effects  of  natural  agents,  so  active  in  districts  agitated  by  subterranean 
movements. 

If  it  be  asked  why,  if  such  wonderful  monuments  exist,  so  few  have 
hitherto  been  brought  to  light,  we  reply — because  they  have  not  been 
searched  for.  In  order  to  rescue  from  oblivion  the  memorials  of  former 
occurrences,  the  inquirer  must  know  what  he  may  reasonably  expect  to 
discover,  and  under  what  peculiar  local  circumstances.  He  must  be 
acquainted  with  the  action  and  effect  of  physical  causes,  in  order  to  rec- 


CH.  XXIX.]        BAY    OF   BAI^. ELEVATION   AND   SUBSIDENCE.  507 

ognize,  explain,  and  describe  correctly  the  phenomena  when  they  pre- 
sent themselves. 

The  best  known  of  the  great  volcanic  regions,  of  which  the  boundaries 
were  sketched  in  the  twenty-second  chapter,  is  that  which  includes 
Southern  Europe,  Northern  Africa,  and  Central  Asia ;  yet  nearly  the 
whole,  even  of  this  region,  must  be  laid  down,  in  a  geological  map,  as 
"  Terra  Incognita."  Even  Calabria  may  be  regarded  as  unexplored,  as 
also  Spain,  Portugal,  the  Barbary  States,  the  Ionian  Isles,  Asia  Minor, 
Cyprus,  Syria,  and  the  countries  between  the  Caspian  and  Black  seas. 
We  are,  in  truth,  beginning  to  obtain  some  insight  into  one  small  spot 
of  that  great  zone  of  volcanic  disturbance,  the  district  around  Naples  ;  a 
tract  by  no  means  remarkable  for  the  violence  of  the  earthquakes  which 
have  convulsed  it. 

If,  in  this  part  of  Campania,  we  are  enabled  to  establish  that  consider- 
able changes  in  the  relative  level  of  land  and  sea  have  taken  place  since 
the  Christian  era,  it  is  all  that  we  could  have  expected  ;  and  it  is  to  re- 
cent antiquarian  and  geological  research,  not  to  history,  that  we  are 
principally  indebted  for  the  information.  I  shall  now  proceed  to  lay 
before  the  reader  some  of  the  results  of  modern  investigations  in  the 
Bay  of  Baise  and  the  adjoining  coast. 

PROOFS    OF    ELEVATION    AND    SUBSIDENCE    IN    THE    BAY    OF   BAI^E. 

Temple  of  Jupiter  Serapis. — This  celebrated  monument  of  antiquity, 
a  representation  of  which  is  given  in  the  frontispiece,*  affords  in  itself 

Fig.  86. 

Monte 
Barbara. 


jlcntt 

.Mum. 


Ground  plan  of  the  coast  of  the  Bay  of  Baiae,  in  the  environs  of  Puzzuoli. 

alone,  unequivocal  evidence  that  the  relative  level  of  land  and  sea  has 
changed  twice  at  Puzzuoli  since  the  Christian  era  ;  and  each  movement, 

*  This  view  of  the  temple  (substituted  for  one  by  A.  de  Jorio,  given  in  the  ear- 
lier editions)  has  been  reduced  from  part  of  a  beautiful  colored  drawing  taken  in 
1836,  with  the  aid  of  the  camera  lucida,  by  Mr.  I'Anson,  to  illustrate  a  paper  by 
Mr.  Babbage  on  the  temple,  read  March,  1834,  and  published  in  the  Quart.  Journ. 
of  the  Geol.  Soc.  of  London,  vol.  iii.  1847. 


508 


CHANGES    OF   LEVEL,    PUZZUOLI. 


[Cn.  XXIX. 


Fig.  8T. 


both  of  elevation  and  subsidence,  has  exceeded  twenty  feet.  Before 
examining  these  proofs,  I  may  observe,  that  a  geological  examination  of 
the  coast  of  Baiae,  both  on  the  north  and  south  of  Puzzuoli,  establishes, 
in  the  most  satisfactory  manner,  an  elevation,  at  no  remote  period,  of 
more  than  twenty  feet,  and,  at  one  point,  of  more  than  thirty  feet ;  and 
the  evidence  of  this  change  would  have  been  complete,  if  even  the  tem- 
ple had,  to  this  day,  remained  undiscovered. 

Coast  south  of  Puzzuoli, — If  we  coast  along  the  shore  from  Naples 
to  Puzzuoli,  we  find,  on  approaching  the  latter  place,  that  the  lofty  and 
precipitous  cliffs  of  indurated  tuff,  resembling  that  of  which  Naples  is 
built,  retire  slightly  from  the  sea ;  and  that  a  low  level  tract  of  fertile 
land,  of  a  very  different  aspect,  intervenes  between  the  present  sea-beach 
and  what  was  evidently  the  ancient  line  of  coast. 

The  inland  cliff  may  be  seen  opposite  the  small  island  of  Nisida,  about 
two  miles  and  a  half  southeast  of  Puzzuoli  (see  Map,  fig.  40,  p.  361), 
where,  at  the  height  of  thirty-two  feet  above  the  level  of  the  sea,  Mr. 
Babbage  observed  an  ancient  mark,  such  as  might  have  been  worn  by 
the  waves  ;  and,  upon  farther  examination,  discovered  that,  along  that 
line,  the  face  of  the  perpendicular  rock,  consisting  of  very  hard  tuff,  was 
covered  with  barnacles  (Balanus  sulcatus,  Lamk.),  and  drilled  by  boring 
testacea.  Some  of  the  hollows  of  the  lithodomi  contained  the  shells  ; 

while  others  were  filled  with  the  valves  of 
a  species  of  Area.*  Nearer  to  Puzzuoli, 
the  inland  cliff  is  eighty  feet  high,  and  as 
perpendicular  as  if  it  was  still  undermined 
by  the  waves.  At  its  base,  a  new  deposit, 
constituting  the  fertile  tract  above  alluded 
to,  attains  a  height  of  about  twenty  feet 
above  the  sea ;  and,  since  it  is  composed 
a,  Antiquities  on  hill  s.  E.  of  Puzzuoli  of  regular  sedimentary  deposits,  containing 

6,  iSSdiff  Sow'infand6?'  marine  shells>  its  P0siti°n  PrOV6S  that>  S"b- 

c'  ^neadepco°suposed  °f  recent  Subma"  sequently to  its  formation,  there  has  been  a 

change  of  more  than  twenty  feet  in  the 
relative  level  of  land  and  sea. 

The  sea  encroaches  on  these  new  incoherent  strata  ;  and  as  the  soil  is 
valuable,  a  wall  has  been  built  for  its  protection  ;  but  when  I  visited  the 
spot  in  1828,  the  waves  had  swept  away  part  of  this  rampart,  and  ex- 
posed to  view  a  regular  series  of  strata  of  tuff,  more  or  less  argillaceous, 
alternating  with  beds  of  pumice  and  lapilli,  and  containing  great  abun- 
dance of  marine  shells,  of  species  now  common  on  this  coast,  and  amongst 
them  Cfardium  rusticum,  Ostrea  edulis,  Donax  trunculus,  Lamk.,  and 
others.  The  strata  vary  from  about  a  foot  to  a  foot  and  a  half  in  thick- 
ness, and  one  of  them  contains  abundantly  remains  of  works  of  art,  tiles, 
squares  of  mosaic  pavement  of  different  colors,  and  small  sculptured  or- 

*  Mr.  Babbage  examined  this  spot  in  company  with  Sir  Edmund  Head  in  June, 
1828,  and  has  shown  me  numerous  specimens  of  the  shells  collected  there,  and  in 
the  Temple  of  Serapis. 


OH.  XXIX.] 


VIEW    OF   BAY    OF   BALZE. 


509 


510 


CHANGES    OF   LEVEL     PUZZUOLI. 


[Cm.  XXIX. 


naments,  perfectly  uninjured.  Intermixed  with  these  I  collected  some 
teeth  of  the  pig  and  ox.  These  fragments  of  building  occur  below  as 
well  as  above  strata  containing  marine  shells.  Puzzuoli  itself  stands 
chiefly  on  a  promontory  of  the  older  tufaceous  formation,  which  cuts  off 
the  new  deposit,  although  I  detected  a  small  patch  of  the  latter  in  a  gar- 
den under  the  town. 

From  the  town  the  ruins  of  a  mole,  called  Caligula's  Bridge,  run  out 
into  the  sea  (see  fig.  88,  p.  509).*  This  mole,  which  is  believed  to  be 
eighteen  centuries  old,  consists  of  a  number  of  piers  and  arches,  thirteen 
of  which  are  now  standing,  and  two  others  appear  to  have  been  over- 
thrown. Mr.  Babbage  found,  on  the  sixth  pier,  perforations  of  litho- 
domi  four  feet  above  the  level  of  the  sea  ;  and,  near  the  termination  of 
the  mole  on  the  last  pier  but  one,  marks  of  the  same,  ten  feet  above  the 
level  of  the  sea,  together  with  great  numbers  of  balani  and  flustra.  The 
depth  of  the  sea,  at  a  very  small  distance  from  most  of  the  piers,  is 
from  thirty  to  fifty  feet. 

Coast  north  of  Puzzuoli. — If  we  then  pass  to  the  north  of  Puzzuoli, 
and  examine  the  coast  between  that  town  and  Monte  Nuovo,  we  find  a 
repetition  of  analogous  phenomena.  The  sloping  sides  of  Monte  Barbaro 
slant  down  within  a  short  distance  of  the  coast,  and  terminate  in  an 
inland  cliff  of  moderate  elevation,  to  which  the  geologist  perceives  at 

Fig.  89. 


a,  Kemains  of  Cicero's  villa,  N.  Bide  of  Puzzuoli.  t  &,  Ancient  cliff  now  inland, 

o,  Terrace  (called  La  Starza)  composed  of  recent  submarine  deposits. 
d,  Temple  of  Serapis. 

once  that  the  sea  must,  at  some  former  period,  have  extended.  Between 
this  cliff  and  the  sea  is  a  low  plain  or  terrace,  called  La  Starza  (c,  fig.  89), 
corresponding  to  that  before  described  on  the  southeast  of  the  town ; 
and  as  the  sea  encroaches  rapidly,  fresh  sections  of  the  strata  may  readily 
be  obtained,  of  which  the  annexed  is  an  example. 

Section  on  the  shore  north  of  the  town  of  Puzzuoli : — 

Ft.  In. 

1.  Vegetable  soil         - 10 

2.  Horizontal  beds  of  pumice  and  scoriae,  with  broken  fragments  of  un- 

rolled bricks,  bones  of  animals,  and  marine  shells  -         -        -        -     1     6 

3.  Beds  of  lapilli,  containing  abundance  of  marine  shells,  principally  Car- 

diumruiiticum,Donaztrunciilus,TLia,m.,  Ostrea  edulis,  Triton  cutaceum,        .'   '. 
Lam.,  and  Buccinum  serratum,  Brocchi,  the  beds  varying  in  thickness 
from  one  to  eighteen  inches  -        -        -        -        -        -        -        -100 

4.  Argillaceous  tuff,  containing  bricks  and  fragments  of  buildings  not 

rounded  by  attrition 16 

*  This  view  is  taken  from  Sir  "W.  Hamilton,  Campi  Phlegraei,  plate  26. 

f  This  spot  here  indicated  on  the  summit  of  the  cliff  is  that  from  which  Hamil- 
ton's view,  plate  26,  Campi  Phlegraei  (reduced  in  fig.  88,  p.  509)  is  taken,  and  on 
which,  he  says,  Cicero's  villa,  called  the  Academia,  anciently  stood. 


CH.  XXIX.]  TEMPLE   OF   JUPITER   SERAPI8.  511 

The  thickness  of  many  of  these  beds  varies  greatly  as  we  trace  them 
along  the  shore,  and  sometimes  the  whole  group  rises  to  a  greater  height 
than  at  the  point  above  described.  The  surface  of  the  tract  which 
they  compose  appears  to  slope  gently  upwards  towards  the  base  of  the 
old  cliffs. 

Now,  if  such  appearances  presented  themselves  on  the  coast  of  Eng- 
land, a  geologist  might  endeavor  to  seek  an  explanation  in  some  local 
change  in  the  set  of  the  tides  and  currents  :  but  there  are  scarce  any 
tides  in  the  Mediterranean  ;  and,  to  suppose  the  sea  to  have  sunk  gen- 
erally from  twenty  to  twenty-five  feet  since  the  shores  of  Campania  were 
covered  with  sumptuous  buildings  is  an  hypothesis  obviously  untenable. 
The  observations,  indeed,  made  during  modern  surveys  on  the  moles 
and  cothons  (docks)  constructed  by  the  ancients  in  various  ports  of  the 
Mediterranean,  have  proved  that  there  has  been  no  sensible  variation  of 
level  in  that  sea  during  the  last  two  thousand  years.* 

Thus  we  arrive,  without  the  aid  of  the  celebrated  temple,  at  the  con- 
clusion, that  the  recent  marine  deposit  at  Puzzuoli  was  upraised  in 
modern  times  above  the  level  of  the  sea,  and  that  not  only  this  change 
of  position,  but  the  accumulation  of  the  modern  strata,  was  posterior  to 
the  destruction  of  many  edifices,  of  which  they  contain  the  imbedded 
remains.  If  we  next  examine  the  evidence  afforded  by  the  temple 
itself,  it  appears,  from  the  most  authentic  accounts,  that  the  three  pillars 
now  standing  erect  continued,  down  to  the  middle  of  the  last  century, 
almost  buried  in  the  new  marine  strata  (c,  fig.  89).  The  upper  part  of 
each  protruding  several  feet  above  the  surface  was  concealed  by  bushes, 
and  had  not  attracted,  until  the  year  1749,  the  notice  of  antiquaries; 
but,  when  the  soil  was  removed  in  1750,  they  were  seen  to  form  part 
of  the  remains  of  a  splendid  edifice,  the  pavement  of  which  was  still 
preserved,  and  upon  it  lay  a  number  of  columns  of  African  breccia  and 
of  granite.  The  original  plan  of  the  building  could  be  traced  distinctly : 
it  was  of  a  quadrangular  form,  seventy  feet  in  diameter,  and  the  roof 
had  been  supported  by  forty-six  noble  columns,  twenty-four  of  granite 
and  the  rest  of  marble.  The  large  court  was  surrounded  by  apart- 
ments, supposed  to  have  been  used  as  bathing-rooms ;  for  a  thermal 
spring,  still  used  for  medicinal  purposes,  issues  just  behind  the  building, 
and  the  water  of  this  spring  appears  to  have  been  originally  conveyed 
by  a  marble  duct,  still  extant,  into  the  chambers,  and  then  across  the 
pavement  by  a  groove  an  inch  or  two  deep,  to  a  conduit  made  of  Roman 
brickwork,  by  which  it  gained  the  sea. 

Many  antiquaries  have  entered  into  elaborate  discussions  as  to  the 
deity  to  which  this  edifice  was  consecrated.  It  is  admitted  that,  among 
other  images  found  in  excavating  the  ruins,  there  was  one  of  the  god 
Serapis ;  and  at  Puzzuoli  a  marble  column  was  dug  up,  on  which  was 
carved  an  ancient  inscription,  of  the  date  of  the  building  of  Rome  648 
(or  B.  c.  105),  entitled  "  Lex  parieti  faciundo."  This  inscription,  written 

*  On  the  authority  of  Captain  W.  H.  Smyth,  R.  N. 


512  TEMPLE    OF   JUPITEK   SERAPIS.  [On.  XXIX. 

in  very  obscure  Latin,  sets  forth  a  contract,  between  the  municipality  of 
the  town,  and  a  company  of  builders  who  undertook  to  keep  in  repair 
certain  public  edifices,  the  Temple  of  Serapis  being  mentioned  amongst 
the  rest^ffnd  described  as  being  near  or  towards  the  sea,  "  mare  vorsum." 
Sir  Edmund  Head,  after  studying,  in  1828,  the  topography  and  anti- 
quities of  this  district,  and  the  Greek,  Roman,  and  Italian  writers  on  the 
subject,  informed  me,  that  at  Alexandria,  on  the  Nile,  the  chief  seat  of 
the  worship  of  Serapis,  there  was  a  Serapeum  of  the  same  form  as  this 
temple  at  Puzzuoli,  and  surrounded  in  like  manner  by  chambers,  in 
which  the  devotees  were  accustomed  to  pass  the  night,  in  the  hope  of 
receiving  during  sleep  a  revelation  from  the  god,  as  to  the  nature  and 
cure  of  their  diseases.  Hence  it  was  very  natural  that  the  priests  of 
Serapis,  a  pantheistic  divinity,  who,  among  other  usurpations,  had  ap- 
propriated to  himself  the  attributes  of  Esculapius,  should  regard  the 
hot  spring  as  a  suitable  appendage  to  the  temple,  although  the  original 
Serapeum  of  Alexandria  could  boast  no  such  medicinal  waters.  Signer 
Carelli*  and  others,  in  objecting  to  these  views,  have  insisted  on  the 
fact,  that  the  worship  of  Serapis,  which  we  know  prevailed  at  Rome  in 
the  days  of  Catullus  (in  the  first  century  before  Christ),  was  prohibited 
by  the  Roman  Senate,  during  the  reign  of  the  Emperor  Tiberius.  But 
there  is  little  doubt  that,  during  the  reigns  of  that  emperor's  successors, 
the  shrines  of  the  Egyptian  god  were  again  thronged  by  zealous  vota- 
ries ;  and  in  no  place  more  so  than  at  Puteoli  (now  Puzzuoli),  one  of 
the  principal  marts  for  the  produce  of  Alexandria. 

Without  entering  farther  into  an  inquiry  which  is  not  strictly  geolo- 
gical, I  shall  designate  this  valuable  relic  of  antiquity  by  its  generally 
received  name,  and  proceed  to  consider  the  memorials  of  physical 
changes  inscribed  on  the  three  standing  columns  in  most  legible  charac- 
ters by  the  hand  of  Nature.  (See  Frontispiece.)  These  pillars,  which 
have  been  carved  each  out  of  a  single  block  of  marble,  are  forty  feet 
three  inches  and  a  half  in  height.  A  horizontal  fissure  nearly  inter- 
sects one  of  the  columns ;  the  other  two  are  entire.  They  are  all 
slightly  out  of  the  perpendicular,  inclining  somewhat  to  the  southwest, 
that  is,  towards  the  sea.f  Their  surface  is  smooth  and  uninjured  to  the 
height  of  about  twelve  feet  above  their  pedestals.  Above  this  is  a  zone, 
about  nine  feet  in  height,  where  the  marble  has  been  pierced  by  a  spe- 
cies of  marine  perforating  bivalve — Lithodomus,  Cuv.J  The  holes  of 
these  animals  are  pear-shaped,  the  external  opening  being  minute,  and 
gradually  increasing  downwards.  At  the  bottom  of  the  cavities,  many 
shells  are  still  found,  notwithstanding  the  great  numbers  that  have  been 


*  Dissertazione  sulla  Sagra  Archittetura  degli  Antichi. 

f  This  appears  from  the  measurement  of  Captain  Basil  Hall,  R.  N.,  Proceed- 
ings of  Geol.  Soc.,  No.  38,  p.  114  ;  sec  also  Patchwork,  by  the  same  author,  vol.  in. 
p.  168.  The  fact  of  the  three  standing  columns  having  been  each  formed  out  of 
a  single  stone  was  tii>t  pointed  out  to  me  by  Mr.  James  Hall,  and  is  important,  as 
helping  to  explain  why  they  were  not  shaken  down. 

\.  Modiola  lithophaaa,  Lam.     Mytilut  lithophagus,  Linn. 


CH.  XXIX.]  TEMPLE   OF   JUPITER    SERAPIS.  513 

taken  out  by  visitors ;  in  many  the  valves  of  a  species  of  area,  an  ani- 
mal which  conceals  itself  in  small  hollows,  occur.  The  perforations  are 
so  considerable  in  depth  and  size,  that  they  manifest  a  long- continued 
abode  of  the  lithodomi  in  the  columns,  for,  as  the  inhabitant  grows 
older  and  increases  in  size,  it  bores  a  larger  cavity,  to  correspond  with 
the  increased  magnitude  of  its  shell.  We  must,  consequently,  infer  a 
long-continued  immersion  of  the  pillars  in  sea-water,  at  a  time  when  the 
lower  part  was  covered  up  and  protected  by  marine,  fresh- water,  and 
volcanic  strata,  afterwards  to  be  described,  and  by  the  rubbish  of  build- 
ings ;  the  highest  part,  at  the  same  time,  projecting  above  the  waters, 
and  being  consequently  weathered,  but  not  materially  injured.  (See  fig. 
90,  p.  514.) 

On  the  pavement  of  the  temple  lie  some  columns  of  marble,  which  are 
also  perforated  in  certain  parts;  one,  for  example,  to  the  length  of  eight 
feet,  while,  for  the  length  of  four  feet,  it  is  uninjured.  Several  of  these 
broken  columns  are  eaten  into,  not  only  on  the  exterior,  but  on  the  cross 
fracture,  and,  on  some  of  them,  other  marine  animals  (serpulas,  <fec.)  have 
fixed  themselves.*  All  the  granite  pillars  are  untouched  by  lithodomi. 
The  platform  of  the  temple,  which  is  not  perfectly  even,  was,  when  I 
visited  it  in  1828,  about  one  foot  below  high- water  mark  (for  there  are 
small  tides  in  the  bay  of  Naples) ;  and  the  sea,  which  was  only  one  hun- 
dred feet  distant,  soaked  through  the  intervening  soil.  The  upper  part 
of  the  perforations,  therefore,  were  at  least  twenty-three  feet  above  high- 
water  mark  ;  and  it  is  clear  that  the  columns  must  have  continued  for  a 
long  time  in  an  erect  position,  immersed  in  salt  water,  and  then  the  sub- 
merged portion  must  have  been  upraised  to  the  height  of  about  twenty- 
three  feet  above  the  level  of  the  sea. 

By  excavations  carried  on  in  1828,  below  the  marble  pavement  on 
which  the  columns  stand,  another  costly  pavement  of  mosaic  was  found, 
at  the  depth  of  about  five  feet  below  the  upper  one  (a,  b,  fig.  90).  The 
existence  of  these  two  pavements,  at  different  levels,  clearly  implies  some 
subsidence  previously  to  the  building  of  the  more  modern  temple  which 
had  rendered  it  necessary  to  construct  the  new  floor  at  a  higher  level. 

We  have  already  seen  (p.  512)  that  a  temple  of  Serapis  existed  long 
before  the  Christian  era.  The  change  of  level  just  mentioned  must  have 
taken  place  some  time  before  the  end  of  the  second  century,  for  inscrip- 
tions- have  been  found  in  the  temple,  from  which  we  learn  that  Septimius 
Severus  adorned  its  walls  with  precious  marbles,  between  the  years  194 
and  211  of  our  era,  and  the  emperor  Alexander  Severus  displayed  the 
like  munificence  between  the  years  222  and  235. f  From  that  era  there 
is  an  entire  dearth  of  historical  information  for  a  period  of  more  than 
twelve  centuries,  except  the  significant  fact  that  Alaric  and  his  Goths 
sacked  Puzzuoli  in  456,  and  that  Genseric  did  the  like  in  545,  A.  D.  Yet 
we  have  fortunately  a  series  of  natural  archives  self-registered  during  the 

*  Serpula  contortuplicata,  Linn.,  and  Vermi.Ha  triquetra,  Lam.     These  species, 
as  well  as  the  Lithodomus,  are  now  inhabitants  of  the  neighboring  sea. 
\  Brieslak,  Voy.  dam  la  Campanie,  torn.  ii.  p.  167. 

33 


514:  TEMPLE  OF  JUPITER  SERAPIS.  [On.  XXIX 

dark  ages,  by  which  many  events  which  occurred  in  and  about  the  tem- 
ple are  revealed  to  us.  These  natural  records  consist  partly  of  deposits, 
which  envelop  the  pillars  below  the  zone  of  lithodomous  perforations,  and 
partly  of  those  which  surround  the  outer  walls  of  the  temple.  Mr. 
Babbage,  after  a  minute  examination  of  these,  has  shown  (see  p.  507,  note) 
that  incrustations  on  the  walls  of  the  exterior  chambers  and  on  the  floor 
of  the  building  demonstrate  that  the  pavement  did  not  sink  down  sud- 
denly, but  was  depressed  by  a  gradual  movement.  The  sea  first  entered 
the  court  or  atrium  and  mingled  its  waters  partially  with  those  of  the 
hot  spring.  From  this  brackish  medium  a  dark  calcareous  precipitate 
(c  c,  tig.  90)  was  thrown  down,  which  became,  in  the  course  of  time, 


Fig.  90. 


Sea 


Temple  of  Serapis  at  its  period  of  greatest  depression. 

.„     iKisL  -, 

a  &,  Ancient  mosaic  pavement  e  f,  Freshwater  calcareous  deposit. 

c  c,  Dark  marine  incrustation.  /£  Second  filling  up. 

dd,  First  filling  up,  shower  of  ashes.  A,  Stadium. 

more  than  two  feet  thick,  including  some  serpula?  in  it.  The  presence  of 
these  annelids  teaches  us  that  the  water  was  salt  or  brackish.  After  this 
period  the  temple  was  filled  up  with  an  irregular  mass  of  volcanic  tuff 
(d  d,  fig.  90),  probably  derived  from  an  eruption  of  the  neighboring 
crater  of  the  Solfatara,  to  the  height  of  from  five  to  nine  feet  above  the 
pavement.  Over  this  again  a  purely  freshwater  deposit  of  carbonate  of 
lime  (e  e,  fig.  90)  accumulated  with  an  uneven  bottom  since  it  necessarily 
accommodated  itself  to  the  irregular  outline  of  the  upper  surface  of  the 
volcanic  shower  before  thrown  down.  The  top  of  the  same  deposit  (a 
freshwater  limestone)  was  perfectly  even  and  flat,  bespeaking  an  ancient 
water  level.  It  is  suggested  by  Mr.  Babbage  that  this  freshwater  lake 
may  have  been  caused  by  the  fall  of  ashes  which  choked  up  the  channel 
previously  communicating  with  the  sea,  so  that  the  hot  spring  threw 
down  calcareous  matter  in  the  atrium,  without  any  marine  intermixture. 
To  the  freshwater  limestone  succeeded  another  irregular  mass  of  volcanic 
ashes  and  rubbish  (//,  fig;  90),  some  of  it  perhaps  washed  in  by  the 
waves  of  the  sea  during  a  storm,  its  surface  rising  to  ten  or  eleven  feet 
above  the  pavement.  And  thus  we  arrive  at  the  period  of  greatest 
depression  expressed  in  the  accompanying  diagram,  when  the  lower  half 
of  the  pillars  were  enveloped  in  the  deposits  above  enumerated,  and  the 
uppermost  twenty  feet  were  exposed  in  the  atmosphere,  the  remaining 
or  middle  portion,  about  nine  feet  long,  being  for  years  immersed  in  salt 


CH.  XXIX.]  TEMPLE   OF  JUPITER   SERAPIS.  515 

water  nnd  drilled  by  perforating  bivalves.  After  this  period  other  strata, 
consisting  of  showers  of  volcanic  ashes  and  materials  washed  in  during 
storms,  covered  up  the  pillars  to  the  height  in  some  places  of  thirty- five 
feet  above  the  pavement.  The  exact  time  when  these  enveloping  masses 
were  heaped  up,  and  how  much  of  them  were  formed  during  submer- 
gence, and  how  much  after  the  re-elevation  of  the  temple,  cannot  be 
made  out  with  certainty. 

The  period  of  deep  submergence  was  certainly  antecedent  to  the  close 
of  the  fifteenth  century.  Professor  James  Forbes*  has  reminded  us  of 
a  passage  in  an  old  Italian  writer  Loffredo,  who  says  that  in  1530,  or 
fifty  years  before  he  wrote,  which  was  in  1580,  the  sea  washed  the  base 
of  the  hills  which  rise  from  the  flat  land  called  La  Starza,  as  represented 
in  fig.  90,  so  that,  to  quote  his  words,  "  a  person  might  then  have  fished 
from  the  site  of  those  ruins  which  are  now  called  the  stadium"  (A, 
fig.  90). 

But  we  know  from  other  evidence  that  the  upward  movement  had 
begun  before  1530,  for  the  Ganonico  Andrea  di  Jorio  cites  two  authen- 
tic documents  in  illustration  of  this  point.  The  first,  dated  Oct.  1503, 
is  a  deed  written  in  Italian,  by  which  Ferdinand  and  Isabella  grant  to 
the  University  of  Puzzuoli  a  portion  of  land,  "  where  the  sea  is  drying 
up"  (che  va  seccando  el  mare) ;  the  second,  a  document  in  Latin,  dated 
May  23,  1511,  or  nearly  eight  years  after,  by  which  Ferdinand  grants 
to  the  city  a  certain  territory  around  Puzzuoli,  where  the  ground  is  dried 
up  from  the  sea  (desiccatum).f 

The  principal  elevation,  however,  of  the  low  tract  unquestionably  took 
place  at  the  time  of  the  great  eruption  of  Monte  Nuovo  in  1538.  That 
event  and  the  earthquakes  which  preceded  it  have  been  already  de- 
scribed (p.  368) ;  and  we  have  seen  that  two  of  the  eye-witnesses  of  the 
convulsion,  Falconi  and  Giacomo  di  Toledo,  agree  in  declaring  that  the 
sea  abandoned  a  considerable  tract  of  the  shore,  so  that  fish  were  taken 
by  the  inhabitants ;  and,  among  other  things,  Falconi  mentions  that  he 
saw  two  springs  in,  the  newly  discovered  ruins. 

The  flat  land,  when  first  upraised,  must  have  been  more  extensive  than 
now,  for  the  sea  encroaches  somewhat  rapidly,  both  to  the  north  and 
southeast  of  Puzzuoli.  The  coast  had,  when  I  examined  it  in  1828,  given 
way  more  than  a  foot  in  a  twelvemonth ;  and  I  was  assured,  by  fisher- 
men in  the  bay,  that  it  has  lost  ground  near  Puzzuoli,  to  the  extent  of 
thirty  feet,  within  their  memory. 

It  is,  moreover,  very  probable  that  the  land  rose  to  a  greater  height 
at  first  before  it  ceased  to  move  upwards,  than  the  level  at  which  it  was 
observed  to  stand  when  the  temple  was  rediscovered  in  1749,  for  we 
learn  from  a  memoir  of  Niccolini,  published  in  1838,  that  since  the  be- 
ginning of  the  nineteenth  century,  the  temple  of  Serapis  has  subsided 
more  than  two  feet.  That  learned  architect  visited  the  ruins  frequently, 
for  the  sake  of  making  drawings,  in  the  beginning  of  the  year  1807,  and 

*  Ed.  Journ.  of  Science,  new  series,  No.  II.  p.  281. 
f  Sul  Tempio  di  Scrap,  ch.  viii. 


516  TEMPLE  OF  JUPITER   SEEAPIS.  [Cn.  XXIX. 

was  in  the  habit  of  remaining  there  throughout  the  day,  yet  never  saw 
the  pavement  overflowed  by  the  sea,  except  occasionally  when  the  south 
wind  blew  violently.  On  his  return,  sixteen  years  after,  to  superintend 
some  excavations  ordered  by  the  king  of  Naples,  he  found  the  pavement 
covered  by  sea-water  twice  every  day  at  high  tide,  so  that  he  was 
obliged  to  place  there  a  line  of  stones  to  stand  upon.  This  induced  him 
to  make  a  series  of  observations  from  Oct.  1822  to  July  1838,  by  which 
means  he  ascertained  that  the  ground  had  been  and  was  sinking,  at  the 
average  rate  of  about  seven  millimetres  a  year,  or  about  one  inch  in  four 
years;  so  that,  in  1838,  fish  were  caught  every  day  on  that  part  of  the 
pavement  where,  in  1807,  there  was  never  a  drop  of  water  in  calm 
weather.* 

On  inquiring  still  more  recently  as  to  the  condition  of  the  temple  and 
the  continuance  of  the  sinking  of  the  ground,  I  learn  from  Signor 
Scacchi  in  a  letter,  dated  June  1852,  that  the  downward  movement  has 
ceased  for  several  years,  or  has  at  least  become  almost  inappreciable. 
During  an  examination  undertaken  by  him  at  my  request  in  the  summer 
of  that  year  (1852),  he  observed  that  the  rising  tide  spread  first  over  the 
seaward  side  of  the  flat  surface  of  the  pedestals  of  each  column  (con- 
firming the  fact  previously  noticed  by  others,  that  they  are  out  of  the 
perpendicular) ;  and  he  also  remarked  that  the  water  gained  unequally 
on  the  base  of  each  pillar,  in  such  a  manner  as  to  prove  that  they  have 
neither  the  same  amount  of  inclination,  nor  lean  precisely  in  the  same 
direction. 

From  what  was  said  before  (p.  510),  we  saw  that  the  marine  shells 
in  the  strata  forming  the  plain  called  La  Starza,  considered  separately, 
establish  the  fact  of  an  upheaval  of  the  ground  to  the  height  of  twenty- 
three  feet  and  upwards.  The  temple  proves  much  more,  because  it 
could  not  have  been  built  originally  under  water,  and  must  therefore 
first  have  sunk  down  twenty  feet  at  least  below  the  waves,  to  be  after- 
wards restored  to  its  original  position.  Yet  if  such  was  the  order  of 
events  we  ought  to  meet  with  other  independent  signs  of  a  like  subsi- 
dence round  the  margin  of  a  bay  once  so  studded  with  buildings  as  the 
Bay  of  Baiae.  Accordingly  memorials  of  such  submergence  are  not 
wanting.  About  a  mile  northwest  of  the  temple  of  Serapis,  and  about 
500  feet  from  the  shore,  are  the  ruins  of  a  temple  of  Neptune  and  others 
of  a  temple  of  the  Nymphs,  now  under  water.  The  columns  of  the 
former  edifice  stand  erect  in  five  feet  water,  their  upper  portions  just 
rising  to  the  surface  of  the  sea.  The  pedestals  are  doubtless  buried  in 
the  sand  or  mud  ;  so  that,  if  this  part  of  the  bottom  of  the  bay  should 
hereafter  be  elevated,  the  exhumation  of  these  temples  might  take  place 
after  the  manner  of  that  of  Serapis.  Both  these  buildings  probably  par- 
ticipated in  the  movement  which  raised  the  Starza ;  but  either  they  were 
deeper  under  water  than  the  temple  of  Serapis,  or  they  were  not  raised 

*  Tavola  Metrica  Chronologica,  <fcc.  Napoli,  1838.  Mr.  Smith,  of  Jordan  Hill, 
writing  in  1847,  estimated  the  rate  of  subsidence,  at  that  period,  at  one  inch  an- 
nually. Quart.  Journ.  Geol.  Soc.  vol.  iii.  p.  237. 


CH.  XXIX.]  ROMAN   ROADS   UNDER   WATER.  517 

up  again  to  so  great  a  height.  There  are  also  two  Roman  roads  under 
water  in  the  bay,  one  reaching  from  Puzzuoli  to  the  Lucrine  Lake,  which 
may  still  be  seen,  and  the  other  near  the  castle  of  Baise  (No.  8,  fig.  88, 
p.  509).  The  ancient  mole,  too,  of  Puzzuoli  (No.  4,  ibid.)  before  alluded 
to,  has  the  water  up  to  a  considerable  height  of  the  arches ;  whereas 
Brieslak  justly  observes,  it  is  next  to  certain  that  the  piers  must  formerly 
have  reached  the  surface  before  the  springing  of  the  arches  ;*  so  that, 
although  the  phenomena  before  described  prove  that  this  mole  has  been 
uplifted  ten  feet  above  the  level  at  which  it  once  stood,  it  is  still  evident 
that  it  has  not  yet  been  restored  to  its  original  position. 

A  modern  writer  also  reminds  us,  that  these  effects  are  not  so  local 
as  some  would  have  us  to  believe  ;  for  on  the  opposite  side  of  the  Bay 
of  Naples,  on  the  Sorrentine  coast,  which,  as  well  as  Puzzuoli,  is  sub- 
ject to  earthquakes,  a  road,  with  some  fragments  of  Roman  buildings, 
is  covered  to  some  depth  by  the  sea.  In  the  island  of  Capri,  also, 
which  is  situated  some  way  out  at  sea,  in  the  opening  of  the  Bay  of 
Naples,  one  of  the  palaces  of  Tiberius  is  now  covered  with  water.f 

That  buildings  should  have  been  submerged,  and  afterwards  up- 
heaved, without  being  entirely  reduced  to  a  heap  of  ruins,  will  appear 
no  anomaly,  when  we  recollect  that,  in  the  year  1819,  when  the  delta 
of  the  Indus  sank  down,  the  houses  within  the  fort  of  Sindree  subsided 
beneath  the  waves  without  being  overthrown.  In  like  manner,  in  the 
year  1692,  the  buildings  round  the  harbor  of  Port  Royal,  in  Jamaica, 
descended  suddenly  to  the  depth  of  between  thirty  and  fifty  feet  under 
the  sea  without  falling.  Even  on  small  portions  of  land  transported  to 
a  distance  of  a  mile  down  a  declivity,  tenements,  like  those  near  Mileto, 
in  Calabria,  were  carried  entire.  At  Valparaiso  buildings  were  left 
standing  in  1822,  when  their  foundations,  together  with  a  long  tract  of 
the  Chilian  coast,  were  permanently  upraised  to  the  height  of  several 
feet.  It  is  still  more  easy  to  conceive  that  an  edifice  may  escape  falling 
during  the  upheaval  or  subsidence  of  land,  if  the  walls  are  supported 
on  the  exterior  and  interior  with  a  deposit  like  that  which  surrounded 
and  filled  to  the  height  of  ten  or  eleven  feet  the  temple  of  Serapis  all 
the  time  it  was  sinking,  and  which  enveloped  it  to  more  than  twice 
that  height  when  it  was  rising  again  to  its  original  level. 

We  can  scarcely  avoid  the  conclusion,  as  Mr.  Babbage  has  hinted, 
"  that  the  action  of  heat  is  in  some  way  or  other  the  cause  of  the  phe- 
nomena of  the  change  of  level  of  the  temple.  Its  own  hot  spring,  its 
immediate  contiguity  to  the  Solfatara,  its  nearness  to  the  Monte  Nuovo, 
the  hot  spring  at  the  baths  of  Nero  (No.  6,  fig.  88),  on  the  opposite 
side  of  the  Bay  of  Baiae ;  the  boiling  springs  and  ancient  volcanoes  of 
Ischia  on  one  side  and  Vesuvius  on  the  other,  are  the  most  prominent 

*  Voy.  dans  la  Campanie,  tome  ii.  p.  162. 

f  Mr.  Forbes,  Physical  Notices  of  the  Bay  of  Naples.  Ed.  Journ.  of  Sci.,  No. 
II.,  new  series,  p.  280.  October,  1829.  When  I  visited  Puzzuoli,  and  arrived  at 
the  above  conclusions,  I  knew  nothing  of  Mr.  Forbes's  observations,  which  I  first 
saw  on  my  return  to  England  the  year  following. 


518  PERMANENCE   OF   THE   OCEAN'S   LEVEL.         [On.  XXIX. 

of  a  multitude  of  facts  which  point  to  that  conclusion."*  And  when 
we  reflect  on  the  dates  of  the  principal  oscillations  of  level,  and  the 
volcanic  history  of  the  country  before  described  (chap.  23),  we  seem  to 
discover  a  connection  between  each  era  of  upheaval  and  a  local  devel- 
opment of  volcanic  heat,  and  again  between  each  era  of  depression  and 
the  local  quiescence  or  dormant  condition  of  the  subterranean  igneous 
causes.  Thus  for  example,  before  the  Christian  era,  when  so  many 
vents  were  in  frequent  eruption  in  Ischia,  and  when  Avernus  and  other 
points  in  the  Phlegrsean  Fields  were  celebrated  for  their  volcanic  aspect 
and  character,  the  ground  on  which  the  temple  stood  was  several  feet 
above  water.  Vesuvius  was  then  regarded  as  a  spent  volcano ;  but 
when,  after  the  Christian  era,  the  fires  of  that  mountain  were  rekindled, 
scarcely  a  single  outburst  was  ever  witnessed  in  Ischia,  or  around  the 
Bay  of  Baise.  Then  the  temple  was  sinking.  Vesuvius,  at  a  subsequent 
period,  became  nearly  dormant  for  five  centuries  preceding  the  great 
outbreak  of  1631  (see  p.  374),  and  in  that  interval  the  Solfatara  was 
in  eruption  A.  D.  1198,  Ischia  in  1302,  and  Monte  Nuovo  was  formed  in 
1538.  Then  the  foundations  on  which  the  temple  stood  were  rising 
again.  Lastly,  Vesuvius  once  more  became  a  most  active  vent,  and  has 
been  so  ever  since,  and  during  the  same  lapse  of  time  the  area  of  the 
temple,  so  far  as  we  know  any  thing  of  its  history,  has  been  subsiding. 

These  phenomena  would  agree  well  with  the  hypothesis,  that  when 
the  subterranean  heat  is  on  the  increase,  and  when  lava  is  forming 
without  obtaining  an  easy  vent,  like  that  afforded  by  a  great  habitual 
chimney,  such  as  Vesuvius,  the  incumbent  surface  is  uplifted ;  but  when 
the  heated  rocks  below  are  cooling  and  contracting,  and  sheets  of  lava 
are  slowly  consolidating  and  diminishing  in  volume,  then  the  incumbent 
land  subsides. 

Signer  Niccolini,  when  he  ascertained  in  1838  that  the  relative  levels 
of  the  floor  of  the  temple  and  of  the  sea  were  slowly  changing  from 
year  to  year,  embraced  the  opinion  that  it  was  the  sea  which  was  rising. 
But  Signer  Capocci  successfully  controverted  this  view,  appealing  to 
many  appearances  which  attest  the  local  character  of  the  movements  of 
the  adjoining  country,  besides  the  historical  fact  that  in  1538,  when 
the  sea  retired  permanently  200  yards  from  the  ancient  shore  at  Puz- 
zuoli,  there  was  no  simultaneous  retreat  of  the  waters  from  Naples, 
Castelamare,  and  Ischia.f 

Permanence  of  the  ocean's  level. — In  concluding  this  subject  I  may 
observe,  that  the  interminable  controversies  to  which  the  phenomena  of 
the  Bay  of  Baiae  gave  rise,  have  sprung  from  an  extreme  reluctance  to 
admit  that  the  land,  rather  than  the  sea,  is  subject  alternately  to  rise 
and  fall.  Had  it  been  assumed  that  the  level  of  the  ocean  was  invaria- 
ble, on  the  ground  that  no  fluctuations  have  as  yet  been  clearly  estab- 
lished, and  that,  on  the  other  hand,  the  continents  are  inconstant  in 


*  Quart.  Journ.  Geol.  Soc.  1847,  vol.  iii.  p.  203. 
f  Nuove  Ricerche  sul  Temp,  cli  Serap. 


OH.  XXX.]  ELEVATION   AND   SUBSIDENCE   OF   LAND.  519 

their  level,  as  has  been  demonstrated  by  the  most  unequivocal  proofs 
again  and  again,  from  the  time  of  Strabo  to  our  own  times,  the  appear- 
ances of  the  temple  at  Puzzuoli  could  never  have  been  regarded  as 
enigmatical.  Even  if  contemporary  accounts  had  not  distinctly  attested 
the  upraising  of  the  coast,  this  explanation  should  have  been  proposed  in 
the  first  instance  as  the  most  natural,  instead  of  being  now  adopted 
unwillingly  when  all  others  have  failed. 

To  the  strong  prejudices  still  existing  in  regard  to  the  mobility  of  the 
land,  we  may  attribute  the  rarity  of  such  discoveries  as  have  been  re- 
cently brought  to  light  in  the  Bay  of  Baiae  and  the  Bay  of  Conception. 
A  false  theory,  it  is  well  known,  may  render  us  blind  to  facts  which  are 
opposed  to  our  prepossessions,  or  may  conceal  from  us  their  true  im- 
port when  we  behold  them.  But  it  is  time  that  the  geologist  should,  in 
some  degree,  overcome  those  first  and  natural  impressions,  which  induced 
the  poets  of  old  to  select  the  rock  as  the  emblem  of  firmness — the  sea 
as  the  image  of  inconstancy.  Our  modern  poet,  in  a  more  philosophical 
spirit,  saw  in  the  sea  "  The  image  of  eternity,"  and  has  finely  contrasted 
the  fleeting  existence  of  the  successive  empires  which  have  flourished  and 
fallen  on  the  borders  of  the  ocean  with  its  own  unchanged  stability. 

Their  decay 


Has  dried  up  realms  to  deserts : — not  so  thou, 

Unchangeable,  save  to  thy  wild  wave's  play  : 

Time  writes  no  wrinkle  on  thine  azure  brow ; 

Such  as  creation's  dawn  beheld,  thou  rollest  now. 

CHILDK  HAROLD,  Canto  iv. 


CHAPTER  XXX. 

ELEVATION    AND    SUBSIDENCE    OF    LAND    WITHOUT    EARTHQUAKES. 

Changes  in  the  relative  level  of  land  and  sea  in  regions  not  volcanic — Opinion  of 
Celsius  that  the  waters  of  the  Baltic  Sea  and  Northern  Ocean  were  sinking — 
Objections  raised  to  his  opinion — Proofs  of  the  stability  of  the  sea  level  in  the 
Baltic — Playfair's  hypothesis  that  the  land  was  rising  in  Sweden — Opinion  of 
Von  Buch — Marks  cut  on  the  rocks — Survey  of  these  in  1820 — Facility  of  de- 
tecting slight  alterations  of  level  on  coast  of  Sweden — Shores  of  the  ocean  also 
rising — Area  upheaved — Shelly  deposits  of  Uddevalla — Of  Stockholm,  contain- 
ing fossil  shells  characteristic  of  the  Baltic — Subsidence  in  south  of  Sweden— 
Fishing  hut  buried  under  marine  strata — Upheaval  in  Sweden  not  always  in 
horizontal  planes — Sinking  of  land  in  Greenland — Bearing  of  these  facts  on 
geology. 

WE  have  now  considered  the  phenomena  of  volcanoes  and  earthquakes 
according  to  the  division  of  the  subject  before  proposed  (p.  345),  and 
have  next  to  turn  our  attention  to  those  slow  and  insensible  changes  in 
the  relative  level  of  land  and  sea  which  take  place  in  countries  remote 
from  volcanoes,  and  where  no  violent  earthquakes  have  occurred  within 
the  period  of  human  observation.  Early  in  the  last  century  the  Swedish 


520  KISE   OF   LAND   IN   SWEDEN.  [Cfl.  XXX. 

naturalist,  Celsius,  expressed  his  opinion  that  the  waters,  both  of  the 
Baltic  and  Northern  Ocean,  were  gradually  subsiding.  From  numerous 
observations,  he  inferred  that  the  rate  of  depression  was  about  fifty 
Swedish  inches  in  a  century.*  In  support  of  this  position,  he  alleged 
that  there  were  many  rocks  both  on  the  shores  of  the  Baltic  and  the 
ocean  known  to  have  been  once  sunken  reefs,  and  dangerous  to  naviga- 
tors, but  which  were  in  his  time  above  water — that  the  waters  of  the 
Gulf  of  Bothnia  had  been  gradually  converted  into  land,  several  ancient 
ports  having  been  changed  into  inland  cities,  small  islands  joined  to  the 
continent,  and  old  fishing-grounds  deserted  as  being  too  shallow,  or  en- 
tirely dried  up.  Celsius  also  maintained,  that  the  evidence  of  the  change 
rested  not  only  on  modern  observations,  but  on  the  authority  of  the 
ancient  geographers,  who  had  stated  that  Scandinavia  was  formerly  an 
island.  This  island,  he  argued,  must  in  the  course  of  centuries,  by  the 
gradual  retreat  of  the  sea,  have  become  connected  with  the  continent ; 
an  event  which  he  supposed  to  have  happened  after  the  time  of  Pliny, 
and  before  the  ninth  century  of  our  era. 

To  this  argument  it  was  objected  that  the  ancients  were  so  ignorant 
of  the  geography  of  the  most  northern  parts  of  Europe,  that  their  au- 
thority was  entitled  to  no  weight ;  and  that  their  representation  of  Scan- 
dinavia as  an  island,  might  with  more  propriety  be  adduced  to  prove 
the  scantiness  of  their  information,  than  to  confirm  so  bold  an  hypoth- 
esis. It  was  also  remarked  that  if  the  land  which  connected  Scan- 
dinavia with  the  main  continent  was  laid  dry  between  the  time  of  Pliny 
and  the  ninth  century,  to  the  extent  to  which  it  is  known  to  have  risen 
above  the  sea  at  the  latter  period,  the  rate  of  depression  could  not  have 
been  uniform,  as  was  pretended  ;  for  it  ought  to  have  fallen  much  more 
rapidly  between  the  ninth  and  eighteenth  centuries. 

Many  of  the  proofs  relied  on  by  Celsius  and  his  followers  were  im- 
mediately controverted  by  several  philosophers,  who  saw  clearly  that  a 
fall  of  the  sea  in  any  one  region  could  not  take  place  without  a  general 
sinking  of  the  waters  over  the  whole  globe :  they  denied  that  this  was 
the  fact,  or  that  the  depression  was  universal,  even  in  the  Baltic.  In 
proof  of  the  stability  of  the  level  of  that  sea,  they  appealed  to  the  posi- 
tion of  the  island  of  Saltholm,  not  far  from  Copenhagen.  This  island  is 
so  low,  that  in  autumn  and  winter  it  is  permanently  overflowed ;  and  it 
is  only  dry  in  summer,  when  it  serves  for  pasturing  cattle.  It  appears, 
from  the  documents  of  the  year  1280,  that  Saltholm  was  then  also  in 
the  same  state,  and  exactly  on  a  level  with  the  mean  height  of  the  sea, 
instead  of  having  been  about  twenty  feet  under  water,  as  it  ought  to 
have  been,  according  to  the  computation  of  Celsius.  Several  towns,  also, 
on  the  shores  of  the  Baltic,  as  Lubeck,  Wismar,  Rostock,  Stralsund,  and 
others,  after  six  and  even  eight  hundred  years,  are  as  little  elevated 
above  the  sea  as  at  the  era  of  their  foundation,  being  now  close  to  the 
water's  edge.  The  lowest  part  of  Dantzic  was  no  higher  than  the  mean 

*  The  Swedish  measure  scarcely  differs  from  ours ;  the  foot  being  divided  into 
twelve  inches,  and  being  less  than  ours  by  three-eighths  of  an  inch  only. 


CH.  XXX.]  RISE   OF  LAND   IN   SWEDEN.  521 

level  of  the  sea  in  the  year  1000  ;  and  after  eight  centuries  its  relative 
position  remains  exactly  the  same.* 

Several  of  the  examples  of  the  gain  of  land  and  shallowing  of  the  sea 
pointed  out  by  Celsius,  and  afterwards  by  Linnaeus,  who  embraced  the 
same  opinions,  were  ascribed  by  others  to  the  deposition  of  sediment  at 
points  where  rivers  entered  ;  and,  undoubtedly,  Celsius  had  not  suffi- 
ciently distinguished  between  changes  due  to  these  causes  and  such  as 
would  arise  if  the  waters  of  the  ocean  itself  were  diminishing.  Many 
large  rivers  descending  from  a  mountainous  country,  at  the  head  of  the 
Gulf  of  Bothnia,  enter  the  sea  charged  with  sand,  mud,  and  pebbles  ; 
and  it  was  said  that  in  these  places  the  low  land  had  advanced  rapidly, 
especially  near  Torneo.  At  Piteo  also,  half  a  mile  had  been  gained  in 
forty-five  years  ;  at  Luleo,f  no  less  than  a  mile  in  twenty-eight  years ; 
facts  which  might  all  be  admitted  consistently  with  the  assumption  that 
the  level  of  the  Baltic  has  remained  unchanged,  like  that  of  the  Adriatic, 
during  a  period  when  the  plains  of  the  Po  and  the  Adige  have  greatly 
extended  their  area. 

It  was  also  alleged  that  certain  insular  rocks,  once  entirely  covered 
with  water,  had  at  length  protruded  themselves  above  the  waves,  and 
grown,  in  the  course  of  a  century  and  a  half,  to  be  eight  feet  high. 
The  following  attempt  was  made  to  explain  away  this  phenomenon  : — 
In  the  Baltic,  large  erratic  blocks,  as  well  as  sand  and  smaller  stones 
which  lie  on  shoals,  are  liable  every  year  to  be  frozen  into  the  ice,  where 
the  sea  freezes  to  the  depth  of  five  or  six  feet.  On  the  melting  of  the 
snow  in  spring,  when  the  sea  rises  about  half  a  fathom,  numerous  ice- 
islands  float  away,  bearing  up  these  rocky  fragments  so  as  to  convey 
them  to  a  distance  ;  and  if  they  are  driven  by  the  waves  upon  shoals, 
they  may  convert  them  into  islands  by  depositing  the  blocks  ;  if  stranded 
upon  low  islands,  they  may  considerably  augment  their  height. 

Browallius,  also,  and  some  other  Swedish  naturalists,  affirmed  that 
some  islands  were  lower  than  formerly ;  and  that,  by  reference  to  this 
kind  of  evidence,  there  was  equally  good  reason  for  contending  that  the 
level  of  the  Baltic  was  gradually  rising.  They  also  added  another 
curious  proof  of  the  permanency  of  the  water  level,  at  some  points  at 
least,  for  many  centuries.  On  the  Finland  coast  were  some  large  pines, 
growing  close  to  the  water's  edge  ;  these  were  cut  down,  and,  by 
counting  the  concentric  rings  of  annual  growth,  as  seen  in  a  transverse 
section  of  the  trunk,  it  was  demonstrated  that  they  had  stood  there  for 
four  hundred  years.  Now,  according  to  the  Celsian  hypothesis,  the 
sea  had  sunk  about  fifteen  feet  during  that  period,  in  which  case  the 
germination  and  early  growth  of  these  pines  must  have  been,  for  many 
seasons,  below  the  level  of  the  water.  In  like  manner  it  was  asserted, 
that  the  lower  walls  of  many  ancient  castles,  such  as  those  of  Sonder- 

*  For  a  full  account  of  the  Celsian  controversy,  we  may  refer  our  readers  to 
Von  Hoff,  Geschichte,  <fec.  vol.  i.  p.  439. 

f  Piteo,  Lnleo,  and  Obo  are  spelt,  in  many  Englisho maps,  Pitea,  Lulea,  Abo: 
the  a  is  not  sounded  in  the  Swedish  diphthong  ao  or  a. 


522 


GRADUAL   RISE   OF 
Fig.  91. 


[On.  XXX 


35 


burg  and  Abo,  reached  then  to  the  water's  edge,  and  must,  therefore, 
according  to  the  theory  of  Celsius,  have  been  originally  constructed 
below  the  level  of  the  sea. 

In  reply  to  this  last  argument,  Colonel  Hiillstrom,  a  Swedish  engi- 
neer, well  acquainted  with  the  Finland  coast,  assured  me,  that  the  base 
of  the  walls  of-  the  castle  of  Abo  is  now  ten  feet  above  the  water,  so 


CH.  XXX.]  LAND   IN   SWEDEN.  523 

that  there  may  have  been  a  considerable  rise  of  the  land  at  that  point 
since  the  building  was  erected. 

Playfair,  in  his  "  Illustrations  of  the  Huttonian  Theory,"  in  1802, 
admitted  the  sufficiency  of  the  proofs  adduced  by  Celsius,  but  attributed 
the  change  of  level  to  the  movement  of  the  land,  rather  than  to  a 
diminution  of  the  waters.  He  observed,  "  that  in  order  to  depress  or 
elevate  the  absolute  level  of  the  sea,  by  a  given  quantity,  in  any  one 
place,  we  must  depress  or  elevate  it  by  the  same  quantity  over  the 
whole  surface  of  the  earth ;  whereas  no  such  necessity  exists  with  re- 
spect to  the  elevation  or  depression  of  the  land."*  The  hypothesis  of 
the  rising  of  the  land  he  adds,  "  agrees  well  with  the  Huttonian  theory, 
which  holds,  that  our  continents  are  subject  to  be  acted  upon  by  the  ex- 
pansive forces  of  the  mineral  regions  ;  that  by  these  forces  they  have  been 
actually  raised  up,  and  are  sustained  by  them  in  their  present  situation. f 

In  the  year  1807,  Von  Buch,  after  returning  from  a  tour  in  Scan- 
dinavia, announced  his  conviction,  "that  the  whole  country,  from  Fred- 
erickshall  in  Norway  to  Abo  in  Finland,  and  perhaps  as  far  as  St. 
Petersburgh,  was  slowly  and  insensibly  rising."  He  also  suggested 
"  that  Sweden  may  rise  more  than  Norway,  and  the  northern  more  than 
the  southern  part."J  He  was  led  to  these  conclusions  principally  by 
information  obtained  from  the  inhabitants  and  pilots,  and  in  part  by  the 
occurrence  of  marine  shells  of  recent  species,  which  he  had  found  at 
several  points  on  the  coast  of  Norway  above  the  level  of  the  sea.  He 
also  mentions  the  marks  set  on  the  rocks.  Von  Buch,  therefore,  has  the 
merit  of  being  the  first  geologist  who,  after  a  personal  examination  of  the 
evidence,  declared  in  favor  of  the  rise  of  land  in  Scandinavia. 

The  attention  excited  by  this  subject  in  the  early  part  of  the  last 
century,  induced  many  philosophers  in  Sweden  to  endeavor  to  deter- 
mine, by  accurate  observations,  whether  the  standard  level  of  the  Baltic 
was  really  subject  to  periodical  variations  ;  and  under  their  direction, 
lines  or  grooves,  indicating  the  ordinary  level  of  the  water  on  a  calm 
day,  together  with  the  date  of  the  year,  were  chiselled  out  upon  the 
rocks.  In  1820-21,  all  the  marks  made  before  those  years  were  ex- 
amined by  the  officers  of  the  pilotage  establishment  of  Sweden  ;  and  in 
their  report  to  the  Royal  Academy  of  Stockholm  they  declared,  that 
on  comparing  the  level  of  the  sea  at  the  time  of  their  observations  with 
that  indicated  by  the  ancient  marks,  they  found  that  the  Baltic  was 
lower  relatively  to  the  land  in  certain  places,  but  the  amount  of  change 
during  equal  periods  of  time  had  not  been  everywhere  the  same.  Dur- 
ing their  survey,  they  cut  new  marks  for  the  guidance  of  future  ob- 
servers, several  of  which  I  had  an  opportunity  of  examining  fourteen 
years  after  (in  the  summer  of  1834),  and  in  that  interval  the  lar.d  ap- 
peared to  me  to  have  risen  at  certain  places  north  of  Stockholm  four 
or  five  inches.  I  also  convinced  myself,  during  my  visit  to  Sweden, 
after  conversing  with  many  civil  engineers,  pilots,  and  fishermen,  and 

*  Sect.  393.  f  Sect.  398.  J  Transl.  of  his  Travels,  p.  387. 


. 

524:  GRADUAL   RISE  OF  [€H.  XXX. 

after  examining  some  of  the  ancient  marks,  that  the  evidence  formerly 
adduced  in  favor  of  the  change  of  level,  both  on  the  coasts  of  Sweden 
and  Finland,  was  full  and  satisfactory.*  The  alteration  of  level  evi- 
dently diminishes  as  we  proceed  from  the  northern  parts  of  the  Gulf  of 
Bothnia  towards  the  south,  being  very  slight  around  Stockholm.  Some 
writers  have  indeed  represented  the  rate  of  depression  of  the  waters  at 
Stockholm  as  very  considerable,  because  certain  houses  in  that  city 
which  are  built  on  piles  have  sunk  down  within  the  memory  of  persons 
stiL  living,  so  as  to  be  out  of  the  perpendicular ;  and  this  in  conse- 
quence of  the  tops  of  the  piles  giving  way  and  decaying,  owing  to  a  fall 
of  the  waters  which  has  exposed  them  to  be  alternately  wet  and  dry. 
The  houses  alluded  to  are  situated  on  the  borders  of  Lake  Maeler,  a 
large  lake,  the  outlet  of  which  joins  the  Baltic,  in  the  middle  of  Stock- 
holm. This  lake  is  certainly  lower  than  formerly  ;  but  the  principal 
cause  of  the  change  is  not  the  elevation  of  the  land,  but  the  removal  of 
two  old  bridges  built  on  piles,  which  formerly  obstructed  the  discharge 
of  the  fresh  water  into  the  sea.  Another  cause  is  the  opening,  in  the 
year  1819,  of  a  new  canal  at  Sodertelje,  a  place  south  of  Stockholm,  by 
means  of  which  a  new  line  of  communication  was  formed  between  Lake 
Maeler  and  the  Baltic,  f 

It  will  naturally  be  asked,  whether  the  mean  level  of  a  sea  like  the 
Baltic  can  ever  be  determined  so  exactly  as  to  permit  us  to  appreciate 
a  variation  of  level,  amounting  only  to  one  or  two  feet.  In  reply,  I 
may  observe,  that,  except  near  the  Cattegat,  there  are  no  tides  in  the 
Baltic  ;  and  it  is  only  when  particular  winds  have  prevailed  for  several 
days  in  succession,  or  at  certain  seasons  when  there  has  been  an  un- 
usually abundant  influx  of  river  water,  or  when  these  causes  have  com- 
bined, that  this  sea  is  made  to  rise  two  or  three  feet  above  its  standard 
level.  The  fluctuations  due  to  these  causes  are  nearly  the  same  from 
year  to  year ;  so  that  the  pilots  and  fishermen  believe  and  apparently 
with  reason,  that  they  can  mark  a  deviation,  even  of  a  few  inches,  from 
the  ordinary  or  mean  height  of  the  waters. 

There  are,  moreover,  peculiarities  in  the  configuration  of  the  shores 
of  Norway  and  Sweden,  which  facilitate  in  a  remarkable  degree  the 
appreciation  of  slight  changes  in  the  relative  level  of  land  and  water. 
It  has  often  been  said,  that  there  are  two  coasts,  an  inner  and  an 
outer  one ;  the  inner  being  the  shore  of  the  main  land  ;  the  outer 
one,  a  fringe  of  countless  rocky  islands  of  all  dimensions,  called  the 
skiir  (shair).  Boats  and  small  vessels  make  their  coasting  voyages 
within  this  skiir :  for  here  they  may  sail  in  smooth  water,  even  when 
the  sea  without  is  strongly  agitated.  But  the  navigation  is  very  intri- 

';   ••;. 

*  In  the  earlier  editions  I  expressed  many  doubts  as  to  the  validity  of  the 
proofs  of  a  gradual  rise  of  land  in  Sweden.  A  detailed  statement  of  the  observa- 
tions  which  T  made  in  1834,  and  which  led  me  to  change  my  opinion,  will  be 
found  in  the  Philosophical  Transactions  for  1835,  part  i. 

f  See  Professor  Johnston's  Paper,  Ed.  New  Phil.  Journ.  No.  29,  July  1883; 
and  my  remarks,  PhiL  Trans.  1835,  p.  12. 


OH.  XXX.]  LAND    IN    SWEDEN.  525 

cate,  and  the  pilot  must  possess  a  perfect  acquaintance  with  the  breadth 
and  depth  of  every  narrow  channel,  and  the  position  bf  innumerable 
sunken  rocks.  If  on  such  a  coast  the  land  rises  one  or  two  feet  in  the 
course  of  half  a  century,  the  minute  topography  of  the  skar  is  entirely 
altered.  To  a  stranger,  indeed,  who  revisits  it  after  an  interval  of  many 
years,  its  general  aspect  remains  the  same  ;  but  the  inhabitant  finds 
that  he  can  no  longer  penetrate  with  his  boat  through  channels  where 
he  formerly  passed,  and  he  can  tell  of  countless  other  changes  in  the 
height  and  breadth  of  isolated  rocks,  now  exposed,  but  once  only  seen 
through  the  clear  water. 

The  rocks  of  gneiss,  mica-schist,  and  quartz  are  usually  very  hard  on 
this  coast,  slow  to  decompose,  and,  when  protected  from  the  breakers, 
remaining  for  ages  unaltered  in  their  form.  Hence  it  is  easy  to  mark 
the  stages  of  their  progressive  emergence  by  the  aid  of  natural  and  arti- 
ficial marks  imprinted  on  them.  Besides  the  summits  of  fixed  rocks, 
there  are  numerous  erratic  blocks  of  vast  size  strewed  over  the  shoals 
and  islands  in  the  skar,  which  have  been  probably  drifted  by  ice  in  the 
manner  before  suggested.*  All  these  are  observed  to  have  increased 
in  height  and  dimension  with  the  last  half  century.  Some,  which  were 
formerly  known  as  dangerous  sunken  rocks,  are  now  only  hidden  when 
the  water  is  highest.  On  their  first  appearance,  they  usually  present  a 
smooth,  bare,  rounded  protuberance,  a  few  feet  or  yards  in  diameter ; 
and  a  single  sea-gull  often  appropriates  to  itself  this  resting-place,  re- 
sorting there  to  devour  its  prey.  Similar  points,  in  the  mean  time,  have 
grown  to  long  reefs,  and  are  constantly  whitened  by  a  multitude  of  sea- 
fowl  ;  while  others  have  been  changed  from  a  reef,  annually  submerged, 
to  a  small  islet,  on  which  a  few  lichens,  a  fir-seedling,  and  a  few  blades 
of  grass,  attest  that  the  shoal  has  at  length  been  fairly  changed  into  dry 
land.  Thousands  of  wooded  islands  around  show  the  great  alterations 
which  time  can  work.  In  the  course  of  centuries  also,  the  spaces  inter- 
vening between  the  existing  islands  may  be  laid  dry,  and  become  grassy 
plains  encircled  by  heights  well  clothed  with  lofty  firs.  This  last  step 
of  the  process,  by  which  long  fiords  and  narrow  channels,  once  separating 
wooded  islands,  are  deserted  by  the  sea,  has  been  exemplified  within  the 
memory  of  living  witnesses  on  several  parts  of  the  coast. 

Had  the  apparent  fall  of  the  waters  been  observed  in  the  Baltic  only, 
we  might  have  endeavored  to  explain  the  phenomenon  by  local  causes 
affecting  that  sea  alone.  For  instance,  the  channel  by  which  the  Baltic 
discharges  its  surplus  waters  into  the  Atlantic,  might  be  supposed  to 
have  been  gradually  widened  and  deepened  by  the  waves  and  currents, 
in  which  case  a  fall  of  the  water  like  that  before  alluded  to  in  Lake 
Maeler,  might  have  occurred.  But  the  lowering  of  level  would  in  that 
case  have  been  uniform  and  universal,  and  the  waters  could  not  have 
sunk  at  Torneo,  while  they  retained  their  former  level  at  Copenhagen. 
Such  an  explanation  is  also  untenable  on  other  grounds  ;  for  it  is  a  fact, 

*  See  p.  522  ;  nlao  chap.  15,  supra. 


526  GRADUAL   KIS£   OF  [Ca  XXX. 

as  Celsius  long  ago  affirmed,  that  the  alteration  of  level  extends  to  the 
western  shores  of  Sweden,  bordering  the  ocean.  The  signs  of  elevation 
observed  between  Uddevalla  and  Gothenburg  are  as  well  established  as 
those  on  the  shores  of  the  Bothnian  Gulf.  Among  the  places  where 
they  may  be  studied,  are  the  islands  of  Marstrand  and  Gulholmen,  the 
last-mentioned  locality  being  one  of  those  particularly  pointed  out  by 
Celsius. 

The  inhabitants  there  and  elsewhere  affirm,  that  the  rate  of  the  sink- 
ing of  the  sea  (or  elevation  of  land)  varies  in  different  and  adjoining  dis- 
tricts, being  greatest  at  points  where  the  land  is  low.  But  in  this  they 
are  deceived  ;  for  they  measure  the  amount  of  rise  by  the  area  gained, 
which  is  most  considerable  where  the  land  descends  with  a  gentle  slope 
into  the  sea.  In  the  same  manner,  some  advocates  of  the  Celsian  the- 
ory formerly  appealed  to  the  increase  of  lands  near  the  mouths  of  rivers, 
not  sufficiently  adverting  to  the  fact,  that  if  the  bed  of  the  sea  is  rising, 
the  change  will  always  be  most  sensible  where  the  bottom  has  been 
previously  rendered  shallow  ;  whereas,  at  a  distance  from  these  points 
where  the  scarped  granitic  cliffs  plunge  at  once  into  deep  water,  a  much 
greater  amount  of  elevation  is  necessary  to  produce  an  equally  conspicu- 
ous change. 

As  to  the  area  in  northern  Europe  which  is  subject  to  this  slow  up- 
heaving movement,  we  have  not  as  yet  sufficient  data  for  estimating  it 
correctly.  It  seems  probable,  however,  that  it  reaches  from  Gothen- 
burg to  Torneo,  and  from  thence  to  the  North  Cape,  the  rate  of  eleva- 
tion increasing  always  as  we  proceed  farther  northwards.  The  two 
extremities  of  this  line  are  more  than  a  thousand  geographical  miles 
distant  from  each  other ;  and  as  both  terminate  in  the  ocean,  we  know 
not  how  much  farther  the  motion  may  be  prolonged  under  water.  As 
to  the  breadth  of  the  tract,  its  limits  are  equally  uncertain,  though  it 
evidently  extends  across  the  widest  parts  of  the  Gulf  of  Bothnia,  and 
may  probably  stretch  far  into  the  interior,  both  of  Sweden  and  Finland. 
Now  if  the  elevation  continue,  a  larger  part  of  the  Gulf  of  Bothnia  will 
be  turned  into  land,  as  also  more  of  the  ocean  off  the  west  coast  of  Swe- 
den between  Gothenburg  and  Uddevalla  ;  and  on  the  other  hand,  if  the 
change  has  been  going  on  for  thousands  of  years  at  the  rate  of  several 
feet  in  a  century,  large  tracts  of  what  is  now  land  must  have  been  sub- 
marine at  periods  comparatively  modern.  It  is  natural  therefore  to 
inquire  whether  there  are  any  signs  of  the  recent  sojourn  of  the  sea  on 
districts  now  inland  ?  The  answer  is  most  satisfactory. — Near  Udde- 
valla and  the  neighboring  coastland,  we  find  upraised  deposits  of  shells 
belonging  to  species  such  as.  now  live  in  the  ocean  ;  while  on  the  oppo- 
site or  eastern  side  of  Sweden,  near  Stockholm,  Gefle,  and  other  places 
bordering  the  Bothnian  Gulf,  there  are  analogous  beds  containing  shells 
of  species  characteristic  of  the  Baltic. 

Von  Buch  announced  in  1807,  that  he  had  discovered  in  Norway  and 
at  Uddevalla  in  Sweden,  beds  of  shells  of  existing  species,  at  considerable 
heights  above  the  sea.  Since  that  time,  other  naturalists  have  confirmed 


CH.  XXX.]  LAND    IN    SWEDEN.  527 

his  observation  ;  and,  according  to  Strom,  deposits  occur  at  an  elevation 
of  more  than  400  feet  above  the  sea  in  the  northern  paft  of  Norway. 
M.  Alex.  Brongniart,  when  he  visited  Uddevalla,  ascertained  that  one  of 
the  principal  masses  of  shells,  that  of  Capellbacken,  is  raised  more  than 
200  feet  above  the  sea,  resting  on  rocks  of  gneiss,  all  the  species  being 
identical  with  those  now  inhabiting  the  contiguous  ocean.  The  same 
naturalist  also  stated,  that  on  examining  with  care  the  surface  of  the 
gneiss,  immediately  above  the  ancient  shelly  deposit,  he  found  barna- 
cles (balani)  adhering  to  the  rocks,  showing  that  the  sea  had  remained 
there  for  a  long  time.  I  was  fortunate  enough  to  be  able  to  verify  this 
observation  by  finding  in  the  summer  of  1834,  at  Kured,  about  two 
miles  north  of  Uddevalla,  and  at  the  height  of  more  than  100  feet  above 
the  sea,  a  surface  of  gneiss  newly  laid  open  by  the  partial  removal  of  a 
mass  of  shells  used  largely  in  the  district  for  making  lime  and  repairing 
the  roads.  So  firmly  did  these  barnacles  adhere  to  the  gneiss,  that  I 
broke  off  portions  of  the  rock  with  the  shells  attached.  The  face  of  the 
gneiss  was  also  incrusted  with  small  zoophytes  (Cellepora?  Lam.)  ;  but 
had  these  or  the  barnacles  been  exposed  in  the  atmosphere  ever  since  the 
elevation  of  the  rocks  above  the  sea,  they  would  doubtless  have  decom- 
posed and  been  obliterated. 

The  town  of  Uddevalla  (see  Map,  p.  523)  stands  at  the  head  of  a 
narrow  creek  overhung  by  steep  and  barren  rocks  of  gneiss,  of  which 
all  the  adjacent  country  is  composed,  except  in  the  low  grounds  and 
bottoms  of  valleys,  where  strata  of  sand,  clay,  and  marl  frequently  hide 
the  fundamental  rocks.  To  these  newer  and  horizontal  deposits  the 
fossil  shells  above  mentioned  belong,  and  similar  marine  remains  are 
found  at  various  heights  above  the  sea  on  the  opposite  island  of  Orust. 
The  extreme  distance  from  the  sea  to  which  such  fossils  extend  is  as  yet, 
unknown ;  but  they  have  been  already  found  at  Trollhattan  in  digging 
the  canal  there,  and  still  farther  inland  on  the  northern  borders  of  Lake 
Wener,  fifty  miles  from  the  sea,  at  an  elevation  of  200  feet  near  Lake 
Rogvarpen. 

To  pass  to  the  Baltic :  I  observed  near  its  shores  at  Sodertelje,  six- 
teen miles  S.  W.  of  Stockholm,  strata  of  sand,  clay,  and  marl,  more  than 
100  feet  high,  and  containing  shells  of  species  now  inhabiting  the  Both- 
nian  Gulf.  These  consist  partly  of  marine  and  partly  of  freshwater  spe- 
cies ;  but  they  are  few  in  number,  the  brackishness  of  the  water  appear- 
ing to  be  very  unfavorable  to  the  development  of  testacea.  The 
most  abundant  species  are  the  common  cockle  and  the  common  mussel 
and  periwinkle  of  our  shores  (Cardium  edule,  Mytilus  edulis,  and  Lit- 
torina  littorea),  together  with  a  small  tellina  (T.  Baltica)  and  a  few 
minute  univalves  allied  to  Paludina  ulva.  These  live  in  the  same 
water  as  a  Lymneus,  a  Neritina  (N.  Jluviatilia),  and  some  other  fresh- 
water shells. 

But  the  marine  mollusks  of  the  Baltic  above  mentioned,  although  very 
numerous  in  individuals,  are  dwarfish  in  size,  scarcely  ever  attaining  a 
third  of  the  average  dimensions  which  they  acquire  in  the  salter  waters  of 


528  GRADUAL   RISE   OF  [On.  XXX. 

the  ocean.  By  this  character  alone  a  geologist  would  generally  be  able 
to  recognize  an  assemblage  of  Baltic  fossils  as  distinguished  from  those 
derived  from  a  deposit  in  the  ocean.  The  absence  also  of  oysters,  bar- 
nacles, whelks,  scallops,  limpets  (ostrea,  balanus,  buccinum,  pecfen,  pa- 
tella), and  many  other  forms  abounding  alike  in  the  sea  near  Uddevalla, 
and  in  the  fossiliferous  deposits  of  modern  date  on  that  coast,  supplies 
an  additional  negative  character  of  the  greatest  value,  distinguishing 
assemblages  of  Baltic  from  those  of  oceanic  shells.  Now  the  strata  con- 
taining Baltic  shells  are  found  in  many  localities  near  Stockholm,  Upsala, 
and  Gefle,  and  will  probably  be  discovered  everywhere  around  the  bor- 
ders of  the  Bothnian  Gulf ;  for  I  have  seen  similar  remains  brought  from 
Finland,  in  marl  resembling  that  found  near  Stockholm.  The  utmost 
distance  to  which  these  deposits  have  yet  been  traced  inland,  is  on  the 
southern  shores  of  Lake  Maeler,  at  a  place  seventy  miles  from  the  sea.* 
Hence  it  appears  from  the  distinct  assemblage  of  fossil  shells  found  on 
the  eastern  and  western  coasts  of  Sweden,  that  the  Baltic  has  been  for 
a  long  period  separated  as  now  from  the  ocean,  although  the  intervening 
tract  of  land  was  once  much  narrower,  even  after  both  seas  had  become 
inhabited  by  all  -the  existing  species  of  testacea. 

As  no  accurate  observations  on  the  rise  of  the  Swedish  coast  refer  to 
periods  more  remote  than  a  century  and  a  half  from  the  present  time, 
and  as  traditional  information,  and  that  derived  from  ancient  buildings 
on  the  coast,  do  not  enable  the  antiquary  to  trace  back  any  monuments 
of  change  for  more  than  five  or  six  centuries,  we  cannot  declare  whether 
the  rate  of  the  upheaving  force  is  uniform  during  very  long  periods. 
In  those  districts  where  the  fossil  shells  are  found  at  the  height  of  more 
than  200  feet  above  the  ocean,  as  at  Uddevalla,  Orust,  and  Lake  Rog- 
varpen,  the  present  rate  of  rise  seems  less  than  four  feet  in  a  century. 
Even  at  that  rate  it  would  have  required  five  thousand  years  to  lift  up 
those  deposits.  But  as  the  movement  is  now  very  different  in  different 
places,  it  may  also  have  varied  much  in  intensity  at  different  eras. 

We  have,  moreover,  yet  to  learn  not  only  whether  the  motion  pro- 
ceeds always  at  the  same  rate,  but  also  whether  it  has  been  uniformly  in 
one  direction.  The  level  of  the  land  may  oscillate  ;  and  for  centuries  there 
may  be  a  depression,  and  afterwards  a  re-elevation,  of  the  same  district. 
Some  phenomena  in  the  neighborhood  of  Stockholm  appear  to  me  only 
explicable  on  the  supposition  of  the  alternate  rising  and  sinking  of  the 
ground  since  the  country  was  inhabited  by  man.  In  digging  a  canal, 
in  1819,  at  Sodertelje,  about  sixteen  miles  to  the  south  of  Stockholm,  to 
unite  Lake  Maeler  with  the  Baltic,  marine  strata,  containing  fossil  shells 
of  Baltic  species,  were  passed  through.  At  a  depth  of  about  sixty  feet, 
they  came  down  upon  what  seems  to  have  been  a  buried  fishing-hut, 
constructed  of  wood  in  a  state  of  decomposition,  which  soon  crumbled 
away  on  exposure  to  the  air.  The  lowest  part,  however,  wnich  had  stood 
on  a  level  with  the  spa,  was  in  a  more  perfect  state  of  preservation.  On 

*  See  a  paper  by  the  Author,  Phil.  Trans.  1835,  part  i 


Cu.  XXX.]  LAND   IN   SWEDEN.  529 

the  floor  of  this  hut  was  a  rude  fireplace,  consisting  of  a  ring  of  stones, 
and  within  this  were  cinders  and  charred  wood.  On  the  outside  lay 
boughs  of  the  fir,  cut  as  with  an  axe,  with  the  leaves  or  needles  still 
attached.  It  seems  very  difficult  to  explain  the  position  of  this  buried 
hut,  without  imagining,  as  in  the  case  of  the  temple  of  Serapis  (see  p. 
486),  first  a  subsidence  to  the  depth  of  more  than  sixty  feet,  then  a  re- 
elevation.  During  the  period  of  submergence,  the  hut  must  have  be- 
come covered  over  with  gravel  and  shelly  marl,  under  which  not  only 
the  hut,  but  several  vessels  also  were  found,  of  a  very  antique  form,  and 
having  their  timbers  fastened  together  by  wooden  pegs  instead  of 
nails.* 

Whether  any  of  the  land  in  Norway  is  now  rising,  must  be  deter- 
mined by  future  investigations.  Marine  fossil  shells,  of  recent  species, 
have  been  collected  from  inland  places  near  Drontheim ;  but  Mr.  Ever- 
est, in  his  "  Travels  through  Norway,"  informs  us  that  the  small  island 
of  Munkholm,  which  is  an  insulated  rock  in  the  harbor  of  Drontheim, 
affords  conclusive  evidence  of  the  land  having  in  that  region  remained 
stationary  for  the  last  eight  centuries.  The  area  of  this  isle  does  not 
exceed  that  of  a  small  village,  and  by  an  official  survey,  its  highest 
point  has  been  determined  to  be  twenty-three  feet  above  the  mean  high- 
water  mark,  that  is,  the  mean  between  neap  and  spring  tides.  Now,  a 
monastery  was  founded  there  by  Canute  the  Great,  A.  D.  1028,  and 
thirty-three  years  before  that  time  it  was  in  use  as  a  common  place  of 
execution.  According  to  the  assumed  average  rate  of  rise  in  Sweden 
(about  forty  inches  in  a  century),  we  should  be  obliged  to  suppose  that 
this  island  had  been  three  feet  eight  inches  below  high-water  mark  when 
it  was  originally  chosen  as  the  site  of  the  monastery. 

Professor  Keilhau  of  Christiania,  after  collecting  the  observations  of 
his  predecessors  respecting  former  changes  of  level  in  Norway,  and  com- 
bining them  with  his  own,  has  made  the  fact  of  a  general  change  of  level 
at  a  modern  period,  that  is  to  say,  within  the  period  of  the  actual  testa- 
ceous fauna,  very  evident.  He  infers  that  the  whole  country  from  Cape 
Lindesnaes  to  Cape  North,  and  beyond  that  as  far  as  the  fortress  of 
Vardhuus,  has  been  gradually  upraised,  and  on  the  southeast  coast  the 
elevation  has  amounted  to  more  than  600  feet.  The  marks  which  de- 
note the  ancient  coast-line  are  so  nearly  horizontal  that  the  deviation 
from  horizontality,  although  the  measurements  have  been  made  at  a 
great  number  of  points,  is  too  small  to  be  appreciated. 

More  recently  (1844),  however,  it  appears  from  the  researches  of  M. 
Bravais,  member  of  the  French  scientific  commission  of  the  North,  that 
in  the  Gulf  of  Alten  in  Finmark,  the  most  northerly  part  of  Norway, 

*  See  my  paper  before  referred  to,  Phil.  Trans.  1835,  part  i.  p.  8,  9.  Attempts 
have  been  since  made  to  explain  away  the  position  of  this  hut,  by  conjecturing 
that  a  more  recent  trench  had  been  previously  dug  here,  which  had  become  filled 
up  in  time  by  sand  drifted  by  the  wind.  The  engineers  who  superintended  the 
works  in  1819,  and  with  whom  I  conversed,  had  considered  every  hypothesis  of 
the  kind,  but  could  not  so  explain  the  facts. 

34 


530  GEADUAL   RISE   OF  [On.  XXX. 

there  are  two  distinct  lines  of  upraised  ancient  sea-coast,  one  above  the 
other,  which  are  not  parallel,  and  both  of  them  imply  that  within  a  dis- 
tance of  fifty  miles  a  considerable  slope  can  be  detected  in  such  a  direc- 
tion as  to  show  that  the  ancient  shores  have  undergone  a  greater  amount 
of  upheaval  in  proportion  as  we  advance  inland.* 

It  has  been  already  stated,  that,  in  proceeding  from  the  North  Cape 
to  Stockholm,  the  rate  of  upheaval  diminishes  from  several  feet  to  a  few 
inches  in  a  century.  To  the  south  of  Stockholm,  the  upward  movement 
ceases,  and  at  length  in  Scania,  or  the  southernmost  part  of  Sweden,  it 
appears  to  give  place  to  a  movement  in  an  opposite  direction.  In  proof 
of  this  fact,  Professor  Nilsson  observes,  in  the  first  place,  that  there  are 
no  elevated  beds  of  recent  marine  shells  in  Scania  like  those  farther  to 
the  north.  Secondly,  Linnaeus,  with  a  view  of  ascertaining  whether  the 
waters  of  the  Baltic  were  retiring  from  the  Scanian  shore,  measured,  in 
1749,  the  distance  between  the  sea  and  a  large  stone  near  Trelleborg. 
This  same  stone  was,  in  1836,  a  hundred  feet  nearer  the  water's  edge 
than  in  Linnseus's  time,  or  eighty-seven  years  before.  Thirdly,  there  is 
also  a  submerged  peat  moss,  consisting  of  land  and  freshwater  plants, 
beneath  the  sea  at  a  point  to  which  no  peat  could  have  been  drifted 
down  by  any  river.  Fourthly,  and  what  is  still  more  conclusive,  it  is 
found  that  in  seaport  towns,  all  along  the  coast  of  Scania,  there  are 
streets  below  the  high-water  level  of  the  Baltic,  and  in  some  cases  below 
the  level  of  the  lowest  tide.  Thus,  when  the  wind  is  high  at  Malmo, 
the  water  overflows  one  of  the  present  streets,  and  some  years  ago  some 
excavations  showed  an  ancient  street  in  the  same  place  eight  feet  lower, 
and  it  was  then  seen  that  there  had  been  an  artificial  raising  of  the 
ground,  doubtless  in  consequence  of  that  subsidence.  There  is  also  a 
street  at  Trelleborg,  and  another  at  Skanor,  a  few  inches  below  high- 
water  mark,  and  a  street  at  Ystad  is  exactly  on  a  level  with  the  sea,  at 
which  it  could  not  have  been  originally  built. 

The  inferences  deduced  from  the  foregoing  facts  are  in  perfect  har- 
mony with  the  proofs  brought  to  light  by  two  Danish  investigators,  Dr. 
Pingel  and  Captain  Graah,  of  the  sinking  down  of  part  of  the  west  coast 
of  Greenland,  for  a  space  of  more  than  600  miles  from  north  to  south. 
The  observations  of  Captain  Graah  were  made  during  a  survey  of 
Greenland  in  1823-24;  and  afterwards  in  1828-29  ;  those  by  Dr.  Pin- 
gel  were  made  in  1830-32.  It  appears  from  various  signs  and  tradi- 
tions, that  the  coast  has  been  subsiding  for  the  last  four  centuries  from 
the  firth  called  Igaliko,  in  lat.  60°  43' N.  to  Disco  Bay,  extending  to 
nearly  the  69th  degree  of  north  latitude.  Ancient  buildings  on  low 
rocky  islands  and  on  the  shore  of  the  main  land  have  been  gradually 
submerged,  and  experience  has  taught  the  aboriginal  Greenlander 
never  to  build  his  hut  near  the  water's  edge.  In  one  case  the  Moravian 
settlers  have  been  obliged  more  than  once  to  move  inland  the  poles  upon 

*  Quart.  Journ.  of  Geol  Soc.  No.  4,  p.  534.  M.  Bravais'  observations  were  veri- 
fied in  1849  by  Mr.  R.  Chambers  in  his  "  Tracings  of  K  of  Europe,"  p.  208. 


Cn.  XXX.]  LAND  IN   SWEDEN.  531 

which  their  large  boats  were  set,  and  the  old  poles  still  remain  beneath 
the  water  as  silent  witnesses  of  the  change.* 

The  probable  cause  of  the  movements  above  alluded  to,  whether  of 
elevation  or  depression,  will  be  more  appropriately  discussed  in  the  fol- 
lowing chapters,  when  the  origin  of  subterranean  heat  is  considered. 
But  I  may  remark  here,  that  the  rise  of  Scandinavia  has  naturally  been 
regarded  as  a  very  singular  and  scarcely  credible  phenomenon,  because 
no  region  on  the  globe  has  been  more  free  within  the  times  of  authentic 
history  from  violent  earthquakes.  In  common,  indeed,  with  our  own 
island  and  with  almost  every  spot  on  the  globe,  some  movements  have 
been,  at  different  periods,  experienced,  both  in  Norway  and  Sweden. 
But  some  of  these,  as  for  example  during  the  Lisbon  earthquake  in  1 755, 
may  have  been  mere  vibrations  or  undulatory  movements  of  the  earth's 
crust  prolonged  from  a  great  distance.  Others,  however,  have  been  suf- 
ficiently local  to  indicate  a  source  of  disturbance  immediately  under  the 
country  itself.  Notwithstanding  these  shocks,  Scandinavia  has,  upon 
the  whole,  been  as  tranquil  in  modern  times,  and  as  free  from  subter- 
ranean convulsions,  as  any  region  of  equal  extent  on  the  globe.  There 
is  also  another  circumstance  which  has  made  the  change  of  level  in 
Sweden  appear  anomalous,  and  has  for  a  long  time  caused  the  proofs  of 
the  fact  to  be  received  with  reluctance.  Volcanic  action,  as  we  have 
seen,  is  usually  intermittent:  and  the  variations  of  level  to  which  it 
has  given  rise  have  taken  place  by  starts,  not  by  a  prolonged  and 
insensible  movement  similar  to  that  experienced  in  Sweden.  Yet,  as 
we  enlarge  our  experience  of  modern  changes,  we  discover  instances 
in  which  the  volcanic  eruption,  the  earthquake,  and  the  permanent  rise 
or  fall  of  land,  whether  slow  or  sudden,  are  all  connected.  The  union 
of  these  various  circumstances  was  exemplified  in  the  case  of  the  temple 
of  Serapis,  described  in  the  last  chapter,  and  we  might  derive  other 
illustrations  from  the  events  of  the  present  century  in  South  America. 

Some  writers,  indeed,  have  imagined  that  there  is  geological  evidence 
in  Norway,  of  the  sudden  upheaval  of  land  to  a  considerable  height 
at  successive  periods,  since  the  era  when  the  sea  was  inhabited  by  the 
living  species  of  testacea.  They  point  in  proof  to  certain  horizontal 
lines  of  inland  cliffs  and  sea-beaches  containing  recent  shells  at  various 
heights  above  the  level  of  the  sea.f  But  these  appearances,  when  truly 
interpreted,  simply  prove  that  there  have  been  long  pauses  in  the  pro- 
cess of  upheaval  or  subsidence.  They  mark  eras  at  which  the  level  of 
the  sea  has  remained  stationary  for  ages,  and  during  which  new  strata 
were  deposited  near  the  shore  in  some  places,  while  in  others  the 
waves  and  currents  had  time  to  hollow  out  rocks,  undermine  cliffs, 
and  throw  up  long  ranges  of  shingle.  They  undoubtedly  show  that 
the  movement  has  not  been  always  uniform  or  continuous,  but  they  do 
not  establish  the  fact  of  any  sudden  alterations  of  level. 

*  See  Proceedings  of  Geol.  Soc.  No.  42,  p.  208.  I  also  conversed  with  Dr.  Pin- 
gel  on  the  subject  at  Copenhagen  in  1834. 

f  Keilhau,  Bulletin  de  la  Soc.  Greol.  de  France,  torn.  vii.  p.  18. 


532  GRADUAL   K1SE  OF  LAND  IN   SWEDEN.  [CH.  XXX. 

When  we  are  once  assured  of  the  reality  of  the  gradual  rise  of  a 
large  region,  it  enables  us  to  account  for  many  geological  appearances 
otherwise  of  very  difficult  explanation.  There  are  large  continental  tracts 
and  high  table-lands  where  the  strata  are  nearly  horizontal,  bearing  no 
marks  of  having  been  thrown  up  by  violent  convulsions,  nor  by  a  series 
of  movements,  such  as  those  which  occur  in  the  Andes,  and  cause  the 
earth  to  be  rent  open,  and  raised  or  depressed  from  time  to  time,  while 
large  masses  are  engulfed  in  subterranean  cavities.  The  result  of  a  series 
of  such  earthquakes  might  be  to  produce  in  a  great  lapse  of  ages  a 
country  of  shattered,  inclined,  and  perhaps  vertical  strata.  But  a  move- 
ment like  that  of  Scandinavia  would  cause  the  bed  of  the  sea,  and  all 
the  strata  recently  formed  in  it,  to  be  upheaved  so  gradually,  that  it 
would  merely  seem  as  if  the  ocean  had  formerly  stood  at  a  higher  level, 
and  had  slowly  and  tranquilly  sunk  down  into  its  present  bed. 

The  fact  also  of  a  very  gradual  and  insensible  elevation  of  land  may 
explain  many  geological  movements  of  denudation,  on  a  grand  scale. 
If,  for  example,  instead  of  the  hard  granitic  rocks  of  Norway  and  Swe- 
den, a  large  part  of  the  bed  of  the  Atlantic,  consisting  chiefly  of  soft 
strata,  should  rise  up  century  after  century,  at  the  rate  of  about  half  an 
inch,  or  an  inch,  in  a  year,  how  easily  might  oceanic  currents  sweep 
away  the  thin  film  of  matter  thus  brought  up  annually  within  the  sphere 
of  aqueous  denudation !  The  tract,  when  it  finally  emerged,  might  pre- 
sent table-lands  and  ridges  of  horizontal  strata,  with  intervening  valleys 
and  vast  plains,  where  originally,  and  during  its  period  of  submergence, 
the  surface  was  level  and  nearly  uniform. 

These  speculations  relate  to  superficial  changes  ;  but  others  must  be 
continually  in  progress  in  the  subterranean  regions.  The  foundations  of 
the  country,  thus  gradually  uplifted  in  Sweden,  must  be  undergoing 
important  modifications.  Whether  we  ascribe  these  to  the  expansion  of 
solid  matter  by  continually  increasing  heat,  or  to  the  liquefaction  of 
rock,  or  to  the  crystallization  of  a  dense  fluid,  or  the  accumulation  of 
pent-up  gases,  in  whatever  conjectures  we  indulge,  we  can  never  doubt 
for  a  moment,  that  at  some  unknown  depth  beneath  Sweden  and  the 
Baltic,  the  structure  of  the  globe  is  in  our  own  times  becoming  changed 
from  day  to  day,  throughout  a  space  probably  more  than  a  thousand 
miles  in  length,  and  several  hundred  in  breadth. 


CHAPTER  XXXI. 

CAUSES  OF  EARTHQUAKES  AND  VOLCANOES. 

In  timate  connection  between  the  causes  of  volcanoes  and  earthquakes — Supposed 
original  state  of  fusion  of  the  planet — Universal  fluidity  not  proved  by  sphe- 
roidal figure  of  the  earth — Attempt  to  calculate  the  thickness  of  the  solid  crust 
of  the  earth  by  processional  motion — Heat  in  mines  increasing  with  the  depth 
— Objections  to  the  supposed  intense  heat  of  a  central  fluid — Whether  chemical 
changes  may  produce  volcanic  heat — Currents  of  electricity  circulating  in  the 
earth's  crust. 

IT  will  hardly  be  questioned,  after  the  description  before  given  of  the 
phenomena  of  earthquakes  and  volcanoes,  that  both  of  these  agents  have, 
to  a  certain  extent,  a  common  origin ;  and  I  may  now,  therefore,  pro- 
ceed to  inquire  into  their  probable  causes.  But  first,  it  may  be  well  to 
recapitulate  some  of  those  points  of  relation  and  analogy  which  lead 
naturally  to  the  conclusion  that  they  spring  from  a  common  source. 

The  regions  convulsed  by  violent  earthquakes  include  within  them 
the  site  of  all  the  active  volcanoes.  Earthquakes,  sometimes  local,  some- 
times extending  over  vast  areas,  often  precede  volcanic  eruptions.  The 
subterranean  movement  and  the  eruption  return  again  and  again,  at 
irregular  intervals  of  time,  and  with  unequal  degrees  of  force,  to  the 
same  spots.  The  action  of  either  may  continue  for  a  few  hours,  or  for 
several  consecutive  years.  Paroxysmal  convulsions  are  usually  followed, 
in  both  cases,  by  long  periods  of  tranquillity.  Thermal  and  mineral 
springs  are  abundant  in  countries  of  earthquakes  and  active  volcanoes. 
Lastly,  hot  springs  situated  in  districts  considerably  distant  from  vol- 
canic vents  have  been  observed  to  have  their  temperature  suddenly 
raised,  and  the  volume  of  their  water  augmented,  by  subterranean  move- 
ments. 

All  these  appearances  are  evidently  more  or  less  connected  with  the 
passage  of  heat  from  the  interior  of  the  earth  to  the  surface ;  and  where 
there  are  active  volcanoes,  there  must  exist,  at  some  unknown  depth  be- 
low, enormous  masses  of  matter  intensely  heated,  and,  in  many  instances, 
in  a  constant  state  of  fusion.  We  have  first,  then,  to  inquire,  whence  is 
this  heat  derived  ? 

It  has  long  been  a  favorite  conjecture,  that  the  whole  of  our  planet 
was  originally  in  a  state  of  igneous  fusion,  and  that  the  central  parts 
still  retain  a  great  portion  of  their  primitive  heat.  Some  have  imagined, 
with  the  late  Sir  W.  Herschel,  that  the  elementary  matter  of  the  earth 
may  have  been  first  in  a  gaseous  state,  resembling  those  nebulae  which 
we  behold  in  the  heavens,  and  which  are  of  dimensions  so  vast,  that  some 
of  them  would  fill  the  orbits  of  the  remotest  planets  of  our  system.  The 
increased  power  of  the  telescope  has  of  late  years  resolved  the  greater 
number  of  these  nebulous  appearances  into  clusters  of  stars,  but  so  long 


534  SPHEKOIDAL  FORM  OF  THE  EARTH.       [On.  XXXL 

as  they  were  confidently  supposed  to  consist  of  aeriform  matter  it  was  a 
favorite  conjecture  that  they  might,  if  concentrated,  form  solid  spheres ; 
and  it  was  also  imagined  that  the  evolution  of  heat,  attendant  on  con- 
densation, might  retain  the  materials  of  the  new  globes  in  a  state  of 
igneous  fusion. 

Without  dwelling  on  such  speculations,  which  can  only  have  a  dis- 
tant bearing  on  geology,  we  may  consider  how  far  the  spheroidal  form 
of  the  earth  affords  sufficient  ground  for  presuming  that  its  primitive 
condition  was  one  of  universal  fluidity.  The  discussion  of  this  question 
would  be  superfluous,  were  the  doctrine  of  original  fluidity  less  popular  ; 
for  it  may  well  be  asked,  why  the  globe  should  be  supposed  to  have 
had  a  pristine  shape  different  from  the  present  one? — why  the  ter- 
restrial materials,  when  first  called  into  existence,  or  assembled  to- 
gether in  one  place,  should  not  have  been  subject  to  rotation,  so  as  to 
assume  at  once  that  form  which  alone  could  retain  their  several  parts  in 
a  state  of  equilibrium  ? 

Let  us,  however,  concede  that  the  statical  figure  may  be  a  modifica- 
tion of  some  other  pre-existing  form,  and  suppose  the  globe  to  have  been 
at  first  a  perfect  and  quiescent  sphere,  covered  with  a  uniform  ocean — 
what  would  happen  when  it  was  made  to  turn  round  on  its  axis  with  its 
present  velocity  ?  This  problem  has  been  considered  by  Playfair  in  his 
Illustrations,  and  he  has  decided,  that  if  the  surface  of  the  earth,  as  laid 
down  in  Hutton's  theory,  has  been  repeatedly  changed  by  the  transpor- 
tation of  the  detritus  of  the  land  to  the  bottom  of  the  sea,  the  figure  of 
the  planet  must  in  that  case,  whatever  it  may  have-  been  originally,  be 
brought  at  length  to  coincide  with  the  spheroid  of  equilibrium.*  Sir 
John  Herschel  also,  in  reference  to  the  same  hypothesis,  observes,  "  a 
centrifugal  force  would  in  that  case  be  generated,  whose  general  tend- 
ency would  be  to  urge  the  water  at  every  point  of  the  surface  to  recede 
from  the  axis.  A  rotation  might  indeed  be  conceived  so  swift  as  to  flirt 
the  whole  ocean  from  the  surface,  like  water  from  a  mop.  But  this  would 
require  a  far  greater  velocity  than  what  we  now  speak  of.  In  the  case 
supposed,  the  weight  of  the  water  would  still  keep  it  on  the  earth  ;  and 
the  tendency  to  recede  from  the  axis  could  only  be  satisfied  therefore  by 
the  water  leaving  the  poles,  and  flowing  towards  the  equator;  there 
heaping  itself  up  in  a  ridge,  and  being  retained  in  opposition  to  its  weight 
or  natural  tendency  towards  the  centre  by  the  pressure  thus  caused. 
This,  however,  could  not  take  place  without  laying  dry  the  polar  regions, 
so  that  protuberant  land  would  appear  at  the  poles,  and  a  zone  of  ocean 
be  disposed  around  the  equator.  This  would  be  the  first  or  immediate 
effect.  Let  us  now  see  what  would  afterwards  happen  if  things  were 
allowed  to  take  their  natural  course. 

"  The  sea  is  constantly  beating  on  the  land,  grinding  it  down,  and 
scattering  its  worn-off  particles  and  fragments,  in  the  state  of  sand  and 
pebbles,  over  its  bed.  Geological  facts  afford  abundant  proof  that  the 

*  Illust.  of  Hutt.  Theory,  §  435-443. 


CH.  XXXI.]  SPHEROIDAL   FORM   OF  THE  EARTH.  535 

existing  continents  have  all  of  them  undergone  this  process  even  more 
than  once,  and  been  entirely  torn  in  fragments,  or  reduced  to  powder, 
and  submerged  and  reconstructed.  Land,  in  this  view  of  the  subject, 
loses  its  attribute  of  fixity.  As  a  mass  it  might  hold  together  in  oppo- 
sition to  forces  which  the  water  freely  obeys  ;  but  in  its  state  of  succes- 
sive or  simultaneous  degradation,  when  disseminated  through  the  water, 
in  the  state  of  sand  or  mud,  it  is  subject  to  all  the  impulses  of  that  fluid. 
In  the  lapse  of  time,  then,  the  protuberant  land  would  be  destroyed,  and 
spread  over  the  bottom  of  the  ocean,  filling  up  the  lower  parts,  and  tend- 
ing continually  to  remodel  the  surface  of  the  solid  nucleus,  in  corre- 
spondence with  the  form  of  equilibrium.  Thus  after  a  sufficient  lapse  of 
time,  in  the  case  of  an  earth  in  rotation,  the  polar  protuberances  would 
gradually  be  cut  down  and  disappear,  being  transferred  to  the  equator 
(as  being  then  the  deepest  sea),  till  the  earth  would  assume  by  de- 
grees the  form  we  observe  it  to  have — that  of  a  flattened  or  oblate 
ellipsoid. 

"  We  are  far  from  meaning  here  to  trace  the  process  by  which  the 
earth  really  assumed  its  actual  form ;  all  we  intend  is  to  show  that  this 
is  the  form  to  which,  under  a  condition  of  a  rotation  on  its  axis,  it  must 
tend,  and  which  it  would  attain  even  if  originally  and  (so  to  speak)  per- 
versely constituted  otherwise."* 

In  this  passage,  the  author  has  contemplated  the  superficial  effects  of 
aqueous  causes  only  ;  but  neither  he  nor  Playfair  seem  to  have  followed 
out  the  same  inquiry  with  reference  to  another  part  of  Mutton's  system ; 
namely,  that  which  assumes  the  successive  fusion  by  heat  of  different 
parts  of  the  solid  earth.  Yet  the  progress  of  geology  has  continually 
strengthened  the  evidence  in  favor  of  the  doctrine  that  local  variations  of 
temperature  have  melted  one  part  after  another  of  the  earth's  crust,  and 
this  influence  has  perhaps  extended  downwards  to  the  very  centre.  If, 
therefore,  before  the  globe  had  assumed  its  present  form,  it  was  made 
to  revolve  on  its  axis,  all  matter  to  which  freedom  of  motion  was  given 
by  fusion,  must  before  consolidating  have  been  impelled  towards  the 
equatorial  regions  in  obedience  to  the  centrifugal  force.  Thus  lava  flow- 
ing out  in  superficial  streams  would  have  its  motion  retarded  when  its 
direction  was  towards  the  pole,  accelerated  when  towards  the  equator  ; 
or  if  lakes  and  seas  of  lava  existed  beneath  the  earth's  crust  in  equato- 
rial regions,  as  probably  now  beneath  the  Peruvian  Andes,  the  impris- 
oned fluid  would  force  outwards  and  permanently  upheave  the  over- 
lying rocks.  The  statical  figure,  therefore,  of  the  terrestrial  spheroid 
(of  which  the  longest  diameter  exceeds  the  shortest  by  about  twenty -five 
miles),  may  have  been  the  result  of  gradual  and  even  of  existing  causes, 
and  not  of  a  primitive,  universal,  and  simultaneous  fluidity.f 

Experiments  made  with  the  pendulum,  and  observations  on  the  man- 
ner in  which  the  earth  attracts  the  moon,  have  shown  that  our  planet  is 

*  Herschel's  Astronomy,  chap.  iii. 

f  See  Hennessy,  On  Changes  in  Earth's  Figure,  &c.  Journ.  Geol.  Soc.  Dublin, 
1849 ;  and  Proc.  Roy.  Irish  Acad.  vol.  iv.  p.  337. 


536  DENSITY    OF   THE   EARTH.  [Cfl.  XXXI, 

not  an  empty  sphere,  but,  on  the  contrary,  that  its  interior,  whether 
solid  or  fluid,  has  a  higher  specific  gravity  than  the  exterior.  It  has 
also  been  inferred,  that  there  is  a  regular  increase  in  density  from  the 
surface  towards  the  centre,  and  that  the  equatorial  protuberance  is  con- 
tinued inwards  ;  that  is  to  say,  that  layers  of  equal  density  are  arranged 
elliptically,  and  symmetrically,  from  the  exterior  to  the  centre.  These 
conclusions,  however,  have  been  deduced  rather  as  a  consequence  of 
the  hypothesis  of  primitive  and  simultaneous  fluidity  than  proved  by 
experiment.  The  inequalities  in  the  moon's  motion,  by  which  some  have 
endeavored  to  confirm  them,  are  so  extremely  slight,  that  the  opinion 
can  be  regarded  as  little  more  than  a  probable  conjecture. 

The  mean  density  of  the  earth  has  been  computed  by  Laplace  to  be 
about  5^,  or  more  than  five  times  that  of  water.  Now  the  specific 
gravity  of  many  of  our  rocks  is  from  2£  to  3,  and  the  greater  part  of 
the  metals  range  between  that  density  and  21.  Hence  some  have 
imagined  that  the  terrestrial  nucleus  may  be  metallic — that  it  may  cor- 
respond, for  example,  with  the  specific  gravity  of  iron,  which  is  about  7. 
But  here  a  curious  question  arises  in  regard  to  the  form  which  mate- 
rials, whether  fluid  or  solid,  might  assume,  if  subjected  to  the  enormous 
pressure  which  must  obtain  at  the  earth's  centre.  Water,  if  it  continued 
to  decrease  in  volume  according  to  the  rate  of  compressibility  deduced 
from  experiment,  would  have  its  density  doubled  at  the  depth  of  ninety- 
three  miles,  and  be  as  heavy  as  mercury  at  the  depth  of  362  miles. 
Dr.  Young  computed  that,  at  the  earth's  centre,  steel  would  be  com- 
pressed into  one-fourth,  and  stone  into  one-eighth  of  its  bulk.*  It  is 
more  than  probable,  however,  that  after  a  certain  degree  of  condensa- 
tion, the  compressibility  of  bodies  may  be  governed  by  laws  altogether 
different  from  those  which  we  can  put  to  the  test  of  experiment ;  but 
the  limit  is  still  undetermined,  and  the  subject  is  involved  in  such  ob- 
scurity, that  we  cannot  wonder  at  the  variety  of  notions  which  have 
been  entertained  respecting  the  nature  and  conditions  of  the  central  nu- 
cleus. Some  have  conceived  it  to  be  fluid,  others  solid  ;  some  have 
imagined  it  to  have  a  cavernous  structure,  and  have  even  endeavored  to 
confirm  this  opinion  by  appealing  to  observed  irregularities  in  the  vibra- 
tions of  the  pendulum  in  certain  countries. 

An  attempt  has  recently  been  made  by  Mr.  Hopkins  to  determine 
the  least  thickness  which  can  be  assigned  to  the  solid  crust  of  the  globe, 
if  we  assume  the  whole  to  have  been  once  perfectly  fluid,  and  a  certain 
portion  of  the  exterior  to  have  acquired  solidity  by  gradual  refrigeration. 
This  result  he  has  endeavored  to  obtain  by  a  new  solution  of  the  deli- 
cate problem  of  the  precessiotial  motion  of  the  pole  of  the  earth.  It  is 
well  known  that  while  the  earth  revolves  round  the  sun  the  direction  of 
its  axis  remains  very  nearly  the  same,  i.  e.  its  different  positions  in  space 
are  all  nearly  parallel  to  each  other.  This  parallelism,  however,  is  not 


*  Young's  Lectures,  and  Mrs.  Somerville's  Connection  of  the  Physical  Sciences, 
p.  90. 


CH.  XXXI.]  DENSITY   OF  THE   EARTH.  537 

accurately  preserved,  so  that  the  axis,  instead  of  coming  exactly  into 
the  position  which  it  occupied  a  year  before,  becomes  inclined  to  it  at  a 
very  small  angle,  but  always  retaining  very  nearly  the  same  inclination 
to  the  plane  of  the  earth's  orbit.  This  motion  of  the  pole  changes  the 
position  of  the  equinoxes  by  about  fifty  seconds  annually,  and  always 
in  the  same  direction.  Thus  the  pole-star,  after  a  certain  time,  will 
entirely  lose  its  claim  to  that  appellation,  until  in  the  course  of  somewhat 
more  than  25,000  years  the  earth's  axis  shall  again  occupy  its  present 
angular  position,  and  again  point  very  nearly  as  now  to  the  pole-star. 
This  motion  of  the  axis  is  called  precession.  It  is  caused  by  the  attrac- 
tion of  the  sun  and  moon,  and  principally  the  moon,  on  the  protuberant 
parts  of  the  earth's  equator ;  and  if  these  parts  were  solid  to  a  great 
depth,  the  motion  thus  produced  would  differ  considerably  from  that 
which  would  exist  if  they  were  perfectly  fluid,  and  incrusted  over  with 
a  thin  shell  only  a  few  miles  thick.  In  other  words,  the  disturbing  ac- 
tion of  the  moon  will  not  be  the  same  upon  a  globe  all  solid  and  upon 
one  nearly  all  fluid,  or  it  will  not  be  the  same  upon  a  globe  in  which 
the  solid  shell  forms  one-half  of  the  mass,  and  another  in  which  it  forms 
only  one-tenth. 

Mr.  Hopkins  has,  therefore,  calculated  the  amount  of  precessional  mo- 
tion which  would  result  if  we  assume  the  earth  to  be  constituted  as 
above  stated ;  i.  e.  fluid  internally,  and  enveloped  by  a  solid  shell ;  and 
he  finds  that  the  amount  will  not  agree  with  the  observed  motion,  unless 
the  crust  of  the  earth  be  of  a  certain  thickness.  In  calculating  the  ex- 
act amount  some  ambiguity  arises  in  consequence  of  our  ignorance  of  the 
effect  of  pressure  in  promoting  the  solidification  of  matter  at  high  tem- 
peratures. The  hypothesis  least  favorable  for  a  great  thickness  is  found 
to  be  that  which  assumes  the  pressure  to  produce  no  effect  on  the  pro- 
cess of  solidification.  Even  on  this  extreme  assumption  the  thickness  of 
the  solid  crust  must  be  nearly  four  hundred  miles,  and  this  would  load 
to  the  remarkable  result  that  the  proportion  of  the  solid  to  the  fluid  part 
would  be  as  49  to  51,  or,  to  speak  in  round  numbers,  there  would  be 
nearly  as  much  solid  as  fluid  matter  in  the  globe.  The  conclusion,  how- 
ever, which  Mr.  Hopkins  announces  as  that  to  which  his  researches 
have  finally  conducted  him,  is  thus  expressed :  "  Upon  the  whole,  then, 
we  may  venture  to  assert  that  the  minimum  thickness  of  the  crust  of  the 
globe,  which  can  be  deemed  consistent  with  the  observed  amount  of  pre- 
cession, cannot  be  less  than  one-fourth  or  one-fifth  of  the  earth's  radius." 
That  is  from  800  to  1000  miles.* 

It  will  be  remarked,  that  this  is  a  minimum,  and  any  still  greater 
amount  would  be  quite  consistent  with  the  actual  phenomena  ;  the  calcu- 
lations not  being  opposed  to  the  supposition  of  the  general  solidity  of  the 
entire  globe.  Nor  do  they  preclude  us  from  imagining  that  great  lakes 
or  seas  of  melted  matter  may  be  distributed  through  a  shell  400  or  800 

*  Phil.  Trans.  1839,  and  Researches  in  Physical  Geology,  1st,  2d,  and  3d  series, 
London,  1839-1842  ;  also  on  Phenomena  and  Theory  of  Volcanoes,  Report  Brit. 
Assoc.  1847. 


538  THEORY  OF  CENTRAL  HEAT.         [Cn.  XXXL 

miles  thick,  provided  they  be  so  inclosed  as  to  move  with  it,  whatever 
motion  of  rotation  may  be  communicated  by  the  disturbing  forces  of  the 
sun  and  moon. 

Central  heat. — The  hypothesis  of  internal  fluidity  calls  for  the  more 
attentive  consideration,  as  it  has  been  found  that  the  heat  in  mines  aug- 
ments in  proportion  a's  we  descend.  Observations  have  been  made,  not 
only  on  the  temperature  of  the  air  in  mines,  but  on  that  of  the  rocks, 
and  on  the  water  issuing  from  them.  The  mean  rate  of  increase,  calcu- 
lated from  results  obtained  in  six  of  the  deepest  coal  mines  in  Durham 
and  Northumberland,  is  1°  Fahr.  for  a  descent  of  forty-four  English 
feet.*  A  series  of  observations,  made  in  several  of  the  principal  lead 
and  silver  mines  in  Saxony,  gave  1°  Fahr.  for  every  sixty-five  feet.  In 
this  case,  the  bulb  of  the  thermometer  was  introduced  into  cavities  pur- 
posely cut  in  the  solid  rock  at  depths  varying  from  200  to  above  900  feet. 
But  in  other  mines  of  the  same  country,  it  was  necessary  to  descend 
thrice  as  far  for  each  degree  of  temperature. f 

A  thermometer  was  fixed  in  the  rock  of  the  Dolcoath  mine,  in  Corn- 
wall, by  Mr.  Fox,  at  the  great  depth  of  1380  feet,  and  frequently  ob- 
served during  eighteen  months ;  the  mean  temperature  was  68°  Fahr., 
that  of  the  surface  being  50°,  which  gives  1°  for  every  seventy-five  feet. 

Kupffer,  after  an  extensive  comparison  of  the  results  in  different  coun- 
tries, makes  the  increase  1°  F.  for  about  every  thirty-seven  English  feet.J 
M.  Cordier  announces,  as  the  result  of  his  experiments  and  observations 
on  the  temperature  of  the  interior  of  the  earth,  that  the  heat  increases 
rapidly  with  the  depth  ;  but  the  increase  does.not  follow  the  same  law 
over  the  whole  earth,  being  twice  or  three  times  as  much  in  one  country 
as  in  another,  and  these  differences  are  not  in  constant  relation  either 
with  the  latitudes  or  longitudes  of  places. §  He  is  of  opinion,  however, 
that  the  increase  would  not  be  overstated  at  1°  Cent,  for  every  twenty- 
five  metres,  or  about  1°  F.  for  every  forty-five  feet.||  The  experimental 
well  bored  at  Grenelle,  near  Paris,  gave  about  1°  F.  for  every  sixty 
English  feet,  when  they  had  reached  a  depth  of  1312  feet. 

Some  writers  have  endeavored  to  refer  these  phenomena  (which,  how- 
ever discordant  as  to  the  ratio  of  increasing  heat,  appear  all  to  point  one 
way)  to  the  condensation  of  air  constantly  descending  from  the  surface 
into  the  mines.  For  the  air  under  pressure  would  give  out  latent  heat, 
on  the  same  principle  as  it  becomes  colder  when  rarefied  in  the  higher 
regions  of  the  atmosphere.  But,  besides  that  the  quantity  of  heat  is 
greater  than  could  be  supposed  to  flow  from  this  source,  the  argument 
has  been  answered  in  a  satisfactory  manner  by  Mr.  Fox,  who  has  shown, 
that  in  the  mines  of  Cornwall  the  ascending  have  generally  a  higher 


*  Ed.  Journ.  of  Sci.  April,  1832. 

f  Cordier,  Mem.  de  1'Instit.  torn.  vii.  \  Pog.  Ann.  torn.  xv.  p.  159. 

§  See  M.  Cordier's  Memoir  on  the  Temperature  of  the  Interior  of  the  Earth, 
read  to  the  Academy  of  Sciences,  4th  June,  1827. — Edin.  New  Phil.  Journal,  No 
Viii.  p.  273. 

|  Cordier,  Me~m.  de  1'Instit.  torn.  vii. 


CH.  XXXL] 


THEORY   OF   CENTRAL   HEAT. 


539 


temperature  than  the  descending  aerial  currents.  The  difference  be- 
tween them  was  found  to  vary  from  9°  to  17°  F. ;  a  proof  that,  instead 
of  imparting  heat,  these  currents  actually  carry  off  a  large  quantity  from 
the  mines.* 

If  we  adopt  M.  Cordier's  estimate  of  1°  F.  for  every  45  feet  of  depth 
as  the  mean  result,  and  assume,  with  the  advocates  of  central  fluidity, 
that  the  increasing  temperature  is  continued  downwards,  we  should 
reach  the  ordinary  boiling  point  of  water  at  about  two  miles  below  the 
surface,  and  at  the  depth  of  about  twenty-four  miles  should  arrive  at 
the  melting  point  of  iron,  a  heat  sufficient  to  fuse  almost  every  known 

Fig.  92. 


Section  of  the  earth,  in  which  the  breadth  of  the  outer  boundary  line  represents  a  thickness  of 
25  miles;  the  space  between  the  circles,  including  the  breadth  of  the  lines,  200  miles. 

substance.  The  temperature  of  melted  iron  was  estimated  at  21,000° 
F.,  by  Wedgwood ;  but  his  pyrometer  gives,  as  is  now  demonstrated, 
very  erroneous  results.  Professor  Daniell  ascertained  that  the  point  of 
fusion  is  2786°  F.f 

According  to  Mr.  Daniell's  scale,  we  ought  to  encounter  the  internal 

*  Phil.  Mag.  and  Ann.  Feb.  1830. 

•f-  The  heat  was  measured  in  Wedgwood's  pyrometer  by  the  contraction  of 
pure  clay,  which  is  reduced  in  volume  when  heated,  first  by  the  loss  of  its  water 
of  combination,  and  afterwards,  on  the  application  of  more  intense  heat,  by  incip- 
ient vitrification.  The  expansion  of  platina  is  the  test  employed  by  Mr.  Daniell 
in  his  pyrometer,  and  this  has  been  found  to  yield  uniform  and  constant  results, 
such  as  are  in  perfect  harmony  with  conclusions  drawn  from  various  other  inde- 
pendent sources.  The  instrument  for  which  the  author  received  the  Rumford 
Medal  from  the  Royal  Society,  in  1833,  is  described  in  the  Phil.  Trans.  1830,  part 
ii.,  and  1831,  part  ii. 


540  HEAT   AND   FLUIDITY.  [On.  XXXI. 

melted  matter  before  penetrating  through  a  thickness  represented  by 
that  of  the  outer  circular  line  in  the  annexed  diagram  (fig.  92) ;  whereas, 
if  the  other  or  less  correct  scale  be  adopted,  we  should  meet  with  it  at 
some  point  between  the  two  circles  ;  the  space  between  them,  together 
with  the  lines  themselves,  representing  a  crust  of  200  miles  in  depth. 
In  either  case,  we  must  be  prepared  to  maintain  that  a  temperature 
many  times  greater  than  that  sufficient  to  melt  the  most  refractory  sub- 
stances known  to  us,  is  sustained  at  the  centre  of  the  globe ;  while  a 
comparatively  thin  crust,  resting  upon  the  fluid,  remains  unmelted  ;  or 
is  even,  according  to  M.  Cordier,  increasing  in  thickness,  by  the  continual 
addition  of  new  internal  layers  solidified  during  the  process  of  refrig- 
eration. 

The  mathematical  calculations  of  Fourier,  on  the  passage  of  heat 
through  conducting  bodies,  have  been  since  appealed  to  in  support  of 
these  views ;  for  he  has  shown  that  it  is  compatible  with  theory  that 
the  present  temperature  of  the  surface  might  coexist  with  an  intense 
heat  at  a  certain  depth  below.  But  his  reasoning  seems  to  be  confined 
to  the  conduction  of  heat  through  solid  bodies ;  and  the  conditions  of 
the  problem  are  wholly  altered  when  we  reason  about  a  fluid  nucleus,  as 
we  must  do  if  it  be  assumed  that  the  heat  augments  from  the  surface 
to  the  interior,  according  to  the  rate  observed  in  mines.  For  when  the 
heat  of  the  lower  portion  of  a  fluid  is  increased,  a  circulation  begins 
throughout  the  mass,  by  the  ascent  of  hotter,  and  the  descent  of  colder 
currents.  And  this  circulation,  which  is  quite  distinct  from  the  mode 
in  which  heat  is  propagated  through  solid  bodies,  must  evidently  occur 
in  the  supposed  central  ocean,  if  the  laws  of  fluids  and  of  heat  are  the 
same  there  as  upon  the  surface. 

In  Mr.  Daniell's  experiments  for  obtaining  a  measure  of  the  heat  of 
bodies  at  their  point  of  fusion,  he  invariably  found  that  it  was  impossible 
to  raise  the  heat  of  a  large  crucible  of  melted  iron,  gold,  or  silver,  a  sin- 
gle degree  beyond  the  melting  point,  so  long  as  a  bar  of  the  respective 
metals  was  kept  immersed  in  the  fluid  portions.  So  in  regard  to  other 
substances,  however  great  the  quantities  fused,  their  temperature  could 
not  be  raised  while  any  solid  pieces  immersed  in  them  remained  un- 
melted ;  every  accession  of  heat  being  instantly  absorbed  during  their 
liquefaction.  These  results  are,  in  fact,  no  more  than  the  extension  of  a 
principle  previously  established,  that  so  long  as  a  fragment  of  ice  re- 
mains in  water,  we  cannot  raise  the  temperature  of  the  water  above 
32°  F. 

If,  then,  the  heat  of  the  earth's  centre  amount  to  450,000°  F.,  as  M. 
Cordier  deems  highly  probable,  that  is  to  say,  about  twenty  times  the 
heat  of  melted  iron,  even  according  to  Wedgwood's  scale,  and  upwards 
of  160  times  according  to  the  improved  pyrometer,  it  is  clear  that  the 
upper  parts  of  the  fluid  mass  could  not  long  have  a  temperature  only 
just  sufficient  to  melt  rocks.  There  must  be  a  continual  tendency  to- 
wards a  uniform  heat ;  and  until  this  were  accomplished,  by  the  inter- 
change of  portions  of  fluid  of  different  densities,  the  surface  could  not 


CH.  XXXI]  THEORY   OF   CENTRAL  HEAT.  541 

begin  to  consolidate.  Nor,  on  the  hypothesis  of  primitive  fluidity,  can 
we  conceive  any  crust  to  have  been  formed  until  the  whole  planet  had 
cooled  down  to  about  the  temperature  of  incipient  fusion. 

It  cannot  be  objected  that  hydrostatic  pressure  would  prevent  a  ten- 
dency to  equalization  of  temperature ;  for,  as  far  as  observations  have 
yet  been  made,  it  is  found  that  the  waters  of  deep  lakes  and  seas  are 
governed  by  the  same  laws  as  a  shallow  pool ;  and  no  experiments  indi- 
cate that  solids  resist  fusion  under  high  pressure.  The  arguments,  in- 
deed, now  controverted,  always  proceed  on  the  admission  that  the  inter- 
nal nucleus  is  in  a  state  of  fusion. 

It  may  be  said  that  we  may  stand  upon  the  hardened  surface  of  a  lava- 
current  while  it  is  still  in  motion, — nay,  may  descend  into  the  crater  of 
Vesuvius  after  an  eruption,  and  stand  on  the  scoriae  while  every  crevice 
shows  that  the  rock  is  red-hot  two  or  three  feet  below  us  ;  and  at  a 
somewhat  greater  depth,  all  is,  perhaps,  in  a  state  of  fusion.  May  not, 
then,  a  much  more  intense  heat  be  expected  at  the  depth  of  several 
hundred  yards,  or  miles  ?  The  answer  is, — that  until  a  great  quantity 
of  heat  has  been  given  off,  either  by  the  emission  of  lava,  or  in  a  latent 
form  by  the  evolution  of  steam  and  gas,  the  melted  matter  continues  to 
boil  in  the  crater  of  a  volcano.  But  ebullition  ceases  when  there  is  no 
longer  a  sufficient  supply  of  heat  from  below,  and  then  a  crust  of  lava 
may  form  on  the  top,  and  showers  of  scoriae  may  then  descend  upon 
the  surface,  and  remain  unmelted.  If  the  internal  heat  be  raised  again, 
ebullition  will  recommence,  and  soon  fuse  the  superficial  crust.  So  in 
the  case  of  the  moving  current,  we  may  safely  assume  that  no  part  of 
the  liquid  beneath  the  hardened  surface  is  much  above  the  temperature 
sufficient  to  retain  it  in  a  state  of  fluidity. 

It  may  assist  us  in  forming  a  clearer  view  of  the  doctrine  now  con- 
troverted, if  we  consider  what  would  happen  were  a  globe  of  homoge- 
neous composition  placed  under  circumstances  analogous,  in  regard  to 
the  distribution  of  heat,  to  those  above  stated.  If  the  whole  planet,  for 
example,  were  composed  of  water  covered  with  a  spheroidal  crust  of  ice 
fifty  miles  thick,  and  with  an  interior  ocean  having  a  central  heat  about 
two  hundred  times  that  of  the  melting  point  of  ice,  or  6400°  F. ;  and  if, 
between  the  surface  and  the  centre,  there  was  every  intermediate  degree 
of  temperature  between  that  of  melting  ice  and  that  of  the  central  nu- 
cleus ; — could  such  a  state  of  things  last  for  a  moment  ?  If  it  must  be 
conceded,  in  this  case,  that  the  whole  spheroid  would  be  instantly  in  a 
state  of  violent  ebullition,  that  the  ice  (instead  of  being  strengthened 
annually  by  new  internal  layers)  would  soon  melt,  and  form  part  of  an 
atmosphere  of  steam — on  what  principle  can  it  be  maintained  that  anal- 
ogous effects  would  not  follow,  in  regard  to  the  earth,  under  the  condi- 
tions assumed  in  the  theory  of  central  heat  ?* 

*  The  above  remarks  are  reprinted  verbatim  from  my  third  edition,  May,  1834. 
A  memoir  was  afterwards  communicated  by  M.  Poisson  to  the  Academy  of 
Sciences,  January,  1837,  on  the  solid  parts  of  the  globe,  containing  an  epitome  of  a 
work  entitled  "  Theorie  Mathematique  de  la  Chaleur,"  published  in  1835.  In  this 
memoir  he  controverts  the  doctrine  of  the  high  temperature  of  a  central  fluid  on 


542  HEAT  PRODUCED   BY   CHEMICAL   CHANGES.         [On.  XXXI. 

M.  Cordier  admits  that  there  must  be  tides  in  the  internal  melted 
ocean ;  but  their  effect,  he  says,  has  become  feeble,  although  originally, 
when  the  fluidity  of  the  globe  was  perfect,  "  the  rise  and  fall  of  these 
ancient  land  tides  could  not  have  been  less  than  from  thirteen  to  sixteen 
feet."  Now,  granting  for  a  moment,  that  these  tides  have  become  so 
feeble  as  to  be  incapable  of  causing  the  fissured  shell  of  the  earth  to  be 
first  uplifted  and  then  depressed  every  six  hours,  still  may  we  not  ask 
whether,  during  eruptions,  the  lava,  which  is  supposed  to  communicate 
with  a  great  central  ocean,  would  not  rise  and  fall  sensibly  in  a  crater 
such  as  Stromboli,  where  there  is  always  melted  matter  in  a  state  of 
ebullition  ? 

Whether  chemical  changes  may  produce  volcanic  heat. — Having  now 
explained  the  reasons  which  have  induced  me  to  question  the  hypothesis 
of  central  heat  as  the  primary  source  of  volcanic  action,  it  remains  to 
consider  what  has  been  termed  the  chemical  theory  of  volcanoes.  It  is 
well  known  that  many,  perhaps  all,  of  the  substances  of  which  the  earth 
is  composed  are  continually  undergoing  chemical  changes.  To  what 
depth  these  processes  may  be  continued  downwards  must,  in  a  great 
degree,  be  matter  of  conjecture ;  but  there  is  no  reason  to  suspect  that, 
if  we  could  descend  to  a  great  distance  from  the  surface,  we  should  find 
elementary  substances  differing  essentially  from  those  with  which  we  are 
acquainted. 

All  the  solid,  fluid,  and  gaseous  bodies  known  to  us  consist  of  a  very 
small  number  of  these  elementary  substances  variously  combined :  the 
total  number  of  elements  at  present  known  is  less  than  sixty  ;  and  not 
half  of  these  enter  into  the  composition  of  the  more  abundant  inorganic 
productions.  Some  portions  of  such  compounds  are  daily  undergoing 
decomposition,  and  their  constituent  parts  being  set  free  are  passing  into 
new  combinations.  These  processes  are  by  no  means  confined  to  miner- 
als at  the  earth's  surface,  and  are  very  often  accompanied  by  the  evolu- 
tion of  heat,  which  is  intense  in  proportion  to  the  rapidity  of  the  combi- 
nations. At  the  same  time  there  is  a  development  of  electricity. 

The  spontaneous  combustion  of  beds  of  bituminous  shale,  and  of  refuse 
coal  thrown  out  of  mines,  is  generally  due  to  the  decomposition  of  pyrites ; 
and  it  is  the  contact  of  air  and  water  which  brings  about  the  change. 
Heat  results  from  the  oxidation  of  the  sulphur  and  iron,  though  on  what 
principle  heat  is  generated,  when  two  or  more  bodies  having  a  strong 
affinity  for  each  other  unite  suddenly,  is  wholly  unexplained. 

Electricity  a  source  of  volcanic  heat. — It  has  already  been  stated,  that 
chemical  changes  develop  electricity;  which,  in  its  turn,  becomes  a 
powerful  disturbing  cause.  As  a  chemical  agent,  says  Davy,  its  silent 
and  slow  operation  in  the  economy  of  nature  is  much  more  important 
than  its  grand  and  impressive  operation  in  lightning  and  thunder.  It 
may  be  considered,  not  only  as  directly  producing  an  infinite  variety  of 

similar  grounds  to  those  above  stated.  He  imagines,  that  if  the  globe  ever  passed 
from  a  liquid  to  a  solid  state  by  radiation  of  heat,  the  central  nucleus  must  have 
begun  to  cool  and  consolidate  first. 


CH.  XXXL]      ELECTKICITY  A  SOURCE  OF  VOLCANIC   HEAT.  543 

changes,  but  as  influencing  almost  all  which  take  place ;  it  would  seem, 
indeed,  that  chemical  attraction  itself  is  only  a  peculiar  form  of  the  exhi- 
bition of  electrical  attraction.* 

Now  that  it  has  been  demonstrated  that  magnetism  and  electricity 
are  always  associated,  and  are  perhaps  only  different  conditions  of  the 
same  power,  the  phenomena  of  terrestrial  magnetism  have  become  of 
no  ordinary  interest  to  the  geologist.  Soon  after  the  first  great  dis- 
coveries of  Oersted  in  electro-magnetism,  Ampere  suggested  that  all 
the  phenomena  of  the  magnetic  needle  might  be  explained  by  suppos- 
ing currents  of  electricity  to  "circulate  constantly  in  the  shell  of  the 
globe  in  directions  parallel  to  the  magnetic  equator.  This  theory  has 
acquired  additional  consistency  the  farther  we  have  advanced  in  science ; 
and  according  to  the  experiments  of  Mr.  Fox,  on  the  electro-magnetic 
properties  of  metalliferous  veins,  some  trace  of  electric  currents  seems  to 
have  been  detected  in  the  interior  of  the  earth. f 

Some  philosophers  ascribe  these  currents  to  the  chemical  action  going 
on  in  the  superficial  parts  of  the  globe  to  which  air  and  water  have  the 
readiest  access  ;  while  others  refer  them,  in  part  at  least,  to  thermo- 
electricity excited  by  the  solar  rays  on  the  surface  of  the  earth  during 
its  rotation ;  successive  parts  of  the  atmosphere,  land,  and  sea  being 
exposed  to  the  influence  of  the  sun,  and  then  cooled  again  in  the  night. 
That  this  idea  is  not  a  mere  speculation,  is  proved  by  the  correspond- 
ence of  the  diurnal  variations  of  the  magnet  with  the  apparent  motion 
of  the  sun  ;  and  by  the  greater  amount  of  variation  in  summer  than  in 
winter,  and  during  the  day  than  in  the  night.  M.  de  la  Rive,  although 
conceding  that  such  minor  variations  of  the  needle  may  be  due  to 
thermo-electricity,  contends  that  the  general  phenomena  of  terrestrial 
magnetism  must  be  attributed  to  currents  far  more  intense ;  which, 
though  liable  to  secular  fluctuations,  act  with  much  greater  constancy 
and  regularity  than  the  causes  which  produce  the  diurnal  variations.]; 
The  remark  seems  just ;  yet  it  is  difficult  to  assign  limits  to  the  accu- 
mulated influence  even  of  a  very  feeble  force  constantly  acting  on  the 
whole  surface  of  the  earth.  This  subject,  however,  must  evidently 
remain  obscure,  until  we  become  acquainted  with  the  causes  which  give 
a  determinate  direction  to  the  supposed  electric  currents.  Already  the 
experiments  of  Faraday  on  the  rotation  of  magnets  have  led  him  to 
speculate  on  the  manner  in  which  the  earth,  when  once  it  had  become 
magnetic,  might  produce  electric  currents  within  itself,  in  consequence 
of  its  diurnal  rotation.§  We  have  seen  also  in  a  former  chapter  (p.  129) 
that  the  recent  observations  of  Schwabe,  1852,  have  led  Col.  Sabine  to 
the  discovery  of  a  connection  between  certain  periodical  changes,  which 
take  place  in  the  spots  on  the  sun,  and  a  certain  cycle  of  variations  in 
terrestrial  magnetism.  These  seem  to  point  to  the  existence  of  a  solar 


*  Consolations  in  Travel,  p.  271.  f  Phil.  Trans.  1830,  p.  399. 

\  Biblioth.  TJnivers.  1833,  Electricit4. 

§  Phil.  Trans.  1832,  p.  176  ;  also  pp.  172,  173,  <fec. 


544  ELECTRICITY   A  SOURCE   OF   VOLCANIC   HEAT.         [Cn.  XXXI. 

magnetic  period,  and  suggest  the  idea  of  the  sun's  magnetism  exerting 
an  influence  on  the  mass  of  our  planet. 

In  regard  to  thermo-electricity,  I  may  remark,  that  it  may  be  gener- 
ated by  great  inequalities  of  temperature,  arising  from  a  partial  distri- 
bution of  volcanic  heat.  Wherever,  for  example,  masses  of  rock  occur 
of  great  horizontal  extent,  and  of  considerable  depth,  which  are  at  one 
point  in  a  state  of  fusion  (as  beneath  some  active  volcano)  ;  at  another, 
red-hot ;  and  at  a  third,  comparatively  cold — strong  thermo-electric 
action  may  be  excited. 

Some,  perhaps,  may  object,  that  this  is  reasoning  in  a  circle  ;  first  to 
introduce  electricity  as  one  of  the  primary  causes  of  volcanic  heat,  and 
then  to  derive  the  same  heat  from  thermo-electric  currents.  But  there 
must,  in  truth,  be  much  reciprocal  action  between  the  agents  now  under 
consideration ;  and  it  is  very  difficult  to  decide  which  should  be  re- 
garded as  the  prime  mover,  or  to  see  where  the  train  of  changes,  once 
begun,  would  terminate.  Whether  subterranean  electric  currents  if 
once  excited  might  sometimes  possess  the  decomposing  power  of  the 
voltaic  pile,  is  a  question  not  perhaps  easily  answered  in  the  present 
state  of  science ;  but  such  a  power,  if  developed,  would  at  once  supply 
us  with  a  never-failing  source  of  chemical  action  from  which  volcanic 
heat  might  be  derived. 

Recapitulation. — Before  entering,  in  the  next  chapter,  still  farther 
into  the  inquiry,  how  far  the  phenomena  of  volcanoes  and  earthquakes 
accord  with  the  hypothesis  of  a  continued  generation  of  heat  by  chemi- 
cal action,  it  may  be  desirable  to  recapitulate,  in  a  few  words,  the  con- 
clusions already  obtained. 

1st.  The  primary  causes  of  the  volcano  and  the  earthquake  are,  to  a 
great  extent,  the  same,  and  must  be  connected  with  the  passage  of  heat 
from  the  interior  to  the  surface. 

2dly.  This  heat  has  been  referred,  by  many,  to  a  supposed  state  of 
igneous  fusion  of  the  central  parts  of  the  planet  when  it  was  first 
created,  of  which  a  part  still  remains  in  the  interior,  but  is  always 
diminishing  in  intensity. 

3dly.  The  spheroidal  figure  of  the  earth,  adduced  in  support  of  this 
theory,  does  not  of  necessity  imply  a  universal  and  simultaneous 
fluidity,  in  the  beginning ;  for  supposing  the  original  figure  of  our  planet 
had  been  strictly  spherical — which,  however,  is  a  gratuitous  assumption, 
resting  on  no  established  analogy — still  the  statical  figure  must  have 
been  assumed,  if  sufficient  time  be  allowed,  by  the  gradual  operation  of 
the  centrifugal  force,  acting  on  the  materials  brought  successively  within 
its  action  by  aqueous  and  igneous  causes. 

4thly.  It  appears,  from  experiment,  that  the  heat  in  mines  increases 
progressively  with  their  depth  ;  and  if  the  ratio  of  increase  be  continued 
uniformly  from  the  surface  to  the  interior,  the  whole  globe,  with  the 
exception  of  a  smnll  external  shell,  must  be  fluid,  and  the  central  parts 
must  have  a  temperature  many  times  higher  than  that  of  melted  iron. 

5thly.  But  the  theory  adopted  by  M.  Cordier  and  others,  which 


OIL  XXXIL]      CAUSES    OF   EARTHQUAKES   AND   VOLCANOES.  545 

maintains  the  actual  existence  of  such  a  state  of  things,  seems  wholly 
inconsistent  with  the  laws  which  regulate  the  circulation  of  heat  through 
fluid  bodies.  For,  if  the  central  heat  were  as  intense  as  is  represented, 
there  must  be  a  circulation  of  currents,  tending  to  equalize  the  tempera- 
ture of  the  resulting  fluids,  and  the  solid  crust  itself  would  be  melted. 

Gthly.  Instead  of  an  original  central  heat,  we  may,  perhaps,  refer  the 
heat  of  the  interior  to  chemical  changes  constantly  going  on  in  the  earth's 
crust ;  for  the  general  effect  of  chemical  combination  is  the  evolution  of 
heat  and  electricity,  which  in  their  turn  become  sources  of  new  chemical 
changes. 


CHAPTER  XXXII. 

CAUSES    OF    EARTHQUAKES    AND    VOLCANOES Continued. 

Review  of  the  proofs  of  internal  heat — Theory  of  an  unoxidated  metallic  nucleus 
— Whether  the  decomposition  of  water  may  be  a  source  of  volcanic  heat — 
Geysers  of  Iceland — Causes  of  earthquakes — Wavelike  motion — Expansive 
power  of  liquid  gases — Connection  between  the  state  of  the  atmosphere  and 
earthquakes — Permanent  upheaval  and  subsidence  of  land — Expansion  of  rocks 
by  heat — The  balance  of  dry  land  how  preserved — Subsidence  in  excess — 
Conclusion. 

WHEN  we  reflect  that  the  largest  mountains  are  but  insignificant  pro- 
tuberances upon  the  surface  of  the  earth,  and  that  these  mountains  are 
nevertheless  composed  of  different  parts  which  have  been  formed  in  suc- 
cession, we  may  well  feel  surprise  that  the  central  fluidity  of  the  planet 
should  have  been  called  in  to  account  for  volcanic  phenomena.  To  sup- 
pose the  entire  globe  to  be  in  a  state  of  igneous  fusion,  with  the  excep- 
tion of  a  solid  shell,  not  more  than  from  thirty  to  one  hundred  miles 
thick,  and  to  imagine  that  the  central  heat  of  this  fluid  spheroid  exceeds 
by  more  than  two  hundred  times  that  of  liquid  lava,  is  to  introduce  a 
force  altogether  disproportionate  to  the  effects  which  it  is  required  to 
explain. 

The  ordinary  repose  of  the  surface  implies,  on  the  contrary,  an  inert- 
ness in  the  internal  mass  which  is  truly  wonderful.  When  we  consider 
the  combustible  nature  of  the  elements  of  the  earth,  so  far  as  they  are 
known  to  us, — the  facility  with  which  their  compounds  may  be  decom- 
posed and  made  to  enter  into  new  combinations, — the  quantity  of  heat 
which  they  evolve  during  these  processes  ;  when  we  recollect  the  expan- 
sive power  of  steam,  and  that  water  itself  is  composed  of  two  gases  which, 
by  their  union,  produce  intense  heat ;  when  we  call  to  mind  the  number 
of  explosive  and  detonating  compounds  which  have  been  already  discov- 
ered, we  may  be  allowed  to  share  the  astonishment  of  Pliny,  that  a  single 

35 


54:6  UNOXIDATED   METALLIC   NUCLEUS.  [Cn.  XXXII. 

day  should  pass  without  a  general  conflagration  : — "  Excedit  profecto 
omnia  miracula,  ullum  diem  fuisse  quo  non  cuncta  conflagrarent."* 

The  signs  of  internal  heat  observable  on  the  surface  of  the  earth  do 
not  necessarily  indicate  the  permanent  existence  of  subterranean  heated 
masses,  whether  fluid  or  solid,  by  any  means  so  vast  as  our  continents 
and  seas ;  yet  how  insignificant  would  these  appear  if  distributed  through 
an  external  shell  of  the  globe  one  or  two  hundred  miles  in  depth  !  The 
principal  facts  in  proof  of  the  accumulation  of  heat  below  the  surface 
may  be  summed  up  in  a  few  words.  Several  volcanoes  are  constantly 
in  eruption,  as  Stromboli  and  Nicaragua ;  others  are  known  to  have  been 
active  for  periods  of  60,  or  even  150  years,  as  those  of  Sangay  in  Quito, 
Popocatepetl  in  Mexico,  and  the  volcano  of  the  Isle  of  Bourbon.  Many 
craters  emit  hot  vapors  in  the  intervals  between  eruptions,  and  solfataras 
evolve  incessantly  the  same  gases  as  volcanoes.  Steam  of  high  temper- 
ature has  continued  for  more  than  twenty  centuries  to  issue  from  the 
"  stufas,"  as  the  Italians  call  them  ;  thermal  springs  abound  not  only 
in  regions  of  earthquakes,  but  are  found  in  almost  all  countries,  however 
distant  from  active  vents ;  and,  lastly,  the  temperature  in  the  mines  of 
various  parts  of  the  world  is  found  to  increase  in  proportion  as  we  de- 
scend. 

The  diagram  (fig.  93)  in  the  next  page,  may  convey  some  idea  of  the 
proportion  which  our  continents  and  the  ocean  bear  to  the  radius  of  the 
earth. f  If  all  the  land  were  about  as  high  as  the  Himalaya  mountains, 
and  the  ocean  everywhere  as  deep  as  the  Pacific,  the  whole  of  both 
might  be  contained  within  a  space  expressed  by  the  thickness  of  the  line 
a  b ;  and  masses  of  nearly  equal  volume  might  be  placed  in  the  space 
marked  by  the  line  c  d,  in  the  interior.  Seas  of  lava,  therefore,  of  the 
size  of  the  Mediterranean,  or  even  of  the  Atlantic,  would  be  as  nothing 
if  distributed  through  such  an  outer  shell  of  the  globe  as  is  represented 
by  the  shaded  portion  of  the  figure  abed.  If  throughout  that  space 
we  imagine  electro-chemical  causes  to  be  continually  in  operation,  even 
of  very  feeble  power,  they  might  give  rise  to  heat  which,  if  accumulated 
at  certain  points,  might  melt  or  render  red-hot  entire  mountains,  or  sus- 
tain the  temperature  of  stufas  and  hot  springs  for  ages. 

Theory  of  an  unoxidated  metallic  nucleus. — When  Sir  H.  Davy  first 
discovered  the  metallic  basis  of  the  earths  and  alkalies,  he  threw  out  the 
idea  that  those  metals  might  abound  in  an  unoxidized  state  in  the  sub- 
terranean regions  to  which  water  must  occasionally  penetrate.  When- 
ever this  happened,  gaseous  matter  would  be  set  free,  the  metals  would 
combine  with  the  oxygen  of  the  water,  and  sufficient  heat  might  be 
evolve/i  to  melt  the  surrounding  rocks.  This  hypothesis,  although  after- 
wards abandoned  by  its  author,  was  at  first  very  favorably  received 
both  by  the  chemist  and  the  geologist :  for  silica,  alumina,  lime,  soda,  and 
oxide  of  iron, — substances  of  which  lavas  are  principally  composed, — 

*  Hist.  Mundi,  lib.  ii.  c.  107. 

f  Reduced,  by  permission,  from  a  figure  in  plate  40  of  Sir  H.  De  la  Beche's 
Geological  Sections  and  Views. 


CH.  XXXIL] 


UNOXIDATED   METALLIC   NUCLEUS. 


547 


would  all  result  from  the  contact  of  the  inflammable  metals  alluded  to 
with  water.  But  whence  this  abundant  store  of  unsaturated  metals  in 
the  interior  ?  It  was  assumed  that,  in  the  beginning  of  things,  the 


Centre  of  the  earth. 

nucleus  of  the  earth  was  mainly  composed  of  inflammable  metals,  and 
that  oxidation  went  on  with  intense  energy  at  first ;  till  at  length,  when 
a  superficial  crust  of  oxides  had  been  formed,  the  chemical  action  be- 
came more  and  more  languid. 

This  speculation,  like  all  others  respecting  the  primitive  state  of  the 
earth's  nucleus,  rests  unavoidably  on  arbitrary  assumptions.     But  we 


548  SOURCES   OF  VOLCANIC   HEAT.  [On.  XXXII. 

may  fairly  inquire  whether  any  existing  causes  may  have  the  power  of 
deoxidating  the  earthy  and  alkaline  compounds  formed  from  time  to 
time  by  the  action  of  water  upon  the  metallic  bases.  If  so,  and  if  the 
original  crust  or  nucleus  of  the  planet  contained  distributed  through  it 
here  and  there  some  partial  stores  of  potassium,  sodium,  and  other  me- 
tallic bases,  these  might  be  oxidated  and  again  deoxidated,  so  as  to  sus- 
tain for  ages  a  permanent  chemical  action.  Yet  even  then  we  should 
be  unable  to  explain  why  such  a  continuous  circle  of  operations,  after 
having  been  kept  up  for  thousands  of  years  in  one  district,  should  en- 
tirely cease,  and  why  another  region,  which  had  enjoyed  a  respite  from 
volcanic  action  for  one  or  many  geological  periods,  should  become  a  the- 
atre for  the  development  of  subterranean  heat. 

It  is  well  known  to  chemists,  that  the  metallization  of  oxides,  the 
most  difficult  to  reduce,  may  be  effected  by  hydrogen  brought  into  con- 
tact with  them  at  a  red  heat ;  and  it  is  more  than  probable  that  the 
production  of  potassium  itself,  in  the  common  gun-barrel  process,  is  due 
to  the  power  of  nascent  hydrogen  derived  from  the  water  which  the 
hydrated  oxide  contains.  According  to  the  recent  experiments,  also,  of 
Faraday,  it  would  appear  that  every  case  of  metallic  reduction  by  vol- 
taic agency,  from  saline  solutions,  in  which  water  is  present,  is  due  to 
the  secondary  action  of  hydrogen  upon  the  oxide  ;  both  of  these  being 
determined  to  the  negative  pole  and  then  reacting  upon  one  another. 

It  is  admitted  that  intense  heat  would  be  produced  by  the  occasional 
contact  of  water  with  the  metallic  bases  ;  and  it  is  certain  that,  during 
the  process  of  saturation,  vast  volumes  of  hydrogen  must  be  evolved. 
The  hydrogen,  thus  generated,  might  permeate  the  crust  of  the  earth 
in  different  directions,  and  become  stored  up  for  ages  in  fissures  and 
caverns,  sometimes  in  a  liquid  form,  under  the  necessary  pressure. 
Whenever,  at  any  subsequent  period,  in  consequence  of  the  changes 
effected  by  earthquakes  in  the  shell  of  the  earth,  this  gas  happened  to 
come  in  contact  with  metallic  oxides  at  a  high  temperature,  the  reduc- 
tion of  these  oxides  might  be  the  result. 

No  theory  seems  at  first  more  startling  than  that  which  represents 
water  as  affording  an  inexhaustible  supply  of  fuel  to  the  volcanic  fires  ; 
yet  is  it  by  no  means  visionary.  It  is  a  fact  that  must  not  be  overlooked, 
that  while  a  great  number  of  volcanoes  are  entirely  submarine,  the  re- 
mainder occur  for  the  most  part  in  islands  or  maritime  tracts.  There 
are  a  few  exceptions ;  but  some  of  these,  observes  Dr.  Daubeny,  are  near 
inland  salt  lakes,  as  in  Central  Tartary  ;  while  others  form  part  of  a 
train  of  volcanoes,  the  extremities  of  which  are  near  the  sea. 

Sir  H.  Davy  suggested  that,  when  the  sea  is  distant,  as  in  the  case  of 
some  of  the  South  American  volcanoes,  they  may  still  be  supplied  with 
water  from  subterranean  lakes  ;  since,  according  to  Humboldt,  large 
quantities  of  fish  are  often  thrown  out  during  eruptions.*  Mr.  Dana 
also,  in  his  valuable  and  original  observations  on  the  volcanoes  of  the 

*  PhiL  Trans.  1828,  p.  250. 


CH.  XXXII.]  SOURCES   OF   VOLCANIC   HEAT.  54:9 

Sandwich  Islands,  reminds  us  of  the  prodigious  volume  of  atmospheric 
water  which  must  be  absorbed  into  the  interior  of  such  large  and  lofty 
domes,  composed  as  they  are  entirely  of  porous  lava.  To  this  source 
alone  he  refers  the  production  of  the  steam  by  which  the  melted  matter 
is  propelled  upwards,  even  to  the  summit  of  cones  three  miles  in  height.* 

When  treating  of  springs  and  overflowing  wells,  I  have  stated  that 
porous  rocks  are  percolated  by  fresh  water  to  great  depths,  and  that 
sea-water  probably  penetrates  in  the  same  manner  through  the  rocks 
which  form  the  bed  of  the  ocean.  But,  besides  this  universal  circu- 
lation in  regions  not  far  from  the  surface,  it  must  be  supposed  that, 
wherever  earthquakes  prevail,  much  larger  bodies  of  water  will  be 
forced  by  the  pressure  of  the  ocean  into  fissures  at  great  depths,  or 
swallowed  up  in  chasms ;  in  the  same  manner  as  on  the  land,  towns, 
houses,  cattle,  and  trees  are  sometimes  engulfed.  It  will  be  remem- 
bered, that  these  chasms  often  close  again  after  houses  have  fallen  into 
them ;  and  for  the  same  reason,  when  water  has  penetrated  to  a  mass 
of  melted  lava,  the  steam  into  which  it  is  converted  may  often  rush  out 
at  a  different  aperture  from  that  by  which  the  water  entered. 

The  gases,  it  is  said,  exhaled  from  volcanoes,  together  with  steam,  are 
such  as  would  result  from  the  decomposition  of  salt  water,  and  the 
fumes  which  escape  from  the  Vesuvian  lava  have  been  observed  to  de- 
posit common  salt.f  The  emission  of  free  muriatic  acid  gas  in  great 
quantities  is  also  thought  by  many  to  favor  the  theory  of  the  decompo- 
sition of  the  salt  contained  in  sea- water.  It  has  been  objected,  however, 
that  M.  Boussingault  did  not  meet  with  this  gas  in  his  examination  of  the 
elastic  fluids  evolved  from  the  volcanoes  of  equatorial  America ;  which 
only  give  out  aqueous  vapor  (in  very  large  quantity),  carbonic  acid  gas, 
sulphurous  acid  gas,  and  sometimes  fumes  of  sulphur.  J  In  reply,  Dr. 
Daubeny  has  remarked,  that  muriatic  acid  may  have  ceased  to  be  dis- 
engaged, because  the  volcanic  action  has  become  languid  in  equatorial 
America,  and  sea-water  may  no  longer  obtain  admission. 

M.  Gay  Lussac,  while  he  avows  his  opinion  that  the  decomposition 
of  water  contributes  largely  to  volcanic  action,  called  attention,  never- 
theless, to  the  supposed  fact,  that  hydrogen  had  not  been  detected  in 
a  separate  form  among  the  gaseous  products  of  volcanoes ;  nor  can  it, 
he  says,  be  present ;  for,  in  that  case,  it  would  be  inflamed  in  the  air 
by  the  red-hot  stones  thrown  out  during  an  eruption.  Dr.  Davy,  in 
his  account  of  Graham  Island,  says,  "  I  watched  when  the  lightning  was 
most  vivid,  and  the  eruption  of  the  greatest  degree  of  violence,  to  see  if 
there  was  any  inflammation  occasioned  by  this  natural  electric  spark — 
any  indication  of  the  presence  of  inflammable  gas ;  but  in  vain."§ 

May  not  the  hydrogen,  Gay  Lussac  inquires,  be  combined  with  chlo- 
rine, and  produce  muriatic  acid  ?  for  this  gas  has  been  observed  to  be 
evolved  from  Vesuvius — and  the  chlorine  may  have  been  derived  from 

*  Geology  of  American  Exploring  Expedition,  p.  369. 

f  Davy,  Phil.  Trans.  1828,  p.  244. 

%  Ann.  de  Chim.  et  de  Phys.  torn.  iii.  p.  181.  §  Phil.  Trans.  1832,  p.  240. 


550  SOURCES   OF   VOLCANIC   HEAT.  [On.  XXXII. 

sea  salt ;  which  was,  in  fact,  extracted  by  simple  washing  from  the 
Vesuvian  lava  of  1822,  in  the  proportion  of  nine  per  cent.*  But  it 
was  answered,  that  Sir  H.  Davy's  experiments  had  shown,  that  hydro- 
gen is  not  combustible  when  mixed  with  muriatic  acid  gas ;  so  that  if 
muriatic  gas  was  evolved  in  large  quantities,  the  hydrogen  might  be 
present  without  inflammation.!  M.  Abich,  on  the  other  hand,  assures 
us,  "  that  although  it  be  true  that  vapor  illuminated  by  incandescent 
lava  has  often  been  mistaken  for  flame,"  yet  he  clearly  detected  in  the 
eruption  of  Vesuvius  in  1834  the  flame  of  hydrogen.}; 

M.  Gay  Lussac,  in  the  memoir  just  alluded  to,  expressed  doubt  as  to 
the  presence  of  sulphurous  acid ;  but  the  abundant  disengagement  of 
this  gas  during  eruptions  has  been  since  ascertained :  and  thus  all  diffi- 
culty in  regard  to  the  general  absence  of  hydrogen  in  an  inflammable 
state  is  removed  ;  for,  as  Dr.  Daubeny  suggests,  the  hydrogen  of  de- 
composed water  may  unite  with  sulphur  to  form  sulphuretted  hydrogen 
gas,  and  this  gas  will  then  be  mingled  with  the  sulphurous  acid  as  it 
rises  to  the  crater.  It  is  shown  by  experiment,  that  these  gases  mutu- 
ally decompose  each  other  when  mixed  where  steam  is  present ;  the 
hydrogen  of  the  one  immediately  uniting  with  the  oxygen  of  the  other 
to  form  water,  while  the  excess  of  sulphurous  acid  alone  escapes  into 
the  atmosphere.  Sulphur  is  at  the  same  time  precipitated. 

This  explanation  is  sufficient ;  but  it  may  also  be  observed  that  the 
flame  of  hydrogen  would  rarely  be  visible  during  an  eruption ;  as  that 
gas,  when  inflamed  in  a  pure  state,  burns  with  a  very  faint  blue  flame, 
which  even  in  the  night  could  hardly  be  perceptible  by  the  side  of  red- 
hot  and  incandescent  cinders.  Its  immediate,  conversion  into  water 
when  inflamed  in  the  atmosphere,  might  also  account  for  its  not  appear- 
ing in  a  separate  form. 

Dr.  Daubeny  is  of  opinion  that  water  containing  atmospheric  air  may 
descend  from  the  surface  of  the  earth  to  the  volcanic  foci,  and  that  the 
same  process  of  combustion  by  which  water  is  decomposed  may  deprive 
such  subterranean  air  of  its  oxygen.  In  this  manner  he  explains  the 
great  quantities  of  nitrogen  evolved  from  volcanic  vents  and  thermal 
waters,  and  the  fact  that  air  disengaged  from  the  earth  in  volcanic  re- 
gions is  either  wholly  or  in  part  deprived  of  its  oxygen. 

Sir  H.  Davy,  in  his  memoir  on  the  "  Phenomena  of  Volcanoes,"  re- 
marks, that  there  was  every  reason  to  suppose  in  Vesuvius  the  exist- 
ence of  a  descending  current  of  air  ;  and  he  imagined  that  subterranean 
cavities  which  threw  out  large  volumes  of  steam  during  the  eruption, 
might  afterwards,  in  the  quie.t  state  of  the  volcano,  become  filled  with 
atmospheric  air.§  The  presence  of  ammoniacal  salts  in  volcanic  emana- 
tions, and  of  ammonia  (which  is  in  part  composed  of  nitrogen)  in  lava, 
favors  greatly  the  notion  of  air  as  well  as  water  being  deoxidated  in  the 
interior  of  the  earth.  | 

*  Ann.  de  Chim.  et  de  Phys.  torn.  xxii. 

f  Quart.  Journ.  of  Sci.  1823,  p.  132,  note  by  editor.        \  Phenom.  Geol.  &c.  p.  3. 

§  Phil.  Trans.  1828.  ||  See  Daubeny,  Encyc.  Metrop.  part  40. 


CH.  XXXIL]  CAUSES    OF   VOLCANIC   ERUPTIONS.  551 

It  has  been  alleged  by  Professor  Bischoff  that  the  slight  specific  grav- 
ity of  the  metals  of  the  alkalies  is  fatal  to  Davy's  hypothesis,  for  if  the 
mean  density  of  the  earth,  as  determined  by  astronomers,  surpass  that 
of  all  kinds  of  rocks,  these  metals  cannot  exist,  at  least  not  in  great 
quantities  in  the  interior  of  the  earth.*  But  Dr.  Daubeny  has  shown, 
that  if  we  take  the  united  specific  gravity  of  potassium,  sodium,  silicon, 
iron,  and  all  the  materials  which,  when  united  with  oxygen,  constitute 
ordinary  lava,  and  then  compare  their  weight  with  lava  of  equal  bulk, 
the  difference  is  not  very  material,  the  specific  gravity  of  the  lava  only 
exceeding  by  about  one-fourth  that  of  the  unoxidized  metals.  Besides, 
at  great  depths,  the  metallic  bases  of  the  earths  and  alkalies  may  very 
probably  be  rendered  heavier  by  pressure. f  Nor  is  it  fair  to  embarrass 
the  chemical  theory  of  volcanoes  with  a  doctrine  so  purely  gratuitous, 
as  that  which  supposes  the  entire  nucleus  of  the  planet  to  have  been  at 
first  composed  of  unoxidated  metals. 

Professor  Bunsen  of  Marburg,  after  analyzing  the  gases  which  escape 
from  the  volcanic  fumeroles  and  solfataras  of  Iceland,  and  after  calcu- 
lating the  quantity  of  hydrogen  evolved  between  two  eruptions,  affirms, 
in  contradiction  of  opinions  previously  entertained,  that  the  hydrogen 
bears  a  perfect  relation  in  quantity  to  the  magnitude  of  the  streams  of 
lava,  assuming  the  fusion  of  these  last  to  have  been  the  result  of  the 
heat  evolved  during  the  oxidation  of  alkaline  and  earthy  metals,  and  this 
to  have  been  brought  about  by  the  decomposition  of  water.  Yet  after 
having  thus  succeeded  in  removing  the  principal  objection  once  so 
triumphantly  urged  against  Davy's  hypothesis,  Bunsen  concludes  by 
declaring  that  the  hydrogen  evolved  in  volcanic  regions  cannot  have 
been  generated  by  the  decomposition  of  water  coming  in  contact  with 
alkaline  and  earthy  metallic  bases.  For,  says  the  Professor,  this  process 
presupposes  the  prevalence  of  a  temperature  in  which  carbonic  acid  can- 
not exist  in  contact  with  hydrogen  without  suffering  a  partial  reduction 
to  carbonic  oxide  ;  "  and  not  a  trace  of  carbonic  oxide  is  ever  found  in 
volcanic  exhalations. "J  At  the  same  time  it  will  be  seen,  by  consulting 
the  able  memoirs  of  the  Marburg  chemist,  that  he  supposes  many  ener- 
getic kinds  of  chemical  action  to  be  continually  going  on  in  the  interior 
of  the  earth,  capable  of  causing  the  disengagement  of  hydrogen  ;  and 
there  can  be  no  doubt  that  this  gas  may  be  a  source  of  innumerable  new 
changes,  capable  of  producing  the  local  development  of  internal  heat. 

Cause  of  volcanic  eruptions. — The  most  probable  causes  of  a  volcanic 
outburst  at  the  surface  have  been  in  a  great  degree  anticipated  in  the 
preceding  speculations  on  the  liquefaction  of  rocks  and  the  generation  of 
gases.  When  a  minute  hole  is  bored  in  a  tube  filled  with  gas  condensed 
into  a  liquid,  the  whole  becomes  instantly  aeriform,  or,  as  some  writers 
have  expressed  it,  "  flashes  into  vapor,"  and  often  bursts  the  tube.  Such 

*  Jam.  Ed.  New  Phil.  Journ.  No.  li.  p.  31. 

f  See  Daubeny's  Reply  to  Bischoff,  Jam.  Ed.  New  Phil.  Journ.  No.  lii.  p.  291 ; 
and  note  in  No.  liii.  p.  158. 

|   Poggend.  Ann.  1851   translated,  Sci.  Mem.  1852. 


552  CAUSES   OF  VOLCANIC   ERUPTIONS.  [On.  XXXII 

an  experiment  may  represent  the  mode  in  which  gaseous  matter  may 
rush  through  a  rent  in  the  rocks,  and  continue  to  escape  for  days  or 
weeks  through  a  small  orifice,  with  an  explosive  power  sufficient  to  re- 
duce every  substance  which  opposes  its  passage  into  small  fragments  or 
even  dust.  Lava  may  be  propelled  upwards  at  the  same  time,  and  ejected 
in  the  form  of  scoriae.  In  some  places,  where  the  fluid  lava  lies  at  the 
bottom  of  a  deep  fissure,  communicating  on  the  one  hand  with  the  sur- 
face, and  on  the  other  with  a  cavern  in  which  a  considerable  body  of 
vapor  has  been  formed,  there  may  be  an  efflux  of  lava,  followed  by  the 
escape  of  gas.  Eruptions  often  commence  and*  close  with  the  discharge 
of  vapor ;  and,  when  this  is  the  case,  the  next  outburst  may  be  expected 
to  take  place  by  the  same  vent,  for  the  concluding  evolution  of  elastic 
fluids  will  keep  open  the  duct,  and  leave  it  unobstructed. 

The  breaking  out  of  lava  from  the  side  or  base  of  a  lofty  cone,  rather 
than  from  the  summit,  may  be  attributed  to  the  hydrostatic  pressure  to 
which  the  flanks  of  the  mountain  are  exposed,  when  the  column  of  lava 
has  risen  to  a  great  height.  Or  if,  before  it  has  reached  the  top,  there 
should  happen  to  be  any  stoppage  in  the  main  duct,  the  upward  pressure 
of  the  ascending  column  of  gas  and  lava  may  burst  a  lateral  opening. 

In  the  case  however  of  Mount  Loa,  in  the  Sandwich  Islands,  there 
appears  to  be  a  singular  want  of  connection  or  sympathy  between  the 
eruptions  of  the  central  and  the  great  lateral  vent.  The  great  volcanic 
cone  alluded  to  rises  to  the  height  of  13,760  feet  above  the  level  of  the 
sea,  having  a  crater  at  its  summit,  from  which  powerful  streams  of  lava 
have  flowed  in  recent  times,  and  having  another  still  larger  crater,  called 
Kilauea,  on  its  southeastern  slope,  about  4000  feet  above  the  sea.  This 
lateral  cavity  resembles  a  huge  quarry  cut  in  the  mountain's  side,  being 
about  1000  feet  deep  when  in  its  ordinary  state.  It  is  seven  miles  and 
a  half  in  circuit,  and  scattered  over  its  bottom,  at  different  levels,  are 
lakes  and  pools  of  lava,  always  in  a  state  of  ebullition.  The  liquid  in  one 
of  these  will  sometimes  sink  100  or  150  feet,  while  it  is  overflowing  in 
another  at  a  higher  elevation,  there  being,  it  should  seem,  no  communi- 
cation between  them.  In  like  manner,  lava  overflows  in  the  summit 
crater  of  Mount  Loa,  nearly  14,000  feet  high,  while  the  great  lateral 
cauldron  just  alluded  to  (of  Kilauea)  continues  as  tranquil  as  usual,  afford- 
ing no  relief  to  any  part  of  the  gases  or  melted  matter  which  are  forcing 
their  way  upwards  in  the  centre  of  the  mountain.  "  How,"  asks  Mr. 
Dana,  "  if  there  were  any  subterranean  channel  connecting  the  two  great 
vents,  could  this  want  of  sympathy  exist  ?  How,  according  to  the  laws 
of  hydrostatic  pressure,  can  a  column  of  fluid  stand  10,000  feet  higher 
in  one  leg  of  the  siphon  than  in  the  other  ?"  The  eruptions,  he  observes, 
are  not  paroxysmal ;  on  the  contrary,  the  lava  rises  slowly  and  gradually 
to  the  summit  of  the  lofty  cone,  and  then  escapes  there  without  any 
commotion  manifesting  itself  in  Kilauea,  a  gulf  always  open  on  the  flanks 
of  the  same  mountain.  One  conclusion,  he  says,  is  certain,  namely,  that 
volcanoes  are  no  safety  valves  as  they  have  been  called ;  for  here  two 
independent  and  apparently  isolated  centres  of  volcanic  activity,  only 


CH.  XXX1L]  GEYSERS   OF   ICELAND.  553 

sixteen  miles  distant  from  each  other,  are  sustained  in  one  and  the  same 
cone.* 

Without  pretending  to  solve  this  enigma,  I  cannot  refrain  from  re- 
marking, that  the  supposed  independence  of  several  orifices  of  eruption 
in  one  crater  like  Kilauea,  when  adduced  in  confirmation  of  the  doctrine 
of  two  distinct  sources  of  volcanic  action  underneath  one  mountain, 
proves  too  much.  No  one  can  doubt,  that  the  pools  of  lava  in  Kilauea 
have  been  derived  from  some  common  reservoir,  and  have  resulted  from 
a  combination  of  causes  commonly  called  volcanic,  which  are  at  work  in 
the  interior  at  some  unknown  distance  below.  These  causes  have  given 
rise  in  Mount  Loa  to  eruptions  from  many  points,  but  principally  from 
one  centre,  so  that  a  vast  dome  of  ejected  matter  has  been  piled  up. 
The  subsidiary  crater  has  evidently  never  given  much  relief  to  the  im- 
prisoned, heated,  and  liquefied  matter,  for  Kilauea  does  not  form  a  lat- 
eral protuberance  interfering  with  the  general  shape  or  uniform  outline 
of  Mount  Loa. 

Geysers  of  Iceland. — As  aqueous  vapor  constitutes  the  most  abundant 
of  the  aeriform  products  of  volcanoes  in  eruption,  it  may  be  well  to  con- 
sider attentively  a  case  in  which  steam  is  exclusively  the  moving  power 
•• — that  of  the  Geysers  of  Iceland.  These  intermittent  hot  springs  occur 
in  a  district  situated  in  the  southwestern  division  of  Iceland,  where 
nearly  one  hundred  of  them  are  said  to  break  out  within  a  circle  of  two 
miles.  That  the  water  is  of  atmospheric  origin,  derived  from  rain  and 
melted  snow,  is  proved,  says  Professor  Bunsen,  by  the  nitrogen  which 
rises  from  them  either  pure  or  mixed  with  other  gases.  The  springs 
rise  through  a  thick  current  of  lava,  which  may  perhaps  have  flowed 
from  Mount  Hecla,  the  summit  of  that  volcano  being  seen  from  the  spot 
at  the  distance  of  more  than  thirty  miles.  In  this  district  the  rushing 
of  water  is  sometimes  heard  in  chasms  beneath  the  surface ;  for  here, 
as  on  Etna,  rivers  flow  in  subterranean  channels  through  the  porous  and 
cavernous  lavas.  It  has  more  than  once  happened,  after  earthquakes, 
that  some  of  the  boiling  fountains  have  increased  or  diminished  in  vio- 
lence and  volume,  or  entirely  ceased,  or  that  new  ones  have  made  their 
appearance — changes  which  may  be  explained  by  the  opening  of  new 
rents  and  the  closing  of  pre-existing  fissures. 

Few  of  the  Geysers  play  longer  than  five  or  six  minutes  at  a  time, 
although  sometimes  half  an  hour.  The  intervals  between  their  eruptions 
are  for  the  most  part  very  irregular.  The  Great  Geyser  rises  out 
of  a  spacious  basin  at  the  summit  of  a  circular  mound  composed  of  sili- 
ceous incrustations  deposited  from  the  spray  of  its  waters.  The  diame- 
ter of  this  basin,  in  one  direction,  is  fifty-six  feet,  and  forty-six  in  another. 
(See  fig.  94.)  In  the  centre  is  a  pipe  seventy-eight  feet  in  perpendicu-' 
lar  depth,  and  from  eight  to  ten  feet  in  diameter,  but  gradually  widening, 
as  it  rises  into  the  basin.  The  inside  of  the  basin  is  whitish,  consisting 
of  a  siliceous  crust,  and  perfectly  smooth,  as  are  likewise  two  small 

*  Proceed.  Americ.  Assoc.  1849. 


554 


GEYSERS   OF   ICELAND. 


[Cn.  XXXH 


channels  on  the  sides  of  the  mound,  down  which  the  water  escapes 
when  the  bowl  is  filled  to  the  margin.  The  circular  basin  is  sometimes 
empty,  as  represented  in  the  following  sketch  ;  but  is  usually  filled  with 
beautifully  transparent  water  in  a  state  of  ebullition.  During  the  rise 
of  the  boiling  water  in  the  pipe,  especially  when  the  ebullition  is  most 
violent,  and  when  the  water  is  thrown  up  in  jets,  subterranean  noises 
are  heard,  like  the  distant  firing  of  cannon,  and  the  earth  is  slightly 
shaken.  The  sound  then  increases  and  the  motion  becomes  more  violent, 

Fig.  94. 


View  of  the  Crater  of  the  Great  Geyser  in  Iceland.* 

till  at  length  a  column  of  water  is  thrown  up,  with  loud  explosions,  to 
the  height  of  one  or  two  hundred  feet.  After  playing  for  a  time  like 
an  artificial  fountain,  and  giving  off  great  clouds  of  vapor,  the  pipe  or 
tube  is  emptied  ;  and  a  column  of  steam,  rushing  up  with  amazing  force 
and  a  thundering  noise,  terminates  the  eruption. 

If  stones  are  thrown  into  the  crater,  they  are  instantly  ejected ;  and 
such  is  the  explosive  force,  that  very  hard  rocks  are  sometimes  shivered 
by  it  into  small  pieces.  Henderson  found  that  by  throwing  a  great 
quantity  of  large  stones  into  the  pipe  of  Strockr,  one  of  the  Geysers,  he 
could  bring  on  an  eruption  in  a  few  minutes. f  The  fragments  of  stone, 
as  well  as  the  boiling  water,  were  thrown  in  that  case  to  a  much  greater 
height  than  usual.  After  the  water  had  been  ejected,  a  column  of  steam 
continued  to  rush  up  with  a  deafening  roar  for  nearly  an  hour ;  but  the 
Geyser,  as  if  exhausted  by  this  effort,  did  not  send  out  a  fresh  eruption 
when  its  usual  interval  of  rest  had  elapsed.  The  account  given  by  Sir 
George  Mackenzie  of  a  Geyser  which  he  saw  in  eruption  in  1810  (see 
fig.  95),  agrees  perfectly  with  the  above  description  by  Henderson.  The 

*  Reduced  from  a  sketch  given  by  Sir  W.  J.  Hooker,  in  his  Tour  in  Iceland, 
vol.  i.  p.  149. 

f  Journal  of  a  Residence  in  Iceland,  p.  74. 


CH.  XXXIL] 


GEYSERS   OF   ICELAND. 


555 


steam  and  water  rose  for  half  an  hour  to  the  height  of  70  feet,  and  the 
white  column  remained  perpendicular  notwithstanding  a  brisk  gale  of 
wind  which  was  blowing  against  it.  Stones  thrown  into  the  pipe  were 
projected  to  a  greater  height  than  the  water.  To  leeward  of  the  vapor 
a  heavy  shower  of  rain  was  seen  to  fall.* 


Fig.  95. 


Eruption  of  the  Ne\v  Geyser  in  1S10.    (Mackenzie.) 

Among  the  different  theories  proposed  to  account  for  these  phenom- 
ena, I  shall  first  mention  one  suggested  by  Sir.  J.  Herschel.  An  imi- 
tation of  these  jets,  he  says,  may  be  produced  on  a  small  scale,  by  heat- 
ing red  hot  the  stem  of  a  tobacco  pipe,  filling  the  bowl  with  water,  and 
so  inclining  the  pipe  as  to  let  the  water  run  through  the  stem.  Its  es- 
cape, instead  of  taking  place  in  a  continued  stream,  is  then  performed  by 
a  succession  of  violent  explosions,  at  first  of  steam  alone,  then  of  water 
mixed  with  steam  ;  and,  as  the  pipe  cools,  almost  wholly  of  water.  At 
every  such  paroxysmal  escape  of  the  water,  a  portion  is  driven  back,  ac- 
companied with  steam,  into  the  bowl.  The  intervals  between  the  explo- 
sions depend  on  the  heat,  length,  and  inclination  of  the  pipe  ;  their  con- 
tinuance, on  its  thickness  and  conducting  power.f  The  application  of 

*  Mackenzie's  Iceland. 

f  MS.  read  to  Geol.  Soc,  of  London,  Feb.  29, 1832. 


556 


GEYSERS    OF   ICELAND. 


[On.  XXXII. 


this  experiment  to  the  Geysers  merely  requires  that  a  subterranean 
stream,  flowing  through  the  pores  and  crevices  of  lava,  should  suddenly 
reach  a  fissure  in  which  the  rock  is  red  hot  or  nearly  so.  Steam  would 
immediately  be  formed,  which,  rushing  up  the  fissure,  might  force  up 
water  along  with  it  to  the  surface,  while,  at  the  same  time,  part  of  the 
steam  might  drive  back  the  water  of  the  supply  for  a  certain  distance 
towards  its  source.  And  when,  after  the  space  of  some  minutes,  the 
steam  was  all  condensed,  the  water  would  return,  and  a  repetition  of  the 
phenomena  take  place. 

There  is,  however,  another  mode  of  explaining  the  action  of  the  Gey- 
ser, perhaps  more  probable  than  that  above  described.  Suppose  water 
percolating  from  the  surface  of  the  earth  to  penetrate  into  the  subterra- 
nean cavity  A  D  (fig.  96)  by  the  fissures  F  F,  while,  at  the  same  time, 


Fig.  96. 


Supposed  reservoir  and  pipe  of  a  Geyser  in  Iceland.* 

steam  at  an  extremely  high  temperature,  such  as  is  commonly  given  out 
from  the  rents  of  lava  currents  during  congelation,  emanates  from  the 
fissures  C.  A  portion  of  the  steam  is  at  first  condensed  into  water, 
while  the  temperature  of  the  water  is  raised  by  the  latent  heat  thus 
evolved,  till,  at  last,  the  lower  part  of  the  cavity  is  filled  with  boiling 
water  and  the  upper  with  steam  under  high  pressure.  The  expansive 
force  of  the  steam  becomes,  at  length,  so  great,  that  the  water  is  forced 
up  the  fissure  or  pipe  E  B,  and  runs  over  the  rim  of  the  basin.  When 
the  pressure  is  thus  diminished,  the  steam  in  the  upper  part  of  the  cavity 
A  expands,  until  all  the  water  D  is  driven  into  the  pipe ;  and  when  this 

*  From  Sir  George  Mackenzie's  Iceland. 


CH.  XXXIL]  GEYSERS   OF  ICELAND.  .  557 

happens,  the  steam,  being  the  lighter  of  the  two  fluids,  rushes  up 
through  the  water  with  great  velocity.  If  the  pipe  be  choked  up  arti- 
ficially, even  for  a  few  minutes,  a  great  increase  of  heat  must  take  place ; 
for  it  is  prevented  from  escaping  in  a  latent  form  in  steam  ;  so  that  the 
water  is  made  to  boil  more  violently,  and  this  brings  on  an  eruption. 

Professor  Bunsen,  before  cited,  adopts  this  theory  to  account  for  the 
play  of  the  "  Little  Geyser,"  but  says  it  will  not  explain  the  phenomena 
of  the  Great  one.  He  considers  this,  like  the  others,  to  be  a  thermal 
spring,  having  a  narrow  funnel-shaped  tube  in  the  upper  part  of  its 
course,  where  the  walls  of  the  channel  have  become  coated  over  with 
siliceous  incrustations.  At  the  mouth  of  this  tube  the  water  has  a 
temperature,  corresponding  to  the  pressure  of  the  atmosphere,  of  about 
212°  Fahr.,  but  at  a  certain  depth  below  it  is  much  hotter.  This  the 
professor  succeeded  in  proving  by  experiment ;  a  thermometer  sus- 
pended by  a  string  in  the  pipe  rising  to  266°  Fahr.,  or  no  less  than  48 
degrees  above  the  boiling  point.  After  the  column  of  water  has  been 
expelled,  what  remains  in  the  basin  and  pipe  is  found  to  be  much  cooled. 

Previously  to  these  experiments  of  Bunsen  and  Descloizeaux,  made  in 
Iceland  in  1846,  it  would  scarcely  have  been  supposed  possible  that  the 
lower  part  of  a  free  and  open  column  of  water  could  be  raised  so  much 
in  temperature  without  causing  a  circulation  of  ascending  and  descend- 
ing currents,  followed  by  an  almost  immediate  equalization  of  heat. 
Such  circulation  is  no  doubt  impeded  greatly  by  the  sides  of  the  well 
not  being  vertical,  and  by  numerous  contractions  of  its  diameter,  but 
the  phenomenon  may  be  chiefly  due  to  another  cause.  According  to 
recent  experiments  on  the  cohesion  of  liquids  by  Mr.  Donny  of  Ghent, 
it  appears  that  when  water  is  freed  from  all  admixture  of  air,  its  tem- 
perature can  be  raised,  even  under  ordinary  atmospheric  pressure,  to 
275°  Fahr.,  so  much  does  the  cohesion  of  its  molecules  increase*  when 
they  are  not  separated  by  particles  of  air.  As  water  long  boiled  be- 
comes more  and  more  deprived  of  air,  it  is  probably  very  free  from  such 
intermixture  at  the  bottom  of  the  Geysers. 

Among  other  results  of  the  experiments  of  Bunsen  and  his  com- 
panion, they  convinced  themselves  that  the  column  of  fluid  filling  the 
tube  is  constantly  receiving  accessions  of  hot  water  from  below,  while  it 
becomes  cooler  above  by  evaporation  on  the  broad  surface  of  the  basin. 
.They  also  came  to  a  conclusion  of  no  small  interest,  as  bearing  on  the 
probable  mechanism  of  ordinary  volcanic  eruptions,  namely  that  the 
tube  itself  is  the  main  seat  or  focus  of  mechanical  force.  This  was 
proved  by  letting  down  stones  suspended  by  strings  to  various  depths. 
Those  which  were  sunk  to  considerable  distances  from  the  surface  were 
not  cast  up  again,  whereas  those  nearer  the  mouth  of  the  tube  were  ejected 
to  great  heights.  Other  experiments  also  were  made  tending  to  de- 
monstrate the  singular  fact,  that  there  is  often  scarce  any  motion  below, 
when  a  violent  rush  of  steam  and  water  is  taking  place  above.  It  seems 

*  See  Mr.  Horner's  Anniversary  Address,  Quart.  Journ.  GeoL  Soc.  1847,  liii 


558  CAUSES   OF  EARTHQUAKES.  [Cn.  XXXII. 

that  when  a  lofty  column  of  water  possesses  a  temperature  increasing 
with  the  depth,  any  slight  ebullition  or  disturbance  of  equilibrium  in  the 
upper  portion  may  first  force  up  water  into  the  basin,  and  then  cause  it 
to  flow  over  the  edge.  A  lower  portion,  thus  suddenly  relieved  of  part 
of  its  pressure,  expands  and  is  converted  into  vapor  more  rapidly  than 
the  first,  owing  to  its  greater  heat.  This  allows  the  next  subjacent 
stratum,  which  is  much  hotter,  to  rise  and  flash  into  a  gaseous  form  ; 
and  this  process  goes  on  till  the  ebullition  has  descended  from  the 
middle  to  near  the  bottom  of  the  funnel.* 

In  speculating,  therefore,  on  the  mechanism  of  an  ordinary  volcanic 
eruption,  we  may  suppose  that  large  subterranean  cavities  exist  at  the 
depth  of  some  miles  below  the  surface  of  the  earth,  in  which  melted 
lava  accumulates ;  and  when  water  containing  the  usual  mixture  of  air 
penetrates  into  these,  the  steam  thus  generated  may  press  upon  the 
lava  and  force  it  up  the  duct  of  a  volcano,  in  the  same  manner  as  a 
column  of  water  is  driven  up  the  pipe  of  a  Geyser.  In  other  cases  we 
may  suppose  a  continuous  column  of  liquid  lava  mixed  with  red-hot 
water  (for  water  may  exist  in  that  state,  as  Professor  Bunsen  reminds 
us,  under  pressure),  and  this  column  may  have  a  temperature  regularly 
increasing  downwards.  A  disturbance  of  equilibrium  may  first  bring  on 
an  eruption  near  the  surface,  by  the  expansion  and  conversion  into  gas 
of  entangled  water  and  other  constituents  of  what  we  call  lava,  so  as  to 
occasion  a  diminution  of  pressure.  More  steam  would  then  be  liberated, 
carrying  up  with  it  jets  of  melted  rock,  which  being  hurled  up  into  the 
air  may  fall  in  showers  of  ashes  on  the  surrounding  country,  and  at 
length,  by  the  arrival  of  lava  and  water  more  and  more  heated  at  the 
orifice  of  the  duct  or  the  crater  of  the  volcano,  expansive  power  may  be 
acquired  sufficient  to  expel  a  massive  current  of  lava.  After  the  erup- 
tion has  ceased,  a  period  of  tranquillity  succeeds,  during  which  fresh 
accessions  of  heat  are  communicated  from  below,  and  additional  masses 
of  rock  fused  by  degrees,  while  at  the  same  time  atmospheric  or  sea 
water  is  descending  from  the  surface.  At  length  the  conditions  re- 
quired for  a  new  outburst  are  obtained,  and  another  cycle  of  similar 
changes  is  renewed. 

Causes  of  earthquakes — wave-like  motion. — I  shall  now  proceed  to 
examine  the  manner  in  which  the  heat  of  the  interior  may  give  rise  to 
earthquakes.  One  of  the  most  common  phenomena  attending  subter- 
ranean movements,  is  the  undulatory  motion  of  the  ground.  And  this, 
says  Michell,  will  seem  less  extraordinary,  if  we  call  to  mind  the  extreme 
elasticity  of  the  earth  and  the  compressibility  of  even  the  most  solid 
materials.  Large  districts,  he  suggests,  may  rest  on  fluid  lava ;  and, 
when  this  is  disturbed,  its  motions  may  be  propagated  through  the  in- 
cumbent rocks.  He  also  adds  the  following  ingenious  speculation  : — 
"  As  a  small  quantity  of  vapor  almost  instantly  generated  at  some  con- 

*  Liebig's  Annalen  der  Chimie  und  Pharmacie,  translated  in  "  Reports  and 
Memoirs"  of  Cavendish  Soc.  London,  1848. 


CH.  XXXIL]  WAVE-LIKE   MOTION.  559 

siderable  depth  below  the  surface  of  the  earth  will  produce  a  vibratory 
motion,  so  a  very  large  quantity  (whether  it  be  generated  almost  in- 
stantly, or  in  any  small  portion  of  time)  will  produce  a  wave-like  mo- 
tion. The  manner  in  which  this  wave-like  motion  will  be  propagated 
may,  in  some  measure,  be  represented  by  the  following  experiment : — 
Suppose  a  large  cloth,  or  carpet  (spread  upon  a  floor),  to  be  raised  at 
one  edge,  and  then  suddenly  brought  down  again  to  the  floor ;  the  air 
under  it,  being  by  this  means  propelled,  will  pass  along  till  it  escapes 
at  the  opposite  side,  raising  the  cloth  in  a  wave  all  the  way  as  it  goes. 
In  like  manner,  a  large  quantity  of  vapor  may  be  conceived  to  raise  the 
earth  in  a  wave,  as  it  passes  along  between  the  strata,  which  it  may 
easily  separate  in  a  horizontal  direction,  there  being  little  or  no  cohesion 
between  one  stratum  and  another.  The  part  of  the  earth  that  is  first 
raised  being  bent  from  its  natural  form,  will  endeavor  to  restore  itself 
by  its  elasticity ;  and  the  parts  next  to  it  being  to  have  their  weight 
supported  by  the  vapor,  which  will  insinuate  itself  under  them,  will  be 
raised  in  their  turn,  till  it  either  finds  some  vent,  or  is  again  condensed 
by  the  cold  into  water,  and  by  that  means  prevented  from  proceeding 
any  farther."*  In  a  memoir  published  in  1843,  on  the  structure  of  the 
Appalachian  chain,  by  the  Professors  Rogers, f  the  following  hypothesis 
is  proposed  as  "  simpler  and  more  in  accordance  with  dynamical  con- 
siderations, and  the  recorded  observations  on  earthquakes." — "  In 
place,"  say  they,  "of  supposing  it  possible  for  a  body  of  vapor  or  gaseous 
matter  to  pass  horizontally  between  the  strata,  or  even  between  the 
crust  and  the  fluid  lava  upon  which  it  floats,  and  with  which  it  must 
be  closely  entangled,  we  are  inclined  to  attribute  the  movement  to  an 
actual  pulsation,  engendered  in  the  molten  matter  itself,  by  a  linear  dis- 
ruption under  enormous  tension,  giving  vent  explosively  to  elastic  vapors, 
escaping  either  to  the  surface,  or  into  cavernous  spaces  beneath.  Ac- 
cording to  this  supposition,  the  movement  of  the  subterranean  vapors 
would  be  towards,  and  not  from,  the  disrupted  belt,  and  the  oscillation 
of  the  crust  would  originate  in  the  tremendous  and  sudden  disturbance 
of  the  previous  pressure  on  the  surface  of  the  lava  mass  below,  brought 
about  by  the  instantaneous  and  violent  rending  of  the  overlying  strata." 
This  theory  requires  us  to  admit  that  the  crust  of  the  earth  is  so 
flexible,  that  it  can  assume  the  form,  and  follow  the  motion  of  an  undu- 
lation in  the  fluid  below.  Even  if  we  grant  this,  says  Mr.  Mallet,  another 
more  serious  objection  presents  itself,,  viz.  the  great  velocity  attributed 
to  the  transit  of  the  wave  in  the  subterranean  sea  of  lava.  We  are  called 
upon  to  admit  that  the  speed  of  the  wave  below  equals  that  of  the  true 
earthquake  shock  at  the  surface,  which  is  so  immense,  that  it  is  not  in- 
ferior to  the  velocity  of  sound  in  the  same  solids.  But  the  undulation 
in  the  fluid  below  must  follow  the  laws  of  a  tidal  wave,  or  of  the  great 
sea- wave  already  spoken  of.  "  Its  velocity,  like  that  of  the  tidal  wave 

*  On  the  Cause  and  Phenomena  of  Earthquakes,  Phil.  Trans,  vol.  li.  sec.  58, 
1760. 

f  Trans,  of  Assoc.  of  American  Geol.  1840-1842,  p.  520. 


560  LIQUID   GASES.  [On.  XXXII. 

of  our  seas,  will  be  a  function  of  its  length  and  of  the  depth  of  the  fluid, 
diminished  in  this  case  by  certain  considerations  as  to  the  density  and 
degree  of  viscidity  of  the  liquid ;  and  although  it  would  be  at  present 
impossible,  for  want  of  data,  to  calculate  the  exact  velocity  with  which 
this  subterraneous  lava-wave  could  move,  it  may  be  certainly  affirmed 
that  its  velocity  would  be  immeasurably  short  of  the  observed  or  theo- 
retic velocity  of  the  great  earth-wave,  or  true  shock  in  earthquakes."* 

Liquid  gases. — The  rending  and  upheaving  of  continental  masses  are 
operations  which  are  not  difficult  to  explain,  when  we  are  once  convinced 
that  heat,  of  sufficient  power,  not  only  to  melt  but  to  reduce  to  a  gase- 
ous form  a  great  variety  of  substances,  is  accumulated  in  certain  parts 
of  the  interior.  We  see  that  elastic  fluids  are  capable  of  projecting  solid 
masses  to  immense  heights  in  the  air ;  and  the  volcano  of  Cotopaxi  has 
been  known  to  throw  out,  to  the  distance  of  eight  or  nine  miles,  a  mass 
of  rock  about  one  hundred  cubic  yards  in  volume.  When  we  observe 
these  aeriform  fluids  rushing  out  from  particular  vents  for  months,  or 
even  years,  continuously,  what  power  may  we  not  expect  them  to  exert 
in  other  places,  where  they  happen  to  be  confined  under  an  enormous 
weight  of  rock  ? 

The  experiments  of  Faraday  and  others  have  shown,  within  the  last 
twelve  years,  that  many  of  the  gases,  including  all  those  which  are  most 
copiously  disengaged  from  volcanic  vents,  as  the  carbonic,  sulphurous, 
and  muriatic  acids,  may  be  condensed  into  liquids  by  pressure.  At 
temperatures  of  from  30°  to  50°  F.,  the  pressure  required  for  this  pur- 
pose varies  from  fifteen  to  fifty  atmospheres  ;  and  this  amount  of  pres- 
sure we  may  regard  as  very  insignificant  in  the  operations  of  nature.  A 
column  of  Yesuvian  lava  that  would  reach  from  the  lip  of  the  crater  to 
the  level  of  the  sea,  must  be  equal  to  about  three  hundred  atmospheres ; 
so  that,  at  depths  which  may  be  termed  moderate  in  the  interior  of  the 
crust  of  the  earth,  the  gases  may  be  condensed  into  liquids,  even  at  very 
high  temperatures.  The  method  employed  to  reduce  some  of  these 
gases  to  a  liquid  state  is,  to  confine  the  materials,  from  the  mutual  action 
of  which  they  are  evolved,  in  tubes  hermetically  sealed,  so  that  the  ac- 
cumulated pressure  of  the  vapor,  as  it  rises  and  expands,  may  force 
some  part  of  it  to  assume  the  liquid  state.  A  similar  process  may,  and 
indeed  must,  frequently  take  place  in  subterranean  caverns  and  fissures, 
or  even  in  the  pores  and  cells  of  many  rocks ;  by  which  means,  a  much 
greater  store  of  expansive  power  may  be  packed  into  a  small  space  than 
could  happen  if  these  vapors  had  not  the  property  of  becoming  liquid. 
For,  although  the  gas  occupies  much  less  room  in  a  liquid  state,  yet  it 
exerts  exactly  the  same  pressure  upon  the  sides  of  the  containing  cavity 
as  if  it  remained  in  the  form  of  vapor. 

If  a  tube,  whether  of  glass  or  other  materials,  filled  with  condensed 
gas,  have  its  temperature  slightly  raised,  it  will  often  burst ;  for  a  slight 
increment  of  heat  causes  the  elasticity  of  the  gas  to  increase  in  a  very 

*  Mallet,  p.  39. 


CH.  XXXII.]  ATMOSPHERIC    PRESSURE.  561 

high  ratio.  We  have  only  to  suppose  certain  rocks,  permeated  by  these 
liquid  gases  (as  porous  strata  are  sometimes  filled  with  water),  to  have 
their  temperature  raised  some  hundred  degrees,  and  we  obtain  a  power 
capable  of  lifting  superincumbent  masses  of  almost  any  conceivable  thick- 
ness ;  while,  if  the  depth  at  which  the  gas  is  confined  be  great,  there  is 
no  reason  to  suppose  that  any  other  appearances  would  be  witnessed  by 
the  inhabitants  of  the  surface  than  vibratory  movements  and  rents,  from 
which  no  vapor  might  escape.  In  making  their  way  through  fissures  a 
very  few  miles  only  in  length,  or  in  forcing  a  passage  through  soft  yield- 
ing strata,  the  vapors  may  be  cooled  and  absorbed  by  water.  For  water 
has  a  strong  affinity  to  several  of  the  gases,  and  will  absorb  large  quan- 
tities, with  a  very  slight  increase  of  volume.  In  this  manner,  the  heat 
or  the  volume  of  springs  may  be  augmented,  and  their  mineral  proper- 
ties made  to  vary. 

Connection  between  the  state  of  the  atmosphere  and  earthquakes. — The 
inhabitants  of  Stromboli,  who  are  mostly  fishermen,  are  said  to  make 
use  of  that  volcano  as  a  weather-glass,  the  eruptions  being  compara- 
tively feeble  when  the  sky  is  serene,  but  increasing  in  turbulence  during 
tempestuous  weather,  so  that  in  winter  the  island  often  seems  to  shake 
from  its  foundations.  Mr.  P.  Scrope,  after  calling  attention  to  these 
and  other  analogous  facts,  first  started  the  idea  (as  long  ago  as  the  year 
1825)  that  the  diminished  pressure  of  the  atmosphere,  the  concomitant 
of  stormy  weather,  may  modify  the  intensity  of  the  volcanic  action.  He 
suggests  that  where  liquid  lava  communicates  with  the  surface,  as  in 
the  crater  of  Stromboli,  it  may  rise  or  fall  in  the  vent  on  the  same  prin- 
ciple as  mercury  in  a  barometer ;  because  the  ebullition  or  expansive 
power  of  the  steam  contained  in  the  lava  would  be  checked  by  every 
increase,  and  augmented  by  every  diminution  of  weight.  In  like  man- 
ner, if  a  bed  of  liquid  lava  be  confined  at  an  immense  depth  below  the 
surface,  its  expansive  force  may  be  counteracted  partly  by  the  weight 
of  the  incumbent  rocks,  and  also  in  part  by  atmospheric  pressure  acting 
contemporaneously  on  a  vast  superficial  area.  In  that  case,  if  the  up- 
heaving force  increase  gradually  in  energy,  it  will  at  length  be  restrained 
by  only  the  slightest  degree  of  superiority  in  the  antagonist  or  repres- 
sive power,  and  then  the  equilibrium  may  be  suddenly  destroyed  by 
any  cause,  such  as  an  ascending  draught  of  air,  which  is  capable  of 
depressing  the  barometer.  In  this  manner  we  may  account  for  the 
remarkable  coincidence  so  frequently  observed  between  the  state  of  the 
weather  and  subterranean  commotions,  although  it  must  be  admitted 
that  earthquakes  and  volcanic  eruptions  react  in  their  turn  upon  the 
atmosphere,  so  that  disturbances  of  the  latter  are  generally  the  conse- 
quences rather  than  the  forerunners  of  volcanic  disturbances.* 

From  an  elaborate  catalogue  of  the  earthquakes  experienced  in  Eu- 
rope and  Syria  during  the  last  fifteen  centuries,  M.  Alexis  Perrey  has 
deduced  the  conclusion  that  the  number  which  happen  in  the  winter 

*  Scrope  on  Volcanoes,  pp.  58-60. 
36 


562  EXPANSION   OF   BOOKS   BY   HEAT.  [Cn.  XXXII. 

season  preponderates  over  those  which  occur  in  any  one  of  the  other 
seasons  of  the  year,  there  being,  however,  some  exceptions  to  this  rule, 
as  in  the  Pyrenees.  Curious  and  valuable  as  are  these  data,  M.  d'Ar- 
chiac  justly  remarks,  in  commenting  upon  them,  that  they  are  not  as 
yet  sufficiently  extensive  or  accordant  in  different  regions,  to  entitle  us 
to  deduce  any  general  conclusions  from  them  respecting  the  laws  of 
subterranean  movements  throughout  the  globe.* 

Permanent  elevation  and  subsidence. — It  is  easy  to  conceive  that  the 
shattered  rocks  may  assume  an  arched  form  during  a  convulsion,  so 
that  the  country  above  may  remain  permanently  upheaved.  In  other 
cases  gas  may  drive  before  it  masses  of  liquid  lava,  which  may  thus  be 
injected  into  newly  opened  fissures.  The  gas  having  then  obtained 
more  room,  by  the  forcing  up  of  the  incumbent  rocks,  may  remain  at 
rest ;  while  the  lava  congealing  in  the  rents  may  afford  a  solid  founda- 
tion for  the  newly  raised  district. 

Experiments  have  recently  been  made  in  America,  by  Colonel  Totten, 
to  ascertain  the  ratio  according  to  which  some  of  the  stones  commonly 
used  in  architecture  expand  with  given  increments  of  heat.f  It  was 
found  impossible,  in  a  country  where  the  annual  variation  of  tempera- 
ture was  more  than  90°  F.,  to  make  a  coping  of  stones,  five  feet  in 
length,  in  which  the  joints  should  fit  so  tightly  as  not  to  admit  water 
between  the  stone  and  the  cement ;  the  annual  contraction  and  expan- 
sion of  the  stones  causing,  at  the  junctions,  small  crevices,  the  width  of 
which  varied  with  the  nature  of  the  rock.  It  was  ascertained  that  fine- 
grained granite  expanded  with  1°  F.  at  the  rate  of  '000004825  ;  while 
crystalline  marble  '000005668;  and  red  sandstone  '000009532,  or 
about  twice  as  much  as  granite. 

Now,  according  to  this  law  of  expansion,  a  mass  of  sandstone  a  mile 
in  thickness,  which  should  have  its  temperature  raised  200  F.,  would 
lift  a  superimposed  layer  of  rock  to  the  height  of  ten  feet  above  its 
former  level.  But,  suppose  a  part  of  the  earth's  crust,  one  hundred 
miles  in  thickness  and  equally  expansive,  to  have  its  temperature  raised 
600°  or  800°,  this  might  produce  an  elevation  of  between  two  and 
three  thousand  feet.  The  cooling  of  the  same  mass  might  afterwards 
cause  the  overlying  rocks  to  sink  down  again  and  resume  their  original 
position.  By  such  agency  we  might  explain  the  gradual  rise  of  Scan- 
dinavia or  the  subsidence  of  Greenland,  if  this  last  phenomenon  should 
also  be  established  as  a  fact  on  farther  inquiry. 

It  is  also  possible  that  as  the  clay  in  Wedgwood's  pyrometer  con- 
tracts, by  giving  off  its  water,  and  then,  by  incipient  vitrification;  so, 
large  masses  of  argillaceous  "strata  on  the  earth's  interior  may  shrink, 
when  subjected  to  heat  and  chemical  changes,  and  allow  the  incumbent 
rocks  to  subside  gradually. 

Moreover,  if  we  suppose  that  lava  cooling  slowly  at  great  depths 

*  Archiac,  Hist,  des  Progres  de  la  Geol,  1847,  vol.  i.  pp.  605-610. 
f  Silliman's  American  Journ.  vol.  xxii.  p.  136.     The  application  of  these  results 
to  the  theory  of  earthquakes  was  first  suggested  to  me  by  Mr.  Babbage. 


CH.  XXXIL]       BALANCE    OF    DRY   LAND,    HOW    PRESERVED.  563 

may  be  converted  into  various  granitic  rocks,  we  obtain  another  source 
of  depression;  for,  according  to  the  experiments  of  Deville  and  the 
calculations  of  Bischoff,  the  contraction  of  granite  when  passing  from  a 
melted  or  plastic  to  a  solid  and  crystalline  state  must  be  more  than  ten 
per  cent.*  The  sudden  subsidence  of  land  may  also  be  occasioned  by 
subterranean  caverns  giving  way,  when  gases  are  condensed,  or  when 
they  escape  through  newly-formed  crevices.  The  subtraction,  more- 
over, of  matter  from  certain  parts  of  the  interior,  by  the  flowing  of  lava 
and  of  mineral  springs,  must,  in  the  course  of  ages,  cause  vacuities 
below,  so  that  the  undermined  surface  may  at  length  fall  in. 

The  balance  of  dry  land,  how  preserved. — In  the  present  state  of  our 
knowledge,  we  cannot  pretend  to  estimate  the  average  number  of  earth- 
quakes which  may  happen  in  the  course  of  a  single  year.  As  the  area  of 
the  ocean  is  nearly  three  times  that  of  the  land,  it  is  probable  that  about 
three  submarine  earthquakes  may  occur  for  one  exclusively  continental ; 
and  when  we  consider  the  great  frequency  of  slight  movements  in  cer- 
tain districts,  we  can  hardly  suppose  that  a  day,  if,  indeed,  an  hour,  ever 
passes  without  one  or  more  shocks  being  experienced  in  some  part  of 
the  globe.  We  have  also  seen  that  in  Sweden,  and  other  countries, 
changes  in  the  relative  level  of  sea  and  land  may  take  place  without 
commotion,  and  these  perhaps  produce  the  most  important  geographi- 
cal and  geological  changes  ;  for  the  position  of  land  may  be  altered  to  a 
greater  amount  by  an  elevation  or  depression  of  one  inch  over  a  vast 
area,  than  by  the  sinking  of  a  more  limited  tract,  such  as  the  forest  of 
Aripao,  to  the  depth  of  many  fathoms  at  once.f 

It  must  be  evident,  from  the  historical  details  above  given,  that  the 
force  of  subterranean  movement,  whether  intermittent  or  continuous, 
whether  with  or  without  disturbance,  does  not  operate  at  random,  but  is 
developed  in  certain  regions  only  ;  and  although  the  alterations  produced 
during  the  time  required  for  the  occurrence  of  a  few  volcanic  eruptions 
may  be  inconsiderable,  we  can  hardly  doubt  that,  during  the  ages 
necessary  for  the  formation  of  large  volcanic  cones,  composed  of  thou- 
sands of  lava  currents,  shoals  might  be  converted  into  lofty  mountains, 
and  low  lands  into  deep  seas. 

In  a  former  chapter  (p.  198),  I  have  stated  that  aqueous  and  igneous 
agents  may  be  regarded  as  antagonist  forces  ;  the  aqueous  laboring  in- 
cessantly to  reduce  the  inequalities  of  the  earth's  surface  to  a  level, 
while  the  igneous  are  equally  active  in  renewing  the  unevenness  of  the 
surface.  By  some  geologists  it  has  been  thought  that  the  levelling  power 
of  running  water  was  opposed  rather  to  the  elevating  force  of  earth- 
quakes than  to  their  action  generally.  This  opinion  is,  however,  un- 
tenable ;  for  the  sinking  down  of  the  bed  of  the  ocean  is  one  of  the 
means  by  which  the  gradual  submersion  of  land  is  prevented.  The  depth 
of  the  sea  cannot  be  increased  at  any  one  point  without  a  universal  fall 
of  the  waters,  nor  can  any  partial  deposition  of  sediment  occur  without 

*  Bulletin  de  la  Soc.  Geol.  2d  series,  vol.  iv.  p.  1312.  f  See  p.  468. 


564:  BALANCE   OF   DRY  LAND   PRESERVED  [Cn.  XXXIL 

the  displacement  of  a  quantity  of  water  of  equal  volume,  which  will 
raise  the  sea,  though  in  an  imperceptible  degree,  even  to  the  antipodes. 
The  preservation,  therefore,  of  the  dry  land  may  sometimes  be  effected 
by  the  subsidence  of  part  of  the  earth's  crust  (that  part,  namely,  which 
is  covered  by  the  ocean),  and  in  like  manner  an  upheaving  movement 
must  often  tend  to  destroy  land  ;  for  if  it  render  the  bed  of  the  sea  more 
shallow,  it  will  displace  a  certain  quantity  of  water,  and  thus  tend  to 
submerge  low  tracts. 

Astronomers  having  proved  (see  above,  p.  129)  that  there  has  been 
no  change  in  the  diameter  of  the  earth  during  the  last  two  thousand 
years,  we  may  assume  it  as  probable,  that  the  dimensions  of  the  planet 
remain  uniform.  If,  then,  we  inquire  in  what  manner  the  force  of  earth- 
quakes must  be  regulated,  in  order  to  restore  perpetually  the  inequalities 
of  the  surface  which  the  levelling  power  of  water  tends  to  efface,  it  will 
be  found,  that  the  amount  of  depression  must  exceed  that  of  elevation. 
It  would  be  otherwise  if  the  action  of  volcanoes  and  mineral  springs  were 
suspended  ;  for  then  the  forcing  outwards  of  the  earth's  envelope  ought 
to  be  no  more  than  equal  to  its  sinking  in. 

To  understand  this  proposition  more  clearly,  it  must  be  borne  in  mind, 
that  the  deposits  of  rivers  and  currents  probably  add  as  much  to  the 
height  of  lands  which  are  rising,  as  they  take  from  those  which  have 
risen.  Suppose  a  large  river  to  bring  down  sediment  to  a  part  of  the 
-  ocean  two  thousand  feet  deep,  and  that  the  depth  of  this  part  is  gradually 
reduced  by  the  accumulation  of  sediment  till  only  a  shoal  remains, 
covered  by  water  at  high  tides  ;  if  now  an  upheaving  force  should  up- 
lift this  shoal  to  the  height  of  2000  feet,  the  result  would  be  a  mountain 
2000  feet  high.  But  had  the  movement  raised  the  same  part  of  the 
bottom  of  the  sea  before  the  sediment  of  the  river  had  filled  it  up  ;  then, 
instead  of  changing  a  shoal  into  a  mountain  2000  feet  high,  it  would 
only  have  converted  a  deep  sea  into  a  shoal. 

It  appears,  then,  that  the  operations  of  the  earthquake  are  often  such 
as  to  cause  the  levelling  power  of  water  to  counteract  itself ;  and, 
although  the  idea  may  appear  paradoxical,  we  may  be  sure,  wherever 
we  find  hills  and  mountains  composed  of  stratified  deposits,  that  such 
inequalities  of  the  surface  would  have  had  no  existence  if  water,  at  some 
former  period,  had  not  been  laboring  to  reduce  the  earth's  surface  to 
one  level. 

But,  besides  the  transfer  of  matter  by  running  water  from  the  conti- 
nents to  the  ocean,  there  is  a  constant  transportation  from  below  up- 
wards, by  mineral  springs  and  volcanic  vents.  As  mountain  masses  are, 
in  the  course  of  ages,  created'  by  the  pouring  forth  of  successive  streams 
of  lava,  so  stratified  rocks,  of  great  extent,  originate  from  the  deposition 
of  carbonate  of  lime,  and  other  mineral  ingredients,  with  which  springs 
are  impregnated.  The  surface  of  the  land,  and  portions  of  the  bottom 
of  the  sea,  being  thus  raised,  the  external  accessions  due  to  these  opera- 
tions would  cause  the  dimensions  of  the  planet  to  enlarge  continually,  if 
the  amount  of  depression  of  the  earth's  crust  were  no  more  than  equal 


CH.  XXXIL]  BY   SUBTERRANEAN  MOVEMENTS.  565 

to  the  elevation.  In  order,  therefore,  that  the  mean  diameter  of  the 
earth  should  remain  uniform,  and  the  unevenness  of  the  surface  be  pre- 
served, it  is  necessary  that  the  amount  of  subsidence  should  be  in  ex- 
cess. And  such  a  predominance  of  depression  is  far  from  improbable, 
on  mechanical  principles,  since  every  upheaving  movement  must  be 
expected  either  to  produce  caverns  in  the  mass  below,  or  to  cause  some 
diminution  of  its  density.  Vacuities  must,  also,  arise  from  the  sub- 
traction of  the  matter  poured  out  from  volcanoes  and  mineral  springs, 
or  from  the  contraction  of  argillaceous  masses  by  subterranean  heat ; 
and  the  foundations  having  been  thus  weakened,  the  earth's  crust,  shaken 
and  rent  by  reiterated  convulsions,  must,  in  the  course  of  time,  fall  in. 

If  we  embrace  these  views,  important  geological  consequences  will 
follow  ;  since,  if  there  be,  upon  the  whole,  more  subsidence  than  eleva- 
tion, the  average  depth  to  which  former  surfaces  have  sunk  beneath 
their  original  level  must  exceed  the  height  which  ancient  marine  strata 
have  attained  above  the  sea.  If,  for  example,  marine  strata,  about  the 
age  of  our  chalk  and  greensand,  have  been  lifted  up  in  Europe  to  an  ex- 
treme height  of  more  than  eleven  thousand  feet,  and  a  mean  elevation  of 
some  hundreds,  we  may  conclude  that  certain  parts  of  the  surface,  which 
existed  when  those  strata  were  deposited,  have  sunk  to  an  extreme  depth 
of  more  than  eleven  thousand  feet  below  their  original  level,  and  to  a 
mean  depth  of  more  than  a  few  hundreds. 

In  regard  to  faults,  also,  we  must  infer,  according  to  the  hypothesis 
now  proposed,  that  a  greater  number  have  arisen  from  the  sinking  down 
than  from  the  elevation  of  rocks. 

To  conclude :  it  seems  to  be  rendered  probable,  by  the  views  above 
explained,  that  the  constant  repair  of  the  land,  and  the  subserviency  of 
our  planet  to  the  support  of  terrestrial  as  well  as  aquatic  species,  are  se- 
cured by  the  elevating  and  depressing  power  of  causes  acting  in  the 
interior  of  the  earth  ;  which,  although  so  often  the  source  of  death  and 
terror  to  the  inhabitants  of  the  globe — visiting  in  succession  every  zone, 
and  filling  the  earth  with  monuments  of  ruin  and  disorder — are  never- 
theless the  agents  of  a  conservative  principle  above  all  others  essential  to 
the  stability  of  the  system. 


BOOK  III. 


CHAPTER  XXXIII. 

CHANGES    OF    THE    ORGANIC    WORLD    NOW    IN    PROGRESS. 

Division  of  the  subject — Examination  of  the  question,  Whether  species  have  a 
real  existence  in  nature  ? — Importance  of  this  question  in  geology — Sketch  of 
Lamarck's  arguments  in  favor  of  the  transmutation  of  species,  and  his  conjectures 
respecting  the  origin  of  existing  animals  and  plants — His  theory  of  the  trans- 
formation of  the  orang-outang  into  the  human  species. 

THE  last  book,  from  chapters  fourteen  to  thirty-three  inclusive,  was  oc- 
cupied with  the  consideration  of  the  changes  brought  about  on  the 
earth's  surface,  within  the  period  of  human  observation,  by  inorganic 
agents  ;  such,  for  example,  as  rivers,  marine  currents,  volcanoes,  and 
earthquakes.  But  there  is  another  class  of  phenomena  relating  to  the 
organic  world,  which  have  an  equal  claim  on  our  attention,  if  we  desire 
to  obtain  possession  of  all  the  preparatory  knowledge  respecting  the  ex- 
isting course  of  nature,  which  may  be  available  in  the  interpretation  of 
geological  monuments.  It  appeared  from  our  preliminary  sketch  of  the 
progress  of  the  science,  that  the  most  lively  interest  was  excited  among 
its  earlier  cultivators,  by  the  discovery  of  the  remains  of  animals  and 
plants  in  the  interior  of  mountains  frequently  remote  from  the  sea. 
Much  controversy  arose  respecting  the  nature  of  these  remains,  the 
causes  which  may  have  brought  them  into  so  singular  a  position,  and  the 
want  of  a  specific  agreement  between  them  and  known  animals  and 
plants.  To  qualify  ourselves  to  form  just  views  on  these  curious  ques- 
tions, we  must  first  study  the  present  condition  of  the  animate  creation 
on  the  globe. 

This  branch  of  our  inquiry  naturally  divides  itself  into  two  parts  :  first, 
we  may  examine  the  vicissitudes  to  which  species  are  subject ;  secondly, 
the  processes  by  which  certain  individuals  of  these  species  occasionally 
become  fossil.  The  first  of  these  divisions  will  lead  us,  among  other 
topics,  to  inquire,  first,  whether  species  have  a  real  and  permanent  ex- 
istence in  nature  ?  or  whether  they  are  capable,  as  some  naturalists  pre- 
tend, of  being  indefinitely  modified  in  the  course  of  a  long  series  of 
generations  ?  Secondly,  whether,  if  species  have  a  real  existence,  the 
individuals  composing  them  have  been  derived  originally  from  many 
similar  stocks,  or  each  from  one  only,  the  descendants  of  which  have 
spread  themselves  gradually  from  a  particular  point  over  the  habitable 
lands  and  waters  ?  Thirdly,  how  far  the  duration  of  each  species  oi 
animal  and  plant  is  limited  by  its  dependence  on  certain  fluctuating  and 
temporary  conditions  in  the  state  of  the  animate  and  inanimate  world  ? 
Fourthly,  whether  there  be  proofs  of  the  successive  extermination  of 


CH.  XXXIII.]        IF   SPECIES    HAVE   A   REAL   EXISTENCE  ?  567 

species  in  the  ordinary  course  of  nature,  and  whether  there  be  any  rea- 
son for  conjecturing  that  new  animals  and  plants  are  created  from  time 
to  time,  to  supply  their  place  ? 

Whether  species  have  a  real  existence  in  nature. — Before  we  can  ad- 
vance a  step  in  our  proposed  inquiry,  we  must  be  able  to  define  pre- 
cisely the  meaning  which  we  attach  to  the  term  species.  This  is  even 
more  necessary  in  geology  than  in  the  ordinary  studies  of  the  naturalist ; 
for  they  who  deny  that  such  a  thing  as  a  species  exists,  concede  never- 
theless that  a  botanist  or  zoologist  may  reason  as  if  the  specific  character 
were  constant,  because  they  confine  their  observations  to  a  brief  period 
of  time.  Just  as  the  geographer,  in  constructing  his  maps  from  century 
to  century,  may  proceed  as  if  the  apparent  places  of  the  fixed  stars  re- 
mained absolutely  the  same,  and  as  if  no  alteration  were  brought  about 
by  the  precession  of  the  equinoxes ;  so,  it  is  said,  in  the  organic  world, 
the  stability  of  a  species  may  be  taken  as  absolute,  if  we  do  not  extend 
our  views  beyond  the  narrow  period  of  human  history  ;  but  let  a  suffi- 
cient number  of  centuries  elapse,  to  allow  of  important  revolutions  in 
climate,  physical  geography,  and  other  circumstances,  and  the  characters, 
say  they,  of  the  descendants  of  common  parents  may  deviate  indefinitely 
from  their  original  type. 

Now,  if  these  doctrines  be  tenable,  we  are  at  once  presented  with  a 
principle  of  incessant  change  in  the  organic  world  ;  and  no  degree  of 
dissimilarity  in  the  plants  and  animals  which  may  formerly  have  existed, 
and  are  found  fossil,  would  entitle  us  to  conclude  that  they  may  not  have 
been  the  prototypes  and  progenitors  of  the  species  now  living.  Accord- 
ingly M.  Geoffroy  St.  Hilaire  has  declared  his  opinion,  that  there  has 
been  an  uninterrupted  succession  in  the  animal  kingdom,  effected  by 
means  of  generation,  from  the  earliest  ages  of  the  world  up  to  the 
present  day,  and  that  the  ancient  animals  whose  remains  have  been 
preserved  in  the  strata,  however  different,  may  nevertheless  have  been 
the  ancestors  of  those  now  in  being.  This  notion  is  not  very  gen- 
erally received,  but  we  are  not  warranted  in  assuming  the  contrary, 
without  fully  explaining  the  data  and  reasoning  by  which  it  may  be 
refuted. 

I  shall  begin  by  stating  as  concisely  as  possible  all  the  facts  and  in- 
genious arguments  by  which  the  theory  has  been  supported ;  and  for 
this  purpose  I  cannot  do  better  than  offer  the  reader  a  rapid  sketch  of 
Lamarck's  statement  of  the  proofs  which  he  regards  as  confirmatory  of 
the  doctrine,  and  which  he  has  derived  partly  from  the  works  of  his 
predecessors  and  in  part  from  original  investigations. 

His  proofs  and  inferences  will  be  best  considered  in  the  order  in  which 
they  appear  to  have  influenced  his  mind,  and  I  shall  then  point  out  some 
of  the  results  to  which  he  was  led  while  boldly  following  out  his  princi- 
ples to  their  legitimate  consequences. 

Lamarck's  arguments  in  favor  of  the  transmutation  of  species. — The 
name  of  species,  observes  Lamarck,  has  been  usually  applied  to  "  every 
collection  of  similar  individuals  produced  by  other  individuals  like  them- 


568  LAMARCK'S  THEORY  OF  THE  [On.  XXXIII. 

selves."*  This  definition,  he  admits,  is  correct ;  because  every  living 
individual  bears  a  very  close  resemblance  to  those  from  which  it  springs. 
But  this  is  not  all  which  is  usually  implied  by  the  term  species ;  for  the 
majority  of  naturalists  agree  with  Linnaeus  in  supposing  that  all  the  in- 
dividuals propagated  from  one  stock  have  certain  distinguishing  charac- 
ters in  common,  which  will  never  vary,  and  which  have  remained  the 
same  since  the  creation  of  each  species. 

In  order  to  shake  this  opinion,  Lamarck  enters  upon  the  following  line 
of  argument : — The  more  we  advance  in  the  knowledge  of  the  different 
organized  bodies  which  cover  the  surface  of  the  globe,  the  more  our  em- 
barrassment increases,  to  determine  what  ought  to  be  regarded  as  a 
species,  and  still  more  how  to  limit  and  distinguish  genera.  In  propor- 
tion as  our  collections  are  enriched,  we  see  almost  every  void  filled  up, 
and  all  our  lines  of  separation  effaced. !  we  are  reduced  to  arbitrary  de- 
terminations, and  are  sometimes  fain  to  seize  upon  the  slight  differences 
of  mere  varieties,  in  order  to  form  characters  for  what  we  choose  to  call 
a  species  ;  and  sometimes  we  are  induced  to  pronounce  individuals  but 
slightly  differing,  and  which  others  regard  as  true  species,  to  be  varieties. 

The  greater  the  abundance  of  natural  objects  assembled  together,  the 
more  do  we  discover  proofs  that  every  thing  passes  by  insensible  shades 
into  something  else  ;  that  even  the  more  remarkable  differences  are 
evanescent,  and  that  nature  has,  for  the  most  part,  left  us  nothing  at  our 
disposal  for  establishing  distinctions,  save  trifling,  and,  in  some  respects, 
puerile  particularities. 

We  find  that  many  genera  amongst  animals  and  plants  are  of  such  an 
extent,  in  consequence  of  the  number  of  species  referred  to  them,  that 
the  study  and  determination  of  these  last  has  become  almost .  impracti- 
cable. When  the  species  are  arranged  in  a  series,  and  placed  near  to 
each  other,  with  due  regard  to  their  natural  affinities,  they  each  differ 
in  so  minute  a  degree  from  those  next  adjoining,  that  they  almost  melt 
into  each  other,  and  are  in  a  manner  confounded  together.  If  we  see 
isolated  species,  we  may  presume  the  absence  of  some  more  closely  con- 
nected, and  which  have  not  yet  been  discovered.  Already  are  there 
genera,  and  even  entire  orders — nay,  whole  classes,  which  present  an 
approximation  to  the  state  of  things  here  indicated. 

If,  when  species  have  been  thus  placed  in  a  regular  series,  we  select 
one,  and  then,  making  a  leap  over  several  intermediate  ones,  we  take  a 
second,  at  some  distance  from  the  first,  these  two  will,  on  comparison, 
be  seen  to  be  very  dissimilar  ;  and  it  is  in  this  manner  that  every  nat- 
uralist begins  to  study  the  objects  which  are  at  his  own  door.  He  then 
finds  it  an  easy  task  to  establish  generic  and  specific  distinctions ;  and  it 
is  only  when  his  experience  is  enlarged,  and  when  he  has  made  himself 
master  of  the  intermediate  links,  that  his  difficulties  and  ambiguities  be- 
gin. But  while  we  are  thus  compelled  to  resort  to  trifling  and  minute 
characters  in  our  attempt  to  separate  the  species,  we  find  a  striking  dis- 

*  Phil.  Zool.  torn.  i.  p.  54. 


CH.  XXXTIL]  TRANSMUTATION    OF   SPECIES.  569 

parity  between  individuals  which  we  know  to  have  descended  from  a 
common  stock  ;  and  these  newly  acquired  peculiarities  are  regularly 
transmitted  from  one  generation  to  another,  constituting  what  are  called 
races. 

From  a  great  number  of  facts,  continues  the  author,  we  learn  that 
in  proportion  as  the  individuals  of  one  of  our  species  change  their  situa- 
tion, climate,  and  manner  of  living,  they  change  also,  by  little  and  little, 
the  consistence  and  proportions  of  their  parts,  their  form,  their  faculties, 
and  even  their  organization,  in  such  a  manner  that  every  thing  in  them 
comes  at  last  to  participate  in  the  mutations  to  which  they  have  been 
exposed.  Even  in  the  same  climate,  a  great  difference  of  situation  and 
exposure  causes  individuals  to  vary  ;  but  if  these  individuals  continue 
to  live  and  to  be  reproduced  under  the  same  difference  of  circumstances, 
distinctions  are  brought  about  in  them  which  become  in  some  degree 
essential  to  their  existence.  In  a  word,  at  the  end  of  many  successive 
generations,  these  individuals,  which  originally  belonged  to  another 
species,  are  transformed  into  a  new  and  distinct  species.* 

Thus,  for  example,  if  the  seeds  of  a  grass,  or  any  other  plant  which 
grows  naturally  in  a  moist  meadow,  be  accidentally  transported,  first  to 
the  slope  of  some  neighboring  hill,  where  the  soil,  although  at  a  greater 
elevation,  is  damp  enough  to  allow  the  plant  to  live  ;  and  if,  after  hav- 
ing lived  there,  and  having  been  several  times  regenerated,  it  reaches  by 
degrees  the  drier  and  almost  arid  soil  of  a  mountain  declivity,  it  will 
then,  if  it  succeeds  in  growing,  and  perpetuates  itself  for  a  series  of  gen- 
erations, be  so  changed  that  botanists  who  meet  with  it  will  regard  it  as 
a  particular  species. f  The  unfavorable  climate  in  this  case,  deficiency 
of  nourishment,  exposure  to  the  winds,  and  other  causes,  give  rise  to  a 
stunted  and  dwarfish  race,  with  some  organ  more  developed  than  others, 
and  having  proportions  often  quite  peculiar. 

What  nature  brings  about  in  a  great  lapse  of  time,  we  occasion  sud- 
denly by  changing  the  circumstances  in  which  a  species  has  been  accus- 
tomed to  live.  All  are  aware  that  vegetables  taken  from  their  birth- 
place, and  cultivated  in  gardens,  undergo  changes  which  render  them 
no  longer  recognizable  as  the  same  plants.  Many  which  were  naturally 
hairy  become  smooth,  or  nearly  so ;  a  great  number  of  such  as  were 
creepers  and  trailed  along  the  ground,  rear  their  stalks  and  grow  erect. 
Others  lose  their  thorns  or  asperities  ;  others,  again,  from  the  ligneous 
state  which  their  stem  possessed  in  hot  climates,  where  they  were  indi- 
genous, pass  to  the  herbaceous ;  and,  among  them,  some  which  were 
perennials  become  mere  annuals.  So  well  do  botanists  know  the  effects 
of  such  changes  of  circumstances,  that  they  are  averse  to  describe  species 
from  garden  specimens,  unless  they  are  sure  that  they  have  been  culti- 
vated for  a  very  short  period. 

"  Is  not  the  cultivated  wheat"  ( Triticum sativum),  asks  Lamarck,  "a 
vegetable  brought  by  man  into  the  state  in  which  we  now  see  it  ?  Let 

*  PhiL  Zool.  torn.  i.  p.  62.  \  Ibid. 


5TO  CHANGES   IN   ANIMALS    AND   PLANTS          [On.  XXXIII- 

any  one  tell  me  in  what  country  a  similar  plant  grows  wild,  unless  where 
it  has  escaped  from  cultivated  fields  ?  Where  do  we  find  in  nature  our 
cabbages,  lettuces,  and  other  culinary  vegetables,  in  the  state  in  which 
they  appear  in  our  gardens  ?  Is  it  not  the  same  in  regard  to  a  great 
quantity  of  animals  which  domesticity  has  changed  or  considerably  mod- 
ified ?"*  Our  domestic  fowls  and  pigeons  are  unlike  any  wild  birds. 
Our  domestic  ducks  and  geese  have  lost  the  faculty  of  raising  them- 
selves into  the  higher  regions  of  the  air,  and  crossing  extensive  countries 
in  their  flight,  like  the  wild  ducks  and  wild  geese  from  which  they  were 
originally  derived.  A  bird  which  we  breed  in  a  cage  cannot,  when  re- 
stored to  liberty,  fly  like  others  of  the  same  species  which  have  been 
always  free.  This  small  alteration  of  circumstances,  however,  has  only 
diminished  the  power  of  flight,  without  modifying  the  form  of  any  part 
of  the  wings.  But  when  individuals  of  the  same  race  are  retained  in 
captivity  during  a  considerable  length  of  time,  the  form  even  of  their 
parts  is  gradually  made  to  differ,  especially  if  climate,  nourishment,  and 
other  circumstances  be  also  altered. 

The  numerous  races  of  dogs  which  we  have  produced  by  domesticity 
are  nowhere  to  be  found  in  a  wild  state.  In  nature  we  should  seek  in 
vain  for  mastiffs,  harriers,  spaniels,  greyhounds,  and  other  races,  between 
which  the  differences  are  sometimes  so  great  that  they  would  be  readily 
admitted  as  specific  between  wild  animals  ;  "  yet  all  these  have  sprung 
originally  from  a  single  race,  at  first  approaching  very  near  to  a  wolf, 
if,  indeed,  the  wolf  be  not  the  true  type  which  at  some  period  or  other 
was  domesticated  by  man." 

Although  important  changes  in  the  nature  of  the  places  which  they 
inhabit  modify  the  organization  of  animals  as  well  as  vegetables  ;  yet  the 
former,  says  Lamarck,  require  more  time  to  complete  a  considerable 
degree  of  transmutation  ;  and,  consequently,  we  are  less  sensible  of  such 
occurrences.  Next  to  a  diversity  of  the  medium  in  which  animals  or 
plants  may  live,  the  circumstances  which  have  most  influence  in  modify- 
ing their  organs  are  differences  in  exposure,  climate,  the  nature  of  the 
soil,  and  other  local  particulars.  These  circumstances  are  as  varied  as 
are  the  characters  of  the  species,  and,  like  them,  pass  by  insensible  shades 
into  each  other,  there  being  every  intermediate  gradation  between  the 
opposite  extremes.  But  each  locality  remains  for  a  very  long  time  the 
same,  and  is  altered  so  slowly  that  we  can  only  become  conscious  of  the 
reality  of  the  change  by  consulting  geological  monuments,  by  which  we 
learn  that  the  order  of  things  which  now  reigns  in  each  place  has  not 
always  prevailed,  and  by  inference  anticipate  that  it  will  not  always  con- 
tinue the  same.f 

Every  considerable  alteration  in  the  local  circumstances  in  which  each 
race  of  animals  exists  causes  a  change  in  their  wants,  and  these  new 
wants  excite  them  to  new  actions  and  habits.  These  actions  require  the 
more  frequent  employment  of  some  parts  before  but  slightly  exercised, 

*  Phil.  Zool.  torn.  i.  p.  227.  f  Ibid.  p.  232. 


CH.  XXXIIL]  CAUSED   BY   DOMESTICATION.  571 

and  then  greater  development  follows  as  a  consequence  of  their  more 
frequent  use.  Other  organs  no  longer  in  use  are  impoverished  and 
diminished  in  size,  nay,  are  sometimes  entirely  annihilated,  while  in  their 
place  new  parts  are  insensibly  produced  for  the  discharge  of  new  func- 
tions.* 

I  must  here  interrupt  the  author's  argument,  by  observing,  that  no 
positive  fact  is  cited  to  exemplify  the  substitution  of  some  entirely  new 
sense,  faculty,  or  organ,  in  the  room  of  some  other  suppressed  as 
useless.  All  the  instances  adduced  go  only  to  prove  that  the  dimen- 
sions and  strength  of  members  and  the  perfection  of  certain  attributes 
may,  in  a  long  succession  of  generations,  be  lessened  and  enfeebled  by 
disuse  ;  or,  on  the  contrary,  be  matured  and  augmented  by  active  ex- 
ertion ;  just  as  we  know  that  the  power  of  scent  is  feeble  in  the  grey- 
hound, while  its  swiftness  of  pace  and  its  acuteness  of  sight  are  remark- 
able— that  the  harrier  and  stag-hound,  on  the  contrary,  are  compara- 
tively slow  in  their  movements,  but  excel  in  the  sense  of  smelling. 

It  was  necessary  to  point  out  to  the  reader  this  important  chasm  in 
the  chain  of  evidence,  because  he  might  otherwise  imagine  that  I  had 
merely  omitted  the  illustrations  for  the  sake  of  brevity ;  but  the  plain 
truth  is,  that  there  were  no  examples  to  be  found  ;  and  when  Lamarck 
talks  "of  the  efforts  of  internal  sentiment,"  "the  influence  of  subtle 
fluids,"  and  "  acts  of  organization,"  as  causes  whereby  animals  and  plants 
may  acquire  new  organs,  he  substitutes  names  for  things  ;  and,  with  a 
disregard  to  the  strict  rules  of  induction,  resorts  to  fictions,  as  ideal  as 
the  "  plastic  virtue,"  and  other  phantoms  of  the  geologists  of  the  middle 
ages. 

It  is  evident  that,  if  some  well-authenticated  facts  could  have  been 
adduced  to  establish  one  complete  step  in  the  process  of  transformation, 
such  as  the  appearance,  in  individuals  descending  from  a  common  stock, 
of  a  sense  or  organ  entirely  new,  and  a  complete  disappearance  of  some 
other  enjoyed  by  their  progenitors,  time  alone  might  then  be  supposed 
sufficient  to  bring  about  any  amount  of  metamorphosis.  The  gratuitous 
assumption,  therefore,  of  a  point  so  vital  to  the  theory  of  transmutation, 
was  unpardonable  on  the  part  of  its  advocate. 

But  to  proceed  with  the  system :  it  being  assumed  as  an  undoubted 
fact,  that  a  change  of  external  circumstances  may  cause  one  organ  to 
become  entirely  obsolete,  and  a  new  one  to  be  developed,  such  as  never 
before  belonged  to  the  species,  the  following  proposition  is  announced, 
which,  however  staggering  and  absurd  it  may  seem,  is  logically  deduced 
from  the  assumed  premises.  It  is  not  the  organs,  or,  in  other  words, 
the  nature  and  form  of  the  parts  of  the  body  of  an  animal,  which  have 
given  rise  to  its  habits,  and  its  particular  faculties ;  but,  on  the  contrary, 
its  habits,  its  manner  of  living,  and  those  of  its  progenitors,  have  in  the 
course  of  time  determined  the  form  of  its  body,  the  number  and  condi- 
tion of  its  organs — in  short,  the  faculties  which  it  enjoys.  Thus  otters, 

*  Phil.  Zool.  torn.  i.  p.  234. 


572  LAMAKCK'S  THEORY  OF  THE  CH.  xxxili] 

beavers,  waterfowl,  turtles,  and  frogs,  were  not  made  web-footed  in 
order  that  they  might  swim  ;  but  their  wants  having  attracted  them  to 
the  water  in  search  of  prey,  they  stretched  out  the  toes  of  their  feet  to 
strike  the  water  and  move  rapidly  along  its  surface.  By  the  repeated 
stretching  of  their  toes,  the  skin  which  united  them  at  the  base  acquired 
a  habit  of  extension,  until,  in  the  course  of  time,  the  broad  membranes 
which  now  connect  their  extremities  were  .formed. 

In  like  manner,  the  antelope  and  the  gazelle  were  not  endowed  with 
light  agile  forms,  in  order  that  they  might  escape  by  flight  from  car- 
nivorous animals  ;  but,  having  been  exposed  to  the  danger  of  being 
devoured  by  lions,  tigers,  and  other  beasts  of  prey,  they  were  compelled 
to  exert  themselves  in  running  with  great  celerity  ;  a  habit  which,  in  the 
course  of  many  generations,  gave  rise  to  the  peculiar  slenderness  of  their 
legs,  and  the  agility  and  elegance  of  their  forms. 

The  camelopard  was  not  gifted  with  a  long  flexible  neck  because  it 
was  destined  to  live  in  the  interior  of  Africa,  where  the  soil  was  arid 
and  devoid  of  herbage  ;  but,  being  reduced  by  the  nature  of  that 
country  to  support  itself  on  the  foliage  of  lofty  trees,  it  contracted  a 
habit  of  stretching  itself  up  to  reach  the  high  boughs,  until  its  neck 
became  so  elongated  that  it  could  raise  its  head  to  the  height  of  twenty 
feet  above  the  ground. 

Another  line  of  argument  is  then  entered  upon,  in  farther  corrob- 
oration  of  the  instability  of  species.  In  order,  it  is  said,  that  individ- 
uals should  perpetuate  themselves  unaltered  by  generation,  those  be- 
longing to  one  species  ought  never  to  ally  themselves  to  those  of 
another ;  but  such  sexual  unions  do  take  place,  both  among  plants  and 
animals ;  and  although  the  offspring  of  such  irregular  connections  are 
usually  sterile,  yet  such  is  not  always  the  case.  Hybrids  have  some- 
times proved  prolific,  where  the  disparity  between  the  species  was  not 
too  great ;  and  by  this  means  alone,  says  Lamarck,  varieties  may  grad- 
ually be  created  by  near  alliances,  which  would  become  races,  and  in  the 
course  of  time  would  constitute  what  we  term  species.* 

But  if  the  soundness  of  all  these  arguments  and  inferences  be  ad- 
mitted, we  are  next  to  inquire,  what  were  the  original  types  of  form, 
organization,  and  instinct,  from  which  the  diversities  of  character,  as 
now  exhibited  by  animals  and  plants,  have  been  derived  ?  We  know 
that  individuals  which  are  mere  varieties  of  the  same  species  would,  if 
their  pedigree  could  be  traced  back  far  enough,  terminate  in  a  single 
stock ;  so,  according  to  the  train  of  reasoning  before  described,  the 
species  of  a  genus,  and  even  the  genera  of  a  great  family,  must  have 
had  a  common  point  of  departure.  What,  then,  was  the  single  stem 
from  which  so  many  varieties  of  form  have  ramified  ?  Were  there 
many  of  these,  or  are  we  to  refer  the  origin  of  the  whole  animate 
creation,  as  the  Egyptian  priests  did  that  of  the  universe,  to  a  single 
egg  ? 

*  Phil.  Zool.  p.  64. 


Co.  XXXIIL]  TRANSMUTATION   OF   SPECIES.  573 

In  the  absence  of  any  positive  data  for  framing  a  theory  on  so  obscure 
a  subject,  the  following  considerations  were  deemed  of  importance  to 
guide  conjecture. 

In  the  first  place,  if  we  examine  the  whole  series  of  known  animals, 
from  one  extremity  to  the  other,  when  they  are  arranged  in  the  order 
of  their  natural  relations,  we  find  that  we  may  pass  progressively,  or,  at 
least,  with  very  few  interruptions,  from  beings  of  more  simple  to  those 
of  a  more  compound  structure  ;  and,  in  proportion  as  the  complexity  of 
their  organization  increases,  the  number  and  dignity  of  their  faculties 
increase  also.  Among  plants,  a  similar  approximation  to  a  graduated 
scale^  of  being  is  apparent.  Secondly,  it  appears,  from  geological  obser- 
vations, that  plants  and  animals  of  more  simple  organization  existed  on 
the  globe  before  the  appearance  of  those  of  more  compound  structure, 
and  the  latter  were  successively  formed  at  more  modern  periods ;  each 
new  race  being  more  fully  developed  than  the  most  perfect  of  the  pre- 
ceding era. 

Of  the  truth  of  the  last-mentioned  geological  theory,  Lamarck  seems 
to  have  been  fully  persuaded ;  and  he  also  shows  that  he  was  deeply 
impressed  with  a  belief  prevalent  amongst  the  older  naturalists,  that  the 
primeval  ocean  invested  the  whole  planet  long  after  it  became  the  habi- 
tation of  living  beings  ;  and  thus  he  was  inclined  to  assert  the  priority  of 
the  types  of  marine  animals  to  those  of  the  terrestrial,  so  as  to  fancy,  for 
example,  that  the  testacea  of  the  ocean  existed  first,  until  some  of  them, 
by  gradual  evolution,  were  improved  into  those  inhabiting  the  land. 

These  speculative  views  had  already  been,  in  a  great  degree,  anticipated 
by  Demaillet  in  his  Telliamed,  and  by  several  modern  writers ;  so  that 
the  tables  were  completely  turned  on  the  philosophers  of  antiquity,  with 
whom  it  was  a  received  maxim,  that  created  things  were  always  most 
perfect  when  they  came  first  from  the  hands  of  their  Maker ;  and  that 
there  was  a  tendency  to  progressive  deterioration  in  sublunary  things 
when  left  to  themselves — 

omnia  fatis 

In  pejus  ruere,  ac  retr6  sublapsa  referri. 

So  deeply  was  the  faith  of  the  ancient  schools  of  philosophy  imbued 
with  this  ddctrine,  that,  to  check  this  universal  proneness  to  degeneracy, 
nothing  less  than  the  reintervention  of  the  Deity  was  thought  adequate ; 
and  it  was  held,  that  thereby  the  order,  excellence,  and  pristine  energy 
of  the  moral  and  physical  world  had  been  repeatedly  restored. 

But  when  the  possibility  of  the  indefinite  modification  of  individuals 
descending  from  common  parents  was  once  assumed,  as  also  the  geolo- 
gical inference  respecting  the  progressive  development  of  organic  life, 
it  was  natural  that  the  ancient  dogma  should  be  rejected,  or  rather  re- 
versed, and  that  the  most  simple  and  imperfect  forms  and  faculties  should 
be  conceived  to  have  been  the  originals  whence  all  others  were  developed. 
Accordingly,  in  conformity  to  these  views,  inert  matter  was  supposed  to 
have  been  first  endowed  with  life  ;  until,  in  the  course  of  ages,  sensation 


574  LAMAKCK'S  THEOEY  OF  THE  [CH.  xxxni. 

was  superadded  to  mere  vitality :  sight,  hearing,  and  the  other  senses 
were  afterwards  acquired  ;  then  instinct  and  the  mental  faculties  ;  until, 
finally,  by  virtue  of  the  tendency  of  things  to  progressive  improvement, 
the  irrational  was  developed  in  the  rational. 

The  reader,  however,  will  immediately  perceive  that  when  all  the 
higher  orders  of  plants  and  animals  were  thus  supposed  to  be  compara- 
tively modern,  and  to  have  been  derived  in  a  long  series  of  generations 
from  those  of  more  simple  conformation,  some  farther  hypothesis  became 
indispensable,  in  order  to  explain  why,  after  an  indefinite  lapse  of  ages, 
there  were  still  so  many  beings  of  the  simplest  structure.  Why  have 
the  majority  of  existing  creatures  remained  stationary  throughout  this 
long  succession  of  epochs,  while  others  have  made  such  prodigious 
advances  ?  Why  are  there  such  multitudes  of  infusoria  and  polyps,  or 
of  confervae  and  other  cryptogamic  plants?  Why,  moreover,  has  the 
process  of  development  acted  with  such  unequal  and  irregular  force  on 
those  classes  of  beings  which  have  been  greatly  perfected,  so  that  there 
are  wide  chasms  in  the  series ;  gaps  so  enormous,  that  Lamarck  fairly 
admits  we  can  never  expect  to  fill  them  up  by  future  discoveries  ? 

The  following  hypothesis  was  provided  to  meet  these  objections. 
Nature,  we  are  told,  is  not  an  intelligence,  nor  the  Deity  ;  but  a  dele- 
gated power — a  mere  instrument — a  piece  of  mechanism  acting  by 
necessity — an  order  of  things  constituted  by  the  Supreme  Being,  and 
subject  to  laws  which  are  the  expressions  of  his  will.  This  Nature  is 
obliged  to  proceed  gradually  in  all  her  operations ;  she  cannot  produce 
animals  and  plants  of  all  classes  at  once,  but  must  always  begin  by  the 
formation  of  the  most  simple  kinds,  and  out  of  them  elaborate  the  more 
compound,  adding  to  them,  successively,  different  systems  of  organs,  and 
multiplying  more  and  more  their  number  and  energy. 

This  nature  is  daily  engaged  in  the  formation  of  the  elementary  rudi- 
ments of  animal  and  vegetable  existence,  which  correspond  to  what  the 
ancients  termed  spontaneous  generation.  She  is  always  beginning  anew, 
day  by  day,  the  work  of  creation,  by  forming  monads,  or  "rough 
draughts"  (ebauches),  which  are  the  only  living  things  she  gives  birth 
to  directly. 

There  are  distinct  primary  rudiments  of  plants  and  animals,  and 
probably  of  each  of  the  great  divisions  of  the  animal  and  vegetable 
kingdoms.*  These  are  gradually  developed  into  the  higher  and  more 
perfect  classes  by  the  slow  but  unceasing  agency  of  two  influential 
principles :  first,  the  tendency  to  progressive  advancement  in  organization, 
accompanied  by  greater  dignity  in  instinct,  intelligence,  &c.  ;  secondly, 
the  force  of  external  circumstances,  or  of  variations  in  the  physical  con- 
dition of  the  earth,  or  the  mutual  relations  of  plants  and  animals.  For, 
as  species  spread  themselves  gradually  over  the  globe,  they  are  exposed 
from  time  to  time  to  variations  in  climate,  and  to  changes  in  the  quantity 
and  quality  of  their  food ;  they  meet  with  new  plants  and  animals  which 

*  Animaux  sans  Vert.  torn.  i.  p.  56,  Introduction. 


CH.  XXXIII.]  TRANSMUTATION   OF   SPECIES.  575 

assist  or  retard  their  development,  by  supplying  them  with  nutriment, 
or  destroying  their  foes.  The  nature,  also,  of  each  locality,  is  in  itself 
fluctuating  ;  so  that,  even  if  the  relation  of  other  animals  and  plants  were 
invariable,  the  habits  and  organization  of  species  would  be  modified  by 
the  influence  of  local  revolutions. 

Now,  if  the  first  of  these  principles,  the  tendency  to  progressive  devel- 
opment, were  left  to  exert  itself  with  perfect  freedom,  it  would  give  rise, 
says  Lamarck,  in  the  course  of  ages,  to  a  graduated  scale  of  being, 
where  the  most  insensible  transition  might  be  traced  from  the  simplest 
to  the  most  compound  structure,  from  the  humblest  to  the  most  exalted 
degree  of  intelligence.  But,  in  consequence  of  the  perpetual  interference 
of  the  external  causes  before  mentioned,  this  regular  order  is  greatly 
interfered  with,  and  an  approximation  only  to  such  a  state  of  things  is 
exhibited  by  the  animate  creation,  the  progress  of  some  races  being 
retarded  by  unfavorable,  and  that  of  others  accelerated  by  favorable, 
combinations  of  circumstances.  Hence,  all  kinds  of  anomalies  interrupt 
the  continuity  of  the  plan ;  and  chasms,  into  which  whole  genera  or 
families  might  be  inserted,  are  seen  to  separate  the  nearest  existing  por- 
tions of  the  series. 

Lamarck's  theory  of  the  transformation  of  the  orang-outang  into  the 
human  species. — Such  is  the  machinery  of  the  Lamarckian  system ;  but 
the  reader  will  hardly,  perhaps,  be  able  to  form  a  perfect  conception  of 
so  complicated  a  piece  of  mechanism,  unless  it  is  exhibited  in  motion, 
so  that  we  may  see  in  what  manner  it  can  work  out,  under  the  author's 
guidance,  all  the  extraordinary  effects  which  we  behold  in  the  present 
state  of  the  animate  creation.  I  have  only  space  for  exhibiting  a  small 
part  of  the  entire  process  by  which  a  complete  metamorphosis  is 
achieved,  and  shall  therefore  omit  the  mode  by  which,  after  a  countless 
succession  of  generations,  a  small  gelatinous  body  is  transformed  into 
an  oak  or  an  ape ;  passing  on  at  once  to  the  last  grand  step  in  the 
progressive  scheme,  by  which  the  orang-outang,  having  been  already 
evolved  out  of  a  monad,  is  made  slowly  to  attain  the  attributes  and 
dignity  of  man. 

One  of  the  races  of  quadrumanous  animals  which  had  reached  the 
highest  state  of  perfection,  lost,  by  constraint  of  circumstances  (con- 
cerning the  exact  nature  of  which  tradition  is  unfortunately  silent),  the 
habit  of  climbing  trees,  and  of  hanging  on  by  grasping  the  boughs  with 
their  feet  as  with  hands.  The  individuals  of  this  race  being  obliged, 
for  a  long  series  of  generations,  to  use  their  feet  exclusively  for  walk- 
ing, and  ceasing  to  employ  their  hands  as  feet,  were  transformed  into 
bimanous  animals,  and  what  before  were  thumbs  became  mere  toes,  no 
separation  being  required  when  their  feet  were  used  solely  for  walking. 
Having  acquired  a  habit  of  holding  themselves  upright,  their  legs  and 
feet  assumed,  insensibly,  a  conformation  fitted  to  support  them  in  an 
erect  attitude,  till  at  last  these  animals  could  no  longer  go  on  all-fours 
without  much  inconvenience. 

The  Angola  orang  (Simia  troglodytes,  Linn,)  is  the  most  perfect  of 


576  CONVERSION   OF   THE   ORANG-OUTANG.        [On.  XXXIII. 

animals  ;  much  more  so  than  the  Indian  orang  (Simia  Satyrus),  which 
has  been  called  the  orang-outang,  although  both  are  very  inferior  to 
man  in  corporeal  powers  and  intelligence.  These  animals  frequently 
hold  themselves  upright ;  but  their  organization  has  not  yet  been  suf- 
ficiently modified  to  sustain  them  habitually  in  this  attitude,  so  that  the 
standing  posture  is  very  uneasy  to  them.  When  the  Indian  orang  is 
compelled  to  take  flight  from  pressing  danger,  he  immediately  falls 
down  upon  all-fours,  showing  clearly  that  this  was  the  original  position 
of  the  animal.  Even  in  man,  whose  organization,  in  the  course  of  a 
long  series  of  generations,  has  advanced  so  much  farther,  the  upright 
posture  is  fatiguing,  and  can  be  supported  only  for  a  limited  time,  and 
by  aid  of  the  contraction  of  many  muscles.  If  the  vertebral  column 
formed  the  axis  of  the  human  body,  and  supported  the  head  and  all 
the  other  parts  in  equilibrium,  then  might  the  upright  position  be  a 
state  of  repose :  but,  as  the  human  head  does  not  articulate  in  the  cen- 
tre of  gravity,  as  the  chest,  belly,  and  other  parts  press  almost  entirely 
forward  with  their  whole  weight,  and  as  the  vertebral  column  reposes 
upon  an  oblique  base,  a  watchful  activity  is  required  to  prevent  the 
body  from  falling.  Children  who  have  large  heads  and  prominent  bel- 
lies can  hardly  walk  at  the  end  even  of  two  years  ;  and  their  frequent 
tumbles  indicate  the  natural  tendency  in  man  to  resume  the  quadru- 
pedal state. 

Now,  when  so  much  progress  had  been  made  by  the  quadrumanous 
animals  before  mentioned,  that  they  could  hold  themselves  habitually 
in  an  erect  attitude,  and  were  accustomed  to  a  wide  range  of  vision,  and 
ceased  to  use  their  jaws  for  fighting  and  tearing,  or  for  clipping  herbs 
for  food,  their  snout  became  gradually  shorter,  their  incisor  teeth  became 
vertical,  and  the  facial  angle  grew  more  open. 

Among  other  ideas  which  the  natural  tendency  to  perfection  engen- 
dered, the  desire  of  ruling  suggested  itself,  and  this  race  succeeded  at 
length  in  getting  the  better  of  the  other  animals,  and  made  themselves 
masters  of  all  those  spots  on  the  surface  of  the  globe  which  best  suited 
them.  They  drove  out  the  animals  which  approached  nearest  them  in 
organization  and  intelligence,  and  which  were  in  a  condition  to  dispute 
with  them  the  good  things  of  this  world,  forcing  them  to  take  refuge  in 
deserts,  woods,  and  wildernesses,  where  their  multiplication  was  checked, 
and  the  progressive  development  of  their  faculties  retarded  ;  while,  in 
the  mean  time,  the  dominant  race  spread  itself  in  every  direction,  and 
lived  in  large  companies,  where  new  wants  were  successively  created, 
exciting  them  to  industry,  -and  gradually  perfecting  their  means  and 
faculties. 

In  the  supremacy  and  increased  intelligence  acquired  by  the  ruling 
race,  we  see  an  illustration  of  the  natural  tendency  of  the  organic  world 
to  grow  more  perfect ;  and,  in  their  influence  in  repressing  the  advance 
of  others,  an  example  of  one  of  those  disturbing  causes  before  enumer- 
ated, that/ore^  of  external  circumstances  which  causes  such  wide  chasms 
in  the  regular  series  of  animated  being. 


CH.  XXXIII.]  INTO   THE   HUMAN   SPECIES.  577 

When  the  individuals  of  the  dominant  race  became  very  numerous, 
their  ideas  greatly  increased  in  number,  and  they  felt  the  necessity  of 
communicating  them  to  each  other,  and  of  augmenting  and  varying  the 
signs  proper  for  the  communication  of  ideas.  ,  Meanwhile  the  inferior 
quadrumanous  animals,  although  most  of  them  were  gregarious,  acquired 
no  new  ideas,  being  persecuted  and  restless  in  the  deserts,  and  obliged 
to  fly  and  conceal  themselves,  so  that  they  conceived  no  new  wants. 
Such  ideas  as  they  already  had  remained  unaltered,  and  they  could  dis- 
pense with  the  communication  of  the  greater  part  of  these.  To  make 
themselves,  therefore,  understood  by  their  fellows,  required  merely  a 
few  movements  of  the  body  or  limbs — whistling,  and  the  uttering  of 
certain  cries  varied  by  the  inflexions  of  the  voice. 

On  the  contrary,  the  individuals  of  the  ascendant  race,  animated  with 
a  desire  of  interchanging  their  ideas,  which  became  more  and  more 
numerous,  were  prompted  to  multiply  the  means  of  communication,  and 
were  no  longer  satisfied  with  mere  pantomimic  signs,  nor  even  with  all 
the  possible  inflexions  of  the  voice,  but  made  continual  efforts  to  acquire 
the  power  of  uttering  articulate  sounds,  employing  a  few  at  first,  but 
afterwards  varying  and  perfecting  them  according  to  the  increase  of  their 
wants.  The  habitual  exercise  of  their  throat,  tongue,  and  lips,  insensibly 
modified  the  conformation  of  these  organs,  until  they  became  fitted  for 
the  faculty  of  speech.* 

In  effecting  this  mighty  change,  "  the  exigencies  of  the  individuals 
were  the  sole  agents ;  they  gave  rise  to  efforts,  and  the  organs  proper 
for  articulating  sounds  were  developed  by  their  habitual  employment." 
Hence,  in  this  peculiar  race,  the  origin  of  the  admirable  faculty  of  speech ; 
hence  also  the  diversity  of  languages,  since  the  distance  of  places  where 
the  individuals  composing  the  race  established  themselves  soon  favored 
the  corruption  of  conventional  signs. ]• 

In  conclusion,  it  may  be  proper  to  observe  that  the  above  sketch  of 
the  Lamarckian  theory  is  no  exaggerated  picture,  and  those  passages 
which  have  probably  excited  the  greatest  surprise  in  the  mind  of  the 
reader  are  literal  translations  from  the  original. 

*  Lamarck's  Phil.  ZooL  torn.  i.  p.  356.  f  Ibid.  p.  357. 

37 


CHAPTER  XXXIV. 

TRANSMUTATION  OF  SPECIES — continued. 

Recapitulation  of  the  arguments  in  favor  of  the  theory  of  transmutation  of 
species — Their  insufficiency — Causes  of  difficulty  in  discriminating  species — 
Some  varieties  possibly  more  distinct  than  certain  individuals  of  distinct  spe- 
cies— Variability  in  a  species  consistent  with  a  belief  that  the  limits  of  devia- 
tion are  fixed — No  facts  of  transmutation  authenticated — Varieties  of  the 
Dog — the  Dog  and  Wolf  distinct  species — Mummies  of  various  animals  from 
Egypt  identical  in  character  with  living  individuals — Seeds  and  plants  from 
the  Egyptian  tombs — Modifications  produced  in  plants  by  agriculture  and 
gardening. 

THE  theory  of  the  transmutation  of  species,  considered  in  the  last 
chapter,  has  met  with  some  degree  of  favor  from  many  naturalists, 
from  their  desire  to  dispense,  as  far  as  possible,  with  the  repeated  inter- 
vention of  a  First  Cause,  as  often  as  geological  monuments  attest  the 
successive  appearance  of  new  races  of  animals  and  plants,  and  the  ex- 
tinction of  those  pre-existing.  But,  independently  of  a  predisposition 
to  account,  if  possible,  for  a  series  of  changes  in  the  organic  world  by 
the  regular  action  of  secondary  causes,  we  have  seen  that  in  truth 
many  perplexing  difficulties  present  themselves  to  one  who  attempts  to 
establish  the  nature  and  reality  of  the  specific  character.  And  if  once 
there  appears  ground  of  reasonable  doubt,  in  regard  to  the  constancy  of 
species,  the  amount  of  transformation  which  they  are  capable  of  under- 
going may  seem  to  resolve  itself  into  a  mere  question  of  the  quantity 
of  time  assigned  to  the  past  duration  of  animate  existence. 

Before  entering  upon  the  reasons  which  may  be  adduced  for  rejecting 
Lamarck's  hypothesis,  I  shall  recapitulate,  in  a  few  words,  the  pheno- 
mena, and  the  whole  train  of  thought,  by  which  I  conceive  it  to  have 
been  suggested,  and  which  have  gained  for  this  and  analogous  theories, 
both  in  ancient  and  modern  times,  a  considerable  number  of  votaries. 

In  the  first  place,  the  various  groups  into  which  plants  and  animals 
may  be  thrown  seem  almost  invariably,  to  a  beginner,  to  be  so  natural, 
that  he  is  usually  convinced  at  first,  as  was  Linna3us  to  the  last,  "  that 
genera  are  as  much  founded  in  nature  as  the  species  which  compose 
them."  *  When  by  examining  the  numerous  intermediate  gradations 
the  student  finds  all  lines  of  demarcation  to  be  in  most  instances  ob- 
literated, even  where  they  at  first  appeared  most  distinct,  he  grow? 
more  and  more  sceptical  as  to  the  real  existence  of  genera,  and  finally 
regards  them  as  mere  arbitrary  and  artificial  signs,  invented,  like  those 

*  Genus  omne  est  natural e,  in  primordio  tale  creatum,  &c.  Phil.  Bot.  §  159. 
See  also  ibid.  §  162. 


CH.  XXXIV.]         PERMANENCE   OP   SPECIFIC    CHARACTER.  579 

which  serve  to  distinguish  the  heavenly  constellations,  for  the  conveni- 
ence of  classification,  and  having  as  little  pretensions  to  reality. 

Doubts  are  then  engendered  in  his  mind  as  to  whether  species  may 
not  also  be  equally  unreal.  The  student  is  probably  first  struck  with 
the  phenomenon,  that  some  individuals  are  made  to  deviate  widely 
from  the  ordinary  type  by  the  force  of  peculiar  circumstances,  and 
with  the  still  more  extraordinary  fact,  that  the  newly  acquired  pecu- 
liarities are  faithfully  transmitted  to  the  offspring.  How  far,  he  asks, 
may  such  variations  extend  in  the  course  of  indefinite  periods  of 
time,  and  during  great  vicissitudes  in  the  physical  condition  of  the 
globe?  His  growing  incertitude  is  at  first  checked  by  the  reflection 
that  nature  has  forbidden  the  intermixture  of  the  descendants  of 
distinct  original  stocks,  or  has,  at  least,  entailed  sterility  on  their 
offspring,  thereby  preventing  their  being  confounded  together,  and 
pointing  out  that  a  multitude  of  distinct  types  must  have  been  created 
in  the  beginning,  and  must  have  remained  pure  and  uncorrupted  to 
this  day. 

Relying  on  this  general  law,  he  endeavors  to  solve  each  difficult  pro- 
blem by  direct  experiment,  until  he  is  again  astounded  by  the  phe- 
nomenon of  a  prolific  hybrid,  and  ,  still  more  by  an  example  of  a 
hybrid  perpetuating  itself  throughout  several  generations  in  the  vege- 
table world.  He  then  feels  himself  reduced  to  the  dilemma  of  choosing 
between  two  alternatives;  either  to  reject  the  test,  or  to  declare  that 
the  two  species,  from  the  union  of  which  the  fruitful  progeny  has 
sprung,  were  mere  varieties.  If  he  prefer  the  latter,  he  is  compelled 
to  question  the  reality  of  the  distinctness  of  all  other  supposed  spe- 
cies which  differ  no  more  than  the  parents  of  such  prolific  hybrids ;  for 
although  he  may  not  be  enabled  immediately  to  procure,  in  all  such 
instances,  a  fruitful  offspring  ;  yet  experiments  show,  that  after  repeated 
failures,  the  union  of  two  recognized  species  may  at  last,  under  very 
favorable  circumstances,  give  birth  to  a  fertile  progeny.  Such  circum- 
stances, therefore,  the  naturalist  may  conceive  to  have  occurred  again 
and  again,  in  the  course  of  a  great  lapse  of  ages. 

His  first  opinions  are  now  fairly  unsettled,  and  every  stay  at  which  he 
has  caught  has  given  way  one  after  another;  he  is  in  danger  of 
falling  into  any  new  and  visionary  doctrine  which  may  be  presented  to 
him;  for  he  now  regards  every  part  of  the  animate  creation  as  void  of 
stability,  and  in  a  state  of  continual  flux.  In  this  mood  he  encounters 
the  Geologist,  who  relates  to  him  how  there  have  been  endless  vicis- 
situdes in  the  shape  and  structure  of  organic  beings  in  former  ages 
— how  the  approach  to  the  present  system  of  things  has  been  gradual 
—that  there  has  been  a  progressive  development  of  organization  sub- 
servient to  the  purposes  of  life,  from  the  most  simple  to  the  most 
complex  state — that  the  appearance  of  man  is  the  last  phenomenon  in 
a  long  succession  of  events — and,  finally,  that  a  series  of  physical  revo- 
lutions can  be  traced  in  the  inorganic  world,  coeval  and  co-extensive 
with  those  of  organic  nature. 


580  PERMANENCE   OF   SPECIFIC    CHARACTER.        [On.  XXXIV. 

These  views  seem  immediately  to  confirm  all  his  preconceived  doubts 
as  to  the  stability  of  the  specific  character,  and  he  begins  to  think  there 
may  exist  an  inseparable  connection  between  a  series  of  changes  in 
the  inanimate  world,  and  the  capability  of  the  species  to  be  indefinitely 
modified  bv  the  influence  of  external  circumstances.  Henceforth  his 
speculations  know  no  definite  bounds ;  he  gives  the  rein  to  conjecture, 
and  fancies  that  the  outward  form,  internal  structure,  instinctive  facul- 
ties, nay,  that  reason  itself  may  have  been  gradually  developed  from 
some  of  the  simplest  states  of  existence — that  all  animals,  that  man 
himself,  and  the  irrational  beings,  may  have  had  one  common  origin  ; 
that  all  may  be  parts  of  one  continuous  and  progressive  scheme  of 
development,  from  the  most  imperfect  to  the  more  complex ;  in  fine,  he 
renounces  his  belief  in  the  high  genealogy  of  his  species,  and  looks  for- 
ward, as  if  in  compensation,  to  the  future  perfectibility  of  man  in  his 
physical,  intellectual,  and  moral  attributes. 

Let  us  now  proceed  to  consider  what  is  defective  in  evidence,  and 
what  fallacious  in  reasoning,  in  the  grounds  of  these  strange  conclu- 
sions. Blumenbach  judiciously  observes,  that  "  no  general  rule  can  be 
laid  down  for  determining  the  distinctness  of  species,  as  there  is  no  parti- 
cular class  of  characters  which  can  serve  as  a  criterion.  In  each 
case  we  must  be  guided  by  analogy  and  probability"  The  multitude, 
in  fact,  and  complexity  of  the  proofs  to  be  weighed  is  so  great,  that  we 
can  only  hope  to  obtain  presumptive  evidence,  and  we  must,  therefore, 
be  the  more  careful  to  derive  our  general  views  as  much  as  possi- 
ble from  those  observations  where  the  chances  of  deception  are  least. 
We  must  be  on  our  guard  not  to  tread  in  the  footsteps  of  the  natural- 
ists of  the  middle  ages,  who  believed  the  doctrine  of  spontaneous 
generation  to  be  applicable  to  all  those  parts  of  the  animal  and  vegetable 
kingdoms  which  they  least  understood,  in  direct  contradiction  to  the 
analogy  of  all  the  parts  best  known  to  them ;  and  who,  when  at  length 
they  found  that  insects  and  cryptogamous  plants  were  also  propagated 
from  eggs  or  seeds,  still  persisted  in  retaining  their  old  prejudices 
respecting  the  infusory  animalcules  and  other  minute  beings,  the  gene- 
ration of  which  had  not  then  been  demonstrated  by  the  microscope  to 
be  governed  by  the  same  laws.  ..';•;  • 

Lamarck  has,  indeed,  attempted  to  raise  an'  argument  in  favor  of  his 
system,  out  of  the  very  confusion  which  has  arisen  in  the  study  of  some 
orders  of  animals 'and  plants,  in  consequence  of  the  slight  shades  of 
difference  which  separate  the  new  species  discovered  within  the  last 
half  century.  That  the  embarrassment  of  those  who  attempt  to  classify 
and  distinguish  the  new  acquisitions,  poured  in  such  multitudes  into 
our  museums,  should  increase  with  the  augmentation  of  their  number, 
is  quite  natural ;  since  to  obviate  this,  it  is  not  enough  that  our  powers 
of  discrimination  should  keep  pace  with  the  increase  of  the  objects,  but 
we  ought  to  possess  greater  opportunities  of  studying  each  animal  and 
plant  in  all  stages  of  its  growth,  and  to  know  profoundly  their  history, 
their  habits,  and  physiological  characters,  throughout  several  generations; 


Cii.  XXXIV.]         DIFFICULTY  OF  DISCRIMINATING  SPECIES.  581 

for,  in  proportion  as  the  series  of  known  animals  grows  more  complete 
none  can  doubt  there  is  a  nearer  approximation  to  a  graduated  scale 
of  being;  and  thus  the  most  closely  allied  species  will  be  found  to 
possess  a  greater  number  of  characters  in  common. 

Causes  of  the  difficulty  of  discriminating  species. — But,  in  point  of 
fact,  our  new  acquisitions  consist,  more  and  more  as  we  advance,  of 
specimens  brought  from  foreign  and  often  very  distant  and  barbarous 
countries.  A  large  proportion  have  never  even  been  seen  alive  by 
scientific  inquirers.  Instead  of  having  specimens  of  the  young,  the 
adult,  and  the  aged  individuals  of  each  sex,  and  possessing  means  of 
investigating  the  anatomical  structure,  the  peculiar  habits,  and  instincts 
of  each,  what  is  usually  the  state  of  our  information  ?  A  single  speci- 
men, perhaps,  of  a  dried  plant,  or  a  stuffed  bird  or  quadruped  ;  a  shell, 
without  the  soft  parts  of  the  animal ;  an  insect  in  one  stage  of  its  nume- 
rous transformations  ; — these  are  the  scanty  and  imperfect  data  which 
the  naturalist  possesses.  Such  information  may  enable  us  to  separate 
species  which  stand  at  a  considerable  distance  from  each  other ;  but  we 
have  no  right  to  expect  any  thing  but  difficulty  and  ambiguity,  if  we 
attempt,  from  such  imperfect  opportunities,  to  obtain  distinctive  marks 
for  defining  the  characters  of  species  which  are  closely  related. 

If  Lamarck  could  introduce  so  much  certainty  and  precision  into  the 
classification  of  several  thousand  species  of  recent  and  fossil  shells,  not- 
withstanding the  extreme  remoteness  of  the  organization  of  these  ani- 
mals from  the  type  of  those  vertebrated  species  which  are  best  known, 
and  in  the  absence  of  so  many  of  the  living  inhabitants  of  shells,  we  are 
led  to  form  an  exalted  conception  of  the  degree  of  exactness  to  which 
specific  distinctions  are  capable  of  being  carried,  rather  than  to  call  in 
question  their  reality. 

When  our  data  are  so  defective,  the  most  acute  naturalist  must  ex- 
pect to  be  sometimes  at  fault,  and,  like  the  novice,  to  overlook  essential 
points  of  difference,  passing  unconsciously  from  one  species  to  another, 
until,  like  one  who  is  borne  along  in  a  current,  he  is  astonished  on 
looking  back,  at  observing  that  he  has  reached  a  point  so  remote  from 
that  whence  he  set  out. 

It  is  by  no  means  improbable,  that,  when  the  series  of  species  of 
certain  genera  is  very  full,  they  may  be  found  to  differ  less  widely  from 
each  other  than  do  the  mere  varieties  or  races  of  certain  species.  If 
such  a  fact  could  be  established,  it  would,  undoubtedly,  diminish  the 
chance  of  our  obtaining  certainty  in  our  results ;  but  it  would  by  no 
means  overthrow  our  confidence  in  the  reality  of  species. 

Some  mere  varieties  possibly  more  distinct  than  certain  individuals 
of  distinct  species. — It  is  almost  necessary,  indeed,  to  suppose  that  vari- 
eties will  differ  in  some  cases  more  decidedly  than  some  species,  if  we 
admit  that  there  is  a  graduated  scale  of  being,  and  assume  that  the  fol- 
lowing laws  prevail  in  the  economy  of  the  animate  creation  : — first, 
that  the  organization  of  individuals  is  capable  of  being  modified  to  a 
limited  extent,  by  the  force  of  external  causes ;  secondly,  that  these 


582  CAUSES   OF   THE   DIFFICULTY  [On.  XXXIV. 

modifications  are,  to  a  certain  extent,  transmissible  to  their  offspring ; 
thirdly,  that  there  are  fixed  limits,  beyond  which  the  descendants  from 
common  parents  can  never  deviate  from  a  certain  type ;  fourthly,  that 
each  species  springs  from  one  original  stock,  and  can  never  be  perma- 
nently confounded  by  intermixing  with  the  progeny  of  any  other  stock ; 
fifthly,  that  each  species  shall  endure  for  a  considerable  period  of  time. 
Now,  let  us  assume,  for  the  present,  these  rules  hypothetically,  and  see 
what  consequences  may  naturally  be  expected  to  result  from  them. 

We  must  suppose  that  when  the  Author  of  Nature  creates  an  animal 
or  plant,  all  the  possible  circumstances  in  which  its  descendants  are 
destined  to  live  are  foreseen,  and  that  an  organization  is  conferred  upon 
it  which  will  enable  the  species  to  perpetuate  itself  and  survive  under  all 
the  varying  circumstances  to  which  it  must  be  inevitably  exposed. 
Now,  the  range  of  variation  of  circumstances  will  differ  essentially  in 
almost  every  case.  Let  us  take,  for  example,  any  one  of  the  most  in- 
fluential conditions  of  existence,  such  as  temperature.  In  some  extensive 
districts  near  the  equator,  the  thermometer  might  never  vary,  through- 
out several  thousand  centuries,  for  more  than  20°  Fahrenheit ;  so  that 
if  a  plant  or  animal  be  provided  with  an  organization  fitting  it  to  endure 
such  a  range,  it  may  continue  on  the  globe  for  that  immense  period, 
although  every  individual  might  be  liable  at  once  to  be  cut  off  by  the 
least  possible  excess  of  heat  or  cold  beyond  the  determinate  degree.  But 
if  a  species  be  placed  in  one  of  the  temperate  zones,  and  have  a  consti- 
tution conferred  on  it  capable  of  supporting  a  similar  range  of  tempera- 
ture only,  it  will  inevitably  perish  before  a  single  year  has  passed  away. 

Humboldt  has  shown  that,  at  Cumana,  within  the  tropics,  there  is  a 
difference  of  only  4°  Fahr.  between  the  temperature  of  the  warmest  and 
coldest  months  ;  whereas,  in  the  temperate  zones,  the  annual  variation 
amounts  to  about  60°,  and  the  extreme  range  of  the  thermometer  in 
Canada  is  not  less  than  90°. 

The  same  remark  might  be  applied  to  any  other  condition,  as  food, 
for  example ;  it  may  be  foreseen  that  the  supply  will  be  regular  through- 
out indefinite  periods  in  one  part  of  the  world,  and  in  another  very  pre- 
carious and  fluctuating  both  in  kind  and  quantity.  Different  qualifica- 
tions may  be  required  for  enabling  species  to  live  for  a  considerable  time 
under  circumstances  so  changeable.  If,  then,  temperature  and  food  be 
among  those  external  causes  which,  according  to  certain  laws  of  animal 
and  vegetable  physiology,  modify  the  organization,  form,  or  faculties,  of 
individuals,  we  instantly  perceive  that  the  degrees  of  variability  from  a 
common  standard  must  differ  widely  in  the  two  cases  above  supposed  ; 
since  there  is  a  necessity  of  accommodating  a  species  in  one  case  to  a 
much  greater  latitude  of  circumstances  than  in  the  other. 

If  it  be  a  law,  for  instance,  that  scanty  sustenance  should  check  those 
individuals  in  their  growth  which  are  enabled  to  accommodate  them- 
selves to  privations  of  this  kind,  and  that  a  parent,  prevented  in  this 
manner  from  attaining  the  size  proper  to  its  species,  should  produce  a 
dwarfish  offspring,  a  stunted  race  will  arise,  as  is  remarkably  exemplified 


CH.  XXXIV.]  OF    DISCRIMINATING   SPECIES.  583 

in  some  varieties  of  the  horse  and  dog.  The  difference  of  stature  in 
some  races  of  dogs,  when  compared  to  others,  is  as  one  to  five  in  linear 
dimensions,  making  a  difference  of  a  hundred-fold  in  volume.*  Now, 
there  is  a  good  reason  to  believe  that  species  in  general  are  by  no  means 
susceptible  of  existing  under  a  diversity  of  circumstances,  which  may 
give  rise  to  such  a  disparity  in  size,  and,  consequently,  there  will  be  a 
multitude  of  distinct  species,  of  which  no  two  adult  individuals  can  ever 
depart  so  widely  from  a  certain  standard  of  dimensions  as  the  mere  vari- 
eties of  certain  other  species — the  dog,  for  instance.  Now,  we  have 
only  to  suppose  that  what  is  true  of  size,  may  also  hold  in  regard  to 
color  and  many  other  attributes ;  and  it  will  at  once  follow,  that  the 
degree  of  possible  discordance  between  varieties  of  the  same  species 
may,  in  certain  cases,  exceed  the  utmost  disparity  which  can  arise  be- 
tween two  individuals  of  many  distinct  species. 

The  same  remarks  may  hold  true  in  regard  to  instincts ;  for,  if  it 
be  foreseen  that  one  species  will  have  to  encounter  a  great  variety 
of  foes,  it  may  be  necessary  to  arm  it  with  great  cunning  and 
circumspection,  or  with  courage  or  other  qualities  capable  of  developing 
themselves  on  certain  occasions  ;  such,  for  example,  as  those  migratory 
instincts  which  are  so  remarkably  exhibited  at  particular  periods,  after 
they  have  remained  dormant  for  many  generations.  The  history  and 
habits  of  one  variety  of  such  a  species  may  often  differ  more  considerably 
from  some  other  than  those  of  many  distinct  species  which  have  no 
such  latitude  of  accommodation  to  circumstances. 

Extent  of  known  variability  in  species. — Lamarck  has  somewhat 
mis-stated  the  idea  commonly  entertained  of  a  species ;  for  it  is  not 
true  that  naturalists  in  general  assume  that  the  organisation  of  an 
animal  or  plant  remains  absolutely  constant,  and  that  it  can  never 
vary  in  any  of  its  parts.f  All  must  be  aware  that  circumstances 
influence  the  habits,  and  that  the  habits  may  alter  the  state  of  the 
parts  and  organs ;  but  the  difference  of  opinion  relates  to  the  extent 
to  which  these  modifications  of  the  habits  and  organs  of  a  particular 
species  may  be  carried. 

Now,  let  us  first  inquire  what  positive  facts  can  be  adduced  in  the 
history  of  known  species,  to  establish  a  great  and  permanent  amount 
of  change  in  the  form,  structure,  or  instinct  of  individuals  descending 
from  some  common  stock.  The  best  authenticated  examples  of  the 
extent  to  which  species  can  be  made  to  vary  may  be  looked  for  in 
the  history  of  domesticated  animals  and  cultivated  plants.  It  usually 
happens,  that  those  species,  both  of  the  animal  and  vegetable  kingdom, 
which  have  the  greatest  pliability  of  organisation,  those  which 
are  most  capable  of  accommodating  themselves  to  a  great  variety  of 
new  circumstances,  are  most  serviceable  to  man.  These  only  can 
be  carried  by  him  into  different  climates,  and  can  have  their  properties 
or  instincts  variously  diversified  by  differences  of  nourishment 

*  Cuvier,  Discours  Prelimin.  p.  128.  \  Phil.  Zool.  torn.  i.  p.  266. 


584  VARIABILITY   IN   SPECIES.  [Cii.  XXXIV, 

and  habits.  If  the  resources  of  a  species  be  so  limited,  and  its  habits 
and  faculties  be  of  such  a  confined  and  local  character,  that  it  can 
only  flourish  in  a  few  particular  spots,  it  can  rarely  be  of  great 
utility. 

We  may  consider,  therefore,  that  in  the  domestication  of  animals 
and  the  cultivation  of  plants,  mankind  have  first  selected  those  species 
which  have  the  most  flexible  frames  and  constitutions,  and  have  then 
been  engaged  for  ages  in  conducting  a  series  of  experiments,  with 
much  patience  and  at  great  cost,  to  ascertain  what  may  be  the  greatest 
possible  deviation  from  a  common  type  which  can  be  elicited  in  these 
extreme  cases. 

Varieties  of  the  dog — no  transmutation. — The  modifications  pro- 
duced in  the  different  races  of  dogs  exhibit  the  influence  of  man 
in  the  most  striking  point  of  view.  These  animals  have  been 
transported  into  every  climate  and  placed  in  every  variety  of  circum- 
stances ;  they  have  been  made,  as  a  modern  naturalist  observes,  the 
servant,  the  companion,  the  guardian,  and  the  intimate  friend  of 
man,  and  the  power  of  a  superior  genius  has  had  a  wonderful  influ- 
ence not  only  on  their  forms,  but  on  their  manners  and  intelligence.* 
Different  races  have  undergone  remarkable  changes  in  the  quantity 
and  color  of  their  clothing ;  the  dogs  of  Guinea  are  almost  naked,  while 
those  of  the  arctic  circle  are  covered  with  a  warm  coat  both  of  hair  and 
wool,  which  enables  them  to  bear  the  most  intense  cold  without 
inconvenience.  There  are  differences  also  of  another  kind  no  less 
remarkable,  as  in  size,  the  length  of  their  muzzles,  and  the  convexity  of 
their  foreheads. 

But,  if  we  look  for  some  of  those  essential  changes  which  would 
be  required  to  lend  even  the  semblance  of  a  foundation  for  the  theory 
of  Lamarck,  respecting  the  growth  of  new  organs  and  the  gradual 
obliteration  of  others,  we  find  nothing  of  the  kind.  For,  in  all  these 
varieties  of  the  dog,  says  Cuvier,  the  relation  of  the  bones  with  each 
other  remains  essentially  the  same ;  the  form  of  the  teeth  never 
changes  in  any  perceptible  degree,  except  that,  in  some  individuals, 
one  additional  false  grinder  occasionally  appears,  sometimes  on  the  one 
side,  and  sometimes  on  the  other.f  The  greatest  departure  from  a 
common  type — and  it  constitutes  the  maximum  of  variation  as  yet 
known  in  the  animal  kingdom — is  exemplified  in  those  races  of 
dogs  which  have  a  supernumerary  toe  on  the  hind  foot  with  the  corres- 
ponding tarsal  bones  ;  a  variety  analogous  to  one  presented  by  six-fingered 
families  of  the  human  race.J  - 

Lamarck  has  thrown  out  as  a  conjecture,  that  the  wolf  may 
have  been  the  original  of  the  dog ;  and  eminent  naturalists  are  still 
divided  in  opinion  on  this  subject.  It  seems  now  admitted  that  both 
species  agree  in  the  period  of  gestation,  and  Mr.  Owen  has  been  unable 

*  Bureau  de  la  Malle,  An.  des  Sci.  Nat.  torn.  xxi.  p.  53.  Sept.  1830. 
f  Disc.  Prel.  p.  139.  sixth  edition.  \  Ibid. 


CH.  XXXIV.]  VARIABILITY   IN   SPECIES.  585 

to  confirm  the  alleged  difference  in  the  structure  of  a  part  of  the  intes- 
tinal canal.*  Mr.  Bell  inclines  to  the  opinion  that  all  the  various  races 
of  dogs  have  descended  from  one  common  stock,  of  which  the  wolf  is 
the  original  source. 

It  is  well  known  that  the  horse,  the  ox,  the  boar,  and  other  domestic 
animals  which  have  been  introduced  into  South  America,  and  have  run 
wild  in  many  parts,  have  entirely  lost  all  marks  of  domesticity,  and  have 
reverted  to  the  original  characters  of  their  species.  But  dogs  have  also 
become  wild  in  Cuba,  Hayti,  and  in  all  the  Caribbean  islands.  In  the 
course  of  the  seventeenth  century,  they  hunted  in  packs  from  twelve  to 
fifty,  or  more,  in  number,  and  fearlessly  attacked  herds  of  wild  boars 
and  other  animals.  It  is  natural,  therefore,  to  inquire  to  what  form 
they  reverted  ?  Now,  they  are  said  by  many  travellers  to  have  resem- 
bled very  nearly  the  shepherd's  dog ;  but  it  is  certain  that  they  were 
never  turned  into  wolves.  They  were  extremely  savage,  and  their 
ravages  appear  to  have  been  as  much  dreaded  as  those  of  wolves ;  but 
when  any  of  their  whelps  were  caught,  and  brought  from  the  woods  to 
the  towns,  they  grew  up  in  the  most  perfect  submission  to  man. 

Many  examples  might  be  adduced  to  prove  that  the  extent  to  which 
the  alteration  of  species  can  be  pushed  in  the  domestic  state  depends 
on  the  original  capacity  of  the  species  to  admit  of  variation.  The  horse 
has  been  as  long  domesticated  as  the  dog,  yet  its  different  races  depart 
much  less  widely  from  a  common  type  ;  the  ass  has  been  still  less 
changed,  the  camel  scarcely  at  all ;  yet  these  species  have  probably 
been  subjected  to  the  influence  of  domestication  as  long  as  the  horse. 

Mummies  of  animals  in  Egyptian  tombs  identical  with  species  still 
living. — As  the  advocates  of  the  theory  of  transmutation  trust  much  to 
the  slow  and  insensible  changes  which  time  may  work,  they  are  accus- 
tomed to  lament  the  absence  of  accurate  descriptions,  and  figures  of 
particular  animals  and  plants,  handed  down  from  the  earliest  periods  of 
history,  such  as  might  have  afforded  data  for  comparing  the  condition 
of  species,  at  two  periods  considerably  remote.  But,  fortunately,  we 
are  in  some  measure  independent  of  such  evidence  :  for,  by  a  singular 
accident,  the  priests  of  Egypt  have  bequeathed  to  us,  in  their  cemeteries, 
that  information  which  the  museums  and  works  of  the  Greek  philoso- 
phers have  failed  to  transmit. 

For  the  careful  investigation  of  these  documents,  we  are  greatly 
indebted  to  the  skill  and  diligence  of  those  naturalists  who  accom- 
panied the  French  armies  during  their  brief  occupation  of  Egypt :  that 
conquest  of  four  years,  from  which  we  may  date  the  improvement  of  the 
modern  Egyptians  in  the  arts  and  sciences,  and  the  rapid  progress  which 
has  been  made  of  late  in  our  knowledge  of  the  arts  and  sciences  of  their 
remote  predecessors.  Instead  of  wasting  their  whole  time,  as  so  many 
preceding  travellers  had  done,  in  exclusively  collecting  human  mum- 

*  Giildenstadt,  cited  by  Pritchard,  Phys.  Hist,  of  Mankind,  vol.  i.  p.  96. 
f  History  of  British  Quadrupeds,  p.  200.  1887. 


586  EGYPTIAN   MUMMIES   IDENTICAL  [Cn.  XXXIV. 

mies,  M.  Geoffroy  and  his  associates  examined  diligently,  and  sent  home 
great  numbers  of  embalmed  bodies  of  consecrated  animals,  such  as  the 
bull,  the  dog,  the  cat,  the  ape,  the  ichneumon,  the  crocodile,  and 
the  ibis. 

To  those  who  have  never  been  accustomed  to  connect  the  facts  of 
Natural  History  with  philosophical  speculations,  who  have  never  raised 
their  conceptions  of  the  end  and  import  of  such  studies  beyond  the  mere 
admiration  of  isolated  and  beautiful  objects,  or  the  exertion  of  skill  in 
detecting  specific  differences,  it  will  seem  incredible  that  amidst  the  din 
of  arms,  and  the  stirring  excitement  of  political  movements,  so  much 
enthusiasm  could  have  been  felt  in  regard  to  these  precious  remains. 

In  the  official  report  drawn  up  by  the  Professors  of  the  Museum  at 
Paris,  on  the  value  of  these  objects,  there  are  some  eloquent  passages, 
which  may  appear  extravagant,  unless  we  reflect  how  fully  these  natu- 
ralists could  appreciate  the  bearing  of  the  facts  thus  brought  to  light  on 
the  past  history  of  the  globe. 

"  It  seems,"  say  they,  "  as  if  the  superstition  of  the  ancient  Egyptians 
had  been  inspired  by  Nature,  with  a  view  of  transmitting  to  after  ages 
a  monument  of  her  history.  That  extraordinary  and  eccentric  people, 
by  embalming  with  so  much  care  the  brutes  which  were  the  objects  of 
their  stupid  adoration,  have  left  us  in  their  secret  grottoes,  cabinets  of 
zoology  almost  complete.  The  climate  has  conspired  with  the  art  of 
embalming  to  preserve  the  bodies  from  corruption,  and  we  can  now  as- 
sure ourselves  by  our  own  eyes  what  was  the  state  of  a  great  number  of 
species  three  thousand  years  ago.  We  can  scarcely  restrain  the  trans- 
ports of  our  imagination,  on  beholding  thus  preserved,  with  their 
minutest  bones,  with  the  smallest  portions  of  their  skin,  and  in  every 
particular  most  perfectly  recognizable,  many  an  animal,  which  at  The- 
bes or  Memphis,  two  or  three  thousand  years  ago,  had  its  own  priests 
and  altars."* 

Among  the  Egyptian  mummies  thus  procured  were  not  only  those  of 
numerous  wild  quadrupeds,  birds,  and  reptiles ;  but  what  was  perhaps 
of  still  higher  importance  in  deciding  the  great  question  under  discus- 
sion, there  were  the  mummies  of  domestic  animals,  among  which  those 
above  mentioned,  the  bull,  the  dog,  and  the  cat,  were  frequent.  Now, 
such  was  the  conformity  of  the  whole  of  these  species  to  those  now 
living,  that  there  was  no  more  difference,  says  Cuvier,  between  them 
than  between  the  human  mummies  and  the  embalmed  bodies  of 
men  of  the  present  day.  Yet  some  of  these  animals  have  since  that 
period  been  transported  by  man  to  almost  every  climate,  and  forced  to 
accommodate  their  habits  to  the  greatest  variety  of  circumstances.  The 
cat,  for  example,  has  been  carried  over  the  whole  earth,  and  within  the 
last  three  centuries,  has  been  naturalized  in  every  part  of  the  new  world, 
— from  the  cold  regions  of  Canada  to  the  tropical  plains  of  Guiana ; 

*  Ann.  du  Museum  d'Hist.  Nat.  torn.  i.  p.  234.  1802.  The  reporters  were  MM. 
Cuvier,  Lacepede,  and  Lamarck. 


CH.  XXXIV.]  WITH   SPECIES   STILL   LIVING.  587 

yet  it  has  scarcely  undergone  any  perceptible  mutation,  and  is  still  the 
same  animal  which  was  held  sacred  by  the  Egyptians. 

Of  the  ox,  undoubtedly,  there  are  many  very  distinct  races  ;  but  the 
bull  Apis,  which  was  led  in  solemn  processions  by  the  Egyptian  priests, 
did  not  differ  from  some  of  those  now  living.  The  black  cattle  that 
have  run  wild  in  America,  where  there  were  many  peculiarities  in  the  cli- 
mate not  to  be  found,  perhaps,  in  any  part  of  the  old  world,  and  where 
scarcely  a  single  plant  on  which  they  fed  was  of  precisely  the  same 
species,  instead  of  altering  their  form  and  habits,  have  actually  reverted 
to  the  exact  likeness  of  the  aboriginal  wild  cattle  of  Europe. 

In  answer  to  the  arguments  drawn  from  the  Egyptian  mummies, 
Lamarck  said  they  were  identical  with  their  living  descendants  in  the 
same  country,  because  the  climate  and  physical  geography  of  the  banks 
of  the  Nile  have  remained  unaltered  for  the  last  thirty  centuries.  But 
why,  it  may  be  asked,  have  other  individuals  of  these  species  retained 
the  same  characters  in  many  different  quarters  of  the  globe,  where  the 
climate  and  many  other  conditions  are  so  varied  ? 

Seeds  and  plants  from  the  Egyptian  tombs. — The  evidence  derived 
from  the  Egyptian  monuments  was  not  confined  to  the  animal  kingdom ; 
the  fruits,  seeds,  and  other  portions  of  twenty  different  plants,  were 
faithfully  preserved  in  the  same  manner ;  and  among  these  the  com- 
mon wheat  was  procured  by  Delille,  from  closed  vessels  in  the  sepul- 
chres of  the  kings,  the  grain  of  which  retained  not  only  their  form 
but  even  their  color  ;  so  effectual  has  proved  the  process  of  embalming 
with  bitumen  in  a  dry  and  equable  climate.  No  difference  could  be 
detected  between  this  wheat  and  that  which  now  grows  in  the  East 
and  elsewhere ;  and  in  regard  to  the  barley,  I  am  informed  by  Mr. 
Brown,  the  celebrated  botanist,  that  its  identity  with  the  grain  of  our 
own  times  can  be  tested  by  the  closest  comparison.  On  examining,  for 
example,  one  of  the  seeds  from  Mr.  Sam's  Egyptian  collection  in  the 
British  Museum,  it  is  found  that  "  the  structure  of  the  husks  or  that 
part  of  the  flower  which  is  persistent,  agrees  precisely  with  the  barley  of 
the  present  day,  in  having  one  perfect  flower  and  the  filiform  rudiments 
of  a  second."  Some  naturalists  believe  that  the  perfect  identification 
of  the  ancient  Egyptian  cerealia  with  the  varieties  now  cultivated  has 
been  carried  still  further,  by  sowing  the  seeds  taken  out  of  the  cata- 
combs, and  raising  plants  from  them  ;  but  we  want  more  evidence  of 
this  fact.  Certain  it  is,  that  when  the  experiment  was  recently  made 
in  the  botanic  garden  at  Kew,  with  100  seeds  of  wheat,  barley,  and 
lentils,  from  the  Egyptian  collection  before  mentioned  of  the  British 
Museum,  not  one  of  them  would  germinate.* 

*  I  by  no  means  wish  to  express  an  opinion  that  seeds  cannot  retain  their 
vitality 'after  an  entombment  of  3,000  years;  but  one  of  my  botanical  friends 
who  entertained  a  philosophical  doubt  on  this  subject,  being  desirous  of  ascer- 
taining the  truth  of  three  or  four  alleged  instances  of  the  germination  of 
"mummy  wheat,"  discovered,  on  communicating  with  several  Egyptian  travel- 
lers, that  they  had  procured  the  grains  in  question,  not  directly  from  the  cata- 
combs, but  from  the  Arabs,  who  are  always  ready  to  supply  strangers  with  an 


588  VARIETIES   IN    PLANTS  [Cii.  XXXIV 

Native  country  of  the  common  wheat. — And  here  I  may  observe  that 
there  is  an  obvious  answer  to  Lamarck's  objection,  that  the  botanist  can- 
not point  out  a  country  where  the  common  wheat  grows  wild,  unless  in 
places  where  it  may  have  been  derived  from  neighboring  cultivation.* 
All  naturalists  are  well  aware  that  the  geographical  distribution  of  a 
great  number  of  species  is  extremely  limited ;  that  it  was  to  be  ex- 
pected that  every  useful  plant  should  first  be  cultivated  successfully  in 
the  country  where  it  was  indigenous ;  and  that,  probably,  every  station 
which  it  partially  occupied,  when  growing  wild,  would  be  selected  by 
the  agriculturist  as  best  suited  to  it  when  artificially  increased.  Pales- 
tine has  been  conjectured,  by  a  late  writer  on  the  cerealia,  to  have  been 
the  original  habitation  of  wheat  and  barley;  a  supposition  which  is 
rendered  the  more  plausible  by  Hebrew  and  Egyptian  traditions,  and 
by  tracing  the  migrations  of  the  worship  of  Ceres,  as  indicative  of  the 
migrations  of  the  plant.f 

If  we  are  to  infer  that  some  one  of  the  wild  grasses  has  been  trans- 
formed into  the  common  wheat,  and  that  some  animal  of  the  genus 
CaniSj  still  unreclaimed,  has  been  metamorphosed  into  the  dog,  merely 
because  we  cannot  find  the  domestic  dog,  or  the  cultivated  wheat,  in  a 
state  of  nature,  we  may  be  next  called  upon  to  make  similar  admissions 
in  regard  to  the  camel ;  for  it  seems  very  doubtful  whether  any  race  of 
this  species  of  quadruped  is  now  wild. 

Changes  in  plants  produced  by  cultivation. — But  if  agriculture,  it 
will  be  said,  does  not  supply  examples  of  extraordinary  changes  of 
form  and  organization,  the  horticulturist  can,  at  least,  appeal  to  facts 
which  may  confound  the  preceding  train  of  reasoning.  The  crab  has 
been  transformed  into  the  apple ;  the  sloe  into  the  plum ;  flowers 
have  changed  their  color,  and  become  double ;  and  these  new  charac- 
ters can  be  perpetuated  by  seed ;  a  bitter  plant,  with  wavy  sea-green 
leaves,  has  been  taken  from  the  sea-side,  where  it  grew  like  wild  char- 
lock ;  has  been  transplanted  into  the  garden,  lost  its  saltness,  and  has 
been  metamorphosed  into  two  distinct  vegetables,  as  unlike  each  other 
as  is  each  to  the  parent  plant — the  red  cabbage  and  the  cauliflower. 
These,  and  a  multitude  of  analogous  facts,  are  undoubtedly  among  the 
wonders  of  nature,  and  attest  more  strongly,  perhaps,  the  extent  to 
which  species  may  be  modified,  than  any  examples  derived  from  the 
animal  kingdom.  But  in  these  cases  we  find  that  we  soon  reach  certain 
limits,  beyond  which  we  are  unable  to  cause  the  individuals  descend- 
ing from  the  same  stock  to  vary ;  while,  on  the  other  hand,  it  is  easy 
to  show  that  these  extraordinary  varieties  could  seldom  arise,  and  could 
never  be  perpetuated  in  a  wild  state  for  many  generations,  under  any 
imaginable  combination  of  accidents.  They  may  be  regarded  as  ex- 
article  now  very  frequently  in  demand.  The  presence  of  an  occasional  grain  of 
Indian  corn  or  maize  in  several  of  the  parcels  of  grain  shown  to  my  friend  as 
coming  from  the  catacombs  confirmed  his  scepticism. 

*  Phil.  Zool..  torn.  i.  p.  227. 

f  L'Origine  et  la  Paine  des  CYveales,  etc.,  Annales  des  Sciences  Natur.,  torn. 
ix.  p.  61.  " 


CH.  XXXIV.]  PRODUCED    BY   HORTICULTURE.  589 

treme  cases,  brought  about  by  human  interference,  and  not  as  pheno- 
mena which  indicate  a  capability  of  indefinite  modification  in  the 
natural  world. 

The  propagation  of  a  plant  by  buds  or  grafts,  and  by  cuttings,  is 
obviously  a  mode  which  nature  does  not  employ ;  and  this  multiplica- 
tion, as  well  as  that  produced  by  roots  and  layers,  seems  merely  to 
operate  as  an  extension  of  the  life  of  an  individual,  and  nol  as  a  repro- 
duction of  the  species  such  as  happens  by  seed.  All  plants  increased 
by  grafts  or  layers  retain  precisely  the  peculiar  qualities  of  the  indivi- 
dual to  which  they  owe  their  origin,  and,  like  an  individual,  they  have 
only  a  determinate  existence  ;  in  some  cases  longer,  and  in  others 
shorter.*  It  seems  now  admitted  by  horticulturists,  that  none  of  our 
garden  varieties  of  fruit  are  entitled  to  be  considered  strictly  permanent, 
but  that  they  wear  out  after  a  time  ;f  and  we  are  thus  compelled  to  resort 
again  to  seeds ;  in  which  case  there  is  so  decided  a  tendency  in  the 
seedlings  to  revert  to  the  original  type,  that  our  utmost  skill  is  some- 
times baffled  in  attempting  to  recover  the  desired  variety. 

Varieties  of  the  cabbage. — The  different  races  of  cabbages  afford,  as 
was  admitted,  an  astonishing  example  of  deviation  from  a  common 
type  ;  but  we  can  scarcely  conceive  them  to  have  originated,  much 
less  to  have  lasted  for  several  generations,  without  the  intervention  of 
man.  It  is  only  by  strong  manures  that  these  varieties  have  been  ob- 
tained, and  in  poorer  soils  they  instantly  degenerate.  If,  therefore,  we 
suppose  in  a  state  of  nature  the  seed  of  the  wild  Brassica  oleracea  to 
have  been  wafted  from  the  sea-side  to  some  spot  enriched  by  the  dung 
of  animals,  and  to  have  there  become  a  cauliflower,  it  would  soon  diffuse 
its  seed  to  some  comparatively  sterile  soils  around,  and  the  offspring 
would  relapse  to  the  likeness  of  the  parent  stock. 

But  if  we  go  so  far  as  to  imagine  the  soil,  in  the  spot  first  occupied, 
to  be  constantly  manured  by  herds  of  wild  animals,  so  as  to  continue 
as  rich  as  that  of  a  garden,  still  the  variety  could  not  be  maintained ; 
because  we  know  that  each  of  these  races  is  prone  to  fecundate  others, 
and  gardeners  are  compelled  to  exert  the  utmost  diligence  to  prevent 
cross-breeds.  The  intermixture  of  the  pollen  of  varieties  growing  in 
the  poorer  soil  around  would  soon  destroy  the  peculiar  characters  of 
the  race  which  occupied  the  highly  manured  tract ;  for,  if  these  acci- 
dents so  continually  happen,  in  spite  of  our  care,  among  the  culinary 
varieties,  it  is  easy  to  see  how  soon  this  cause  might  obliterate  every 
marked  singularity  in  a  wild  state. 

Besides,  it  is  well  known  that,  although  the  pampered  races  which 
we  rear  in  our  gardens  for  use  or  ornament  may  often  be  perpetuated 
by  seed,  yet  they  rarely  produce  seed  in  such  abundance,  or  so  prolific 
in  quality,  as  wild  individuals ;  so  that  if  the  care  of  man  were  with- 
drawn, the  most  fertile  variety  would  always,  in  the  end,  prevail  over 
the  more  sterile. 

*  Smith's  Introduction  to  Botany,  p.  138,  edit.  1807. 

f  See  Mi-.  Knight's  Observations,  Hort.  Trans.,  vol.  ii.  p.  160. 


590  VARIETIES   OF   THE   PRIMROSE.  [On.  XXXVI. 

Similar  remarks  may  be  applied  to  the  double  flowers,  which  present 
such  strange  anomalies  to  the  botanist.  The  ovarium,  in  such  cases,  is 
frequently  abortive ;  and  the  seeds,  when  prolific,  are  generally  much 
fewer  than  where  the  flowers  are  single. 

Changes  caused  by  soil. — Some  curious  experiments,  recently  made 
on  the  production  of  blue  instead  of  red  flowers  in  the  Hydrangea 
hortensis,  illustrate  the  immediate  effect  of  certain  soils  on  the  colors 
of  the  calvx  and  petals.  In  garden-mould  or  compost,  the  flowers  are 
invariably  red  ;  in  some  kinds  of  bog-earth  they  are  blue  ;  and  the  same 
change  is  always  produced  by  a  particular  sort  of  yellow  loam. 

Varieties  of  the  primrose. — Linnaeus  was  of  opinion  that  the  prim- 
rose, oxlip,  cowslip,  and  polyanthus,  were  only  varieties  of  the  same 
species.  The  majority  of  the  modern  botanists,  on  the  contrary,  con- 
sider them  to  be  distinct,  although  some  conceived  that  the  oxlip  might 
be  a  cross  between  the  cowslip  and.  the  primrose.  Mr.  Herbert  has 
lately  recorded  the  following  experiment : — "  I  raised  from  the  natural 
seed  of  one  umbel  of  a  highly  manured  red  cowslip  a  primrose,  a 
cowslip,  oxlips  of  the  usual  and  other  colors,  a  black  polyanthus,  a 
hose-in-hose  cowslip,  and  a  natural  primrose  bearing  its  flower  on  a 
polyanthus  stalk.  From  the  seed  of  that  very  hose-in-hose  cowslip 
I  have  since  raised  a  hose-in-hose  primrose.  I  therefore  consider  all 
these  to  be  only  local  varieties,  depending  upon  soil  and  situation."* 
Professor  Henslow,  of  Cambridge,  has  since  confirmed  this  experiment 
of  Mr.  Herbert ;  so  that  we  have  an  example,  not  only  of  the  remark- 
able varieties  which  the  florist  can  obtain  from  a  common  stock,  but  of 
the  distinctness  of  analogous  races  found  in  a  wild  state.f 

On  what  particular  ingredient,  or  quality  in  the  earth,  these  changes 
depend,  has  not  yet  been  ascertained.];  But  gardeners  are  well  aware 
that  particular  plants,  when  placed  under  the  influence  of  certain  cir- 
cumstances, are  changed  in  various  ways,  according  to  the  species ;  and 
as  often  as  the  experiments  are  repeated,  similar  results  are  obtained. 
The  nature  of  these  results,  however,  depends  upon  the  species,  and 
they  are,  therefore,  part  of  the  specific  character ;  they  exhibit  the 
same  phenomena,  again  and  again,  and  indicate  certain  fixed  and  in- 
variable relations  between  the  physiological  peculiarities  of  the  plant, 
and  the  influence  of  certain  external  agents.  They  afford  no  ground 
for  questioning  the  instability  of  species,  but  rather  the  contrary ; 
they  present  us  with  a  class  of  phenomena,  which,  when  they  are  more 
thoroughly  understood,  may  afford  some  of  the  best  tests  for  identifying 
species,  and  proving  that  the  attributes  originally  conferred  endure  so 
long  as  any  issue  of  the  original  stock  remains  upon  the  earth. 

*  Hort.  Trans,  vol.  iv.  p.  19. 

f  London's  Mag.  of  Nat.  Hist.,  Sept.  1830,  vol.  iii.  p.  408. 

\  Hort.  Trans,  vol.  iii.  p.  173. 


CHAPTER  XXXV. 

WHETHER    SPECIES    HAVE    A    REAL   EXISTENCE    IN    NATURE — 

continued. 

Limits  of  the  variability  of  species — Species  susceptible  of  modification  may  be 
altered  greatly  in  a  short  time,  and  in  a  few  generations  ;  after  which  they  re- 
main stationary — The  animals  now  subject  to  man  had  originally  an  aptitude  to 
domesticity — Acquired  peculiarities  which  become  hereditary  have  a  close  con- 
nexion with  the  habits  or  instincts  of  the  species  in  a  wild  state — Some  qualities 
in  certain  animals  have  been  conferred  with  a  view  of  their  relation  to  man — 
Wild  elephant  domesticated  in  a  few  years,  but  its  faculties  incapable  of  farther 
development] 

Variability  of  a  species  compared  to  that  of  an  individual. — I 
endeavored,  in  the  last  chapter,  to  show,  that  a  belief  in  the  reality 
of  species  is  not  inconsistent  with  the  idea  of  a  considerable  degree 
of  variability  in  the  specific  character.  This  opinion,  indeed,  is  little 
more  than  an  extension  of  the  idea  which  we  must  entertain  of 
the  identity  of  an  individual,  throughout  the  changes  which  it  is  capable 
of  undergoing. 

If  a  quadruped,  inhabiting  a  cold  northern  latitude,  and  covered 
with  a  warm  coat  of  hair  or  wool,  be  transported  to  a  southern  climate, 
it  will  often,  in  the  course  of  a  few  years,  shed  a  considerable  portion 
of  its  coat,  which  it  gradually  recovers  on  being  again  restored  to  its 
native  country.  Even  there  the  same  changes  are,  perhaps,  superin- 
duced to  a  certain  extent  by  the  return  of  winter  and  summer. 
We  know  that  the  Alpine  hare  (Lepus  variabilis,  Pal.)  and  the 
ermine,  or  stoat,  (Mustela  erminea,  Linn.)  become  white  during  winter, 
and  again  obtain  their  full  color  during  the  warmer  season  ;  that  the 
plumage  of  the  ptarmigan  undergoes  a  like  metamorphosis  in  color 
and  quantity,  and  that  the  change  is  equally  temporary.  We 
are  aware  that,  if  we  reclaim  some  wild  animal,  and  modify  its  habits 
and  instincts  by  domestication,  it  may,  if  it  escapes,  become  in  a  few 
years  nearly  as  wild  and  untractable  as  ever  ;  and  if  the  same  individual 
be  again  retaken,  it  may  be  reduced  to  its  former  tame  state.  A  plant 
is  sown  in  a  prepared  soil,  in  order  that  the  petals  of  its  flowers  may 
multiply,  and  their  color  be  heightened  or  changed :  if  we  then  with- 
hold our  care,  the  flowers  of  this  same  species  become  again  single.  In 
these,  and  innumerable  other  instances,  we  must  suppose  that  the 
species  was  produced  with  a  certain  number  of  qualities ;  and,  in  the 
case  of  animals,  with  a  variety  of  instincts,  some  of  which  may  or  may 
not  be  developed  according  to  circumstances,  or  which,  after  having 
been  called  forth,  may  again  become  latent  when  the  exciting  causes  are 
removed. 


592  EXTENT   OF   CHANGE   IN   SPECIES.  [Ce.  XXXV. 

Now,  the  formation  of  races  seems  the  necessary  consequence 
of  such  a  capability  in  species  to  vary,  if  it  be  a  general  law  that  the 
offspring  should  very  closely  resemble  the  parent.  But,  before 
we  can  infer,  that  there  are  no  limits  to  the  deviation  from  an  original 
type  which  may  be  brought  about  in  the  course  of  an  indefinite 
number  of  generations,  we  ought  to  have  some  proof  that,  in  each 
successive  generation,  individuals  may  go  on  acquiring  an  equal 
amount  of  new  peculiarities,  under  the  influence  of  equal  changes 
of  circumstances.  The  balance  of  evidence,  however,  inclines  most 
decidedly  on  the  opposite  side ;  for  in  all  cases  we  find  that  the  quantity 
of  divergence  diminishes  after  a  few  generations  in  a  very  rapid 
ratio. 

Species  susceptible  of  modification  may  be  greatly  altered  in  a  few 
generations. — It  cannot  be  objected,  that  it  is  out  of  our  power  to  go 
on  varying  the  circumstances  in  the  same  manner  as  might  happen 
in  the  natural  course  of  events  during  some  great  geological  cycle. 
For  in  the  first  place,  where  a  capacity  is  given  to  individuals  to  adapt 
themselves  to  new  circumstances,  it  does  not  generally  require  a  very 
long  period  for  its  development :  if,  indeed,  such  were  the  case,  it  is 
not  easy  to  see  how  the  modification  would  answer  the  ends  proposed, 
for  all  the  individuals  would  die  before  new  qualities,  habits,  or  instincts 
were  conferred. 

When  we  have  succeeded  in  naturalizing  some  tropical  plant  in 
a  temperate  climate,  nothing  prevents  us  from  attempting  gradually  to 
extend  its  distribution  to  higher  latitudes,  or  to  greater  elevations 
above  the  level  of  the  sea,  allowing  equal  quantities  of  time,  or  an 
equal  number  of  generations,  for  habituating  the  species  to  successive 
increments  of  cold.  But  every  husbandman  and  gardener  is  aware 
that  such  experiments  will  fail ;  and  we  are  more  likely  to  succeed  in 
making  some  plants,  in  the  course  of  the  first  two  generations,  support 
a  considerable  degree  of  difference  of  temperature,  than  a  very  small 
difference  afterwards,  though  we  persevere  for  many  centuries. 

It  is  the  same  if  we  take  any  other  cause  instead  of  temperature  ; 
such  as  the  quality  of  the  food,  or  the  kind  of  dangers  to  which  an 
animal  is  exposed,  or  the  soil  in  which  a  plant  lives.  The  alteration 
in  habits,  form,  or  organization,  is  often  rapid  during  a  short  period ; 
but  when  the  circumstances  are  made  to  vary  farther,  though  in  ever 
so  slight  a  degree,  all  modification  ceases,  and  the  individual  perishes. 
Thus  some  herbivorous  quadrupeds  may  be  made  to  feed  partially  on 
fish  or  flesh ;  but  even  these  can  never  be  taught  to  live  on  some  herbs 
which  they  reject,  and  which  would  even  poison  them,  although  the 
same  may  be  very  nutritious  to  other  species  of  the  same  natural  order. 
So  when  man  uses  force  or  stratagem  against  wild  animals,  the  perse- 
cuted race  soon  becomes  more  cautious,  watchful,  and  cunning;  new 
instincts  seem  often  to  be  developed,  and  to  become  hereditary  in  the 
first  two  or  three  generations :  but  let  the  skill  and  address  of  man 
increase,  however  gradually,  no  farther  variation  can  take  place,  no  new 


CH.  XXXV.]  EXTENT   OF    CHANGE   IN   SPECIES.  593 

qualities  are  elicited  by  the  increasing  dangers.  The  alteration  of  the 
habits  of  the  species  has  reached  a  point  beyond  which  no  ulterior 
modification  is  possible,  however  indefinite  the  lapse  of  ages  during 
which  the  new  circumstances  operate.  Extirpation  then  follows,  rather 
than  such  a  transformation  as  could  alone  enable  the  species  to  perpe- 
tuate itself  under  the  new  state  of  things. 

Animals  now  subject  to  man  had  originally  an  aptitude  to  domes- 
ticity.— It  has  been  well  observed  by  M.  F.  Cuvier  and  M.  Dureau  de 
la  Malle,  that  unless  some  animals  had  manifested  in  a  wild  state  an 
aptitude  to  second  the  efforts  of  man,  their  domestication  would  never 
have  been  attempted.  If  they  had  all  resembled  the  wolf,  the  fox,  and 
the  hy»3na,  the  patience  of  the  experimentalist  would  have  been 
exhausted  by  innumerable  failures  before  he  at  last  succeeded  in  obtain- 
ing some  imperfect  results ;  so  if  the  first  advantages  derived  from  the 
cultivation  of  plants  had  been  elicited  by  as  tedious  and  costly  a  pro- 
cess as  that  by  which  we  now  make  some  slight  additional  improve- 
ments in  certain  races,  we  should  have  remained  to  this  day  in  ignorance 
of  the  greater  number  of  their  useful  qualities. 

Acquired  instincts  of  some  animals  become  hereditary. — It  is  un- 
doubtedly true,  that  many  new  habits  and  qualities  have  not  only  been 
acquired  in  recent  times  by  certain  races  of  dogs,  but  have  been  trans- 
mitted to  their  offspring.  But  in  these  cases  it  will  be  observed,  that 
the  new  peculiarities  have  an  intimate  relation  to  the  habits  of  the 
animal  in  a  wild  state,  and  therefore  do  not  attest  any  tendency  to 
a  departure  to  an  indefinite  extent  from  the  original  type  of  the 
species.  A  race  of  dogs  employed  for  hunting  deer  in  the  platform  of 
Sante  Fe,  in  Mexico,  affords  a  beautiful  illustration  of  a  new  hereditary 
instinct.  The  mode  of  attack,  observes  M.  Roulin,  which  they  employ 
consists  in  seizing  the  animal  by  the  belly  and  overturning  it  by  a 
sudden  effort,  taking  advantage  of  the  moment  when  the  body  of  the 
deer  rests  only  upon  the  fore-legs.  The  weight  of  the  animal  thus  thrown 
over  is  often  six  times  that  of  its  antagonist.  The  dog  of  pure  breed 
inherits  a  disposition  to  this  kind  of  chase,  and  never  attacks  a  deer 
from  before  while  running.  Even  should  the  deer,  not  perceiving  him, 
come  directly  upon  him,  the  dog  steps  aside  and  makes  his  assault  on 
the  flank ;  whereas  other  hunting  dogs,  though  of  superior  strength, 
and  general  sagacity,  which  are  brought  from  Europe,  are  destitute  of 
this  instinct.  For  want  of  similar  precautions,  they  are  often  killed  by 
the  deer  on  the  spot,  the  vertebras  of  their  neck  being  dislocated  by  the 
violence  of  the  shock.* 

A  new  instinct  has  also  become  hereditary  in  a  mongrel  race  of  dogs 
employed  by  the  inhabitants  of  the  banks  of  the  Magdalena  almost 
exclusively  in  hunting  the  white-lipped  pecari.  The  address  of  these 
dogs  consists  in  restraining  their  ardor,  and  attaching  themselves  to  no 
animal  in  particular,  but  keeping  the  whole  herd  in  check.  Now, 

*  M.  Roulin,  Ann.  des  Sci.  Nat.  torn.  xvi.  p.  16.  1829. 
38 


594  INFLUENCE   OF  [On.  XXXV 

among  these  dogs  some  are  found,  which  the  very  first  time  they  are 
taken  to  the  woods,  are  acquainted  with  this  mode  of  attack  ;  whereas, 
a  dog  of  another  breed  starts  forward  at  once,  is  surrounded  by  the 
pecari,  and,  whatever  may  be  his  strength,  is  destroyed  in  a  moment. 

Some  of  our  countrymen,  engaged  of  late  in  conducting  one  of  the 
principal  mining  associations  in  Mexico,  that  of  Real  del  Monte,  carried 
out  with  them  some  English  greyhounds  of  the  best  breed,  to  hunt  the 
hares  which  abound  in  that  country.  The  great  platform  which  is  the 
scene  of  sport  is  at  an  elevation  of  about  nine  thousand  feet  above  the 
level  of  the  sea,  and  the  mercury  in  the  barometer  stands  habitually  at 
the  height  of  about  nineteen  inches.  It  was  found  that  the  greyhounds 
could  not  support  the  fatigues  of  a  long  chase  in  this  attenuated  atmo- 
sphere, and  before  they  could  come  up  with  their  prey,  they  lay  down 
gasping  for  breath  ;  but  these  same  animals  have  produced  whelps 
which  have  grown  up,  and  are  not  in  the  least  degree  incommoded  by 
the  want  of  density  in  the  air,  but  run  down  the  hares  with  as  much 
ease  as  the  fleetest  of  their  race  in  this  country. 

The  fixed  and  deliberate  stand  of  the  pointer  has  with  propriety  been 
regarded  as  a  mere  modification  of  a  habit,  which  may  have  been  use- 
ful to  a  wild  race  accustomed  to  wind  game,  and  steal  upon  it  by  sur- 
prise, first  pausing  for  an  instant,  in  order  to  spring  with  unerring  aim. 
The  faculty  of  the  retriever,  however,  may  justly  be  regarded  as  more 
inexplicable  and  less  easily  referable  to  the  instinctive  passions  of  the 
species.  M.  Majendie,  says  a  French  writer  in  a  recently  published 
memoir,  having  learnt  that  there  was  a  race  of  dogs  in  England  which 
stopped  and  brought  back  game  of  their  own  accord,  procured  a 
pair,  and  having  obtained  a  whelp  from  them,  kept  it  constantly  under 
his  eyes,  until  he  had  an  opportunity  of  assuring  himself  that,  without 
having  received  any  instruction,  and  on  the  very  first  day  that  it  was 
carried  to  the  chase,  it  brought  back  game  with  as  much  steadiness  as 
dogs  which  had  been  schooled  into  the  same  manoauvre  by  means  of  the 
whip  and  collar. 

Attributes  of  animals  in  their  relation  to  man. — Such  attainments,  as 
well  as  the  habits  and  dispositions  which  the  shepherd's  dog  and  many 
others  inherit,  seem  to  be  of  a  nature  and  extent  which  we  can  hardly 
explain  by  supposing  them  to  be  modifications  of  instincts  necessary 
for  the  preservation  of  the  species  in  a  wild  state.  When  such  re- 
markable habits  appear  in  races  of  this  species  we  may  reasonably 
conjecture  that  they  were  given  with  no  other  view  than  for  the  use  of 
man  and  the  preservation  of  the  dog,  which  thus  obtains  protection. 

As  a  general  rule,  I  fully  agree  with  M.  F.  Cuvier,  that,  in  studying 
the  habits  of  animals,  we  must  attempt,  as  far  as  possible,  to  refer  their 
domestic  qualities  to  modifications  of  instincts  which  are  implanted  in 
them  in  a  state  of  nature ;  and  that  writer  has  successfully  pointed  out, 
in  an  admirable  essay  on  the  domestication  of  the  mammalia*,  the  true 

*  Mem.  du  Mus.  d'Hist.  Nat. — Jameson,  Ed.  New  Phil.  Journ.  Nos.  6,  7,  8. 


CH.  XXXV.]  DOMESTICATION   OF   ANIMALS.  595 

origin  of  many  dispositions  which  are  vulgarly  attributed  to  the  influ- 
ence of  education  alone.  But  we  should  go  too  far  if  we  did  not  admit 
that  some  of  the  qualities  of  particular  animals  and  plants  may  have 
been  given  solely  with  a  view  to  the  connection  which  it  was  foreseen 
would  exist  between  them  and  man — especially  when  we  see  that  con- 
nexion to  be  in  many  cases  so  intimate,  that  the  greater  number,  and 
sometimes,  as  in  the  case  of  the  camel,  all  the  individuals  of  the  species 
which  exist  on  the  earth  are  in  subjection  to  the  human  race. 

We  can  perceive  in  a  multitude  of  animals,  especially  in  some  of  the 
parasitic  tribes,  that  certain  instincts  and  organs  are  conferred  for  the 
purpose  of  defence  or  attack  against  some  other  species.  Now  if  we 
are  reluctant  to  suppose  the  existence  of  similar  relations  between 
man  and  the  instincts  of  many  of  the  inferior  animals,  we  adopt  an 
hypothesis  no  less  violent,  though  in  the  opposite  extreme  to  that  which 
has  led  some  to  imagine  the  whole  animate  and  inanimate  creation  to 
have  been  made  solely  for  the  support,  gratification,  and  instruction  of 
mankind. 

Many  species,  most  hostile  to  our  persons  or  property,  multiply,  in 
spite  of  our  efforts  to  repress  them;  others,  on  the  contrary,  are 
intentionally  augmented  many  hundred  fold  in  number  by  our  exertions. 
In  such  instances,  we  must  imagine  the  relative  resources  of  man,  and 
of  species  friendly  or  inimical  to  him,  to  have  been  prospectively  calcu- 
lated and  adjusted.  To  withhold  assent  to  this  supposition,  would  be 
to  refuse  what  we  must  grant  in  respect  to  the  economy  of  nature  in 
every  other  part  of  the  organic  creation ;  for  the  various  species  of 
contemporary  plants  and  animals  have  obviously  their  relative  forces, 
nicely  balanced,  and  their  respective  tastes,  passions,  and  instincts  so 
contrived,  that  they  are  all  in  perfect  harmony  with  each  other.  In  no 
other  manner  could  it  happen  that  each  species,  surrounded,  as  it  is,  by 
countless  dangers,  should  be  enabled  to  maintain  its  ground  for  periods 
of  considerable  duration. 

The  docility  of  the  individuals  of  some  of  our  domestic  species, 
extending,  as  it  does,  to  attainments  foreign  to  their  natural  habits  and 
faculties,  may,  perhaps,  have  been  conferred  with  a  view  to  their  asso- 
ciation with  man.  But,  lest  species  should  be  thereby  made  to  vary 
indefinitely,  we  find  that  such  habits  are  never  transmissible  by 
generation. 

A  pig  has  been  trained  to  hunt  and  point  game  with  great  activity 
and  steadiness  * ;  and  other  learned  individuals,  of  the  same  species, 
have  been  taught  to  spell;  but  such  fortuitous  acquirements  never 
become  hereditary,  for  they  have  no  relation  whatever  to  the  exigencies 
of  the  animal  in  a  wild  state,  and  cannot,  therefore,  be  developments  of 
any  instinctive  propensities. 

Influence  of  domestication. — An  animal  in  domesticity,  says  M.  F. 

*  In  the  New  Forest,  near  Ringwood,  Hants,  by  Mr.  Toomer,  keeper  of  Broomy 
Lodge.  1  have  conversed  with  witnesses  of  the  fact. 


596  INFLUENCE   OF  [Cn.  XXXV. 

Cuvier,  is  not  essentially  in  a  different  situation,  in  regard  to  the 
feeling  of  restraint,  from  one  left  to  itself.  It  lives  in  society  without 
constraint,  because,  without  doubt,  it  was  a  social  animal ;  and  it  con- 
forms itself  to  the  will  of  man,  because  it  had  a  chief,  to  which,  in  a 
wild  state,  it  would  have  yielded  obedience.  There  is  nothing  in  its 
new  situation  that  is  not  conformable  to  its  propensities  ;  it  is  satisfy- 
ing its  wants  by  submission  to  a  master,  and  makes  no  sacrifice  of  its 
natural  inclinations.  All  the  social  animals,  when  left  to  themselves, 
form  herds  more  or  less  numerous ;  and  all  the  individuals  of  the 
same  herd  know  each  other,  are  mutually  attached,  and  will  not  allow 
a  strange  individual  to  join  them.  In  a  wild  state,  moreover,  they 
obey  some  individual,  which,  by  its  superiority,  has  become  the  chief 
of  the  herd.  Our  domestic  species  had,  originally,  this  sociability  of 
disposition ;  and  no  solitary  species,  however  easy  it  may  be  to  tame 
it,  has  yet  afforded  true  domestic  races.  We  merely,  therefore,  develope, 
to  our  own  advantage,  propensities  which  propel  the  individuals  of 
certain  species  to  draw  near  to  their  fellows. 

The  sheep  which  we  have  reared  is  induced  to  follow  us,  as  it 
would  be  led  to  follow  the  flock  among  which  it  was  brought  up ;  and, 
when  individuals  of  gregarious  species  have  been  accustomed  to  one 
master,  it  is  he  alone  whom  they  acknowledge  as  their  chief — he  only 
whom  they  obey.  "  The  elephant  allows  himself  to  be  directed  only 
by  the  carnac  whom  he  has  adopted ;  the  dog  itself,  reared  in  solitude 
with  its  master,  manifests  a  hostile  disposition  towards  all  others ; 
and  every  body  knows  how  dangerous  it  is  to  be  in  the  midst  of  a  herd 
of  cows,  in  pasturages  that  are  little  frequented,  when  they  have  not  at 
their  head  the  keeper  who  takes  care  of  them. 

"  Every  thing,  therefore,  tends  to  convince  us,  that  formerly  men 
were  only  with  regard  to  the  domestic  animals,  what  those  who  are 
particularly  charged  with  the  care  of  them  still  are — namely,  members 
of  the  society  which  these  animals  form  among  themselves ;  and,  that 
they  are  only  distinguished,  in  the  general  mass,  by  the  authority 
which  they  have  been  enabled  to  assume  from  their  superiority  of  in- 
tellect. Thus,  every  social  animal  which  recognizes  man  as  a  member, 
and  as  the  chief  of  its  herd,  is  a  domestic  animal.  It  might  even  be 
said,  that,  from  the  moment  when  such  an  animal  admits  man  as  a 
member  of  its  society,  it  is  domesticated,  as  man  could  not  enter  into 
such  society  without  becoming  the  chief  of  it."  * 

But  the  ingenious  author  whose  observations  I  have  here  cited, 
admits  that  the  obedience  -which  the  individuals  of  many  domestic 
species  yield  indifferently  to  exery  person,  is  without  analogy  in  any 
state  of  things  which  could  exist  previously  to  their  subjugation  by 
man.  Each  troop  of  wild  horses,  it  is  true,  has  some  stallion  for  its 
chief,  who  draws  after  him  all  the  individuals  of  which  the  herd  is  com- 
posed ;  but  when  a  domesticated  horse  has  passed  from  hand  to  hand, 

*  Mem.  du  Mus.  d'Hist.  Nat 


Cn.  XXXV.]  DOMESTICATION'   OF   ANIMALS.  597 

and  has  served  several  masters,  he  becomes  equally  docile  towards  any 
person,  and  is  subjected  to  the  whole  human  race.  It  seems  fair  to  pre- 
sume that  the  capability  in  the  instinct  of  the  horse  to  be  thus  modi- 
fied, was  given  to  enable  the  species  to  render  greater  services  to 
man ;  and,  perhaps,  the  facility  with  which  many  other  acquired 
characters  become  hereditary  in  various  races  of  the  horse,  may  be 
explicable  only  on  a  like  supposition.  The  amble,  for  example,  a 
pace  to  which  the  domestic  races  in  some  parts  of  Spanish  America 
are  exclusively  trained,  has,  in  the  course  of  several  generations,  become 
hereditary,  and  is  assumed  by  all  the  young  colts  before  they  are 
broken  in.* 

It  seems,  also,  reasonable  to  conclude,  that  the  power  bestowed  on 
the  horse,  the  dog,  the  ox,  the  sheep,  the  cat,  and  many  species  of 
domestic  fowls,  of  supporting  almost  every  climate,  was  given  ex- 
pressly to  enable  them  to  follow  man  throughout  all  parts  of  the 
globe,  in  order  that  we  might  obtain  their  services,  and  they  our  pro- 
tection. If  it  be  objected  that  the  elephant  which,  by  the  union  of 
strength,  intelligence,  and  docility,  can  render  the  greatest  services  to 
mankind,  is  incapable  of  living  in  any  but  the  warmest  latitudes,  we  may 
observe  that  the  quantity  of  vegetable  food  required  by  this  quadruped 
would  render  its  maintenance  in  the  temperate  zones  too  costly,  and  in 
the  arctic  impossible. 

Among  the  changes  superinduced  by  man,  none  appear,  at  first  sight, 
more  remarkable  than  the  perfect  tameness  of  certain  domestic  races. 
It  is  well  known  that,  at  however  early  an  age  we  obtain  possession  of 
the  young  of  many  unreclaimed  races,  they  will  retain,  throughout  life, 
a  considerable  timidity  and  apprehensiveness  of  danger ;  whereas,  after 
one  or  two  generations,  the  descendants  of  the  same  stock  will  habitu- 
ally place  the  most  implicit  confidence  in  man.  There  is  good  reason, 
however,  to  suspect  that  such  changes  are  not  without  analogy  in  a 
state  of  nature  ;  or,  to  speak  more  correctly,  in  situations  where  man 
has  not  interfered. 

AVe  learn  from  Mr.  Darwin,  that  in  the  Galapagos  archipelago,  placed 
directly  under  the  equator,  and  nearly  600  miles  west  of  the  American 
continent,  all  the  terrestrial  birds,  as  the  finches,  doves,  hawks,  and 
others,  are  so  tame,  that  they  may  be  killed  with  a  switch.  One  day, 
says  this  author,  "a  mocking  bird  alighted  on  the  edge  of  a  pitcher 
which  I  held  in  my  hand,  and  began  quietly  to  sip  the  water,  and 
allowed  me  to  lift  it  with  the  vessel  from  the  ground."  Yet  formerly, 
when  the  first  Europeans  landed,  and  found  no  inhabitants  in  these 
islands,  the  birds  were  even  tamer  than  now :  already  they  are  begin- 
ning to  acquire  that  salutary  dread  of  man  which  in  countries  long 
settled  is  natural  even  to  young  birds  which  have  never  received  any 
injury.  So  in  the  Falkland  Islands,  both  the  birds  and  foxes  are  entirely 
without  fear  of  man ;  whereas,  in  the  adjoining  mainland  of  South 

*  Dureau  de  la  Malle.  Ann.  des  Sci.  Nat,  torn.  xxi.  p.  58. 


598  MODIFICATION  OP  INSTINCTS  [Ca.  XXXV. 

America,  many  of  the  same  species  of  birds  are  extremely  wild ;  for  there 
they  have  for  ages  been  persecuted  by  the  natives.* 

Dr.  Richardson  informs  us,  in  his  able  history  of  the  habits  of  the 
North  American  animals,  that,  "in  the  retired  parts  of  the  mountains 
where  the  hunters  had  seldom  penetrated,  there  is  no  difficulty  in 
approaching  the  Rocky  Mountain  sheep,  which  there  exhibit  the  simpli- 
city of  character  so  remarkable  in  the  domestic  species  ;  but  where  they 
have  been  often  fired  at,  they  are  exceedingly  wild,  alarm  their  compa- 
nions, on  the  approach  of  danger,  by  a  hissing  noise,  and  scale  the  rocks 
with  a  speed  and  agility  that  baffle  pursuit."f 

It  is  probable,  therefore,  that  as  man,  in  diffusing  himself  over  the 
globe,  has  tamed  many  wild  races,  so,  also,  he  has  made  many  tame 
races  wild.  Had  some  of  the  larger  carnivorous  beasts,  capable  of  scal- 
ing the  rocks,  made  their  way  into  the  North  American  mountains 
before  our  hunters,  a  similar  alteration  in  the  instincts  of  the  sheep 
would  doubtless  have  been  brought  about. 

Wild  elephants  domesticated  in  a  few  years. — No  animal  affords  a 
more  striking  illustration  of  the  principal  points  which  I  have  been  en- 
deavouring to  establish  than  the  elephant ;  for,  in  the  first  place,  the 
wonderful  sagacity  with  which  he  accommodates  himself  to  the  society  of 
man,  and  the  new  habits  which  he  contracts,  are  not  the  result  of  time, 
nor  of  modifications  produced  in  the  course  of  many  generations. 
These  animals  will  breed  in  captivity,  as  is  now  ascertained,  in  opposi- 
tion to  the  vulgar  opinion  of  many  modern  naturalists,  and  in  conformity 
to  that  of  the  ancients  JElian  and  ColumellaJ;:  yet  it  has  always  been  the 
custom,  as  the  least  expensive  mode  of  obtaining  them,  to  capture  wild 
individuals  in  the  forests,  usually  when  full  grown  ;  and,  in  a  few  years 
after  they  are  taken — sometimes,  it  is  said,  in  the  space  of  a  few  months 
— their  education  is  completed. 

Had  the  whole  species  been  domesticated  from  an  early  period  in  the 
history  of  man,  like  the  camel,  their  superior  intelligence  would,  doubt- 
less, have  been  attributed  to  their  long  and  familiar  intercourse  with  the 
lord  of  the  creation  ;  but  we  know  that  a  few  years  is  sufficient  to  bring 
about  this  wonderful  change  of  habits;  and  although  the  same  indivi- 
dual may  continue  to  receive  tuition  for  a  century  afterwards,  yet  it 
makes  no  farther  progress  in  the  general  development  of  its  faculties. 
Were  it  otherwise,  indeed,  the  animal  would  soon  deserve  more  than  the 
poet's  epithet  of  "  half-reasoning." 

From  the  authority  of  our  countrymen  employed  in  the  late  Burmese 
war,  it  appears,  in  corroboration  of  older  accounts,  that  when  elephants 
are  required  to  execute  extraordinary  tasks,  they  may  be  made  to  under- 
stand that  they  will  receive  unusual  rewards.  Some  favourite  dainty  is 
shown  to  them,  in  the  hope  of  acquiring  which  the  work  is  done ;  and 
so  perfectly  does  the  nature  of  the  contract  appear  to  be  understood, 

*  Darwin's  Journ.  in  Voyage  of  H.M.S.  Beagle,  p.  475. 

f  Fauna  Boreali-Americana,  p.  273. 

\  Mr.  Corse  on  the  Habits,  Ac.  of  the  Elephant,  Phil.  Trans.,  1799. 


CM.  XXXV.]  BY   DOMESTICATION.  599 

that  the  breach  of  it,  on  the  part  of  the  master,  is  often  attended  with 
danger.  In  this  case,  a  power  has  been  given  to  the  species  to  adapt 
their  social  instincts  to  new  circumstances  with  surprising  rapidity  ;  but 
the  extent  of  this  change  is  defined  by  strict  and  arbitrary  limits. 
There  is  no  indication  of  a  tendency  to  continued  divergence  from 
certain  attributes  with  which  the  elephant  was  originally  endued — no 
ground  whatever  for  anticipating  that,  in  thousands  of  centuries,  any 
material  alteration  could  ever  be  effected.  All  that  we  can  infer  from 
analogy  is,  that  some  more  useful  and  peculiar  races  might  probably 
be  formed,  if  the  experiment  were  fairly  tried ;  and  that  some  individual 
characteristic,  now  only  casual  and  temporary,  might  be  perpetuated 
by  generation. 

In  all  cases,  therefore,  where  the  domestic  qualities  exist  in  animals, 
they  seem  to  require  no  lengthened  process  for  their  developement ; 
and  they  appear  to  have  been  wholly  denied  to  some  classes,  which, 
from  their  strength  and  social  disposition,  might  have  rendered  great 
services  to  man  ;  as,  for  example,  the  greater  part  of  the  quadrumana. 
The  orang-outang,  indeed,  which,  for  its  resemblance  in  form  to  man, 
and  apparently  for  no  other  good  reason,  has  been  assumed  by  Lamarck 
to  be  the  most  perfect  of  the  inferior  animals,  has  been  tamed  by  the 
savages  of  Borneo,  and  made  to  climb  lofty  trees,  and  to  bring  down 
the  fruit.  But  he  is  said  to  yield  to  his  masters  an  unwilling  obedience, 
and  to  be  held  in  subjection  only  by  severe  discipline.  We  know 
nothing  of  the  faculties  of  this  animal  which  can  suggest  the  idea  that 
it  rivals  the  elephant  in  intelligence  ;  much  less  anything  which  can 
countenance  the  dreams  of  those  who  have  fancied  that  it  might  have 
been  transmuted  into  the  "  dominant  race."  One  of  the  baboons  of 
Sumatra  (Simia  carpolegus)  appears  to  be  more  docile,  and  is  frequently 
trained  by  the  inhabitants  to  ascend  trees,  for  the  purpose  of  gathering 
cocoa-nuts  ;  a  service  in  which  the  animal  is  very  expert.  He  selects, 
says  Sir  Stamford  Raffles,  the  ripe  nuts,  with  great  judgment,  and  pulls 
no  more  than  he  is  ordered.*  The  capuchin  and  cacajao  monkeys  are, 
according  to  Humboldt,  taught  to  ascend  trees  in  the  same  manner, 
and  to  throw  down  fruit  on  the  banks  of  the  lower  Orinoco.f 

It  is  for  the  Lamarckians  to  explain  how  it  happens  that  those  same 
savages  of  Borneo  have  not  themselves  acquired,  by  dint  of  longing,  for 
many  generations,  for  the  power  of  climbing  trees,  the  elongated  arms 
of  the  ourang,  or  even  the  prehensile  tails  of  some  American  monkeys : 
Instead  of  being  reduced  to  the  necessity  of  subjugating  stubborn  and 
untractable  brutes,  we  should  naturally  have  anticipated  "  that  their 
wants  would  have  excited  them  to  efforts,  and  that  continued  efforts 
would  have  given  rise  to  new  organs ;"  or  rather  to  the  re-acquisition 
of  organs  which,  in  a  manner  irreconcileable  with  the  principle  of  the 

*  Linn.  Trans,  vol.  xiii.  p.  244. 

f  Pers.  Narr.  of  Travels  to  the  Equinoctial  Regions  of  the  New  Continent  in 
the  years  1779—1804. 


600  EXPERIMENTS   ON  [CiL  XXXVI. 

progressive  system,  have  grown  obsolete  in  tribes  of  men  which  have 
such  constant  need  of  them. 

Recapitulation. — It  follows,  then,  from  the  different  facts  which  have 
been  considered  in  this  chapter,  that  a  short  period  of  time  is  generally 
sufficient  to  effect  nearly  the  whole  change  which  an  alteration  of  exter- 
nal circumstances  can  bring  about  in  the  habits  of  a  species,  and  that 
such  capacity  of  accommodation  to  new  circumstances  is  enjoyed  in 
very  different  degrees,  by  different  species. 

Certain  qualities  appear  to  be  bestowed  exclusively  with  a  view  to 
the  relations  which  are  destined  to  exist  between  different  species,  and, 
among  others,  between  certain  species  and  man ;  but  these  latter  are 
always  so  nearly  connected  with  the  original  habits  and  propensities  of 
each  species  in  a  wild  state,  that  they  imply  no  indefinite  capacity  of 
varying  from  the  original  type.  The  acquired  habits  derived  from  hu- 
man tuition  are  rarely  transmitted  to  the  offspring ;  and  when  this  hap- 
pens, it  is  almost  universally  the  case  with  those  merely  which  have 
some  obvious  connexion  with  the  attributes  of  the  species  when  in  a 
state  of  independence. 


CHAPTER  XXXVI. 

WHETHER  SPECIES  HAVE  A  REAL  EXISTENCE  IN  NATtTRE 

continued. 

Phenomena  of  hybrids — Hunter's  opinions — Mules  not  strictly  intermediate 
between  parent  species — Hybrid  plants — Experiments  of  Kolreuter  and  Wieg- 
mann — Vegetable  hybrids  prolific  throughout  several  generations — Why  rare 
in  a  wild*  state — Decundolle  on  hybrid  plants — The  phenomena  of  hybrids 
confirm  the  distinctness  of  species — Theory  of  the  gradation  in  the  intelli- 
gence of  animals  as  indicated  by  the  facial  angle — Doctrine  that  certain 
organs  of  the  foetus  in  mammalia  assume  successively  the  forms  of  fish,  rep- 
tile, and  bird — Recapitulation. 

Phenomena  of  hybrids. — We  have  yet  to  consider  another  class  of  phe- 
nomena, those  relating  to  the  production  of  hybrids,  which  have  been 
regarded  in  a  very  different  light  with  reference  to  their  bearing  on  the 
question  of  the  permanent  distinctness  of  species ;  some  naturalists  con- 
sidering them  as  affording  the  strongest  of  all  proofs  in  favor  of  the 
reality  of  species  ;  others,  on  the  contrary,  appealing  to  them  as  counte- 
nancing the  opposite  doctrine,  that  all  the  varieties  of  organization  and 
instinct  now  exhibited  in  the  animal  and  vegetable  kingdoms  may  have 
been  propagated  from  a  small  number  of  original  types. 

In  regard  to  the  mammifers  and  birds  it  is  found  that  no  sexual 
union  will  take  place  between  races  which  are  remote  from  each  other 
in  their  habits  and  organization  ;  and  it  is  only  in  species  that  are  very 
nearly  allied  that  such  unions  produce  offspring.  It  may  be  laid  down 


CH.  XXXVI.]  HYBRID   ANIMALS.  601 

as  a  general  rule,  admitting  of  very  few  exceptions  among  quadrupeds, 
that  the  hybrid  progeny  is  sterile ;  and  there  seem  to  be  no  well 
authenticated  examples  of  the  continuance  of  the  mule  race  beyond 
one  generation.  The  principal  number  of  observations  and  experi- 
ments relate  to  the  mixed  offspring  of  the  horse  and  the  ass ;  and 
in  this  case  it  is  well  established  that  -the  he-mule  can  generate,  and 
the  she-mule  produce.  Such  cases  occur  in  Spain  and  Italy,  and  much 
more  frequently  in  the  West  Indies  and  New  Holland  ;  but  these  mules 
have  never  bred  in  cold  climates,  seldom  in  warm  regions,  and  still 
more  rarely  in  temperate  countries. 

The  hybrid  offspring  of  the  she-ass  and  the  stallion,  the  yivvoj  of 
Aristotle,  and  the  hinnus  of  Pliny,  differs  from  the  mule,  or  the  off- 
spring of  the  ass  and  mare.  In  both  cases,  says  Buffon,  these  animals 
retain  more  of  the  dam  than  of  the  sire,  not  only  in  the  magnitude,  but 
in  the  figure  of  the  body  :  whereas,  in  the  form  of  the  head,  limbs,  and 
tail,  they  bear  a  greater  resemblance  to  the  sire.  The  same  naturalist 
infers,  from  various  experiments  respecting  cross-breeds  between  the 
he-goat  and  ewe,  the  dog  and  she-wolf,  the  goldfinch  and  canary-bird, 
that  the  male  transmits  his  sex  to  the  greatest  number,  and  that  the 
preponderance  of  males  over  females  exceeds  that  which  prevails  where 
the  parents  are  of  the  same  species. 

Hunter's  opinion. — The  celebrated  John  Hunter  has  observed,  that 
the  true  distinction  of  species  must  ultimately  be  gathered  from  their 
incapacity  of  propagating  with  each  other,  and  producing  offspring 
capable  of  again  continuing  itself.  He  was  unwilling,  however,  to  ad- 
mit that  the  horse  and  the  ass  were  of  the  same  species,  because  some 
rare  instances  had  been  adduced  of  the  breeding  of  mules,  although  he 
maintained  that  the  wolf,  the  dog,  and  the  jackal  were  all  of  one  species ; 
because  he  had  found,  by  two  experiments,  that  the  dog  would  breed 
both  with  the  wolf  and  the  jackal ;  and  that  the  mule,  in  each  case, 
would  breed  again  with  the  dog.  In  these  cases,  however,  it  may  be 
observed,  that  there  was  always  one  parent  at  least  of  pure  breed,  and 
no  proof  was  obtained  that  a  true  hybrid  race  could  be  perpetuated ;  a 
fact  of  which  I  believe  no  examples  are  yet  recorded,  either  in  regard  to 
mixtures  of  the  horse  and  ass,  or  any  other  of  the  mammalia. 

Should  the  fact  be  hereafter  ascertained,  that  two  mules  can  propa- 
gate their  kind,  we  must  still  inquire  whether  the  offspring  may  not  be 
regarded  in  the  light  of  a  monstrous  birth,  proceeding  from  some  acci- 
dental cause,  or,  rather,  to  speak  more  philosophically,  from  some  general 
law  not  yet  understood,  but  which  may  not  be  permitted  permanently 
to  interfere  with  those  laws  of  generation  by  which  species  may,  in 
general,  be.  prevented  from  becoming  blended.  If,  for  example,  we 
discovered  that  the  progeny  of  a  mule  race  degenerated  greatly,  in  the 
first  generation,  in  force,  sagacity,  or  any  attribute  necessary  for  its 
preservation  in  a  state  of  nature,  we  might  infer  that,  like  a  monster,  it 
is  a  mere  temporary  and  fortuitous  variety.  Nor  does  it  seem  probable 
that  the  greater  number  of  such  monsters  could  ever  occur  unless  ob- 


602  EXPERIMENTS   ON  [Cii.  XXXVI. 

tained  by  art ;  for,  in  Hunter's  experiments,  stratagem  or  force  was,  in 
most  instances,  employed  to  bring  about  the  irregular  connexion.* 

Mules  not  strictly  intermediate  between  the  parent  species. — It  seems 
rarely  to  happen  that  the  mule  offspring  is  truly  intermediate  in  char- 
acter between  the  two  parents.  Thus  Hunter  mentions  that,  in  his 
experiments,  one  of  the  hybrid  pups  resembled  the  wolf  much  more 
than  the  rest  of  the  litter ;  and  we  are  informed  by  Wiegmann,  that,  in 
a  litter  lately  obtained  in  the  Royal  Menagerie  at  Berlin,  from  a  white 
pointer  and  a  she-wolf,  two  of  the  cubs  resembled  the  common  wolf-dog, 
but  the  third  was  like  a  pointer  with  hanging  ears. 

There  is  undoubtedly  a  very  close  analogy  between  these  phenomena 
and  those  presented  by  the  intermixture  of  distinct  races  of  the  same 
species,  both  in  the  inferior  animals  and  in  man.  Dr.  Prichard,  in  his 
"  Physical  History  of  Mankind,"  cites  examples  where  the  peculiarities 
of  the  parents  have  been  transmitted  very  unequally  to  the  offspring ; 
as  where  children,  entirely  white,  or  perfectly  black,  have  sprung  from 
the  union  of  the  European  and  the  negro.  Sometimes  the  colour  or 
other  peculiarities  of  one  parent,  after  having  failed  to  show  themselves 
in  the  immediate  progeny,  reappear  in  a  subsequent  generation ;  as 
where  a  white  child  is  born  of  two  black  parents,  the  grandfather  having 
been  a  white.f 

The  same  author  judiciously  observes  that,  if  different  species  mixed 
their  breed,  and  hybrid  races  were  often  propagated,  the  animal  world 
would  soon  present  a  scene  of  confusion ;  its  tribes  would  be  every  where 
blended  together,  and  we  should  perhaps  find  more  hybrid  creatures 
than  genuine  and  uncorrupted  races.J 

Hybrid  plants. — Kolreuter^s  experiments. — The  history  of  the  vege- 
table kingdom  has  been  thought  to  afford  more  decisive  evidence  in 
favour  of  the  theory  of  the  formation  of  new  and  permanent  species 
from  hybrid  stocks.  The  first  accurate  experiments  in  illustration  of 
this  curious  subject  appear  to  have  been  made  by  Kolreuter,  who  ob- 
tained a  hybrid  from  two  species  of  tobacco,  Nicotiana  rustica  and  N. 
paniculata,  which  differ  greatly  in  the  shape  of  their  leaves,  the  colour 
of  the  corolla,  and  the  height  of  the  stem.  The  stigma  of  a  plant  of  N. 
rustica  was  impregnated  with  the  pollen  of  a  plant  of  N.  paniculata. 
The  seed  ripened,  and  produced  a  hybrid  which  was  intermediate 
between  the  two  parents,  and  which,  like  all  the  hybrids  which  this 
botanist  brought  up,  had  imperfect  stamens.  He  afterwards  impreg- 
nated this  hybrid  with  the  pollen  of  N.  paniculata,  and  obtained  plants 
which  much  more  resembled  the  last.  This  he  continued  through 
several  generations,  until,  by  due  perseverance,  he  actually  changed  the 
Nicotiana  rustica  into  the  Nicotiana  paniculata. 

The  plan  of  impregnation  adopted,  was  the  cutting  off  of  the  anthers 

*  Phil.  Trans.  1787.  Additional  Remarks,  Phil.  Trans.  1789.  See  also  Essays 
by  the  late  Dr.  Samuel  G.  Morton,  on  Prolific  Hybrids,  <fec. ;  and  on  Hybridity 
as  a  Test  of  Species. — American  Journ.  of  Science,  vol.  iii.  1847. 

f  Prichard,  vol.  i.  p.  217.  J  Ibid.  p.  97. 


CH.  XXXVL]  HYBRID    PLANTS.  603 

of  the  plant  intended  for  fructification  before  they  had  shed  pollen,  and 
then  laying  on  foreign  pollen  upon  the  stigma. 

Wiegmann'1  s  experiments. — The  same  experiment  has  since  been 
repeated  with  success  by  Wiegmann,  who  found  that  he  could  bring 
back  the  hybrids  to  the  exact  likeness  of  either  parent,  by  crossing  them 
a  sufficient  number  of  times. 

The  blending  of  the  characters  of  the  parent  stocks,  in  many  other 
of  Wiegmann's  experiments,  was  complete  ;  the  colour  and  shape  of  the 
leaves  and  flowers,  and  even  the  scent,  being  intermediate,  as  in  the 
offspring  of  the  two  species  of  verbascum.  An  intermarriage,  also,  be- 
tween the  common  onion  and  the  leek  (Allium  cepa  and  A.  porrum) 
gave  a  mule  plant,  which,  in  the  character  of  its  leaves  and  flowers, 
approached  most  nearly  to  the  garden  onion,  but  had  the  elongated 
bulbous  root  and  smell  of  the  leek. 

The  same  botanist  remarks,  that  vegetable  hybrids,  when  not  strictly 
intermediate,  more  frequently  approach  the  female  than  the  male  parent 
species ;  but  they  never  exhibit  characters  foreign  to  both.  A  re-cross 
with  one  of  the  original  stocks  generally  causes  the  mule  plant  to  revert 
towards  that  stock ;  but  this  is  not  always  the  case,  the  offspring  some- 
times continuing  to  exhibit  the  character  of  a  full  hybrid. 

In  general,  the  success  attending  the  production  and  perpetuity  of 
hybrids  among  plants  depends,  as  in  the  animal  kingdom,  on  the  degree 
of  proximity  between  the  species  intermarried.  If  their  organization  be 
very  remote,  impregnation  never  takes  place ;  if  somewhat  less  distant, 
seeds  are  formed,  but  always  imperfect  and  sterile.  The  next  degree  of 
relationship  yields  hybrid  seedlings,  but  these  are  barren  ;  and  it  is  only 
when  the  parent  species  are  very  nearly  allied  that  the  hybrid  race  may 
be  perpetuated  for  several  generations.  Even  in  this  case  the  best  au- 
thenticated examples  seem  confined  to  the  crossing  of  hybrids  with 
individuals  of  pure  breed.  In  none  of  the  experiments  most  accurately 
detailed  does  it  appear  that  both  the  parents  were  mules. 

Wiegmann  diversified  as  much  as  possible  his  mode  of  bringing 
about  these  irregular  unions  among  plants.  He  often  sowed  parallel 
rows,  near  to  each  other,  of  the  species  from  which  he  desired  to  breed ; 
and,  instead  of  mutilating,  after  Kolreuter's  fashion,  the  plants  of  one 
of  the  parent  stocks,  he  merely  washed  the  pollen  off  their  anthers. 
The  branches  of  the  plants  in  each  row  were  then  gently  bent  towards 
each  other  and  intertwined ;  so  that  the  wind,  and  numerous  insects,  as 
they  passed  from  the  flowers  of  one  to  those  of  the  other  species,  carried 
the  pollen  and  produced  fecundation. 

Vegetable  hybrids  why  rare  in  a  wild  state. — The  same  observer  saw 
a  good  exemplification  of  the  manner  in  which  hybrids  may  be  formed  in 
a  state  of  nature.  Some  wallflowers  and  pinks  had  been  growing  in  a 
garden,  in  a  dry  sunny  situation,  and  their  stigmas  had  been  ripened  so 
as  to  be  moist,  and  to  absorb  pollen  with  avidity,  although  their  anthers 
were  not  yet  developed.  These  stigmas  became  impregnated  by  pollen 
blown  from  some  other  adjacent  plants  of  the  same  species;  but  had 


604  RARITY  OF  HYBRIDS   AMONG  [Cn.  XXXVL 

they  been  of  different  species,  and  not  too  remote  in  their  organization, 
mule  races  must  have  resulted. 

When,  indeed,  we  consider  how  busily  some  insects  have  been  shown 
to  be  engaged  in  conveying  anther-dust  from  flower  to  flower,  especially 
bees,  flower-eating  beetles,  and  the  like,  it  seems  a  most  enigmatical 
problem  how  it  can  happen  that  promiscuous  alliances  between  distinct 
species  are  not  perpetually  occurring. 

How  continually  do  we  observe  the  bees  diligently  employed  in  col- 
lectibg  the  red  and  yellow  powder  by  which  the  stamens  of  flowers  are 
covered,  loading  it  on  their  hind  legs,  and  carrying  it  to  their  hive  for 
the  purpose  of  feeding  their  young  !  In  thus  providing  for  their  own 
progeny,  these  insects  assist  materially  the  process  of  fructification.* 
Few  persons  need  be  reminded  that  the  stamens  in  certain  plants  grow 
on  different  blossoms  from  the  pistils ;  and  unless  the  summit  of  the  pis- 
til be  touched  with  the  fertilizing  dust,  the  fruit  does  not  swell,  nor  the 
seed  arrive  at  maturity.  It  is  by  the  help  of  bees  chiefly,  that  the  deve- 
lopment of  the  fruit  of  many  such  species  is  secured,  the  powder  which 
they  have  collected  from  the  stamens  being  unconsciously  left  by  them 
in  visiting  the  pistils. 

How  often,  during  the  heat  of  a  summer's  day,  do  we  see  the  males  of 
dicecious  plants,  such  as  the  yew-tree,  standing  separate  from  the  females, 
and  sending  off  into  the  air,  upon  the  slightest  breath  of  wind,  clouds  of 
buoyant  pollen  !  That  the  zephyr  should  so  rarely  intervene  to  fecundate 
the  plants  of  one  species  with  the  anther-dust  of  others,  seems  almost  to 
realize  the  converse  of  the  miracle  believed  by  the  credulous  herdsmen 
of  the  Lusitanian  mares — 

Ore  omnes  versae  in  Zephyrum,  stant  rupibus  altis 
Exceptantque  leves  auras :  et  soepe  sine  ullis 
Conjugiis,  vento  gravidse,  mirabile  dicta  f 

But,  in  the  first  place,  it  appears  that  there  is  a  natural  aversion  in 
plants,  as  well  as  in  animals,  to  irregular  sexual  unions ;  and  in  most  of  the 
successful  experiments  in  the  animal  and  vegetable  world,  some  violence 
has  been  used  in  order  to  procure  impregnation.  The  stigma  imbibes, 
slowly  and  reluctantly,  the  granules  of  the  pollen  of  another  species, 
even  when  it  is  abundantly  covered  with  it ;  and  if  it  happen  that,  dur- 
ing this  period,  ever  so  slight  a  quantity  of  the  anther-dust  of  its  own 
species  alight  upon  it,  this  is  instantly  absorbed,  and  the  effect  of  the 
foreign  pollen  destroyed.  Besides,  it  does  not  often  happen  that  the 
male  and  female  organs  of  fructification,  in  different  species,  arrive  at  a 
state  of  maturity  at  precisely  the  same  time.  Even  where  such  syn- 
chronism does  prevail,  so  that  a  cross  impregnation  is  effected,  the 
chances  are  very  numerous  against  the  establishment  of  a  hybrid  race. 

If  we  consider  the  vegetable  kingdom  generally,  it  must  be  recollected 
that  even  of  the  seeds  which  are  well  ripened,  a  great  part  are  either 

*  See  Barton  on  the  Geography  of  Plants,  p.  67.     f  Georg.  lib.  iii.  273. 


CH.  XXXVL]  PLANTS   IN   A   WILD    STATE.  605 

eaten  by  insects,  birds,  and  other  animals,  or  decay  for  want  of  room 
and  opportunity  to  germinate.  Unhealthy  plants  are  the  first  which  are 
cut  oft'  by  causes  prejudicial  to  the  species,  being  usually  stifled  by  more 
vigorous  individuals  of  their  own  kind.  If,  therefore,  the  relative 
fecundity  or  hardiness  of  hybrids  be  in  the  least  degree  inferior,  they 
cannot  maintain  their  footing  for  many  generations,  even  if  they  were 
ever  produced  beyond  one  generation  in  a  wild  state.  In  the  universal 
struggle  for  existence,  the  right  of  the  strongest  eventually  prevails  ; 
and  the  strength  and  durability  of  a  race  depend  mainly  on  its  prolific- 
ness,  in  which  hybrids  are  acknowledged  to  be  deficient. 

Centaurea  hybrida,  a  plant  which  never  bears  seed,  and  is  supposed 
to  be  produced  by  the  frequent  intermixture  of  two  well-known  species 
of  Centaurea,  grows  wild  upon  a  hill  near  Turin.  Ranunculus  lacerus, 
also  sterile,  has  been  produced  accidentally  at  Grenoble,  and  near  Paris, 
by  the  union  of  two  Ranunculi ;  but  this  occurred  in  gardens.* 

Mr.  Herbert's  experiments. — Mr.  Herbert,  in  one  of  his  ingenious 
papers  on  mule  plants,  endeavors  to  account  for  their  non-occurrence 
in  a  state  of  nature,  from  the  circumstance  that  all  the  combinations 
that  were  likely  to  occur  have  already  been  made  many  centuries  ago, 
and  have  formed  the  various  species  of  botanists  ;  but  in  our  gardens, 
he  says,  whenever  species,  having  a  certain  degree  of  affinity  to  each 
other,  are  transported  from  different  countries,  and  brought  for  the  first 
time  into  contact,  they  give  rise  to  hybrid  species.f  But  we  have  no 
data,  as  yet,  to  warrant  the  conclusion,  that  a  single  permanent  hybrid 
race  has  ever  been  formed,  even  in  gardens,  by  the  intermarriage  of  two 
allied  species  brought  from  distant  habitations.  Until  some  fact  of  this 
kind  is  fairly  established,  and  a  new  species,  capable  of  perpetuating 
itself  in  a  state  of  perfect  independence  of  man,  can  be  pointed  out,  it 
seems  reasonable  to  call  in  question  entirely  this  hypothetical  source 
of  new  species.  That  varieties  do  sometimes  spring  up  from  cross- 
breeds, in  a  natural  way,  can  hardly  be  doubted ;  but  they  probably  die 
out  even  more  rapidly  than  races  propagated  by  grafts  or  layers. 

Opinion  of  De  Candolle. — De  Candolle,  whose  opinion  on  a  philo- 
sophical question  of  this  kind  deserves  the  greatest  attention,  has  ob- 
served, in  his  Essay  on  Botanical  Geography,  that  the  varieties  of  plants 
range  themselves  under  two  general  heads  :  those  produced  by  external 
circumstances,  and  those  formed  by  hybridity.  After  adducing  various 
arguments  to  show  that  neither  of  these  causes  can  explain  the  perma- 
nent diversity  of  plants  indigenous  in  different  regions,  he  says,  in  regard 
to  the  crossing  of  races,  "  I  can  perfectly  comprehend  without  altogether 
sharing  the  opinion,  that,  where  many  species  of  the  same  genera  occur 
near  together,  hybrid  species  may  be  formed,  and  I  am  aware  that  the 
great  number  of  species  of  certain  genera  which  are  found  in  particular 
regions  may  be  explained  in  this  manner  ;  but  I  am  unable  to  conceive 
how  any  one  can  regard  the  same  explanation  as  applicable  to  species 

*  Hon.  and  Rev.  W.  Herbert,  Hort.  Trans.,  vol.  iv.  p.  41.  f  Ibid. 


606  PROPAGATION   OF   HYBRIDS.  [Cm  XXXVI. 

which  live  naturally  at  great  distances.  If  the  three  larches,  for  exam- 
ple, now  known  in  the  world,  lived  in  the  same  localities,  I  might  then 
believe  that  one  of  them  was  the  produce  of  the  crossing  of  the  two 
others  ;  but  I  never  could  admit  that  the  Siberian  species  has  been  pro- 
duced by  the  crossing  of  those  of  Europe  and  America.  I  see,  then, 
that  there  exist  in  organized  beings,  permanent  differences  which  cannot 
be  referred  to  any  one  of  the  actual  causes  of  variation,  and  these  dif- 
ferences are  what  constitute  species"* 

Reality  of  species  confirmed  by  the  phenomena  of  hybrids. — The  most 
decisive  arguments  perhaps,  amongst  many  others,  against  the  probability 
of  the  derivation  of  permanent  species  from  cross-breeds,  are  to  be 
drawn  from  the  fact  alluded  to  by  De  Candolle,  of  species  having  a 
close  affinity  to  each  other  occurring  in  distinct  botanical  provinces,  or 
countries  inhabited  by  groups  of  distinct  species  of  indigenous  plants ; 
for  in  this  case  naturalists,  who  are  not  prepared  to  go  the  whole  length 
of  the  transmutationists,  are  under  the  necessity  of  admitting  that,  in 
some  cases,  species  which  approach  very  near  to  each  other  in  their 
characters,  were  so  created  from  their  origin ;  an  admission  fatal  to  the 
idea  of  its  being  a  general  law  of  nature  that  a  few  original  types  only 
should  be  formed,  and  that  all  intermediate  races  should  spring  from 
the  intermixture  of  those  stocks. 

This  notion,  indeed,  is  wholly  at  variance  with  all  that  we  know  of 
hybrid  generation ;  for  the  phenomena  entitle  us  to  affirm,  that  had  the 
types  been  at  first  somewhat  distinct,  no  cross-breeds  would  ever  have 
been  produced,  much  less  those  prolific  races  which  we  now  recognize  as 
distinct  species. 

In  regard,  moreover,  to  the  permanent  propagation  of  hybrid  races 
among  animals,  insuperable  difficulties  present  themselves,  when  we 
endeavor  to  conceive  the  blending  together  of  the  different  instincts  and 
propensities  of  two  species,  so  as  to  insure  the  preservation  of  the  inter- 
mediate race.  The  common  mule,  when  obtained  by  human  art,  may 
be  protected  by  the  power  of  man ;  but,  in  a  wild  state,  it  would  not 
have  precisely  the  same  wants  either  as  the  horse  or  the  ass ;  and  if 
in  consequence  of  some  difference  of  this  kind,  it  strayed  from  the  herd, 
it  would  soon  be  hunted  down  by  beasts  of  prey,  and  destroyed. 

If  we  take  some  genus  of  insects,  such  as  the  bee,  we  find  that  each 
of  the  numerous  species  has  some  difference  in  its  habits,  its  mode  of 
collecting  honey,  or  constructing  its  dwelling,  or  providing  for  its  young, 
and  other  particulars.  In  the  case  of  the  common  hive  bee,  the  workers 
are  described,  by  Kirby  and  Spence,  as  being  endowed  with  no  less 
than  thirty  distinct  instincts.f  So  also  we  find  that,  amongst  a  most 
numerous  class  of  spiders,  there  are  nearly  as  many  different  modes  of 
spinning  their  webs  as  there  are  species.  When  we  recollect  how  com- 
plicated are  the  relations  of  these  instincts  with  co-existing  species,  both 

*  Essai  E16mentaire,  <fec.,  3me  partie. 
f  Intr.  to  Entom.  voL  ii.  p.  504.  ed.  1817 


CH.  XXXVL]  HYBRIDS.  607 

of  the  animal  and  vegetable  kingdoms,  it  is  scarcely  possible  to  imagine 
that  a  bastard  race  could  spring  from  the  union  of  two  of  these  species, 
and  retain  just  so  much  of  the  qualities  of  each  parent  stock  as  to  pre- 
serve its  ground  in  spite  of  the  dangers  which  surround  it. 

We  might  also  ask,  if  a  few  generic  types  alone  have  been  created 
among  insects,  and  the  intermediate  species  have  proceeded  from 
hybridity,  where  are  those  original  types,  combining,  as  they  ought  to 
do,  the  elements  of  all  the  instincts  which  have  made  their  appearance 
in  the  numerous  derivative  races  ?  So  also  in  regard  to  animals  of  all 
classes,  and  of  plants ;  if  species  are  in  general  of  hybrid  origin,  where 
are  the  stocks  which  combine  in  themselves  the  habits,  properties,  and 
organs,  of  which  all  the  intervening  species  ought  to  afford  us  mere 
modifications  ? 

Recapitulation  of  the  arguments  from  hybrids. — I  shall  now  conclude 
this  subject  by  summing  up,  in  a  few  words,  the  results  to  which  I  have 
been  led  by  the  consideration  of  the  phenomena  of  hybrids.  It  appears 
that  the  aversion  of  individuals  of  distinct  species  to  the  sexual  union  is 
common  to  animals  and  plants ;  and  that  it  is  only  when  the  species 
approach  near  to  each  other  in  their  organization  and  habits,  that  any 
offspring  are  produced  from  their  connexion.  Mules  are  of  extremely 
rare  occurrence  in  a  state  of  nature,  and  no  examples  are  yet  known  of 
their  having  procreated  in  a  wild  state.  But  it  has  been  proved,  that 
hybrids  are  not  universally  sterile,  provided  the  parent  stocks  have  a 
near  affinity  to  each  other,  although  the  continuation  of  the  mixed 
race,  for  several  generations,  appears  hitherto  to  have  been  obtained 
only  by  crossing  the  hybrids  with  individuals  of  pure  species ;  an 
experiment  which  by  no  means  bears  out  the  hypothesis  that  a  true 
hybrid  race  could  ever  be  permanently  established. 

Hence  we  may  infer,  that  aversion  to  sexual  intercourse  is,  in  gene- 
ral, a  good  test  of  the  distinctness  of  original  stocks,  or  of  species  ;  and 
the  procreation  of  hybrids  is  a  proof  of  the  near  affinity  of  species.  Per- 
haps, hereafter,  the  number  of  generations  for  which  hybrids  may  be 
continued,  before  the  race  dies  out  (for  it  seems  usually  to  degenerate 
rapidly),  may  afford  the  zoologist  and  botanist  an  experimental  test  of 
the  difference  in  the  degree  of  affinity  of  allied  species. 

I  may  also  remark,  that  if  it  could  have  been  shown  that  a  single 
permanent  species  had  ever  been  produced  by  hybridity  (of  which  there 
is  no  satisfactory  proof),  it  might  certainly  have  lent  some  countenance 
to  the  notions  of  the  ancients  respecting  the  gradual  deterioration  of 
created  things,  but  none  whatever  to  Lamarck's  theory  of  their  progres- 
sive perfectibility,  for  observations  have  hitherto  shown  that  there  is  a 
tendency  in  mule  animals  and  plants  to  degenerate  in  organization. 

It  was  before  remarked,  that  the  theory  of  progressive  development 
arose  partly  from  an  attempt  to  ingraft  the  doctrines  of  the  .transmuta- 
tionists  upon  one  of  the  most  popular  generalizations  in  geology.  But  we 
have  seen  in  the  ninth  chapter,  that  the  modern  researches  of  geologists 
have  broken  at  many  points  the  chain  of  evidence  once  supposed  to  ex- 


608  FACIAL   ANGLE.  [Ca  XXXVL 

ist  in  favor  of  the  doctrine,  that,  at  each  successive  period  in  the  earth's 
history,  animals  arid  plants  of  a  higher  grade,  or  more  complex  organ- 
ization, have  been  created.  The  recent  origin  of  man,  and  the  absence 
of  all  signs  of  any  rational  being  holding  an  analogous  relation  to  for- 
mer states  of  the  animate  world,  affords  one,  and  perhaps  in  the  present 
state  of  science  the  only  argument  of  much  weight  in  support  of  the 
hypothesis  of  a  progressive  scheme  ;  but  none  whatever  in  favor  of  the 
fancied  evolution  of  one  species  out  of  another. 

Theory  of  the  gradation  of  intellect  as  shown  by  the  facial  angle. — 
When  the  celebrated  anatomist,  Camper,  first  attempted  to  estimate  the 
degrees  of  sagacity  of  different  animals,  and  of  the  races  of  man,  by  the 
measurement  of  the  facial  angle,  some  speculators  were  bold  enough  to 
affirm  that  certain  Simia3,  or  apes,  differed  as  little  from  the  more 
savage  races  of  men,  as  those  do  from  the  human  race  in  general ;  and 
that  a  scale  might  be  traced  from  "  apes  with  foreheads  villanous  low" 
to  the  African  variety  of  the  human  species,  and  from  that  to  the  Euro- 
pean. The  facial  angle  was  measured  by  drawing  a  line  from  the  pro- 
minent centre  of  the  forehead  to  the  most  advanced  part  of  the  lower 
jaw-bone,  and  observing  the  angle  which  it  made  with  the  horizontal 
line  ;  and  it  was  affirmed,  that  there  was  a  regular  series  of  such  angles 
from  birds  to  the  mammalia. 

The  gradation  from  the  dog  to  the  monkey  was  said  to  be  perfect, 
and  from  that  again  to  man.  One  of  the  ape  tribe  has  a  facial  angle  of 
42°  ;  and  another,  which  approximated  nearest  to  man  in  figure,  an 
angle  of  50°.  To  this  succeeds  (longo  sed  proximus  intervallo)  the 
head  of  the  African  negro,  which,  as  well  as  that  of  the  Calmuck, 
forms  an  angle  of  70°  ;  while  that  of  the  European  contains  80°.  The 
Roman  painters  preferred  the  angle  of  95°  ;  and  the  character  of  beauty 
and  sublimity  so  striking  in  some  works  of  Grecian  sculpture,  as  in  the 
head  of  the  Apojlo,  and  in  the  Medusa  of  Sisocles,  is  given  by  an  angle 
which  amounts  to  100°.* 

A  great  number  of  valuable  facts  and  curious  analogies  in  compara- 
tive anatomy  were  brought  to  light  during  the  investigations  which 
were  made  by  Camper,  John  Hunter,  and  others,  to  illustrate  this  scale 
of  organization ;  and  their  facts  and  generalizations  must  not  be  con- 
founded with  the  fanciful  systems  which  White  and  others  deduced 
from  them.f 

That  there  is  some  connexion  between  an  elevated  and  capacious 
forehead,  in  certain  races  of  men,  and  a  large  developement  of  the  intel- 
lectual faculties,  seems  highly  probable  ;  and  that  a  low  facial  angle  is 
frequently  accompanied  with  inferiority  of  mental  powers,  is  certain  ; 
but  the  attempt  to  trace  a  gradual  scale  of  intelligence  through  the  differ- 
ent species  of  animals  accompanying  the  modifications  of  the  form  of  the 
scull,  is  a  mere  visionary  speculation.  It  has  been  found  necessary  to 

*  Richard's  Tliys.  Hist,  of  Mankind,  vol.  i.  p.  159. 
f  Ch.  White  on  the  Regular  Gradation  in  Man,  <fec.  1799. 


CH.  XXXVL]  DIFFERENT   RACES   OF   MAN.  609 

exaggerate  the  sagacity  of  the  ape  tribe  at  the  expense  of  the  dog  ;  and 
strange  contradictions  have  arisen  in  the  conclusions  deduced  from  the 
structure  of  the  elephant ;  some  anatomists  being  disposed  to  deny  the 
quadruped  the  intelligence  which  he  really  possesses,  because  they 
found  that  the  volume  of  his  brain  was  small  in  comparison  to  that  of 
the  other  mammalia ;  while  others  were  inclined  to  magnify  extrava- 
gantly the  superiority  of  his  intellect,  because  the  vertical  height  of  his 
skull  is  so  great  when  compared  to  its  horizontal  length 

Different  races  of  men  are  all  of  one  species. — It  would  be  irrelevant 
to  our  subject  if  we  were  to  enter  into  a  farther  discussion  on  these 
topics ;  because,  even  if  a  graduated  scale  of  organization  and  intelligence 
could  have  been  established,  it  would  prove  nothing  in  favor  of  a  ten- 
dency, in  each  species,  to  attain  a  higher  state  of  perfection.  I  may 
refer  the  reader  to  the  writings  of  Blumenbach,  Prichard,  Lawrence,  and 
more  recently  Latham*,  for  convincing  proofs  that  the  varieties  of  form, 
color,  and  organization  of  different  races  of  men,  are  perfectly  consistent 
with  the  generally  received  opinion,  that  all  the  individuals  of  the  species 
have  originated  from  a  single  pair ;  and,  while  they  exhibit  in  man  as 
many  diversities  of  a  physiological  nature  as  appear  in  any  other  species, 
they  confirm  also  the  opinion  of  the  slight  deviation  from  a  common 
standard  of  which  species  are  capable. 

The  power  of  existing  and  multiplying  in  every  latitude,  and  in  every 
variety  of  situation  and  climate,  which  has  enabled  the  great  human 
family  to  extend  itself  over  the  habitable  globe,  is  partly,  says  Lawrence, 
the  result  of  physical  constitution,  and  partly  of  the  mental  prerogative 
of  man.  If  he  did  not  possess  the  most  enduring  and  flexible  corporeal 
frame,  his  arts  would  not  enable  him  to  be  the  inhabitant  of  all  climates, 
and  to  brave  the  extremes  of  heat  and  cold,  and  the  other  destructive 
influences  of  local  situation.!  Yet,  notwithstanding  this  flexibility  of 
bodily  frame,  we  find  no  signs  of  indefinite  departure  from  a  common 
standard,  and  the  intermarriages  of  individuals  of  the  most  remote 
varieties  are  not  less  fruitful  than  between  those  of  the  same  tribe. 

Tiedemann  on  the  brain  of  the  foetus  in  vertebrated  animals. — There 
is  yet  another  department  of  anatomical  discovery  to  which  I  must 
allude,  because  it  has  appeared  to  some  persons  to  afford  a  distant  ana- 
logy, at  least,  to  that  progressive  development  by  which  some  of  the 
inferior  species  may  have  been  gradually  perfected  into  those  of  more 
complex  organization.  Tiedemann  found,  and  his  discoveries  have  been 
most  fully  confirmed  and  elucidated  by  M.  Serres,  that  the  brain  of  the 
foetus,  in  the  highest  class  of  vertebrated  animals,  assumes,  in  succession, 
forms,  bearing  a  certain  degree  of  resemblance  to  those  which  belong  to 
fishes,  reptiles,  and  birds,  before  it  acquires  the  additions  and  modifica- 
tions which  are  peculiar  to  the  mammiferous  tribe  ;  so  that,  in  the  passage 
from  the  embryo  to  the  perfect  mammifer,  there  is  a  typical  representa- 

*  R.  Gk  Latham,  The  Nat.  Hist,  of  the  Varieties  of  Man,  8vo.  London,  1850. 
f  Lawrence,  Lectures  on  Phys.  Zool.  and  Nat  Hist,  of  Man,  p.  190.     Ed.  1823. 

39 


610  FCETAL   DEVELOPMENT.  [On.  XXXVI. 

tion,  it  is  said,  of  ail  those  transformations  which  the  primitive  species 
are  supposed  to  have  undergone,  during  a  long  series  of  generations, 
between  the  present  period  and  the  remotest  geological  era. 

"  If  you  examine  the  brain  of  the  mammalia,"  says  M.  Serres,  "  at  an 
early  stage  of  uterine  life,  you  perceive  the  cerebral  hemispheres  consoli- 
dated, as  in  fish,  in  two  vesicles,  isolated  one  from  the  other  ;  at  a  later 
period,  you  see  them  affect  the  configuration  of  the  cerebral  hemispheres 
of  reptiles ;  still  later  again,  they  present  you  with  the  forms  of  those  of 
birds  ;  finally  they  acquire,  at  the  era  of  birth,  and  sometimes  later,  the 
permanent  forms  which  the  adult  mammalia  present. 

"  The  cerebral  hemispheres,  then,  arrive  at  the  state  which  we  observe 
.  in  the  higher  animals  only  by  a  series  of  successive  metamorphoses.  If 
we  reduce  the  whole  of  these  evolutions  to  four  periods,  we  shall  see, 
that  in  the  first  are  born  the  cerebral  lobes  of  fishes ;  and  this  takes  place 
homogeneously  in  all  classes.  The  second  period  will  give  us  the  orga- 
nization of  reptiles ;  the  third,  the  brain  of  birds  ;  and  the  fourth,  the 
complex  hemispheres  of  mammalia. 

"  If  we  could  develope  the  different  parts  of  the  brain  of  the  inferior 
classes,  we  should  make,  in  succession,  a  reptile  out  of  a  fish,  a  bird  out 
of  a  reptile,  and  a  mammiferous  quadruped  out  of  a  bird.  If,  on  the 
contrary,  we  could  starve  this  organ  in  the  mammalia,  we  might  reduce 
it  successively  to  the  condition  of  the  brain  of  the  three  inferior  classes. 

"  Nature  often  presents  us  with  this  last  phenomenon  in  monsters,  but 
never  exhibits  the  first.  Among  the  various  deformities  which  organized 
beings  may  experience,  they  never  pass  the  limits  of  their  own  classes  to 
put  on  the  forms  of  the  class  above  them.  Never  does  a  fish  elevate 
itself  so  as  to  assume  the  form  of  the  brain  of  a  reptile ;  nor  does  the 
latter  ever  attain  that  of  birds  ;  nor  the  bird  that  of  the  mammifer.  It 
may  happen  that  a  monster  may  have  two  heads ;  but  the  conformation 
of  the  brain  always  remains  circumscribed  narrowly  within  the  limits  of 
its  class."* 

Dr.  Clark  of  Cambridge,  in  a  memoir  on  "  Foetal  Development"  (1845), <- 
has  shown  that  the  concurrent  labours  of  Valentin,  Ratke,  and  Bischoff 
disprove  the  reality  of  the  supposed  anatomical  analogy  between  the 
embryo  condition  of  certain  organs  in  the  higher  orders,  and  the  perfect 
structure  of  the  same  organs  in  animals  of  an  inferior  class.  The  hearts 
and  brains,  for  example,  of  birds  and  mammals  do  not  pass  through 
forms  which  are  permanent  in  fishes  and  reptiles ;  there  is  only  just  so 
much  resemblance  as  may  point  to  a  unity  of  plan  running  through  the 
organization  of  the  whole  series  of  vertebrated  animals  ;  but  which  lends 
no  support  whatever  to  the  notion  of  a  gradual  transmutation  of  one 
species  into  another ;  least  of  all  of  the  passage,  in  the  course  of  many 
generations,  from  an  animal  of  a  more  simple  to  one  of  a  mo-re  complex 
structure. 


*  E.  R.  A.  Serres,  Anatomic  compare'e  du  Cerveau,  illustrated  by  numerous 
plates,  tome  i.  1824. 


OIL  XXXVL]  RECAPITULATION.  611 

Recapitulation. — For  the  reasons,  therefore,  detailed  'in  this  and 
the  two  preceding  chapters,  we  may  draw  the  following  inferences  in 
regard  to  the  reality  of  species  in  nature : — 

1st.  That  there  is  a  capacity  in  all  species  to  accommodate  themselves, 
to  a  certain  extent,  to  a  change  of  external  circumstances,  this  extent 
varying  greatly,  according  to  the  species. 

2ndly.  When  the  change  of  situation  which  they  can  endure  is  great, 
it  is  usually  attended  by  some  modifications  of  the  form,  colour,  size, 
structure,  or  other  particulars ;  but  the  mutations  thus  superinduced  are 
governed  by  constant  laws,  and  the  capability  of  so  varying,  forms  part 
of  the  permanent  specific  character. 

3dly.  Some  acquired  peculiarities,  of  form,  structure,  and  instinct,  are 
transmissible  to  the  offspring ;  but  these  consist  of  such  qualities  and 
attributes  only  as  are  intimately  related  to  the  natural  wants  and  propen- 
sities of  the  species. 

4thly.  The  entire  variation  from  the  original  type,  which  any  given 
kind  of  change  can  produce,  may  usually  be  effected  in  a  brief  period  of 
time,  after  which  no  farther  deviation  can  be  obtained  by  continuing  to 
alter  the  circumstances,  though  ever  so  gradually ;  indefinite  divergence, 
either  in  the  way  of  improvement  or  deterioration,  being  prevented,  and 
the  least  possible  excess  beyond  the  defined  limits  being  fatal  to  the  ex- 
istence of  the  individual. 

5thly.  The  intermixture  of  distinct  species  is  guarded  against  by  the 
aversion  of  the  individuals  composing  them  to  sexual  union,  or  by  the 
sterility  of  the  mule  offspring.  It  does  not  appear  that  true  hybrid  races 
have  ever  been  perpetuated  for  several  generations,  even  by  the  assistance 
of  man ;  for  the  cases  usually  cited  relate  to  the  crossing  of  mules  with 
individuals  of  pure  species,  and  not  to  the  intermixture  of  hybrid  with 
hybrid. 

6thly.  From  the  above  considerations,  it  appears  that  species  have  a 
real  existence  in  nature ;  and  that  each  was  endowed,  at  the  time  of  its 
creation,  with  the  attributes  and  organization  by  which  it  is  now  distin- 
guished. 


CHAPTER   XXXVII. 

LAWS    WHICH    REGULATE    THE    GEOGRAPHICAL    DISTRIBUTION    OF    SPECIES. 

Analogy  of  climate  not  attended  with  identity  of  species — Botanical  geography 
— Stations — Habitations — Distinct  provinces  of  indigenous  plants — Vegeta- 
tion of  islands — Marine  vegetation — In  what  manner  plants  become  diffused 
— Effects  of  wind,  rivers,  marine  currents — Agency  of  animals — Many  seeds 
pass  through  the  stomachs  of  animals  and  birds  undigested — Agency  of  man 
in  the  dispersion  of  plants,  both  voluntary  and  involuntary — Its  analogy  to 
that  of  the  inferior  animals. 

NEXT  to  determining  the  question  whether  species  have  a  real  existence, 
the  consideration  of  the  laws  which  regulate  their  geographical  distribu- 
tion is  a  subject  of  primary  importance  to  the  geologist.  It  is  only  by 
studying  these  laws  with  attention,  by  observing  the  positions  which 
groups  of  species  occupy  at  present,  and  inquiring  how  these  may  be 
varied  in  the  course  of  time  by  migrations,  by  changes  in  physical  geo- 
graphy, and  other  causes,  that  we  can  hope  to  learn  whether  the  duration 
of  species  be  limited,  or  in  what  manner  the  state  of  the  animate  world 
is  affected  by  the  endless  vicissitudes  of  the  inanimate. 

Different  regions  inhabited  by  distinct  species. — That  different  regions 
of  the  globe  are  inhabited  by  entirely  distinct  animals  and  plants,  is  a 
fact  which  has  been  familiar  to  all  naturalists  since  Buffon  first  pointed 
out  the  want  of  specific  identity  between  the  land  quadrupeds  of  America 
and  those  of  the  Old  World.  The  same  phenomenon  has,  in  later  times, 
been  forced  in  a  striking  manner  upon  our  attention,  by  the  examination 
of  New  Holland,  where  the  indigenous  species  of  animals  and  plants  were 
found  to  be,  almost  without  exception,  distinct  from  those  known  in  other 
parts  of  the  world. 

But  the  extent  of  this  parcelling  out  of  the  globe  amongst  different 
nations,  as  they  have  been  termed,  of  plants  and  animals — the  universality 
of  a  phenomenon  so  extraordinary  and  unexpected,  may  be  considered  as 
one  of  the  most  interesting  facts  clearly  established  by  the  advance  of 
modern  science. 

Scarcely  fourteen  hundred  species  of  plants  appear  to  have  been  known 
and  described  by  the  Greeks,  Romans,  and  Arabians.  At  present,  more 
than  three  thousand  species  are  enumerated,  as  natives  of  our  own  island.* 
In  other  parts  of  the  world  there  have  been  now  collected  (1846)  upwards 
of  100,000  species,  specimens  of  which  are  preserved  in  European  her- 
bariums. It  was  not  to  be  supposed,  therefore,  that  the  ancients  should 
have  acquired  any  correct  notions  respecting  what  may  be  called  the 
geography  of  plants,  although  the  influence  of  climate  on  the  character 
of  the  vegetation  could  hardly  have  escaped  their  observation. 

*  Barton's  Lectures  on  the  Geography  of  Plants,  p.  2.  1827. 


CH.  XXXVII.]  BOTANICAL   GEOGRAPHY.  613 

Antecedently  to  investigation,  there  was  no  reason  for  presuming  that 
the  vegetable  productions,  growing  wild  in  the  eastern  hemisphere, 
should  be  unlike  those  of  the  western,  in  the  same  latitude ;  nor  that 
the  plants  of  the  Cape  of  Good  Hope  should  be  unlike  those  of  the 
south  of  Europe  ;  situations  where  the  climate  is  little  dissimilar.  The 
contrary  supposition  would  have  seemed  more  probable,  and  we  might 
have  anticipated  an  almost  perfect  identity  in  the  animals  and  plants 
which  inhabit  corresponding  parallels  of  latitude.  The  discovery,  there- 
fore, that  each  separate  region  of  the  globe,  both  of  the  land  and  water, 
is  occupied  by  distinct  groups  of  species,  and  that  most  of  the  excep- 
tions to  this  general  rule  may  be  referred  to  disseminating  causes  now  in 
operation,  is  eminently  calculated  to  excite  curiosity,  and  to  stimulate 
us  to  seek  some  hypothesis  respecting  the  first  introduction  of  species 
which  may  be  reconcileable  with  such  phenomena. 

Botanical  geography. — A  comparison  of  the  plants  of  different  regions 
of  the  globe  affords  results  more  to  be  depended  upon  in  the  present  state 
of  our  knowledge  than  those  relating  to  the  animal  kingdom,  because 
the  science  of  botany  is  more  advanced,  and  probably  comprehends  a 
great  proportion  of  the  total  number  of  the  vegetable  productions  of  the 
whole  earth.  Humboldt,  in  several  eloquent  passages  of  his  Personal 
Narrative,  was  among  the  first  to  promulgate  philosophical  views  on  this 
subject.  Every  hemisphere,  says  this  traveller,  produces  plants  of  different 
species ;  and  it  is  not  by  the  diversity  of  climates  that  we  can  attempt 
to  explain  why  equinoctial  Africa  has  no  Laurina3,  and  the  New  World 
no  Heaths ;  why  the  Calceolariae  are  found  only  in  thes  outhern  hemi- 
sphere ;  why  the  birds  of  the  continent  of  India  glow  with  colors  less 
splendid  than  the  birds  of  the  hot  parts  of  America :  finally,  why  the 
tiger  is  peculiar  to  Asia,  and  the  ornithorhynchus  to  New  Holland.* 

"  We  can  conceive,"  he  adds,  "  that  a  small  number  of  the  families  of 
plants,  for  instance,  the  Musacese  and  the  Palms,  cannot  belong  to  very 
cold  regions,  on  account  of  their  internal  structure  and  the  importance  of 
certain  organs ;  but  we  cannot  explain  why  no  one  of  the  family  of 
Melastomas  vegetates  north  of  the  parallel  of  thirty  degrees ;  or  why  no 
rose-tree  belongs  to  the  southern  hemisphere.  Analogy  of  climates  is 
often  found  in  the  two  continents  without  identity  of  productions."! 

The  luminous  essay  of  De  Candolle  on  "  Botanical  Geography"  pre- 
sents us  with  the  fruits  of  his  own  researches  and  those  of  Humboldt, 
Brown,  and  other  eminent  botanists,  so  arranged,  that  the  principal  phe- 
nomena of  the  distribution  of  plants  are  exhibited  in  connexion  with  the 
causes  to  which  they  are  chiefly  referrible.J  "  It  might  not,  perhaps,  be 
difficult,"  observes  this  writer,  "  to  find  two  points,  in  the  United  States 
and  in  Europe,  or  in  Equinoctial  America  and  Africa,  which  present 
all  the  same  circumstances :  as,  for  example,  the  same  temperature, 

*  Pers.  Nar.,  vol.  v.  p.  180. 
f  Ibid. 

\  Essai  Elementaire  de  Geographic  Botanique.  Extrait  du  18me  voL  du 
Diet,  des  Sci.  Nat. 


614  STATIONS   AND    HABITATIONS   OP   PLANTS.       [Ca  XXXVII. 

the  same  height  above  the  sea,  a  similar  soil,  an  equal  dose  of 
humidity ;  yet  nearly  all,  perhaps  all,  the  plants  in  these  two  similar 
localities  shall  be  distinct.  A  certain  degree  of  analogy,  indeed,  of 
aspect,  and  even  of  structure,  might  very  possibly  be  discoverable  between 
the  plants  of  the  two  localities  in  question ;  but  the  species  would  in 
general  be  different.  Circumstances,  therefore,  different  from  those  which 
now  determine  the  stations,  have  had  an  influence  on  the  habitations  of 
plants" 

Stations  and  habitations  of  plants. — As  I  shall  frequently  have  occa- 
sion to  speak  of  the  stations  and  habitations  of  plants  in  the  technical 
sense  in  which  the  terms  are  used  in  the  above  passage,  I  may  remind 
the  geologist  that  station  indicates  the  peculiar  nature  of  the  locality  where 
each  species  is  accustomed  to  grow,  and  has  reference  to  climate,  soil, 
humidity,  light,  elevation  above  the  sea,  and  other  analogous  circum- 
stances ;  whereas,  by  habitation  is  meant  a  general  indication  of  the 
country  where  a  plant  grows  wild.  Thus  the  station  of  a  plant  may  be  a 
salt-marsh,  a  hill-side,  the  bed  of  the  sea,  or  a  stagnant  pool.  Its  habita- 
tion may  be  Europe,  North  America,  or  New  Holland,  between  the 
tropics.  The  study  of  stations  has  been  styled  the  topography,  that  of 
habitations  the  geography,  of  botany.  The  terms  thus  defined,  express 
each  a  distinct  class  of  ideas,  which  have  been  often  confounded  together, 
and  which  are  equally  applicable  in  zoology. 

In  farther  illustration  of  the  principle  above  alluded  to,  that  difference 
of  longitude,  independently  of  any  influence  of  temperature,  is  accompa- 
nied by  a  great,  and  sometimes  a  complete,  diversity  in  the  species  of 
plants,  De  Candolle  observes,  that,  out  of  2891  species  of  phsenogamous 
plants  described  by  Pursh,  in  the  United  States,  there  are  only  385  which 
are  found  in  northern  or  temperate  Europe.  MM.  Humboldt  and  Bon- 
pland,  in  all  their  travels  through  equinoctial  America,  found  only  twenty- 
four  species  (these  being  all  Cyperaceae  and  Gramineae)  common  to  Ame- 
rica and  any  part  of  the  Old  World.  They  collected,  it  is  true,  chiefly 
on  the  mountains,  or  the  proportion  would  have  been  larger ;  for  Dr.  J . 
Hooker  informs  me  that  many  tropical  plants  of  the  New  World  are 
identical  with  African  species.  Nevertheless,  the  general  discordance  of 
these  Floras  is  very  striking.  On  comparing  New  Holland  with  Europe, 
Mr.  Brown  ascertained  that,  out  of  4100  species,  discovered  in  Australia, 
there  were  only  166  common  to  Europe,  and  of  this  small  number  there 
were  some  few  which  may  have  been  transported  thither  by  man.  Al- 
most all  of  the  166  species  were  cryptogamic,  and  the  rest  consist,  in 
nearly  every  case,  of  phsenogamous  plants  which  also  inhabit  intervening 
regions. 

But  what  is  still  more  remarkable,  in  the  more  widely  separated  parts 
of  the  ancient  continent,  notwithstanding  the  existence  of  an  uninter- 
rupted land-communication,  the  diversity  in  the  specific  character  of  the 
respective  vegetations  is  almost  as  striking.  Thus  there  is  found  one 
assemblage  of  species  in  China,  another  in  the  countries  bordering  the 
Black  Sea  and  the  Caspian,  a  third  in  those  surrounding  the  Mediterra- 


OIL  XXXVII.  ]  VEGETATION   OF   ISLANDS.  615 

nean,  a  fourth  in  the  great  platforms  of  Siberia  and  Tartary,  and  so 
forth. 

The  distinctness  of  the  groups  of  indigenous  plants,  in  the  same  parallel 
of  latitude,  is  greatest  where  continents  are  disjoined  by  a  wide  expanse 
of  ocean.  In  the  northern  hemisphere,  near  the  pole,  where  the  extremi- 
ties of  Europe,  Asia,  and  America  unite  or  approach  near  to  one  another, 
a  considerable  number  of  the  same  species  of  plants  are  found,  common 
to  the  three  continents.  But  it  has  been  remarked,  that  these  plants, 
which  are  thus  so  widely  diffused  in  the  arctic  regions,  are  also  found  in 
the  chain  of  the  Aleutian  islands,  which  stretch  almost  across  from  Ame- 
rica to  Asia,  and  which  may  probably  have  served  as  the  channel  of  com- 
munication for  the  partial  blending  of  the  Floras  of  the  adjoining  regions. 
It  has,  indeed,  been  observed  to  be  a  general  rule,  that  plants  found  at 
two  points  very  remote  from  each  other  occur  also  in  places  intermediate. 

Dr.  J.  Hooker  informs  me  that  in  high  latitudes  in  the  southern  ocean, 
in  spite  of  the  great  extent  of  the  sea,  Floras  of  widely  disconnected  islands 
contain  many  species  in  common.  Perhaps  icebergs,  transporting  to  vast 
distances  not  only  stones,  but  soil  with  the  seeds  of  plants,  may  explain 
this  unusually  wide  diffusion  of  insular  plants. 

In  islands  very  distant  from  continents  the  total  number  of  plants  is 
comparatively  small ;  but  a  large  proportion  of  the  species  are  such  as 
occur  nowhere  else.  In  so  far  as  the  Flora  of  such  islands  is  not  peculiar 
to  them,  it  contains,  in  general,  species  common  to  the  nearest  main 
lands.*  The  islands  of  the  great  southern  ocean  exemplify  these  rules  ; 
the  easternmost  containing  more  American,  and  the  western  more  Indian 
plants.f  Madeira  and  Teneriffe  contain  many  species,  and  even  entire 
genera,  peculiar  to  them ;  but  they  have  also  plants  in  common  with 
Portugal,  Spain,  the  Azores,  and  the  north-west  coast  of  Africa.J; 

In  the  Canaries,  out  of  533  species  of  phsenogamous  plants,  it  is  said 
that  310  are  peculiar  to  these  islands,  and  the  rest  identical  with  those 
of  the  African  continent ;  but  in  the  Flora  of  St.  Helena,  which  is  so  far 
distant  even  from  the  western  shores  of  Africa,  there  have  been  found, 
out  of  thirty  native  species  of  the  phaenogamous  class,  only  one  or  two 
which  are  to  be  found  in  any  other  part  of  the  globe.  On  the  other 
hand,  of  sixty  cryptogamic  plants,  collected  by  Dr.  J.  Hooker  in  the  same 
island,  twelve  only  were  peculiar. 

The  natural  history  of  the  Galapagos  archipelago,  described  by  Mr. 
Darwin,  affords  another  very  instructive  illustration  of  the  laws  governing 
the  geographical  distribution  of  plants  and  animals  in  islands.  This 
group  consists  of  ten  principal  islands,  situated  in  the  Pacific  Ocean,  under 
the  equator,  about  600  miles  westward  of  the  coast  of  South  America. 
As  they  are  all  formed  of  volcanic  rocks,  many  of  the  craters,  of  which 
there  are  about  2000  in  number,  having  a  very  fresh  aspect,  we  may 

*  Prichard,  vol.  i.  p.  36.     Brown,  Appendix  to  Flinders, 
f  Foster,  Observations,  <fec. 

j  Humboldt,  Pers.  Nar.,  vol.  i.  p.  270  of  the  translation.  Prichard,  Phys.  Hiet. 
of  Mankind,  vol.  i.  p.  37. 


616  DISTINCT   BOTANICAL   REGIONS.  [Cn.  XXXVII. 

regard  the  whole  as  much  more  modern  in  origin  than  the  mass  of  the 
adjoining  continent ;  yet  neither  has  the  Flora  nor  Fauna  been  derived  from 
South  America,  but  consist  of  species  for  the  most  part  indigenous,  yet 
stamped  with  a  character  decidedly  South  American. 

What  is  still  more  singular,  there  is  a  difference  between  the  species 
inhabiting  the  different  islands.  Of  flowering  plants,  for  example,  there 
are  185  species  at  present  known,  and  forty  cryptogamic,  making  together 
225.  One  hundred  of  the  former  class  are  new  species,  probably  confined 
to  this  archipelago ;  and  of  the  rest,  ten  at  least  have  been  introduced  by 
man.  Of  twenty-one  species  of  Composite,  all  but  one  are  peculiar,  and 
they  belong  to  twelve  genera,  no  less  than  ten  of  which  genera  are  con- 
fined to  the  Galapagos.  Dr.  Hooker  observes,  that  the  type  of  this  Flora 
has  an  undoubted  relation  to  that  of  the  western  side  of  South  America, 
and  he  detects  in  it  no  affinity  with  that  of  the  numerous  islands  scatter- 
ed over  other  parts  of  the  Pacific.  So  in  regard  to  the  birds,  reptiles, 
land-shells,  and  insects,  this  archipelago,  standing  as  it  does  in  the  Pacific 
Ocean,  is  zoologically  part  of  America.  Although  each  small  island  is 
not  more  than  fifty  or  sixty  miles  apart,  and  most  of  them  are  in  sight  of 
each  other,  formed  of  precisely  the  same  rocks,  rising  nearly  to  an  equal 
height,,  and  placed  under  a  similar  climate,  they  are  tenanted  each  by  a 
different  set  of  beings,  the  tortoises,  mocking-thrushes,  finches,  beetles, 
scarcely  any  of  them  ever  ranging  over  the  whole,  and  often  not  even 
common  to  any  two  of  the  islands. 

"  The  archipelago,"  says  Mr.  Darwin,  "  is  a  little  world  within  itself,  or 
rather  a  satellite  attached  to  America;  whence  it  has 'derived  a  few  stray 
colonists,  and  has  received  the  general  character  of  its  indigenous  pro- 
ductions. One  is  astonished,"  he  adds,  "  at  the  amount  of  creative  force 
displayed  on  so  many  small,  barren,  and  rocky  islands,  and  still  more  so, 
at  its  diverse,  yet  analogous  action  on  points  so  near  each  other.  I  have 
said  that  the  Galapagos  archipelago  might  be  called  a  satellite  attached 
to  America,  but  it  should  rather  be  called  a  group  of  satellites  physically 
similar,  organically  distinct,  yet  intimately  related  to  each  other,  and  all 
related  in  a  marked,  though  much  lesser  degree,  to  the  great  American 
continent."* 

Number  of  botanical  provinces. — De  Candolle  has  enumerated  twenty 
great  botanical  provinces  inhabited  by  indigenous  or  aboriginal  plants ; 
and  although  many  of  these  contain  a  variety  of  species  which  are  com- 
mon to  several  others,  and  sometimes  to  places  very  remote,  yet  the  lines 
of  demarcation  are,  upon  the  whole,  astonishingly  well  defmed.f  Nor  is 
it  likely  that  the  bearing  of  the  evidence  on  which  these  general  views 
are  founded  will  ever  be  materially  affected,  since  they  are  already  con- 
firmed by  the  examination  of  nearly  one  hundred  thousand  species  of 
plants. 

*  Voyage  of  the  "Ponpvle,  2d  edition,  1845,  p.  377. 

f  See  a  farther  subdivision,  by  which  twenty-seven  provinces  are  made,  by 
M.  Alph.  De  Candolle,  son  of  De  Candolle.  Monogr.  des  Campanulees.  Paris, 
1830. 


CH.  XXXVII. ]  MARINE   VEGETATION.  617 

The  entire  change  of  opinion  Avhich  the  contemplation  of  these  phe- 
nomena has  brought  about  is  worthy  of  remark.  The  first  travellers  were 
persuaded  that  they  should  find,  in  distant  regions,  the  plants  of  their  own 
country,  and  they  took  a  pleasure  in  giving  them  the  same  names.  It 
was  some  time  before  this  illusion  was  dissipated ;  but  so  fully  sensible  did 
botanists  at  last  become  of  the  extreme  smallness  of  the  number  of  phae- 
nogarnous  plants  common  to  different  continents,  that  the  ancient  Floras 
fell  into  disrepute.  All  grew  diffident  of  the  pretended  identifications ; 
and  we  now  find  that  every  naturalist  is  inclined  to  examine  each  supposed 
exception  with  scrupulous  severity.*  If  they  admit  the  fact,  they  begin 
to  speculate  on  the  mode  whereby  the  seeds  may  have  been  transported 
from  one  country  into  the  other,  or  enquire  on  which  of  two  continents 
the  plant  was  indigenous,  assuming  that  a  species,  like  an  individual, 
cannot  have  two  birthplaces. 

Marine  vegetation. — The  marine  vegetation  is  divisible  into  different 
systems,  like  those  prevailing  on  the  land ;  but  they  are  much  fewer,  as 
we  might  have  expected,  the  temperature  of  the  ocean  being  more  uniform 
than  that  of  the  atmosphere,  and  consequently  the  dispersion  of  species 
from  one  zone  to  another  being  less  frequently  checked  by  the  interven- 
tion of  uncongenial  climates.  The  proportion  also  of  land  to  sea  through- 
out the  globe  being  small,  the  migration  of  marine  plants  is  not  so  often 
stopped  by  barriers  of  land,  as  is  that  of  the  terrestrial  species  by  the 
ocean.  The  number  of  hydrophytes,  as  they  are  termed,  is  very  conside- 
rable, and  their  stations  are  found  to  bo  infinitely  more  varied  than  could 
have  been  anticipated ;  for  while  some  plants  are  covered  and  uncovered 
daily  by  the  tide,  others  live  at  the  depth  of  several  hundred  feet.  Among 
the  known  provinces  of  Algse,  we  may  mention,  1st,  The  north  circum- 
polar,  from  lat.  60°  N.  to  the  pole ;  2dly,  The  North  Atlantic  or  the 
region  of  Fucus  proper  and  Delesserise,  extending  from  lat.  40°  N.  to  lat. 
60°  N. ;  3dly,  That  of  the  Mediterranean,  which  may  be  regarded  as  a 
sub-region  of  the  fourth  or  warmer  temperate  zone  of  the  Atlantic,  between 
lat.  23°  N.  and  lat.  40°  N.;  5thly,  The  Tropical  Atlantic,  in  which  Sar- 
gassum,  Rhodomelia,  Corallinea,  and  Siphonia  abound ;  6thly,  The  South 
Atlantic,  where  the  Fucus  reappears ;  7thly,  The  Antarctic  American, 
comprehending  from  Chili  to  Cape  Horn,  the  Falkland  Islands,  and  thence 
round  the  world  south  of  latitude  50°  S. ;  Sthly,  The  Australian  and  New 
Zealand,  which  is  very  peculiar,  being  characterized,  among  other  generic 
forms,  by  Cystoseiriae  and  Fucese  ;  9thly,  The  Indian  Ocean  and  Red  Sea; 
and,  lOthly,  The  Chinese  and  Japanese  seas.f  In  addition  to  the  above 
provinces,  there  are  several  others  not  yet  well  determined  in  the  Pacific 
Ocean  and  elsewhere.  There  are,  however,  many  species  which  range 
through  several  of  these  geographical  regions  of  subaqueous  vegetation, 
being  common  to  very  remote  countries ;  as,  for  example,  to  the  coasts  of 

*  De  Candolle,  Essai  Elemen.  de  Geog.  Botan.,  p.  45. 

f  I  am  indebted  for  the  above  sketch  of  distinct  regions  of  algffi  to  my  friend 
Dr.  Joseph  Hooker,  who  refers  the  botanical  student  to  the  labors  of  Dr.  Har- 
vey, of  Trinity  College,  Dublin. 


618  DIFFUSION   OF   PLANTS  BY  WINDS.  [Ca  XXXVIL 

Europe  and  the  United  States,  and  others,  to  Cape  Horn  and  Van  Diemen's 
Land,  the  same  plants  extending  also  for  the  most  part  to  the  New  Zea- 
land sea.  Of  the  species  strictly  antarctic  (excluding  the  New  Zealand 
and  Tasmanian  groups)  Dr.  Hooker  has  identified  not  less  than  a  fifth  part 
of  the  whole  with  British  Algae  !  Yet  is  there  a  much  smaller  proportion 
of  cosmopolite  species  among  the  Algae  than  among  the  terrestrial  cellular 
plants,  such  as  lichens,  mosses,  and  Hepaticse. 

It  must  always  be  borne  in  mind,  that  the  distinctness  alluded  to  be- 
tween the  provinces,  whether  of  subaqueous  or  terrestrial  plants,  relates 
strictly  to  species,  and  not  to  forms.  In  regard  to  the  numerical  prepon- 
derance of  certain  forms,  and  many  peculiarities  of  internal  structure, 
there  is  usually  a  marked  agreement  in  the  vegetable  productions  of  dis- 
tricts placed  in  corresponding  latitudes,  and  under  similar  physical  circum- 
stances, however  remote  their  position.  Thus  there  are  innumerable 
points  of  analogy  between  the  vegetation  of  the  Brazils,  equinoctial  Africa, 
and  India ;  and  there  are  also  points  of  difference  wherein  the  plants  of 
these  regions  are  distinguishable  from  all  extra-tropical  groups.  But  there 
is  a  very  small  proportion  of  the  entire  number  of  species  common  to  the 
three  continents.  The  same  may  be  said,  if  we  compare  the  plants  of  the 
United  States  with  that  of  the  middle  of  Europe ;  the  species  are  distinct, 
but  the  forms  are  often  so  analogous,  as  to  have  been  styled  "geographical 
representatives."  There  are  very  few  species  of  phsen.ogamous  plants,  says 
Dr.  J.  Hooker,  common  to  Van  Diemen's  Land,  New  ^ealand,  and  Fuegia, 
but  a  great  many  genera,  and  some  of  them  are  confined  to  those  three 
distant  regions  of  the  southern  hemisphere,  being  in  many  instances  each 
severally  represented  by  a  single  species.  The  same  naturalist  also 
observes  that  the  southern  temperate  as  well  as  the  antarctic  regions, 
possess  each  of  them  representatives  of  some  of  the  genera  of  the  analogous 
climates  of  the  opposite  hemisphere ;  but  very  few  of  the  species  are  iden- 
tical unless  they  be  such  as  are  equally  diffused  over  other  countries,  or 
which  inhabit  the  Andes,  by  the  aid  of  which  they  have  evidently  effected 
their  passage  southwards. 

Manner  in  which  plants  become  diffused. —  Winds.— Let  us  now  con- 
sider what  means  of  diffusion,  independently  of  the  agency  of  man,  are 
possessed  by  plants,  whereby,  in  the  course  of  ages,  they  may  be  enabled 
to  stray  from  one  of  the  botanical  provinces  above  mentioned  to  another, 
and  to  establish  new  colonies  at  a  great  distance  from  their  birth- 
place. 

The  principal  of  the  inanimate  agents  provided  by  nature  for  scattering 
the  seeds  of  plants  over  the  globe,  are  the  movements  of  the  atmosphere 
and  of  the  ocean,  and  the  constant  flow  of  water  from  the  mountains  to 
the  sea.  To  begin  with  the  winds :  a  great  number  of  seeds  are  furnished 
with  downy  and  feathery  appendages,  enabling  them,  when  ripe,  to  float 
in  the  air,  and  to  be  wafted  easily  to  great  distances  by  the  most  gentle 
breeze.  Other  plants  are  fitted  for  dispersion  by  means  of  an  attached 
wing,  as  in  the  case  of  the  fir  tree,  so  that  they  are  caught  up  by  the  wind 
as  they  fall  from  the  cone,  and  are  carried  to  a  distance.  Amongst  the 


Cn.XXXVIL]  DISPERSION    OF   PLANTS.  619 

comparatively  small  number  of  plants  known  to  Linnaeus,  no  less  than  138 
genera  are  enumerated  as  having  winged  seeds. 

As  winds  often  prevail  for  days,  weeks,  or  even  months  together,  in  the 
same  direction,  these  means  of  transportation  may  sometimes  be  without 
limits  ;  and  even  the  heavier  grains  may  be  borne  through  considerable 
spaces,  in  a  very  short  time,  during  ordinary  tempests;  for  strong  gales, 
which  can  sweep  along  grains  of  sand,  often  move  at  the  rate  of  about 
forty  miles  an  hour,  and  if  the  storm  be  very  violent,  at  the  rate  of  fifty- 
six  miles.*  The  hurricanes  of  tropical  regions,  which  root  up  trees  and 
throw  down  buildings,  sweep  along  at  the  rate  of  ninety  miles  an  hour ; 
so  that,  for  however  short  a  time  they  prevail,  they  may  carry  even  the 
heavier  fruits  and  seeds  over  friths  and  seas  of  considerable  width,  and 
doubtless  are  often  the  means  of  introducing  into  islands  the  vegetation 
of  adjoining  continents.  Whirlwinds  are  also  instrumental  in  bearing 
along  heavy  vegetable  substances  to  considerable  distances.  Slight  ones 
may  frequently  be  observed  in  our  fields,  in  summer  carrying  up  haycocks 
into  the  air,  and  then  letting  fall  small  tufts  of  hay  far  and  wide  over 
the  country  ;  but  they  are  sometimes  so  powerful  as  to  dry  up  lakes  and 
ponds,  and  to  break  off  the  boughs  of  trees,  and  carry  them  up  in  a 
whirling  column  of  air. 

Franklin  tells  us,  in  one  of  his  letters,  that  he  saw,  in  Maryland,  a 
whirlwind  which  began  by  taking  up  the  dust  which  lay  in  the  road,  in 
the  form  of  a  sugar  loaf  with  the  pointed  end  downwards,  and  soon  after 
grew  to  the  height  of  forty  or  fifty  feet,  being  twenty  or  thirty  in  diame- 
ter. It  advanced  in  a  direction  contrary  to  the  wind  ;  and  although  the 
rotary  motion  of  the  column  was  surprisingly  rapid,  its  onward  progress 
was  sufficiently  slow  to  allow  a  man  to  keep  pace  with  it  on  foot.  Frank- 
lin followed  it  on  horseback,  accompanied  by  his  son,  for  three  quarters 
of  a  mile,  and  saw  it  enter  a  wood,  where  it  twisted  and  turned  round 
large  trees  with  surprising  force.  These  were  carried  up  in  a  spiral  line, 
and  were  seen  flying  in  the  air,  together  with  boughs  and  innumerable 
leaves,  which,  from  their  height,  appeared  reduced  to  the  apparent  size 
of  flies.  As  this  cause  operates  at  different  intervals  of  time  throughout 
a  great  portion  of  the  earth's  surface,  it  may  be  the  means  of  bearing  not 
only  plants  but  insects,  land  testacea  and  their  eggs,  with  many  other  spe- 
cies of  animals,  to  points  which  they  could  never  otherwise  have  reached, 
and  from  which  they  may  then  begin  to  propagate  themselves  again  as 
from  a  new  centre. 

Distribution  of  cry ptogamous  plants. — It  has  been  found  that  a  great 
numerical  proportion  of  the  exceptions  to  the  limitation  of  species  to 
certain  quarters  of  the  globe  occur  in  the  various  tribes  of  cryptogamic 
plants.  Linnaeus  observed  that,  as  the  germs  of  plants  of  this  class,  such 
as  mosses,  fungi,  and  lichens,  consist  of  an  impalpable  powder,  the  par- 
ticles of  which  are  scarcely  visible  to  the  naked  eye,  there  is  no  difficulty 
to  account  for  their  being  dispersed  throughout  the  atmosphere,  and  car- 
ried to  every  point  of  the  globe,  where  there  is  a  station  fitted  for  them. 
*  Anmiaire  du  Bureau  des  Longitudes. 


620  DISPERSION   OP   PLANTS  [Cn.  XXXVII. 

Lichens  in  particular  ascend  to  great  elevations,  sometimes  growing  two 
thousand  feet  above  the  the  line  of  perpetual  snow,  at  the  utmost  limits 
of  vegetation,  and  where  the  mean  temperature  is  nearly  at  the  freezing 
point.  This  elevated  position  must  contribute  greatly  to  facilitate  the 
dispersion  of  those  buoyant  particles  of  which  their  fructification  consists.* 

Some  have  inferred,  from  the  springing  up  of  mushrooms  whenever 
particular  soils  and  decomposed  organic  matter  are  mixed  together,  that 
the  production  of  fungi  is  accidental,  and  not  analogous  to  that  of  perfect 
plants.  But  Fries,  whose  authority  on  these  questions  is  entitled  to  the 
highest  respect,  has  shown  the  fallacy  of  this  argument  in  favor  of  the 
old  doctrine  of  equivocal  generation.  "  The  sporules  of  fungi,"  says  this 
naturalist,  "  are  so  infinite,  that  in  a  single  individual  of  Reticularia 
maxima,  I  have  counted  above  ten  millions,  and  so  subtile  as  to  be 
scarcely  visible,  often  resembling  thin  smoke  ;  so  light  that  they  may  be 
raised  perhaps  by  evaporation  into  the  atmosphere,  and  dispersed  in  so 
many  ways  by  the  attraction  of  the  sun,  by  insects,  wind,  elasticity,  ad- 
hesion, <fec.,  that  it  is  difficult  to  conceive  a  place  from  which  they  may 
be  excluded."f 

The  club-moss  called  Lycopodium  cernuum  affords  a  striking  example 
of  a  cryptogamous  plant  universally  distributed  over  all  equinoctial  coun- 
tries. It  scarcely  ever  passes  beyond  the  northern  tropic,  except  in  one 
instance,  where  it  appears  around  the  hot-springs  in  the  Azores,  although 
it  is  neither  an  inhabitant  of  the  Canaries  nor  Madeira.  Doubtless  its 
microscopic  sporules  are  everywhere  present,  ready  to  germinate  on  any 
spot  where  they  can  enjoy  throughout  the  year  the  proper  quantity  of 
warmth,  moisture,  light,  and  other  conditions  essential  to  the  species. 

Almost  every  lichen  brought  home  from  the  southern  hemisphere  by 
the  antarctic  expedition  under  Sir  James  Ross,  amounting  to  no  less  than 
200  species,  was  ascertained  to  be  also  an  inhabitant  of  the  northern 
hemisphere,  and  almost  all  of  them  European. 

Agency  of  rivers  and  currents. — In  considering,  in  the  next  place,  the 
instrumentality  of  the  aqueous  agents  of  dispersion,  I  cannot  do  better 
than  cite  the  words  of  one  of  our  ablest  botanical  writers.  "  The  moun- 
tain stream  or  torrent,"  observes  Keith,  "  washes  down  to  the  valley  the 
seeds  which  may  accidentally  fall  into  it,  or  which  it  may  happen  to 
sweep  from  its  banks  when  it  suddenly  overflows  them.  The  broad  and 
majestic  river,  winding  along  the  extensive  plain,  and  traversing  the  con- 
tinents of  the  world,  conveys  to  the  distance  of  many  hundreds  of  miles 
the  seeds  that  may  have  vegetated  at  its  source.  Thus  the  southern 
shores  of  the  Baltic  are  visited  by  seeds  which  grew  in  the  interior  of 
Germany,  and  the  western  shores  of  the  Atlantic  by  seeds  that  have  been 
generated  in  the  interior  of  Am  erica."  J  Fruits,  moreover,  indigenous  to 
America  and  the  West  Indies,  such  as  that  of  the  Mimosa  scandens,  the 
cashewnut  and  others,  have  been  known  to  be  drifted  across  the  Atlantic 

*  Linn.,  Tour  in  Lapland,  vol.  ii.  p.  282. 

f  Fries,  cited  by  Lindley,  Introd.  to  Nat.  Syst.  of  Botany. 

\  System  of  Physiological  Botany,  vol.  ii.  p.  405. 


Cu.  XXXVII.]  BY   RIVERS   AND    CURRENTS.  621 

by  the  Gulf  stream,  on  the  western  coasts  of  Europe,  in  such  a  state 
that  they  might  have  vegetated  had  the  climate  and  soil  been  favourable. 
Among  these  the  Gruilandina  Bonduc,  a  leguminous  plant,  is  particularly 
mentioned,  as  having  been  raised  from  a  seed  found  on  the  west  coast  of 
Ireland.* 

Sir  Hans  Sloane  states,  that  several  kinds  of  beans  cast  ashore  on  the 
Orkney  Isles,  and  Ireland,  but  none  of  which  appear  to  have  naturalized 
themselves,  are  derived  from  trees  which  grow  in  the  West  Indies,  and 
many  of  them  in  Jamaica.  He  conjectures  that  they  might  have  been 
conveyed  by  rivers  into  the  sea,  and  then  by  the  Gulf  stream  to  greater 
distances,  in  the  same  manner  as  the  sea-weed  called  Lenticula  marina, 
or  Sargasso,  which  grows  on  the  rocks  about  Jamaica,  is  known  to  be 
"  carried  by  the  winds  and  current  towards  the  coast  of  Florida,  and  thence 
into  the  North  American  ocean,  where  it  lies  very  thick  on  the  surface 
of  the  sea."f 

The  absence  of  liquid  matter  in  the  composition  of  seeds  renders  them 
comparatively  insensible  to  heat  and  cold,  so  that  they  may  be  carried 
without  detriment  through  climates  where  the  plants  themselves  would 
instantly  perish.  Such  is  their  power  of  resisting  the  effects  of  heat,  that 
Spallanzani  mentions  some  seeds  that  germinated  after  having  been  boil- 
ed in  water. J  Sir  John  Herschel  informs  me  that  he  has  sown  at  the 
Cape  of  Good  Hope  the  seeds  of  the  Acacia  lophanta  after  they  had 
remained  for  twelve  hours  in  water  of  140°  Fahrenheit,  and  they  germi- 
nated far  more  rapidly  than  unboiled  seeds.  He  also  states  that  an  emi- 
nent botanist,  Baron  Ludwig,  could  not  get  the  seeds  of  a  species  of  cedar 
to  grow  at  the  Cape  till  they  were  thoroughly  boiled. 

When  therefore,  a  strong  gale,  after  blowing  violently  off  the  land  for 
a  time,  dies  away,  and  the  seeds  alight  upon  the  surface  of  the  waters,  or 
wherever  the  ocean,  by  eating  away  the  sea-cliffs,  throws  down  into  its 
waves  plants  which  would  never  otherwise  reach  the  shores,  the  tides  and 
currents  become  active  instruments  in  assisting  the  dissemination  of 
almost  all  classes  of  the  vegetable  kingdom.  The  pandanus  and  many 
other  plants  have  been  distributed  in  this  way  over  the  islands  of  the 
Pacific.  I  have  before  called  attention  (p.  618.)  to  the  interesting  fact 
that  one-fifth  of  all  the  algae  found  in  the  antarctic  regions  in  1841-3,  by 
Dr.  J.  Hooker,  were  of  species  common  to  the  British  seas.  He  has 
suggested  that  cold  currents  which  prevail  from  Cape  Horn  to  the  equator, 
and  are  there  met  by  other  cold  water,  may  by  their  direct  influence,  as 
well  as  by  their  temperature,  facilitate  the  passage  of  antarctic  species  to 
the  Arctic  Ocean.  In  like  manner  the  migration  of  certain  marine  ani- 
mals from  the  southern  to  the  northern  hemisphere  may  have  been  brought 
about  by  the  same  cause. 

In  a  collection  of  six  hundred  plants  from  the  neighborhood  of  the 
river  Zaire,  in  Africa,  Mr.  Brown  found  that  thirteen  species  were  also 

*  Brown,  Append,  to  Tuckey,  No.  v.  p.  481. 

f  Phil.  Trans.  1696. 

\  System  of  Physiological  Botany,  vol.  ii.  p.  403. 


622  DISPERSION   OF  MARINE   PLANTS.  [Ce.  XXXVII. 

met  with  on  the  opposite  shores  of  Guiana  and  Brazil.  He  remarked 
that  most  of  these  plants  were  found  only  on  the  lower  parts  of  the  river 
Zaire,  and  were  chiefly  such  as  produced  seeds  capable  of  retaining  their 
vitality  a  long  time  in  the  currents  of  the  ocean.  Dr.  J.  Hooker  informs 
me  that  after  an  examination  of  a  great  many  insular  floras,  he  has  found 
that  no  one  of  the  large  natural  orders  is  so  rich  in  species  common  to 
other  countries,  as  the  Leguminosse.  The  seeds  in  this  order,  which  com- 
prises the  largest  proportion  of  widely  diffused  littoral  species,  are  better 
adapted  than  those  of  any  other  plants  for  water-carriage. 

The  migration  of  plants  aided  by  islands. — Islands,  moreover,  and 
even  the  smallest  rocks,  play  an  important  part  in  aiding  such  migra- 
tions ;  for  when  seeds  alight  upon  them  from  the  atmosphere,  or  are 
thrown  up  by  the  surf,  they  often  vegetate,  and  supply  the  winds  and 
waves  with  a  repetition  of  new  and  uninjured  crops  of  fruit  and  seeds. 
These  may  afterwards  pursue  their  course  through  the  atmosphere,  or 
along  the  surface  of  the  sea,  in  the  same  direction.  The  number  of  plants 
found  at  any  given  time  on  an  islet  affords  us  no  test  whatever  of  the 
extent  to  which  it  may  have  co-operated  towards  this  end,  since  a  variety 
of  species  may  first  thrive  there  and  then  perish,  and  be  followed  by  other 
chance-comers  like  themselves.  If  neither  St.  Helena  nor  Ascension  have 
promoted  the  botanical  intercourse  between  the  Old  and  New  Worlds, 
we  may  easily  account  for  the  fact  by  remembering  that  they  are  not 
only  extremely  minute  and  isolated  spots,  but  are  also  bounded  by  lofty 
and  precipitous  shores  without  beaches,  where  the  seeds  of  foreign  species 
could  readily  establish  themselves. 

Currents  and  winds  in  the  arctic  regions  drift  along  icebergs  covered 
with  an  alluvial  soil,,  on  which  herbs  and  pine-saplings  are  seen  growing, 
which  may  often  continue  to  vegetate  on  some  distant  shore  where  the 
ice-island  is  stranded. 

Dispersion  of  marine  plants. — With  respect  to  marine  vegetation,  the 
seeds,  being  in  their  native  element,  may  remain  immersed  in  water  with- 
out injury  for  indefinite  periods,  so  that  there  is  no  difficulty  in  conceiving 
the  diffusion  of  species  wherever  uncongenial  climates,  contrary  currents, 
and  other  causes  do  not  interfere.  All  are  familiar  with  the  sight  of  the 
floating  sea-weed, 

"  Flung  from  the  rock  on  ocean's  foam  to  sail, 
Where'er  the  surge  may  sweep,  the  tempest's  breath  prevail." 

Remarkable  accumulations  of  that  species  of  sea-weed  generally  known 
as  gulf-weed,  or  sargasso,  occur  on  each  side  of  the  equator  in  the  Atlantic, 
Pacific,  and  Indian  Oceans.  Columbus  and  other  navigators,  who  first 
encountered  these  banks  of  algae  in  the  Northern  Atlantic,  compared  them 
to  vast  inundated  meadows,  and  state  that  they  retarded  the  progress  of 
their  vessels.  The  most  extensive  bank  is  a  little  west  of  the  meridian 
of  Fayal,  one  of  the  Azores,  between  latitudes  35°  and  36°  :  violent 
north-vinds  sometimes  prevail  in  this  space,  and  drive  the  sea-weed  to 


CH.  XXXVIL]       AGENCY  OF  ANIMALS  IN  DIFFUSING  PLANTS.       623 

low  latitudes,  as  far  as  the  24th  or  even  the  20th  degree.*  Along  the 
northern  edge  of  the  Gulf  stream  Dr.  Hooker  found  Fucus  nodosus,  and 
F.  serratus,  which  he  traced  all  the  way  from  lat.  36°  N.  to  England. 

The  hollow  pod-like  receptacle  in  which  the  seeds  of  many  algae  are 
lodged,  and  the  filaments  attached  to  the  seed-vessels  of  others,  seem 
intended  to  give  buoyancy ;  and  I  may  observe  that  these  hydrophytes 
are  in  general  proliferous,  so  that  the  smallest  fragment  of  a  branch  can 
be  developed  into  a  perfect  plant.  The  seeds,  moreover,  of  the  greater 
number  of  species  are  enveloped  with  a  mucous  matter  like  that  which 
surrounds  the  eggs  of  some  fish,  and  which  not  only  protects  them  from 
injury,  but  serves  to  attach  them  to  floating  bodies  or  to  rocks. 

Agency  of  animals  in  the  distribution  of  plants. — But  we  have  as  yet 
considered  part  only  of  the  fertile  resources  of  nature  for  conveying  seeds 
to  a  distance  from  their  place  of  growth.  The  various  tribes  of  animals 
are  busily  engaged  in  furthering  an  object  whence  they  derive  such  im- 
portant advantages.  Sometimes  an  express  provision  is  found  in  the 
structure  of  seeds  to  enable  them  to  adhere  firmly  by  prickles,  hooks,  and 
hairs,  to  the  coats  of  animals,  or  feathers  of  the  winged  tribe,  to  which 
they  remain  attached  for  weeks,  or  even  months,  and  are  borne  along  into 
every  region  whither  birds  or  quadrupeds  may  migrate.  Linnaeus  enu- 
merates fifty  genera  of  plants,  and  the  number  now  known  to  botanists  is 
much  greater,  which  are  armed  with  hooks,  by  which,  when  ripe,  they 
adhere  to  the  coats  of  animals.  Most  of  these  vegetables,  he  remarks, 
require  a  soil  enriched  with  dung.  Few  have  failed  to  mark  the  locks  of 
wool  hanging  on  the  thorn-bushes,  wherever  the  sheep  pass,  and  it  is  proba- 
ble that  the  wolf  or  lion  never  give  chase  to  herbivorous  animals  without 
being  unconsciously  subservient  to  this  part  of  the  vegetable  economy. 

A  deer  has  strayed  from  the  herd  when  browsing  on  some  rich  pasture, 
when  he  is  suddenly  alarmed  by  the  approach  of  his  foe.  He  instantly 
takes  to  flight,  dashing  through  many  a  thicket,  and  swimming  across 
many  a  river  and  lake.  The  seeds  of  the  herbs  and  shrubs  which  have 
adhered  to  his  smoking  flanks  are  washed  off  again  by  the  waters.  The 
thorny  spray  is  torn  off,  and  fixes  itself  in  its  hairy  coat,  until  brushed  off 
again  in  other  thickets  and  copses.  Even  on  the  spot  where  the  victim 
is  devoured  many  of  the  seeds  which  he  had  swallowed  immediately 
before  the  chase  may  be  left  on  the  ground  uninjured,  and  ready  to  spring 
up  in  a  new  soil. 

The  passage,  indeed,  of  undigested  seeds  through  the  stomachs  of  ani- 
mals is  one  of  the  most  efficient  causes  of  the  dissemination  of  plants,  and 
is  of  all  others,  perhaps,  the  most  likely  to  be  overlooked.  Few  are 
ignorant  that  a  portion  of  the  oats  eaten  by  a  horse  preserve  their  ger- 
minating faculty  in  the  dung.  The  fact  of  their  being  still  nutritious  is 
not  lost  on  the  sagacious  rook.  To  many,  says  Linnaeus,  it  seems  extra- 
ordinary, and  something  of  a  prodigy,  that  when  a  field  is  well  tilled  and 
sown  with  the  best  wheat,  it  frequently  produces  darnel  or  the  wild  oat, 

*  Greville,  Inti'oduetion  to  Algse  Britannicse,  p.  12. 


624  AGENCY   OF   BIRDS  [Cn.  XXXVII. 

especially  if  it  be  manured  with  new  dung ;  they  do  not  consider  that 
the  fertility  of  the  smaller  seeds  is  not  destroyed  in  the  stomachs  of 
animals.* 

Agency  of  birds. — Some  birds  of  the  order  Passeres  devour  the  seeds 
of  plants  in  great  quantities,  which  they  eject  again  in  very  distant  places, 
without  destroying  its  faculty  of  vegetation  :  thus  a  flight  of  larks  will  fill 
the  cleanest  field  with  a  great  quantity  of  various  kinds  of  plants,  as  the 
melilot  trefoil  (Medicago  lupulina),  and  others  whose  seeds  are  so  heavy 
that  the  wind  is  not  able  to  scatter  them  to  any  distance.!  In  like  man- 
ner, the  blackbird  and  misselthrush,  when  they  devour  berries  in  too  great 
quantities,  are  known  to  consign  them  to  the  earth  undigested  in  their 
excrement.]; 

Pulpy  fruits  serve  quadrupeds  and  birds  as  food,  while  their  seeds,  often 
hard  and  indigestible,  pass  uninjured  through  the  intestines,  and  are  de- 
posited far  from  their  original  place  of  growth  in  a  condition  peculiarly 
fit  for  vegetation.§  So  well  are  the  farmers,  in  some  parts  of  England, 
aware  of  this  fact,  that  when  they  desire  to  raise  a  quickset  hedge  in  the 
shortest  possible  time,  they  feed  turkeys  with  the  haws  of  the  common 
white-thorn  (Cratcegus  Oxyacantha),  and  then  sow  the  stones  which  are 
ejected  in  their  excrement,  whereby  they  gain  an  entire  year  in  the  growth 
of  the  plant,  I  Birds,  when  they  pluck  cherries,  sloes,  and  haws,  fly  away 
with  them  to  some  convenient  place ;  and  when  they  have  devoured  the 
fruit,  drop  the  stone  into  the  ground.  Captain  Cook,  in  his  account  of 
the  volcanic  island  of  Tanna,  one  of  the  New  Hebrides,  which  he  visited 
in  his  second  voyage,  makes  the  following  interesting  observation : — "Mr. 
Forster,  in  his  botanical  excursion  this  day,  shot  a  pigeon,  in  the  craw  of 
which  was  a  wild  nutmeg."^]"  It  is  easy,  therefore,  to  perceive,  that  birds 
in  their  migrations  to  great  distances,  and  even  across  seas,  may  transport 
seeds  to  new  isles  and  continents. 

The  sudden  deaths  to  which  great  numbers  of  frugivorous  birds  are 
annually  exposed  must  not  be  omitted  as  auxiliary  to  the  transportation  of 
seeds  to  new  habitations.  When  the  sea  retires  from  the  shore,  and 
leaves  fruits  and  seeds  on  the  beach,  or  in  the  mud  of  estuaries,  it  might, 
by  the  returning  tide,  wash  them  away  again,  or  destroy  them  by  long 
immersion ;  but  when  they  are  gathered  by  land  birds  which  frequent  the 
sea  side,  or  by  waders  and  water-fowl,  they  are  often  borne  inland ;  and 
if  the  bird  to  whose  crop  they  have  been  consigned  is  killed,  they  may  be 
left  to  grow  up  far  from  the  sea.  Let  such  an  accident  happen  but  once 
in  a  century,  or  a  thousand  years,  it  will  be  sufficient  to  spread  many  of 
the  plants  from  one  continent  to  another ;  for  in  estimating  the  activity 
of  these  causes,  we  must  not  consider  whether  they  act  slowly  in  relation 

*  Linnaeus,  Amoen.  Acad.,  vol.  ii.  p.  409. 
f  Amoen.  Acad.,  vol.  iv.  Essay  75.  §8. 
1  Ibid.,  vol.  vi.  §  22. 

§  Smiths  Introd.  to  Phys.  and  Syst.  Botany,  p.  304.  1807. 
|j  This  information  was  communicated  to  me  by  Professor  Henslow,  of  Cam- 
bridge. 

'Book  iii.  eh,  iv. 


GIL  XXXVII]  IN   DIFFUSING   PLANTS.  625 

to  the  period  of  our  observation,  but  in  reference  to  the  duration  of  species 
in  general. 

Let  us  trace  the  operation  of  this  cause  in  connection  with  others.  A 
tempestuous  wind  bears  the  seeds  of  a  plant  many  miles  through  the  air, 
and  then  delivers  them  to  the  ocean ;  the  oceanic  current  drifts  them  to 
a  distant  continent ;  by  the  fall  of  the  tide  they  become  the  food  of  nume- 
rous birds,  and  one  of  these  is  seized  by  a  hawk  or  eagle,  which,  soaring 
across  hill  and  dale  to  a  place  of  retreat,  leaves,  after  devouring  its  prey, 
the  unpalatable  seeds  to  spring  up  and  flourish  in  a  new  soil. 

The  machinery  before  adverted  to,  is  so  capable  of  disseminating  seeds 
over  almost  unbounded  spaces,  that  were  we  more  intimately  acquainted 
with  the  economy  of  nature,  we  might  probably  explain  all  the  instances 
which  occur  of  the  aberration  of  plants  to  great  distances  from  their  native 
countries.  The  real  difficulty  which  must  present  itself  to  every  one  who 
contemplates  the  present  geographical  distribution  of  species,  is  the  small 
number  of  exceptions  to  the  rule  of  the  non-intermixture  of  different  groups 
of  plants.  Why  have  they  not,  supposing  them  to  have  been  ever  so  dis- 
tinct originally,  become  more  blended  and  confounded  together  in  the 
lapse  of  ages  ? 

Agency  of  man  in  the  dispersion  of  plants. — But  in  addition  to  all  the 
agents  already  enumerated  as  instrumental  in  diffusing  plants  over  the 
globe,  we  have  still  to  consider  man — one  of  the  most  important  of  all. 
He  transports  with  him,  into  every  region,  the  vegetables  which  he  culti- 
vates for  his  wants,  and  is  the  involuntary  means  of  spreading  a  still 
greater  number  which  are  useless  to  him,  or  even  noxious.  "  When  the 
introduction  of  cultivated  plants,"  says  De  Candolle,  "  is  of  recent  date, 
there  is  no  difficulty  in  tracing  their  origin ;  but  when  it  is  of  high  anti- 
quity, we  are  often  ignorant  of  the  true  country  of  the  plants  on  which 
we  feed.  No  one  contests  the  American  origin  of  the  maize  or  the  pota- 
toe  ;  nor  the  origin,  in  the  Old  World,  of  the  coffee-tree,  and  of  wheat. 
But  there  are  certain  objects  of  culture,  of  very  ancient  date,  between  the 
tropics,  such  for  example  as  the  banana,  of  which  the  origin  cannot  be 
verified.  Armies,  in  modern  times,  have  been  known  to  carry,  in  all  di- 
rections, grain  and  cultivated  vegetables  from  one  extremity  of  Europe  to 
the  other ;  and  thus  have  shown  us  how,  in  more  ancient  times,  the  con- 
quests of  Alexander,  the  distant  expeditions  of  the  Romans,  and  afterwards 
the  crusades,  may  have  transported  many  plants  from  one  part  of  the 
world  to  the  other."* 

But,  besides  the  plants  used  in  agriculture,  the  numbers  which  have 
been  naturalized  by  accident,  or  which  man  has  spread  unintentionally, 
is  considerable.  One  of  our  old  authors,  Josselyn,  gives  a  catalogue  of 
such  plants  as  had,  in  his  time,  sprung  up  in  the  colony  since  the  English 
planted  and  kept  cattle  in  New  England.  They  were  two-and-twenty  in 
number.  The  common  nettle  was  the  first  which  the  settlers  noticed ; 
and  the  plantain  was  called  by  the  Indians  "  Englishman's  foot,"  as  if  it 
sprung  from  their  footsteps.f 

*  De  Candolle,  Essai  Elemen.  <fec.,  p.  50.  f  Quarterly  Review,  vol.  xxx  p.  8. 

40 


626  AGENCY   OF   MAN  IN  THE  [On.  XXXVIL 

"We  have  introduced  every  where,"  observes  De  Candolle,  "some 
weeds  which  grow  among  our  various  kinds  of  wheat,  and  which  have 
been  received,  perhaps,  originally  from  Asia  along  with  them.  Thus, 
together  with  the  Barbary  wheat,  the  inhabitants  of  the  south  of  Europe 
have  sown,  for  many  ages,  the  plants  of  Algiers  and  Tunis.  With  the 
wools  and  cottons  of  the  East,  or  of  Barbary,  there  are  often  brought  into 
France  the  grains  of  exotic  plants,  some  of  which  naturalize  themselves. 
Of  this  I  will  cite  a  striking  example.  There  is,  at  the  gate  of  Montpellier, 
a  meadow  set  apart  for  drying  foreign  wool,  after  it  has  been  washed. 
There  hardly  passes  a  year  without  foreign  plants  being  found  naturalized 
in  this  drying-ground.  I  have  gathered  there  Centaurea  parviflora, 
Psoralea  palcestina,  and  Hypericum  crispum"  This  fact  is  not  only 
illustrative  of  the  aid  which  man  lends  inadvertently  to  the  propagation 
of  plants,  but  it  also  demonstrates  the  multiplicity  of  seeds  which  are 
borne  about  in  the  woolly  and  hairy  coats  of  wild  animals. 

The  same  botanist  mentions  instances  of  plants  naturalized  in  seaports 
by  the  ballast  of  ships  ;  and  several  examples  of  others  which  have  spread 
through  Europe  from  botanical  gardens,  so  as  to  have  become  more  com- 
mon than  many  indigenous  species. 

It  is  scarcely  a  century,  says  Linnaeus,  since  the  Canadian  erigeron,  or 
flea-bane,  was  brought  from  America  to  the  botanical  garden  at  Paris ; 
and  already  the  Seeds  have  been  carried  by  the  winds  so  that  it  is  diffused 
over  France,  the  British  islands,  Italy,  Sicily,  Holland,  and  Germany.* 
Several  others  are  mentioned  by  the  Swedish  naturalist,  as  having  been 
dispersed  by  similar  means.  The  common  thorn-apple  (Datura  Stra- 
monium), observes  Willdenow,  now  grows  as  a  noxious  weed  throughout 
all  Europe,  with  the  exception  of  Sweden,  Lapland  and  Russia.  It  came 
from  the  East  Indies  and  Abyssinia  to  us,  and  was  thus  universally  spread 
by  certain  quacks,  who  used  its  seeds  as  an  emetic.f  The  same  plant  is 
now  abundant  throughout  the  greater  part  of  the  United  States,  along 
road-sides  and  about  farm-yards.  The  yellow  monkey-flower,  Mimulus 
luteus,  a  plant  from  the  north-west  region  of  America,  has  now  established 
itself  in  various  parts  of  England,  and  is  spreading  rapidly. 

In  hot  and  ill-cultivated  countries,  such  naturalization  takes  place  more 
easily.  Thus  the  Chenvpodium  ambrosioides,  sown  by  Mr.  Burchell  on  a 
point  of  St.  Helena,  multiplied  so  fast  in  four  years  as  to  become  one  of 
the  commonest  weeds  in  the  island,  and  it  has  maintained  its  ground  ever 
since  1845.J 

The  most  remarkable  proof,  says  De  Candolle,  of  the  extent  to  which 
man  is  unconsciously  the  instrument  of  dispersing  and  naturalizing  spe- 
cies, is  found  in  the  fact,  that  in  New  Holland,  America,  and  the  Cape 
of  Good  Hope,  the  aboriginal  European  species  exceed  in  number  all  the 
others  which  have  come  from  any  distant  regions;  so  that,  in  this  instance, 
the  influence  of  man  has  surpassed  that  of  all  the  other  causes  which  tend 

*  Essay  on  the  Habitable  Earth,  Amoen.  Acad.,  vol.  ii.  p.  409. 
f  Principles  of  Botany,  p.  389. 
i  Ibid. 


CH.  XXXVIL]  DISPERSION   OP   PLANTS.  627 

to  disseminate  plants  to  remote  districts.  Of  nearly  1600  British  flower- 
ing plants,  it  is  supposed  that  about  300  species  are  naturalized ;  but  a 
large  proportion  of  these  would  perish  with  the  discontinuance  of  agri- 
culture. 

Although  we  are  but  slightly  acquainted,  as  yet,  with  the  extent  of  our 
instrumentality  in  naturalizing  species,  yet  the  facts  ascertained  afford  no 
small  reason  to  suspect  that  the  number  which  we  introduce  unintention- 
ally exceeds  all  those  transported  by  design.  Nor  is  it  unnatural  to  sup- 
pose that  the  functions,  which  the  inferior  beings,  extirpated  by  man,  once 
discharged  in  the  economy  of  nature,  should  devolve  upon  the  human 
race.  If  we  drive  many  birds  of  passage  from  different  countries,  we  are 
probably  required  to  fulfil  their  office  of  carrying  seeds,  eggs  offish,  insects, 
mollusks,  and  other  creatures,  to  distant  regions :  if  we  extirpate  quadru- 
peds, we  must  replace  them  not  merely  as  consumers  of  the  animal  and 
vegetable  substances  which  they  devour,  but  as  disseminators  of  plants, 
and  of  the  inferior  classes  of  the  animal  kingdom.  I  do  not  mean  to 
insinuate  that  the  very  same  changes  which  man  brings  about,  would  have 
taken  place  by  means  of  the  agency  of  other  species,  but  merely  that  he 
supersedes  a  certain  number  of  agents  ;  and  so  far  as  he  disperses  plants 
unintentionally,  or  against  his  will,  his  intervention  is  strictly  analogous 
to  that  of  the  species  so  extirpated. 

I  may  observe,  moreover,  that  if,  at  former  periods,  the  animals  inha- 
biting any  given  district  have  been  partially  altered  by  the  extinction  of 
some  species,  and  the  introduction  of  others,  whether  by  new  creations  or 
by  immigration,  a  change  must  have  taken  place  in  regard  to  the  parti- 
cular plants  conveyed  about  with  them  to  foreign  countries.  As,  for 
example,  when  one  set  of  migratory  birds  is  substituted  for  another,  the 
countries  from  and  to  which  seeds  are  transported  are  immediately  chang- 
ed. Vicissitudes,  therefore,  analogous  to  those  which  man  has  occasioned, 
may  have  previously  attended  the  springing  up  of  new  relations  between 
species  in  the  vegetable  and  animal  worlds. 

It  may  also  be  remarked,  that  if  man  is  the  most  active  agent  in  en- 
larging, so  also  is  he  in  circumscribing  the  geographical  boundaries  of 
particular  plants.  He  promotes  the  migration  of  some,  he  retards  that 
of  other  species  ;  so  that,  while  in  many  respects  he  appears  to  be  exerting 
his  power  to  blend  and  confound  the  various  provinces  of  indigenous 
species,  he  is,  in  other  ways,  instrumental  in  obstructing  the  fusion  into 
one  group  of  the  inhabitants  of  contiguous  provinces. 

Thus,  for  example,  when  two  botanical  regions  exist  in  the  same  great 
continent,  such  as  the  European  region,  comprehending  the  central  parts 
of  Europe,  and  those  surrounding  the  Mediterranean,  and  the  Oriental 
region,  as  it  has  been  termed,  embracing  the  countries  adjoining  the  Black 
Sea  and  the  Caspian,  the  interposition  between  these  of  thousands  of 
spuare  miles  of  cultivated  lands,  opposes  a  new  and  powerful  barrier  against 
the  mutual  interchange  of  indigenous  plants.  Botanists  are  well  aware 
that  garden  plants  naturalize  and  diffuse  themselves  with  great  facility  in 
comparatively  unreclaimed  countries,  but  spread  themselves  slowly  and 


628  PLANTS   DIFFUSED   BY  MAN.  [On.  XXXVII. 

with  difficulty  in  districts  highly  cultivated.  There  are  many  obvious 
causes  for  this  difference  ;  by  drainage  and  culture  the  natural  variety  of 
stations  is  diminished,  and  those  stray  individuals  by  which  the  passage 
of  a  species  from  one  fit  station  to  another  is  effected,  are  no  sooner  de- 
tected by  the  agriculturist,  than  they  are  uprooted  as  weeds.  The  larger 
shrubs  and  trees,  in  particular,  can  scarcely  ever  escape  observation,  when 
they  have  attained  a  certain  size,  and  will  rarely  fail  to  be  cut  down  if 
unprofitable. 

The  same  observations  are  applicable  to  the  interchange  of  the  insects, 
birds,  and  quadrupeds  of  two  regions  situated  like  those  above  alluded  to. 
No  beasts  of  prey  are  permitted  to  make  their  way  across  the  intervening 
arable  tracts.  Many  birds,  and  hundreds  of  insects,  which  would  have 
found  some  palatable  food  amongst  the  various  herbs  and  trees  of  the 
primeval  wilderness,  are  unable  to  subsist  on  the  olive,  the  vine,  the  wheat, 
and  a  few  trees  and  grasses  favored  by  man.  In  addition,  therefore,  to 
his  direct  intervention,  man,  in  this  case,  operates  indirectly  to  impede 
the  dissemination  of  plants,  by  intercepting  the  migration  of  animals, 
many  of  which  would  otherwise  have  been  active  in  transporting  seeds 
from  one  province  to  another. 

Whether,  in  the  vegetable  kingdom,  the  influence  of  man  will  tend, 
after  a  considerable  lapse  of  ages,  to  render  the  geographical  range  of 
species  in  general  more  extended,  as  De  Candolle  seems  to  anticipate,  or 
whether  the  compensating  agency  above  alluded  to  will  not  counterba 
lance  the  exceptions  caused  by  our  naturalizations,  admits  at  least  of  some 
doubt.  In  the  attempt  to  form  an  estimate  on  this  subject,  we  must  be 
careful  not  to  underrate,  or  almost  overlook,  as  some  appear  to  have  done, 
the  influence  of  man  in  checking  the  diffusion  of  plants,  and  restricting 
their  distribution  to  narrower  limits. 


CHAPTER  XXXVIII. 

LAWS    WHICH    REGULATE    THE    GEOGRAPHICAL    DISTRIBUTION    OF 

SPECIES — continued. 

Geographical  distribution  of  animals — Buffon  on  specific  distinctness  of  qua- 
drupeds of  Old  and  New  World — Doctrine  of  "  natural  barriers  " — Different 
regions  of  indigenous  mammalia — Europe — Africa — India,  and  Indian  Archi- 
pelago— Australia — North  and  South  America — Quadrupeds  in  islands — 
Kange  of  the  Cetacea — Dispersion  of  quadrupeds — Their  powers  of  swim 
ming — Migratory  instincts — Drifting  of  animals  on  ice-floes — On  floating 
islands  of  drift-timber — Migrations  of  Cetacea — Habitations  of  birds — Their 
migrations  and  facilities  of  diffusion — Distribution  of  reptiles,  and  their 
power  of  dissemination. 

Geographical  distribution  of  animals. — Although  in  speculating 
on  "  philosophical  possibilities,"  said  Buffon,  "  the  same  temperature 
might  have  been  expected,  all  other  circumstances  being  equal,  to 
produce  the  same  beings  in  different  parts  of  the  globe,  both  in  the 
animal  and  vegetable  kingdoms,  yet  it  is  an  undoubted  fact,  that  when 
America  was  discovered,  its  indigenous  quadrupeds  were  all  dissimilar 
to  those  previously  known  in  the  Old  World.  The  elephant,  the 
rhinoceros,  the  hippopotamus,  the  camelopard,  the  camel,  the  drome- 
dary, the  buffalo,  the  horse,  the  ass,  the  lion,  the  tiger,  the  apes,  the 
baboons,  and  a  number  of  other  mammalia,  were  nowhere  to  be  met 
with  on  the  new  continent ;  while  in  the  old,  the  American  species, 
of  the  same  great  class,  were  nowhere  to  be  seen — the  tapir,  the  lama, 
the  pecari,  the  jaguar,  the  couguar,  the  agouti,  the  paca,  the  coati,  and 
the  sloth." 

These  phenomena,  although  few  in  number  relatively  to  the  whole 
animate  creation,  were  so  striking  and  so  positive  in  their  nature,  that 
the  great  French  naturalist  caught  sight  at  once  of  a  general  law  in 
the  geographical  distribution  of  organic  beings,  namely,  the  limitation 
of  groups  of  distinct  species  to  regions  separated  from  the  rest  of  the 
globe  by  certain  natural  barriers.  It  was,  therefore,  in  a  truly  philo- 
sophical spirit  that,  relying  on  the  clearness  of  the  evidence  obtained 
respecting  the  larger  quadrupeds,  he  ventured  to  call  in  question  the 
identifications  announced  by  some  contemporary  naturalists  of  species 
of  animals  said  to  be  common  to  the  southern  extremities  of  America 
and  Africa.* 

The  migration  of  quadrupeds  from  one  part  of  the  globe  to  another, 
observes  Dr.  Prichard,  is  prevented  by  uncongenial  climates  and  the 
branches  of  the  ocean  which  intersect  continents.  "  Hence,  by  a 

*  Buffon,  vol.  v. — On  the  Virginian  Opossum. 


630  DIFFERENT  REGIONS  OF  [CH.  XXXVIII 

reference  to  the  geographical  site  of  countries,  we  may  divide  the 
earth  into  a  certain  number  of  regions  fitted  to  become  the  abodes  of 
particular  groups  of  animals,  and  we  shall  find,  on  inquiry,  that  each 
of  these  provinces,  thus  conjecturally  marked  out,  is  actually  inhabited 
by  a  distinct  nation  of  quadrupeds."  *  It  will  be  observed  that  the 
language  of  Buffon  respecting  "natural  barriers,"  which  has  since 
been  so  popular,  would  be  wholly  without  meaning  if  the  geographical 
distribution  of  organic  beings  had  not  led  naturalists  to  adopt  very 
generally  the  doctrine  of  specific  centres,  or,  in  other  words,  to  believe 
that  each  species,  whether  of  plant  or  animal,  originated  in  a  single 
birth-place.  Reject  this  view,  and  the  fact  that  not  a  single  native 
quadruped  is  common  to  Australia,  the  Cape  of  Good  Hope,  and 
South  America,  can  in  no  ways  be  explained  by  adverting  to  the 
wide  extent  of  intervening  ocean,  or  to  the  sterile  deserts,  or  the  great 
heat  or  cold  of  the  climates,  through  which  each  species  must  have 
passed,  before  it  could  migrate  from  one  of  those  distant  regions  to 
another.  It  might  fairly  be  asked  of  one  who  talked  of  impassable 
barriers,  why  the  same  kangaroos,  rhinoceroses,  or  lamas,  should  not 
have  been  created  simultaneously  in  Australia,  Africa,  and  South 
America !  The  horse,  the  ox,  and  the  dog,  although  foreign  to  these 
countries  until  introduced  by  man,  are  now  able  to  support  them- 
selves there  in  a  wild  state,  and  we  can  scarcely  doubt  that  many  of 
the  quadrupeds  at  present  peculiar  to  Australia,  Africa,  and  South 
America,  might  have  continued  in  like  manner  to  inhabit  each  of  the 
three  continents  had  they  been  indigenous  or  could  they  once  have  got 
a  footing  there  as  new  colonists. 

At  the  same  time  every  zoologist  will  be  willing  to  concede,  that 
even  if  the  departure  of  each  species  from  a  single  centre  had  not 
appeared  to  be  part  of  the  plan  of  Nature,  the  range  of  species  in 
general  must  have  become  limited,  under  the  influence  of  a  variety  of 
causes,  especially  in  the  class  of  terrestrial  mammalia.  Scarcely  any 
one  of  these  could  be  expected  to  retain  as  fair  a  claim  to  the  title  of 
cosmopolite  as  man,  although  even  the  human  race,  fitted  as  it  is  by 
its  bodily  constitution  and  intellectual  resources  to  spread  very  widely 
over  the  earth,  is  far  from  being  strictly  cosmopolite.  It  is  excluded 
both  from  the  arctic  and  antarctic  circles,  from  many  a  wide  desert 
and  the  summits  of  many  mountain-chains ;  and  lastly,  from  three- 
fourths  of  the  globe  covered  by  water,  where  there  are  large  areas 
very  prolific  in  animal  life,  even  in  the  highest  order  of  the  vertebrate 
class.  But  the  habitations  of  species  are,  as  before  stated,  in  refer- 
ence to  plants  (see  above,  p.  614),  circumscribed  by  causes  different 
from  those  which  determine  their  stations,  and  these  causes  are  clearly 
connected  with  the  time  and  place  of  the  original  creation  of  each 
species. 

As  the  names  and  characters  of  land  quadrupeds  are  much  better 

*  Prichard's  Phys.  Hist,  of  Mankind,  vol.  i.  p.  54. 


On.  XXXVIIL]  INDIGENOUS   MAMMALIA.  631 

known  to  the  general  reader  than  those  of  other  great  families  of  the 
animal  kingdom,  I  shall  select  this  class  to  exemplify  the  zoological 
provinces  into  which  species  are  divisible,  confining  myself,  however, 
to  those  facts  which  may  help  to  elucidate  some  principle,  or  rule 
apparently  followed  by  the  Author  of  Nature,  in  regard  to  that 
"mystery  of  mysteries,"  the  first  peopling  of  the  earth  with  living 
beings.*  First,  then,  the  European  region  comprehends,  besides  Europe, 
the  borders  of  the  Mediterranean,  and  even  the  north  of  Africa,  and 
extends  into  Asia,  beyond  the  Oural  mountains  and  the  Caspian.  Al- 
though the  species  are  almost  all  peculiar,  the  number  of  characteristic 
genera  is  remarkably  small.  The  bear,  the  fox,  the  hare,  the  rabbit, 
the  deer,  and  almost  every  European  form  is  found  equally  in  several 
of  the  other  large  provinces  of  mammalia,  where  the  species  are 
distinct.  Even  the  mole  (Talpa),  although  confined  to  the  northern 
parts  of  the  old  world,  ranges  eastwards,  as  far  as  the  Himalaya 
mountains. 

2dly.  The  African  Fauna,  on  the  other  hand,  is  singularly  rich  in 
generic  forms,  not  met  with  in  a  living  state  in  any  other  region.  The 
hippopotamus,  for  example,  of  which  two  very  distinct  species  are  known, 
the  giraffe,  the  Chimpanzee,  the  blue-faced  baboon,  the  four-fingered 
monkeys  (Colubus),  many  carnivora,  such  as  Proteles,  allied  to  the 
hyaena,  and  a  multitude  of  other  forms,  are  exclusively  African.  A  few 
of  the  species  inhabiting  the  northern  confines  of  this  continent,  such  as 
the  dromedary,  lion,  and  jackall,  are  also  common  to  Asia ;  and  a  much 
larger  number  of  forms  belong  equally  to  the  great  Asiatic  province, 
the  species  being  distinct.  The  elephant,  for  example,  of  Africa  is 
smaller,  has  a  rounder  head,  and  larger  ears  than  the  Indian  one,  and 
has  only  three  instead  of  four  nails  on  each  hind  foot.  In  like  manner, 
not  one  of  three  African  species  of  Rhinoceros  agrees  with  one  of  the 
three  Indian  kinds. 

3dly.  The  Southern  region  of  Africa,  where  that  continent  extends 
into  the  temperate  zone,  constitutes  another  separate  zoological  province, 
surrounded  as  it  is  on  three  sides  by  the  ocean,  and  cut  off  from  the 
countries  of  milder  climate  in  the  northern  hemisphere,  by  the  interven- 
ing torrid  zone.  In  many  instances,  this  region  contains  the  same 
genera  which  are  found  in  temperate  climates  to  the  northward  of  the 
line:  but  then  the  southern  are  different  from  the  northern  species. 
Thus,  in  the  south  we  find  the  quagga  and  the  zebra ;  in  the  north,  the 
horse,  the  ass,  and  the  jiggetai  of  Asia. 

The  south  of  Africa  is  spread  out  into  fine  level  plains  from  the  tropic 
to  the  Cape.  In  this  region,  says  Pennant,  besides  the  horse  genus,  of 
which  five  species  have  been  found,  there  are  also  peculiar  species  of 

*  In  the  above  enumeration  of  the  leading  zoological  provinces  of  land  qua- 
drupeds I  have  been  most  kindly  assisted  by  Mr.  Waterhouse  of  the  British 
Museum,  author  of  a  most  able  and  comprehensive  work  on  the  "Natural 
History  of  the  Mammalia,"  now  in  the  course  of  publication.  London,  Bail- 
Here,  1846. 


632  DIFFERENT   SPECIES   OF  [Cn.  XXXVIII. 

rhinoceros,  the  hog,  and  the  hyrax,  among  pachydermatous  races  ;  and 
amongst  the  ruminating,  the  Cape  buffalo,  and  a  variety  of  remarkable 
antelopes,  as  the  springbok,  the  oryx,  the  gnou,  the  leucophoe,  the 
pygarga,  and  several  others.* 

4thly.  The  assemblage  of  quadrupeds  in  Madagascar  affords  a  strik- 
ing illustration  of  the  laws  before  alluded  to,  as  governing  the  distribu- 
tion of  species  in  islands.  Separated  from  Africa  by  the  Mozambique 
channel,  which  is  300  miles  wide,  Madagascar  forms,  with  two  or  three 
small  islands  in  its  immediate  vicinity,  a  zoological  province  by  itself, 
all  the  species  except  one,  and  nearly  all  the  genera,  being  peculiar. 
The  only  exception  consists  of  a  small  insectivorous  quadruped  (Centetes), 
found  also  in  the  Mauritius,  to  which  place  it  is  supposed  to  have  been 
taken  in  ships.  The  most  characteristic  feature  of  this  remarkable  fauna 
consists  in  the  number  of  quadrumana  of  the  Lemur  family,  no  less  than 
six  genera  of  these  monkeys  being  exclusively  met  with  in  this  island, 
and  a  seventh  genus  of  the  same,  called  Galago,  which  alone  has  any 
foreign  representative,  being  found,  as  we  might  from  analogy  have 
anticipated,  in  the  nearest  main  land.  Had  the  species  of  quadrupeds 
in  Madagascar  agreed  with  those  of  the  contiguous  parts  of  Africa,  as 
do  those  of  England  with  the  rest  of  Europe,  the  naturalist  would  have 
inferred  that  there  had  been  a  land  communication  since  the  period  of 
the  coming  in  of  the  existing  quadrupeds,  whereas  we  may  now  conclude 
that  the  Mozambique  channel  has  constituted  an  insuperable  barrier  to 
the  fusion  of  the  continental  fauna  with  that  of  the  great  island  during 
the  whole  period  that  has  elapsed  since  the  living  species  were  created. 

5thly.  Another  of  the  great  nations  of  terrestrial  mammalia  is  that 
of  India,  containing  a  great  variety  of  peculiar  forms,  such  as  the  sloth- 
bear  (Prochilus),  the  musk-deer  (Moscus),  the  nylghau,  the  gibbon  or 
long-armed  ape,  and  many  others.  Gthly.  A  portion  of  the  islands  of 
the  Indian  archipelago  might,  perhaps,  be  considered  by  some  geologists 
as  an  appendage  of  the  same  province.  In  fact,  we  find  in  the  large 
islands  of  Java,  Sumatra,  and  Borneo,  the  same  genera,  for  the  most 
part,  as  on  the  continent  of  India,  and  some  of  the  same  species,  e.  g. 
the  tapir  (Tapirus  Malay  anus],  the  rhinoceros  of  Sumatra,  and  some 
others.  Most  of  the  species,  however,  are  distinct,  and  each  island  has 
many,  and  even  a  few  genera,  peculiar  to  itself.  Between  eighty  and 
ninety  species  are  known  to  inhabit  Java,  and  nearly  the  same  number 
occur  in  Sulnatra.  Of  these,  more  than  half  are  common  to  the  two 
islands.  Borneo,  which  is  much  less  explored,  has  yielded  already 
upwards  of  sixty  species,  more  than  half  of  which  are  met  with  either 
in  Java  or  Sumatra.  Of  the  species  inhabiting  Sumatra  and  not  found 
in  Java,  Borneo  contains  the  greater  portion.  Upon  the  whole,  if  these 
three  large  islands  were  united,  and  a  fusion  of  their  respective  indige- 
nous mammalia  should  take  place,  they  would  present  a  fauna  related 
to  that  of  continental  India,  and  comprising  about  as  many  species  as 

*  Pennant's  Hist,  of  Quadrupeds,  cited  by  Prichard,  Phys.  Hist,  of  Mankind, 
vol.  i.  p.  66. 


CH.  XXXVIIL]  INDIGENOUS   MAMMALIA.  033 

we  might  expect  from  analogy  to  discover  in  an  area  of  equal  extent. 
The  Philippine  Islands  are  peopled  with  another  assemblage  of  species 
generically  related  to  the  great  Indian  type. 

7thly.  But  the  islands  of  Celebes,  Amboina,  Timor,  and  New  Guinea, 
constitute  a  different  region  of  mammalia  more  allied  to  the  Australian 
type,  as  having  an  intermixture  of  marsupial  quadrupeds,  yet  showing 
an  affinity  also  to  the  Indian  in  such  forms  as  the  deer  ( Cervus),  the 
weasel  (Viverra),  the  pig  (Sus),  the  Macaque  monkey  (Cercopithecus), 
and  others.  As  we  proceed  in  a  south-westerly  direction,  from  Celebes 
to  Amboina  and  thence  to  New  Guinea,  we  find  the  Indian  types 
diminishing  in  number,  and  the  Australian  (?'.  e.  marsupial  forms) 
increasing.  Thus  in  New  Guinea  seven  species  of  pouched  quadrupeds 
have  been  detected,  and  among  them  two  singular  tree-kangaroos ;  yet 
only  one  species  of  the  whole  seven,  viz.  the  flying  opossum  (Petauris 
ariel),  is  common  to  the  Indian  archipelago  and  the  main  land  of  Aus- 
tralia. The  greater  the  zoological  affinity,  therefore,  between  the  latter 
and  the  New  Guinea  fauna,  although  it  seems  in  some  way  connected 
with  geographical  proximity,  is  not  to  be  explained  simply  by  the 
mutual  migration  of  species  from  the  one  to  the  other. 

8thly.  When  Australia  was  discovered,  its  land  quadrupeds,  belong- 
ing almost  exclusively  to  the  marsupial  or  pouched  tribe,  such  as  the 
kangaroos,  wombats,  flying  opossums,  kangaroo-rats,  and  others,  some 
feeding  on  herbs  and  fruits,  others  carnivorous,  were  so  novel  in  their 
structure  and  aspect,  that  they  appeared  to  the  naturalist  almost  as 
strange  as  if  they  were  the  inhabitants  of  some  other  planet.  We  learn 
from  the  recent  investigations  of  Mr.  Waterhouse,*  that  no  less  than 
lYO  species  of  marsupial  quadrupeds  have  now  been  determined,  and  of 
the  whole  number  all  but  thirty-two  are  exclusively  restricted  to  Aus- 
tralia. Of  these  thirty-two,  nine  belong  to  the  islands  in  the  Indian 
archipelago  before  mentioned,  and  the  other  twenty-three  are  all  species 
of  opossum  inhabiting  the  tropical  parts  of  South  America,  or  a  few  of 
them  extending  into  Mexico  and  California,  and  one,  the  Virginian 
opossum,  into  the  United  States. 

Othly.  It  only  remains  for  me  to  say  something  of  the  mammiferous 
fauna  of  North  and  South  America.  It  has  often  been  said  that, 
where  the  three  continents  of  Asia,  Europe,  and  North  America,  ap- 
proach very  near  to  each  other  towards  the  pole,  the  whole  arctic  region 
forms  one  zoological  and  botanical  province.  The  narrow  straits  which 
separate  the  old  and  new  world  are  frozen  over  in  winter,  and  the  dis- 
tance is  farther  lessened  by  intervening  islands.  Many  plants  and  ani- 
mals of  various  classes  have  accordingly  spread  over  all  the  arctic  lands, 
being  sometimes  carried  in  the  same  manner  as  the  polar  bear,  when  it 
is  drifted  on  floating  ice  from  Greenland  to  Iceland.  But  on  a  close 
inspection  of  the  arctic  mammalia,  it  has  been  found  of  late  years  that 
a  very  small  number  of  the  American  species  are  identical  with  those  of 

*  Natural  History  of  the  Mammalia,  vol.  i.,  on  the  Marsupials.  London, 
Bailliere,  1846. 


684  DOCTRINE   OF   SPECIFIC    CENTRES.      [Cfl.  XXXVIII. 

Europe  or  Asia.  The  genera  are,  in  great  part,  the  same  or  nearly 
allied ;  but  the  species  are  rarely  identical,  and  are  often  very  unlike, 
as  in  the  case  of  the  American  badger  and  that  of  Europe.  Some  of  the 
genera  of  arctic  America,  such  as  the  musk  ox  ( Ovibos),  are  quite  pecu- 
liar, and  the  distinctness  of  the  fauna  of  the  great  continents  goes  on 
increasing  in  proportion  as  we  trace  them  southwards,  or  as  they  recede 
farther  from  each  other,  and  become  more  and  more  separated  by  the 
ocean.  At  length  we  find  that  the  three  groups  of  tropical  mammalia, 
belonging  severally  to  America,  Africa,  and  India,  have  not  a  single 
species  in  common. 

The  predominant  influence  of  climate  over  all  the  other  causes  which 
limit  the  range  of  species  in  the  mammalia  is  perhaps  nowhere  so  con- 
spicuously displayed  as  in  North  America.  The  arctic  fauna,  so  admira- 
bly described  by  Sir  John  Richardson,  has  scarcely  any  species  in  com- 
mon with  the  fauna  of  the  state  of  New  York,  which  is  600  miles  farther 
south,  and  comprises  about  forty  distinct  mammifers.  If  again  we  travel 
farther  south  about  600  miles,  and  enter  another  zone,  running  east  and 
west,  in  South  Carolina,  Georgia,  Alabama,  and  the  contiguous  states, 
we  again  meet  with  a  new  assemblage  of  land  quadrupeds,  and  this 
again  differs  from  the  fauna  of  Texas,  where  frosts  are  unknown.  It  will 
be  observed  that  on  this  continent  there  are  no  great  geographical 
barriers  running  east  and  west,  such  as  high  snow-clad  mountains,  barren 
deserts,  or  wide  arms  of  the  sea,  capable  of  checking  the  free  migration 
of  species  from  north  to  south.  But  notwithstanding  the  distinctness 
of  those  zones  of  indigenous  mammalia,  there  are  some  species,  such  as 
the  buffalo  (Bison  Americanus),  the  racoon  (Procyon  lotor),  and  the 
Virginian  opossum  (Didelphis  Virginiana),  which  have  a  wider  habita- 
tion, ranging  almost  from  Canada  to  the  Gulf  of  Mexico  ;  but  they  form 
exceptions  to  the  general  rule.  The  opossum  of  Texas  (Didelphis 
carnivora)  is  different  from  that  of  Virginia,  and  other  species  of  the 
same  genus  inhabit  westward  of  the  Rocky  Mountains,  in  California,  for 
example,  where  almost  all  the  mammalia  differ  from  those  of  the  United 
States. 

lOthly.  The  West  Indian  land  quadrupeds  are  not  numerous,  but 
several  of  them  are  peculiar;  and  llthly,  South  America  is  the  most 
distinct,  with  the  exception  of  Australia,  of  all  the  provinces  into  which 
the  mammalia  can  be  classed  geographically.  The  various  genera  of 
monkeys,  for  example,  belong  to  the  family  Platyrrhini,  a  large  natural 
division  of  the  quadrumana,  so  named  from  their  widely  separated  nos- 
trils. They  have  a  peculia'r  dentition,  and  many  of  them  prehensile 
tails,  and  are  entirely  unknown  in  other  quarters  of  the  globe.  The 
sloths  and  armadillos,  the  true  blood- sucking  bats  or  vampyres  (Phyl- 
lostomidce),  the  capybara,  the  largest  of  the  rodents,  the  carnivorous  coati- 
mondi  (Nasua),  and  a  great  many  other  forms,  are  also  exclusively 
characteristic  of  South  America. 

"  In  Peru  and  Chili,"  says  Humboldt,  "  the  region  of  the  grasses, 
which  is  at  an  elevation  of  from  12,300  to  15,400  feet,  is  inhabited  by 


CH.  XXXVIIL]  QUADRUPEDS   IN    ISLANDS.  635 

crowds  of  lama,  guanaco,  and  alpaca.  These  quadrupeds,  which  here 
represent  the  genus  camel  of  the  ancient  continent,  have  not  extended 
themselves  either  to  Brazil  or  Mexico ;  because,  during  their  journey, 
they  must  necessarily  have  descended  into  regions  that  were  too  hot  for 
them."*  In  this  passage  it  will  be  seen  that  the  doctrine  of  "  specific 
centres"  is  tacitly  assumed. 

Quadrupeds  in  Islands. — Islands  remote  from  continents,  especially 
those  of  small  size,  are  either  destitute  of  quadrupeds,  except  such  as 
have  been  conveyed  to  them  by  man,  or  contain  species  peculiar  to 
them.  In  the  Galapagos  archipelago  no  indigenous  quadrupeds  were 
found  except  one  mouse,  which  is  supposed  to  be  distinct  from  any 
hitherto  found  elsewhere.  A  peculiar  species  of  fox  is  indigenous  in 
the  Falkland  Islands,  and  a  rat  in  New  Zealand,  which  last  country, 
notwithstanding  its  magnitude,  is  destitute  of  other  mammalia,  except 
bats,  and  these,  says  Dr.  Prichard,  may  have  made  their  way  along 
the  chain  of  islands  which  extend  from  the  shores  of  New  Guinea  far 
into  the  Southern  Pacific.  The  same  author  remarks,  that  among  the 
various  groups  of  fertile  islands  in  the  Pacific,  no  quadrupeds  have 
been  met  with  except  the  rat  and  a  few  bats  as  above  mentioned,  and 
the  dog  and  hog,  which  appear  to  have  been  conveyed  thither  by  the 
natives  from  New  Guinea.  "Rats  are  to  be  found  even  on  some 
desert  islands,  whither  they  may  have  been  conveyed  by  canoes  which 
have  occasionally  approached  the  shore.  It  is  known,  also,  that  rats 
occasionally  swim  in  large  numbers  to  considerable  distances."! 

Geographical  range  of  the  Cetacea. — It  is  natural  to  suppose  that 
the  geographical  range  of  the  different  species  of  Cetacea  should  be 
less  correctly  ascertained  than  that  of  the  terrestrial  mammifers.  It 
is,  however,  well  known  that  the  whales  which  are  obtained  by  our 
fishers  in  the  South  Seas  are  distinct  from  those  of  the  North ;  and 
the  same  dissimilarity  has  been  found  in  all  the  other  marine  animals, 
of  the  same  class,  so  far  as  they  have  yet  been  studied  by  naturalists. 

Dispersion  of  quadrupeds. — Let  us  now  inquire  what  facilities  the 
various  land  quadrupeds  enjoy  of  spreading  themselves  over  the  surface 
of  the  earth.  In  the  first  place,  as  their  numbers  multiply,  all  of  them, 
whether  they  feed  on  plants,  or  prey  on  other  auirnals,  are  disposed  to 
scatter  themselves  gradually  over  as  wide  an  area  as  is  accessible  to 
them.  But  before  they  have  extended  their  migrations  over  a  large 
space,  they  are  usually  arrested  either  by  the  sea,  or  a  zone  of  uncon- 
genial climate,  or  some  lofty  and  unbroken  chain  of  mountains,  or  a 
tract  already  occupied  by  a  hostile  and  more  powerful  species. 

Their  powers  of  swimming. — Rivers  and  narrow  friths  can  seldom 
interfere  with  their  progress ;  for  the  greater  part  of  them  swim  well, 
and  few  are  without  this  power  when  urged  by  danger  and  pressing 
want.  Thus,  amongst  beasts  of  prey,  the  tiger  is  seen  swimming  about 

*  Description  of  the  Equatorial  Regions. 

f  Prichard,  Phys.  Hist,  of  Mankind,  vol.  i.  p.  7  5. 


636  DISPERSION  AND   MIGRATIONS   OF        [Ca  XXXVIII 

among  the  islands  and  creeks  in  the  delta  of  the  Ganges,  and  the 
jaguar  traverses  with  ease  the  largest  streams  in  South  America.* 
The  bear,  also,  and  the  bison,  cross  the  current  of  the  Mississippi. 
The  popular  error,  that  the  common  swine  cannot  escape  by  swimming 
when  thrown  into  the  water,  has  been  contradicted  by  several  curious 
and  well-authenticated  instances  during  the  floods  in  Scotland  of  1829. 
One  pig,  only  six  months  old,  after  having  been  carried  down  from 
Garmouth  to  the  bar  at  the  mouth  of  the  Spey,  a  distance  of  a  quarter 
of  a  mile,  swam  four  miles  eastward  to  Port  Gordon,  and  landed  safe. 
Three  others,  of  the  same  age  and  litter,  swam,  at  the  same  time,  five 
miles  to  the  west,  and  landed  at  Blackhill.f 

In  an  adult  and  wild  state,  these  animals  would  doubtless  have  been 
more  strong  and  active,  and  might,  when  hard  pressed,  have  performed 
a  much  longer  voyage.  Hence  islands  remote  from  the  continent  may 
obtain  inhabitants  by  casualties  which,  like  the  late  storms  in  Moray- 
shire,  may  only  occur  once  in  many  centuries,  or  thousands  of  years, 
under  all  the  same  circumstances.  It  is  obvious  that  powerful  tides, 
winds,  and  currents  may  sometimes  carry  along  quadrupeds  capable, 
in  like  manner,  of  preserving  themselves  for  hours  in  the  sea,  to  very 
considerable  distances;  and  in  this  way,  perhaps,  the  tapir  (Tapir 
Indicus)  may  have  become  common  to  Sumatra  and  the  Malayan 
peninsula. 

To  the  elephant,  in  particular,  the  power  of  crossing  rivers  is  essential 
in  a  wild  state,  for  the  quantity  of  food  which  a  herd  of  these  animals 
consumes  renders  it  necessary  that  they  should  be  constantly  moving 
from  place  to  place.  The  elephant  crosses  the  stream  in  two  ways. 
If  the  bed  of  the  river  be  hard,  and  the  water  not  of  too  great  a  depth, 
he  fords  it.  But  when  he  crosses  great  rivers,  such  as  the  Ganges  and 
the  Niger,  the  elephant  swims  deep,  so  deep,  that  the  end  of  his  trunk 
only  is  out  of  the  water ;  for  it  is  a  matter  of  indifference  to  him 
whether  his  body  be  completely  immersed,  provided  he  can  bring  the 
tip  of  his  trunk  to  the  surface,  so  as  to  breathe  the  external  air. 

Animals  of  the  deer  kind  frequently  take  to  the  water,  especially  in 
the  rutting  season,  when  the  stags  are  seen,  swimming  for  several  leagues 
at  a  time,  from  island  to  island,  in  search  of  the  does,  especially  in  the 
Canadian  lakes ;  and  in  some  countries  where  there  are  islands  near  the 
sea-shore,  they  fearlessly  enter  the  sea  and  swim  to  them.  In  hunting 
excursions,  in  North  America,  the  elk  of  that  country  is  frequently 
pursued  for  great  distances  through  the  water. 

The  large  herbivorous  animals,  which  are  gregarious,  can  never 
remain  long  in  a  confined  region,  as  they  consume  so  much  vegetable 
food.  The  immense  herds  of  bisons  (Bos  Americanus)  which  often, 
in  the  great  valleys  of  the  Mississippi  and  its  tributaries  blacken  the 

*  Buffon,  vol.  v.  p.  204. 

fSir  T.  D.  Lauder,  Bart.,  on  the  Floods  in  Morayshire,  Aug.  1829,  p.  302, 
second  edition. 


CH.  XXXVIIL]  MAMMIFEROUS   QUADRUPEDS.  637 

surface  of  the  prairie  lands,  are  continually  shifting  their  quarters, 
followed  by  wolves,  which  prowl  about  in  their  rear.  "  It  is  no  exag- 
geration," says  Mr.  James,  "  to  assert,  that  in  one  place,  on  the  banks 
of  the  Platte,  at  least  ten  thousand  bisons  burst  on  our  sight  in  an 
instant.  In  the  morning,  we  again  sought  the  living  picture;  but 
upon  all  the  plain,  which  last  evening  was  so  teeming  with  noble 
animals,  not  one  remained."* 

Migratory  instincts. — Besides  the  disposition  common  to  the  indi- 
viduals of  every  species  slowly  to  extend  their  range  in  search  of  food, 
in  proportion  as  their  numbers  augment,  a  migratory  instinct  often 
developes  itself  in  an  extraordinary  manner,  when,  after  an  unusually 
prolific  season,  or  upon  a  sudden  scarcity  of  provisions,  great  multi 
tudes  are  threatened  by  famine.  It  may  be  useful  to  enumerate  some 
examples  of  these  migrations,  because  they  may  put  us  upon  our 
guard  against  attributing  a  high  antiquity  to  a  particular  species  merely 
because  it  is  diffused  over  a  great  space ;  they  show  clearly  how  soon, 
in  a  state  of  nature,  a  newly  created  species  might  spread  itself,  in  every 
direction,  from  a  single  point. 

In  very  severe  winters,  great  numbers  of  the  black  bears  of  America 
migrate  from  Canada  into  the  United  States ;  but  in  milder  seasons, 
when  they  have  been  well  fed,  they  remain  and  hybernate  in  the  north. f 
The  rein-deer,  which,  in  Scandinavia,  can  scarcely  exist  to  the  south  of 
the  sixty-fifth  parallel,  descends,  in  consequence  of  the  greater  coldness 
of  the  climate,  to  the  fiftieth  degree  in  Chinese  Tartary,  and  often  roves 
into  a  country  of  more  southern  latitude  than  any  part  of  England. 

In  Lapland,  and  other  high  latitudes,  the  common  squirrels,  whenever 
they  are  compelled,  by  want  of  provisions,  to  quit  their  usual  abodes, 
migrate  in  amazing  numbers,  and  travel  directly  forwards,  allowing 
neither  rocks  nor  forests,  nor  the  broadest  waters,  to  turn  them  from  their 
course.  Great  numbers  are  often  drowned  in  attempting  to  pass  friths 
and  rivers.  In  like  manner  the  small  Norway  rat  sometimes  pursues 
its  migrations  in  a  straight  line  across  rivers  and  lakes ;  and  Pennant 
informs  us,  that  when  the  rats,  in  Kamtschatka,  become  too  numerous, 
they  gather  together  in  the  spring,  and  proceed  in  great  bodies  west- 
ward, swimming  over  rivers,  lakes,  and  arms  of  the  sea.  Many  are 
drowned  or  destroyed  by  water-fowl  or  fish.  As  soon  as  they  have 
crossed  the  river  Penginsk,  at  the  head  of  the  gulf  of  the  same  name, 
they  turn  southward,  and  reach  the  rivers  Judoma  and  Okotsk  by  the 
middle  of  July ;  a  district  more  than  800  miles  distant  from  their  point 
of  departure. 

The  lemings,  also,  a  small  kind  of  rat,  are  described  as  natives  of  the 
mountains  of  Kolen,  in  Lapland  ;  and  once  or  twice  in  a  quarter  of  a 
century  they  appear  in  vast  numbers,  advancing  along  the  ground,  and 
"  devouring  every  green  thing."  Innumerable  bands  march  from  the 

*  Expedition  from  Pittsburg  to  the  Rocky  Mountains,  vol.  ii.  p.  153. 
f  Richardson's  Fauna  Boreali-Americana,  p.  16. 


MIGRATION   OF  [Cn.  XXXVIIL 

Kolen,  through  Nordland  and  Finmark,  to  the  Western  Ocean,  which 
they  immediately  enter ;  and  after  swimming  about  for  some  time,  perish. 


Fig    97 


The  Leming,  or  Lapland  Marmot  (Mus  Lemmus,  Linn.) 


Other  bands  take  their  route  through  Swedish  Lapland,  to  the  Bothnian 
Gulf,  where  they  are  drowned  in  the  same  manner.  They  are  followed 
in  their  journeys  by  bears,  wolves,  and  foxes,  which  prey  upon  them  in- 
cessantly. They  generally  move  in  lines,  which  are  about  three  feet 
from  each  other,  and  exactly  parallel,  going  directly  forward  through 
rivers  and  lakes  ;  and  when  they  meet  with  stacks  of  hay  or  corn,  gnaw- 
ing their  way  through  them  instead  of  passing  round.*  These  excur- 
sions usually  precede  a  rigorous  winter,  of  which  the  lemings  seem  in 
some  way  forewarned. 

Vast  troops  of  the  wild  ass,  or  onager  of  the  ancients,  which  inhabit 
the  mountainous  deserts  of  Great  Tartary,  feed,  during  the  summer,  in 
the  tracts  east  and  north  of  Lake  Aral.  In  the  autumn  they  collect  in 
herds  of  hundreds,  and  even  thousands,  and  direct  their  course  towards 
Persia,  to  enjoy  a  warm  retreat  during  winter.f  Bands  of  two  or  three 
hundred  quaggas,  a  species  of  wild  ass,  are  sometimes  seen  to  migrate 
from  the  tropical  plains  of  southern  Africa  to  the  vicinity  of  the  Malale- 
veen  River.  During  their  migrations  they  are  followed  by  lions,  who 
slaughter  them  night  by  nightj; 

The  migratory  swarms  of  the  springbok,  or  Cape  antelope,  afford 
another  illustration  of  the  rapidity  with  which  a  species  under  certain 
circumstances  may  be  diffused  over  a  continent.  When  the  stagnant 
pools  of  the  immense  deserts  south  of  the  Orange  River  dry  up,  which 
often  happens  after  intervals  of  three  or  four  years,  myriads  of  these  ani- 
mals desert  the  parched  soil,  and  pour  down  like  a  deluge  on  the  culti- 
vated regions  near  the  Cape.  The  havoc  committed  by  them  resembles 
that  of  the  African  locusts;  and  so  crowded  are  the  herds,  that  "the 
lion  has  been  seen  to  walk" in  the  midst  of  the  compressed  phalanx  with 
only  as  much  room  between  him  and  his  victims  as  the  fears  of  those 
immediately  around  could  procure  by  pressing  outwards."§ 

*  Phil.  Trans.,  vol.  ii.  p.  872. 

•j-  "Wood's  Zoography,  vol.  i.  p.  11. 

\  On  the  authority  of  Mr.  Campbell.  Library  of  Entert.  Know.,  Menageries, 
vol.  i.  p.  152. 

§  Cuvier's  Animal  Kingdom  by  Griffiths,  vol.  ii.  p.  109.  Library  of  Entertain- 
ing Knowledge,  Menageries,  vol.  i.  p.  366. 


CH.XXXVIIL]  MAMMIFEROUS   QUADRUPEDS.  639 

Dr.  Horsfield  mentions  a  singular  fact  in  regard  to  the  geographical 
distribution  of  the  Mydaus  meliceps,  an  animal  intermediate  between 
the  polecat  and  badger.  It  inhabits  Java,  and  is  "  confined  exclusively 
to  those  mountains  which  have  an  elevation  of  more  than  seven  thousand 
feet  above  the  level  of  the  ocean  ;  on  these  it  occurs  with  the  same  regu- 
larity as  many  plants.  The  long  extended  surface  of  Java,  abounding 
with  conical  points  which  exceed  this  elevation,  affords  many  places 
favorable  for  its  resort.  On  ascending  these  mountains,  the  traveller 
scarcely  fails  to  meet  with  this  animal,  which,  from  its  peculiarities,  is 
universally  known  to  the  inhabitants  of  these  elevated  tracts,  while  to 
those  of  the  plains  it  is  as  strange  to  an  animal  from  a  foreign  county. 

Fig.  98. 


Mydaus  meliceps,  or  badger-headed  Mydaus.    Length,  including  the  tail,  16  inches. 

In  my  visits  to  the  mountainous  districts,  I  uniformly  met  with  it ;  and, 
as  far  as  the  information  of  the  natives  can  be  relied  on,  it  is  found  on 
all  the  mountains."* 

ISTow,  if  asked  to  conjecture  how  the  Mydaus  arrived  at  the  elevated 
regions  of  each  of  these  isolated  mountains,  we  might  say  that,  before 
the  island  was  peopled  by  man,  by  whom  their  numbers  are  now 
thinned,  they  may  occasionally  have  multiplied  so  as  to  be  forced  to 
collect  together  and  migrate :  in  which  case  notwithstanding  the  slow- 
ness of  their  motions,  some  few  would  succeed  in  reaching  another 
mountain,  some  twenty,  or  even,  perhaps,  fifty  miles  distant ;  for  although 
the  climate  of  the  hot  intervening  plains  would  be  unfavourable  to  them, 
they  might  support  it  for  a  time,  and  would  find  there  abundance  of 
insects  on  which  they  feed.  Volcanic  eruptions,  which,  at  different 
times  have  covered  the  summits  of  some  of  those  lofty  cones  with  sterile 
sand  and  ashes,  may  have  occasionally  contributed  to  force  on  these 
migrations, 

Drifting  of  animals  on  ice-floes. — The  power  of  the  terrestrial  mam- 
malia to  cross  the  sea  is  very  limited,  and  it  was  before  stated  that  the 
same  species  is  scarcely  ever  common  to  districts  widely  separated  by 
the  ocean.  If  there  be  some  exceptions  to  this  rule,  they  generally 
admit  of  explanation  ;  for  there  are  natural  means  whereby  some  animals 
may  be  floated  across  the  water,  and  the  sea  may  in  the  course  of  ages 

*  Horsfield,  Zoological  Researches  in  Java,  No.  iL,  from  which  the  figure  is 
taken. 


640  DRIFTING  OF   ANIMALS  [Cn.  XXXVIII. 

wear  a  wide  passage  through  a  neck  of  land,  leaving  individuals  of  a 
species  on  each  side  of  the  new  channel.  Polar  bears  are  known  to 
have  been  frequently  drifted  on  the  ice  from  Greenland  to  Iceland  ;  they 
can  also  swim  to  considerable  distances,  for  Captain  Parry,  on  the  return 
of  his  ships  through  Barrow's  Straits,  met  with  a  bear  swimming  in  the 
water  about  midway  between  the  shores,  which  were  about  forty  miles 
apart,  and  where  no  ice  was  in  sight.*  "  Near  the  east  coast  of  Green- 
land," observes  Scoresbj,  "they  have  been  seen  on  the  ice  in  such 
quantities,  that  they  were  compared  to  flocks  of  sheep  on  a  common ; 
and  they  are  often  found  on  field-ice,  above  two  hundred  miles  from  the 
shore."!  Wolves,  in  the  arctic  regions,  often  venture  upon  the  ice  near 
the  shore,  for  the  purpose  of  preying  upon  young  seals  which  they  sur- 
prise when  asleep.  When  these  ice-floes  get  detached,  the  wolves  are 
often  carried  out  to  sea ;  and  though  some  may  be  drifted  to  islands  or 
continents,  the  greater  part  of  them  perish,  and  have  been  often  heard 
in  this  situation  howling  dreadfully,  as  they  die  by  famine.^ 

During  the  short  summer  which  visits  Melville  Island,  various  plants 
push  forth  their  leaves  and  flowers  the  moment  the  snow  is  off  the 
ground,  and  form  a  carpet  spangled  with  the  most  lively  colours.  These 
secluded  spots  are  reached  annually  by  herds  of  musk-oxen  and  rein- 
deer, which  travel  immense  distances  over  dreary  and  desolate  regions, 
to  graze  undisturbed  on  these  luxuriant  pastures.§  The  rein-deer  often 
pass  along  in  the  same  manner,  by  the  chain  of  the  Aleutian  Islands, 
from  Behring's  Straits  to  Kamtschatka,  subsisting  on  the  moss  found  in 
these  islands  during  their  passage.||  But  the  musk-ox,  notwithstanding 
its  migratory  habits,  and  its  long  journeys  over  the  ice,  does  not  exist 
either  in  Asia  or  Greenland.^ 

On  floating  islands  of  drift-wood. — WTithin  the  tropics  there  are  no 
ice-floes ;  but,  as  if  to  compensate  for  that  mode  ©f  transportation,  there 
are  floating  islets  of  matted  trees,  which  are  often  borne  along  through 
considerable  spaces.  These  are  sometimes  seen  sailing  at  the  distance 
of  fifty  or  one  hundred  miles  from  the  mouth  of  the  Ganges,  with  living 
trees  standing  erect  upon  them.  The  Amazon,  the  Congo,  and  the 
Orinoco,  also  produce  these  verdant  rafts,  which  are  formed  in  the 
manner  already  described  when  speaking  of  the  great  raft  of  the  Atcha- 
falaya,  an  arm  of  the  Mississippi,  where  a  natural  bridge  of  timber,  ten 
miles  long,  and  more  than  two  hundred  yards  wide,  existed  for  more 
than  forty  years,  supporting  a  luxuriant  vegetation,  and  rising  and 
sinking  with  the  water  which  flowed  beneath  it. 

On  these  green  islets  of  "the  Mississippi,  observes  Malte-Brun,  young 
trees  take  root,  and  the  pistia  and  nenuphar  display  their  yellow 


*  Append,  to  Parry's  Second  Voyage,  vears  1819-20. 

•j-  Account  of  the  Arctic  Regions,  vol.  i.  p.  518. 

t  Turton  in  a  note  to  Goldsmith's  Nat.  Hist,  vol.  iii.  p.  43. 

8  Supplement  to  Parry's  First  Voyage  of  Discovery,  p.  189 

|  Goldman's  American  Nat.  Hist.  vol.  i.  p.  22. 

^  Dr.  Richardson,  Brit.  Assoc.  Report,  vol.  v.  p.  161. 


CH.  XXXVIII. ]  ON   FLOATING   ISLANDS.  641 

flowers : '  serpents,  birds,  and  the  cayman  alligator,  come  to  repose 
there,  and  all  are  sometimes  carried  to  the  sea  and  engulphed  in  its 
waters.* 

Spix  and  Martius  relate  that,  during  their  travels  in  Brazil,  they  were 
exposed  to  great  danger  while  ascending  the  Amazon  in  a  canoe,  from 
the  vast  quantity  of  drift-wood  constantly  propelled  against  them  by 
the  current ;  so  much  so,  that  their  safety  depended  on  the  crew  being 
always  on  the  alert  to  turn  aside  the  trunks  of  trees  with  long  poles. 
The  tops  alone  of  some  trees  appeared  above  water,  others  had  their 
roots  attached  to  them  with  so  much  soil  that  they  might  be  compared 
to  floating  islets.  On  these,  say  the  travellers,  we  saw  some  very 
singular  assemblages  of  animals,  pursuing  peacefully  their  uncertain 
way  in  strange  companionship.  On  one  raft  were  several  grave-looking 
storks,  perched  by  the  side  of  a  party  of  monkeys,  who  made  comical 
gestures,  and  burst  into  loud  cries,  on  seeing  the  canoe.  On  another 
was  seen  a  number  of  ducks  and  divers,  sitting  by  a  group  of  squirrels. 
Next  came  down  upon  the  stem  of  a  large  rotten  cedar  tree,  an  enormous 
crocodile,  by  the  side  of  a  tiger-cat,  both  animals  regarding  each  other 
with  hostility  and  mistrust,  but  the  saurian  being  evidently  most  at  his 
ease,  as  conscious  of  his  superior  strength.! 

Similar  green  rafts,  principally  composed  of  canes  and  brushwood, 
are  called  "  camelotes"  on  the  Parana  in  South  America ;  and  they  are 
occasionally  carried  down  by  inundations,  bearing  on  them  the  tiger, 
cayman,  squirrels,  and  other  quadrupeds,  which  are  said  to  be  always 
terror-stricken  on  their  floating  habitation.  No  less  than  four  tigers 
(pumas)  were  landed  in  this  mannner  in  one  night  at  Monte  Video,  lat. 
35°  S.,  to  the  great  alarm  of  the  inhabitants,  who  found  them  prowling 
about  the  streets  in  the  morning.  J 

In  a  memoir  lately  published,  a  naval  officer  relates  that,  as  he 
returned  from  China  by  the  eastern  passage,  he  fell  in,  among  the  Mo- 
luccas, with  several  small  floating  islands  of  this  kind,  covered  with  man- 
grove trees  interwoven  with  underwood.  The  trees  and  shrubs  retained 
their  verdure,  receiving  nourishment  from  a  stratum  of  soil  which  formed 
a  white  beach  round  the  margin  of  each  raft,  where  it  was  exposed  to 
the  washing  of  the  waves  and  the  rays  of  the  sun.§  The  occurrence 
of  soil  in  such  situations  may  easily  be  explained ;  for  all  the  natural 
bridges  of  timber  which  occasionally  connect  the  islands  of  the  Ganges, 
Mississippi,  and  other  rivers,  with  their  banks,  are  exposed  to  floods  of 
water,  densely  charged  with  sediment. 

Captain  W.  H.  Smyth  informs  me,  that,  when  cruising  in  the  Cora- 
wallis  amidst  the  Philippine  Islands,  he  has  more  than  once  seen,  after 
those  dreadful  hurricanes  called  typhoons,  floating  masses  of  wood,  with 


*  System  of  Geography,  vol.  v.  p.  157. 
f  Spix  and  Martius,  Reise,  <fcc.,  vol.  iii. 

4-     Qi*»     "Y\T      t>,,^,,"L>,     "O^,  „,       „      A  •»•»  »>.      1  Q 


Spix  and  Martius,  Reise,  <fec.,  vol.  iii.  pp.  1011.  1013. 

Sir  W.  Parish's  Buenos  Ay  res,  p.  187.,  and  Robertson's  Letters  on  Para- 
guay, p.  220. 

§  United  Service  Journal,  No.  xxiv.  p.  697. 

41 


642  MIGRATIONS   OP  THE   CETACEA.  [Ca  XXXVIIL 

trees  growing  upon  them,  and  ships  have  sometimes  been  in  imminent 
peril,  as  often  as  these  islands  were  mistaken  for  terra  firma,  when,  in 
fact,  they  were  in  rapid  motion. 

It  is  highly  interesting  to  trace,  in  imagination,  the  effects  of  the 
passage  of  these  rafts  from  the  mouth  of  a  large  river  to  some  archi- 
pelago, such  as  those  in  the  South  Pacific,  raised  from  the  deep,  in  com- 
paratively modern  times,  by  the  operations  of  the  volcano  and  the  earth- 
quake, and  the  joint  labours  of  coral  animals  and  testacea.  If  a  storm 
arise,  and  the  frail  vessel  be  wrecked,  still  many  a  bird  and  insect  may 
succeed  in  gaining,  by  flight,  some  island  of  the  newly  formed  group, 
while  the  seeds  and  berries  of  herbs  and  shrubs,  which  fall  into  the 
waves,  may  be  thrown  upon  the  strand.  But  if  the  surface  of  the  deep 
be  calm,  and  the  rafts  are  carried  along  by  a  current,  or  wafted  by  some 
slight  breath  of  air  fanning  the  foliage  of  the  green  trees,  it  may  arrive, 
after  a  passage  of  several  weeks,  at  the  bay  of  an  island,  into  which  its 
plants  and  animals  may  be  poured  out  as  from  an  ark,  and  thus  a  colony 
of  several  hundred  new  species  may  at  once  be  naturalized. 

The  reader  should  be  reminded,  that  I  merely  advert  to  the  transpor- 
tation of  these  rafts  as  of  extremely  rare  and  accidental  occurrence  ;  but 
it  may  account,  in  tropical  countries,  for  some  of  the  rare  exceptions  to 
the  general  law  of  the  confined  range  of  mammiferous  species. 

Migrations  of  the  Cetacea. — Many  of  the  Cetacea,  the  whales  of  the 
northern  seas  for  example,  are  found  to  desert  one  tract  of  the  sea,  and 
to  visit  another  very  distant,  when  they  are  urged  by  want  of  food,  or 
danger.  The  seals  also  retire  from  the  coast  of  Greenland  in  July,  return 
again  in  September,  and  depart  again  in  March,  to  return  in  June.  They 
proceed  in  great  droves  northwards,  directing  their  course  where  the  sea 
is  most  free  from  ice,  and  are  observed  to  be  extremely  fat  when  they 
set  out  on  this  expedition,  and  very  lean  when  they  come  home  again.* 

Species  of  the  Mediterranean,  Black  Sea,  and  Caspian  identical. — 
Some  naturalists  have  wondered  that  the  sea-calves,  dolphins,  and  other 
marine  mammalia  of  the  Mediterranean  and  Black  Sea,  should  be  iden- 
tical with  those  found  in  the  Caspian  :  and  among  other  fanciful  theories, 
they  have  suggested  that  they  may  dive  through  subterranean  conduits, 
and  thus  pass  from  one  sea  into  the  other.  But  as  the  occurrence  of 
wolves  and  other  noxious  animals,  on  both  sides  of  the  British  Channel, 
was  adduced,  by  Verstegan  and  Desmarest,  as  one  of  many  arguments 
to  prove  that  England  and  France  were  once  united  ;  so  the  correspon- 
dence of  the  aquatic  species  of  the  inland  seas  of  Asia  with  those  of  the 
Black  Sea  tend  to  confirm  the  hypothesis,  for  which  there  are  abundance 
of  independent  geological  data,  that  those  seas  were  connected  together 
by  straits  at  no  remote  period  of  the  earth's  history. 

Geographical  Distribution  and  Migrations  of  Birds. 
I  shall  now  offer  a  few  observations  on  some  of  the  other  divisions  of 
*  Krantz,  vol.  i.  p.  129.,  cited  by  Goldsmith,  Nat.  Hist,  vol.  iii.  p.  260. 


Ca  XXXVIIL]      GEOGRAPHICAL   DISTRIBUTION   OF   BIRDS.  643 

the  animal  kingdom.  Birds,  notwithstanding  their  great  locomotive 
powers,  form  no  exception  to  the  general  rules  already  laid  down  ;  but, 
in  this  class,  as  in  plants  and  terrestrial  quadrupeds,  different  groups  of 
species  are  circumscribed  within  definite  limits.  We  find,  for  example, 
one  assemblage  in  the  Brazils,  another  in  the  same  latitudes  in  Central 
Africa,  another  in  India,  and  a  fourth  in  New  Holland.  Of  twenty-six 
different  species  of  land  birds  found  in  the  Galapagos  archipelago,  all, 
with  the  exception  of  one,  are  distinct  from  those  inhabiting  other  parts 
of  the  globe;*  and  in  other  archipelagos  a  single  island  sometimes  con- 
tains a  species  found  in  no  other  spot  on  the  whole  earth  ;  as  is  exem- 
plified in  some  of  the  parrot  tribes.  In  this  extensive  family,  which  are, 
with  few  exceptions,  inhabitants  of  tropical  regions,  the  American  group 
has  not  one  in  common  with  the  African,  nor  either  of  these  with  the 
parrots  of  India  .f 

Another  illustration  is  afforded  by  that  minute  and  beautiful  tribe, 
the  humming-birds.  The  whole  of  them  are,  in  the  first  place,  peculiar 
to  the  new  world ;  but  some  species  are  confined  to  Mexico,  while 
others  exist  only  in  some  of  the  West  India  Islands,  and  have  not 
been  found  elsewhere  in  the  western  hemisphere.  Yet  there  are  spe- 
cies of  this  family  which  have  a  vast  range,  as  the  Trochilus  flam- 
mifrons  (or  Mellisuga  Kingii),  which  is  found  over  a  space  of  2500 
miles  on  the  west  coast  of  South  America,  from  the  hot  dry  country 
of  Lima  to  the  humid  forests  of  Tierra  del  Fuego.  Captain  King, 
during  his  survey  in  the  years  1826-30,  found  this  bird  at  the  Straits 
of  Magellan,  in  the  month  of  May — the  depth  of  winter — sucking  the 
flowers  of  a  large  species  of  fuchsia,  then  in  bloom,  in  the  midst  of  a 
shower  of  snow. 

The  ornithology  of  our  own  country  affords  one  well-known  and 
striking  exemplification  of  the  law  of  a  limited  specific  range ;  for  the 
common  grouse  (Tetra  scoticus)  occurs  nowhere  in  the  known  world 
except  in  the  British  isles. 

Some  species  of  the  vulture  tribe  are  said  to  be  cosmopolites;  and 
the  common  wild  goose  (Anas  anser,  Linn.),  if  we  may  believe  some 
ornithologists,  is  a  general  inhabitant  of  the  globe,  being  met  with  from 
Lapland  to  the  Cape  of  Good  Hope,  frequent  in  Arabia,  Persia,  China, 
and  Japan,  and  in  the  American  continent  from  Hudson's  Bay  to  South 
Carolina.  |  An  extraordinary  range  has  also  been  attributed  to  the 
nightingale,  which  extends  from  western  Europe  to  Persia,  and  still  far- 
ther. In  a  work  entitled  Specchio  Comparativo,§  by  Charles  Bonaparte, 
many  species  of  birds  are  enumerated  as  common  to  Rome  and  Phila- 
delphia :  the  greater  part  of  these  are  migratory,  but  some  of  them, 
such  as  the  long-eared  owl  (Strix  otus),  are  permanent  in  both  countries. 
The  correspondence  of  the  ornithological  fauna  of  the  eastern  and 

*  Darwin's  Journal,  <fec.,  p.  461. 

f  Prichard,  vol.  i.  p.  47. 

j  Bewick's  Birds,  voL  ii.  p.  294.,  who  cites  Latham. 

§  Pisa,  1827  (not  sold). 


644  GEOGRAPHICAL   DISTRIBUTION   AND          [Ca  XXXVIII. 

western  hemispheres  increases  considerably,  as  might  have  been  antici- 
pated, in  high  northern  latitudes.  * 

Their  facilities  of  diffusion. — In  parallel  zones  of  the  northern  and 
southern  hemispheres,  a  great  general  correspondence  of  form  is 
observable,  both  in  the  aquatic  and  terrestrial  birds ;  but  there  is  rarely 
any  specific  identity ;  and  this  phenomenon  is  truly  remarkable,  when 
we  recollect  the  readiness  with  which  some  birds,  not  gifted  with  great 
powers  of  flight,  shift  their  quarters  to  different  regions,  and  the  faci- 
lity with  which  others,  possessing  great  strength  of  wing,  perform  their 
aerial  voyage.  Some  migrate  periodically  from  high  latitudes,  to  avoid 
the  cold  of  winter,  and  the  accompaniments  of  cold, — scarcity  of  insects 
and  vegetable  food ;  others,  it  is  said,  for  some  particular  kinds  of  nutri- 
ment required  for  rearing  their  young :  for  this  purpose  they  often  tra- 
verse the  ocean  for  thousands  of  miles,  and  recross  it  at  other  periods, 
with  equal  security. 

Periodical  migrations,  no  less  regular,  are  mentioned  by  Humboldt, 
of  many  American  water-fowl,  from  one  part  of  the  tropics  to  another, 
in  a  zone  where  there  is  the  same  temperature  throughout  the  year. 
Immense  flights  of  ducks  leave  the  valley  of  the  .Orinoco,  when  the 
increasing  depth  of  its  waters  and  the  flooding  of  its  shores  prevent 
them  from  catching  fish,  insects,  and  aquatic  worms.  They  then  betake 
themselves  to  the  Kio  Negro  and  Amazon,  having  passed  from  the 
eighth  and  third  degrees  of  north  latitude  to  the  first  and  fourth  of  south 
latitude,  directing  their  course  south-south-east.  In  September,  when 
the  Orinoco  decreases  and  re-enters  its  channel,  these  birds  return  north- 
wards, f 

The  insectivorous  swallows  which  visit  our  island  would  perish  during 
winter,  if  they  did  not  annually  repair  to  warmer  climes.  It  is  supposed 
that  in  these  aerial  excursions  the  average  rapidity  of  their  flight  is  not 
less  than  fifty  miles  an  hour ;  so  that,  when  aided  by  the  wind,  they 
soon  reach  warmer  latitudes.  Spallanzani  calculated  that  the  swallow 
can  fly  at  the  rate  of  ninety-two  miles  an  hour,  and  conceived  that  the 
rapidity  of  the  swift  might  be  three  times  greater.];  The  rate  of  flight 
of  the  eider  duck  (Anas  mollissima)  is  said  to  be  ninety  miles  an  hour ; 
and  Bachman  says  that  the  hawk,  wild  pigeon  (Columba  migratoria), 
and  several  species  of  wild  ducks,  in  North  America,  fly  at  the  rate  of 
forty  miles  an  hour,  or  nearly  a  thousand  miles  in  twenty-four  hours.  § 

When  we  reflect  how  easily  different  species,  in  a  great  lapse  of  ages, 
may  be  each  overtaken  by  gales  and  hurricanes,  and,  abandoning  them- 
selves to  the  tempest,  be  scattered  at  random  through  various  regions 
of  the  earth's  surface,  where  the  temperature  of  the  atmosphere,  the 
vegetation,  and  the  animal  productions,  might  be  suited  to  their  wants, 
we  shall  be  prepared  to  find  some  species  capriciously  distributed,  and 

*  Bachman,  Silliman's  Amer.  Journ.,  No.  61,  p.  92. 
\  Voyage  aux  Regions  Equinoxiales,  tome  vil  p.  429. 
1  Fleming,  PhiL  Zool.,  vol.  ii.  p.  43. 
§  Silliman's  Amer.  Journ.,  No.  61.  p.  83. 


CH.  XXXVIIL]  DISSEMINATION   OP   REPTILES.  645 

to  be  sometimes  unable  to  determine  the  native  countries  of  each. 
Captain  Smyth  informs  me,  that,  when  engaged  in  his  survey  of  the 
Mediterranean,  he  encountered  a  gale  in  the  Gulf  of  Lyons,  at  the  dis- 
tance of  between  twenty  and  thirty  leagues  from  the  coast  of  France, 
which  bore  along  many  land  birds  of  various  species,  some  of  which 
alighted  on  the  ship,  while  others  were  thrown  with  violence  against  the 
sails.  In  this  manner  islands  become  tenanted  by  species  of  birds 
inhabiting  the  nearest  mainland. 

Geographical  Distribution  and  Dissemination  of  Reptiles. 

A  few  facts  respecting  the  third  great  class  of  vertebrated  animals 
will  suffice  to  show  that  the  plan  of  nature  in  regard  to  their  location 
on  the  globe  is  perfectly  analogous  to  that  already  exemplified  in  other 
parts  of  the  organic  creation,  and  has  probably  been  determined  by 
similar  causes. 

Habitations  of  reptiles. — Of  the  great  saurians,  the  gavials  which 
inhabit  the  Ganges  differ  from  the  cayman  of  America,  or  the  crocodile 
of  the  Nile.  The  monitor  of  New  Holland  is  specifically  distinct  from 
the  Indian  species ;  these  latter,  again,  from  the  African,  and  all  from 
their  congeners  in  the  new  world.  So  in  regard  to  snakes ;  we  find  the 
boa  of  America  represented  by  the  python,  a  different  though  nearly 
allied  genus  in  India.  America  is  the  country  of  the  rattlesnake ; 
Africa,  of  the  cerastes;  and  Asia,  of  the  hooded  snake,  or  cobra  di 
capello.  The  amphibious  genera  Siren  and  Menopoma  belong  to  North 
America,  possessing  both  lungs  and  gills,  and  respiring  at  pleasure 
either  air  or  water.  The  only  analogous  animal  of  the  old  world  is 
the  Proteus  anguinus  of  the  lakes  of  Lower  Carniola,  and  the  grotto  of 
Adelsberg  between  Trieste  and  Vienna.* 

There  is  a  legend  that  St.  Patrick  expelled  all  reptiles  from  Ireland ; 
and  certain  it  is  that  none  of  the  three  species  of  snakes  common  in 
England,  nor  the  toad,  have  been  observed  there  by  naturalists.  They 
have  our  common  frog,  and  our  water-newt,  and  according  to  Ray 
(Quad.  264.),  the  green  lizard  (Lacerta  viridis). 

Migrations  of  the  larger  reptiles. — The  range  of  the  large  reptiles  is, 
in  general,  quite  as  limited  as  that  of  some  orders  of  the  terrestrial 
mammalia.  The  great  saurians  sometimes  cross  a  considerable  tract  in 
order  to  pass  from  one  river  to  another ;  but  their  motions  by  land  are 
generally  slower  than  those  of  quadrupeds.  By  water,  however,  they 
may  transport  themselves  to  distant  situations  more  easily.  The  larger 
alligator  of  the  Ganges  sometimes  descends  beyond  the  brackish  water 
of  the  delta  into  the  sea ;  and  in  such  cases  it  might  chance  to  be 
drifted  away  by  a  current,  and  survive  till  it  reached  a  shore,  at  some 
distance ;  but  such  casualties  are  probably  very  rare. 

Turtles  migrate  in  large  droves  from  one  part  of  the  ocean  to  another 

*  Richardson,  Brit.  Assoc.  Rep.,  vol.  v.  p.  202. 


646  GEOGRAPHICAL  DISTRIBUTION  AND        [On.  XXXIX. 

during  the  ovipositing  season ;  ancj.  they  find  their  way  annually  to  the 
island  of  Ascension,  from  which  the  nearest  land  is  about  800  miles 
distant.  Dr.  Fleming  mentions,  that  an  individual  of  the  hawk's  bill 
turtle  (Chelonia  imbricata),  so  common  in  the  American  seas,  has  been 
taken  at  Papa  Stour,  one  of  the  West  Zetland  Islands  ;*  and,  according 
to  Sibbald,  "  the  same  animal  came  into  Orkney."  Another  was  taken, 
in  1774,  in  the  Severn,  according  to  Turton.  Two  instances,  also,  of 
the  occurrence  of  the  leathern  tortoise  (C.  coriacea),  on  the  coast  of 
Cornwall,  in  1756,  are  mentioned  by  Borlase.  These  animals  of  more 
southern  seas  can  be  considered  only  as  stragglers,  attracted  to  our 
shores  during  uncommonly  warm  seasons  by  an  abundant  supply  of  food, 
or  carried  by  the  Gulf  stream,  or  driven  by  storms  to  high  latitudes. 

Some  of  the  smaller  reptiles  lay  their  eggs  on  aquatic  plants ;  and 
these  must  often  be  borne  rapidly  by  rivers,  and  conveyed  to  distant 
regions  in  a  manner  similar  to  the  dispersion  of  seeds  before  adverted  to. 
But  that  the  larger  ophidians  may  be  themselves  transported  across  the 
seas,  is  evident  from  the  following  most  interesting  account  of  the  arrival 
of  one  at  the  island  of  St.  Vincent.  It  is  worthy  of  being  recorded,  says 
Mr.  Guilding,  "  that  a  noble  specimen  of  the  Boa  constrictor  was  lately 
conveyed  to  us  by  the  currents,  twisted  round  the  trunk  of  a  large  sound 
cedar  tree,  which  had  probably  been  washed  out  of  the  bank  by  the 
floods  of  some  great  South  American  river,  while  its  huge  folds  hung  on 
the  branches,  as  it  waited  for  its  prey.  The  monster  was  fortunately 
destroyed  after  killing  a  few  sheep,  and  his  skeleton  now  hangs  before 
me  in  my  study,  putting  me  in  mind  how  much  reason  I  might  have  had 
to  fear  in  my  future  rambles  through  the  forests  of  St.  Vincent,  had  this 
formidable  reptile  been  a  pregnant  female,  and  escaped  to  a  safe  retreat.'1f 


CHAPTER  XXXIX. 

LAWS    WHICH    REGULATE    THE    GEOGRAPHICAL   DISTRIBUTION    OF 

SPECIES — continued. 

Geographical  distribution  and  migration  of  Fish — of  Testacea — of  Zoophytes — 
Distribution  of  Insects — Migratory  instincts  of  some  species — Certain  types 
characterize  particular  countries — Their  means  of  dissemination — Geographi- 
cal distribution  and  diffusion  of  man — Speculations  as  to  the  birth-place  of 
the  human  species — Progress  of  human  population — Drifting  of  canoes  to  vast 
distances — On  the  involuntary  influence  of  man  in  extending  the  range  of 
many  other  species. 

Geographical  Distribution  and  Migrations  of  Fish. 
• 

ALTHOUGH  we  are  less  acquainted  with  the  habitations  of  marine  animals 
than  with  the  grouping  of  the  terrestrial  species  before  described,  yet  it 

*  Brit.  Animals,  p.  149.,  who  cites  Sibbald. 
f  Zool.  Journ.  vol.  iii.  p.  406.     Dec.  1827. 


CH.  XXXIX.]  MIGRATION   OF   FISH.  647 

is  well  ascertained  that  their  distribution  is  governed  by  the  same  general 
laws.  The  testimony  borne  by  MM.  Peron  and  Lesueur  to  this  important 
fact  is  remarkably  strong.  These  eminent  naturalists,  after  collecting  and 
describing  many  thousand  species  of  marine  animals  which  they  brought 
to  Europe  from  the  southern  hemisphere,  insist  most  emphatically  on 
their  distinctness  from  those  north  of  the  equator ;  and  this  remark  they 
extend  to  animals  of  all  classes,  from  those  of  a  more  simple  to  those  of 
a  more  complex  organization — from  the  sponges  and  Medusae  to  the 
Cetacea.  "  Among  all  those  which  we  have  been  able  to  examine,"  say 
they,  "  with  our  own  eyes,  or  with  regard  to  which  it  has  appeared  to  us 
possible  to  pronounce  with  certainty,  there  is  not  a  single  animal  of  the 
southern  regions  which  is  not  distinguished  by  essential  characters  from 
the  analogous  species  in  the  northern  seas."* 

On  comparing  the  freshwater  fish  of  Europe  and  North  America,  Sir 
John  Richardson  remarks,  that  the  only  species  which  is  unequivocally 
common  to  the  two  continents  is  the  pike  (Esox  Indus) ;  and  it  is  curious 
that  this  fish  is  unknown  to  the  westward  of  the  Rocky  Mountains,  the 
very  coast  which  approaches  nearest  to  the  old  continent.f  According 
to  the  same  author  the  genera  of  freshwater  fish  in  China  agree  closely 
with  those  of  the  peninsula  of  India,  but  the  species  are  not  the  same. 
"  As  in  the  distribution,"  he  adds,  "  of  marine  fish,  the  interposition  of  a 
continent  stretching  from  the  tropics  far  into  the  temperate  or  colder 
parts  of  the  ocean,  separate  different  ichthyological  groups ;  so  with  respect 
to  the  freshwater  species,  the  intrusion  of  arms  of  the  sea  running  far  to 
the  northwards,  or  the  interposition  of  a  lofty  mountain-chain,  effects  the 
same  thing.  The  freshwater  fish  of  the  Cape  of  Good  Hope  and  the 
South  American  ones,  are  different  from  those  of  India  and  China,  &c."J 

Cuvier  and  Valenciennes,  in  their  "  Histoire  des  Poissons,"  observe, 
that  very  few  species  of  fish  cross  the  Atlantic.  Although  their  state- 
ment is  correct,  it  is  found  that  a  great  many  species  are  common  to  the 
opposite  sides  of  the  Indian  Ocean,  inhabiting  alike  the  Red  Sea,  the 
eastern  coast  of  Africa,  Madagascar,  the  Mauritius,  the  Indian  Ocean, 
the  southern  seas  of  China,  the  Malay  archipelago,  the  northern  coasts 
of  Australia,  and  the  whole  of  Polynesia  !§  This  very  wide  diffusion, 
says  Sir  J.  Richardson,  may  have  been  promoted  by  chains  of  islands 
running  east  and  west,  which  are  wanting  in  the  deep  Atlantic.  An 
archipelago  extending  far  in  longitude,  favours  the  migration  of  fish  by 
multiplying  the  places  of  deposit  for  spawn  along  the  shores  of  islands, 
and  on  intervening  coral  banks  ;  and  in  such  places,  also,  fish  find  their 
appropriate  food. 

The  flying  fish  are  found  (some  stragglers  excepted)  only  between  the 
tropics :  in  receding  from  the  line,  they  never  approach  a  higher  latitude 

*  Sur  les  Habitations  des  Animaux  Marins. — Ann.  du  Mus.,[tome.  xv.,  cited  by 
Prichard,  Phys.  Hist,  of  Mankind,  vol.  i.  p.  61. 
f  Brit.  Assoc.  Reports,  vol.  v.  p.  203. 
\  Report  to  the  Brit  Assoc.,  1845,  p.  192. 
§  Richardson,  ibid.  p.  190. 


648  GEOGRAPHICAL   DISTRIBUTION   AND         [Cn.  XXXIX. 

than  the  fortieth  parallel.  The  course  of  the  Gulf  stream,  however,  and 
the  warmth  of  its  water,  enable  some  tropical  fish  to  extend  their  habita- 
tions far  into  the  temperate  zone  ;  thus  the  chaetodons  which  abound  in 
the  seas  of  hot  climates,  are  found  among  the  Bermudas  on  the  thirty- 
second  parallel,  where  they  are  preserved  in  basins  inclosed  from  the  sea, 
as  an  important  article  of  food  for  the  garrison  and  inhabitants.  Other 
fish,  following  the  direction  of  the  same  great  current,  range  from  the 
coast  of  Brazil  to  the  banks  of  Newfoundland.* 

All  are  aware  that  there  are  certain  fish  of  passage  which  have  their 
periodical  migrations,  like  some  tribes  of  birds.  The  salmon,  towards 
the  season  of  spawning,  ascends  the  rivers  for  hundreds  of  miles,  leaping 
up  the  cataracts  which  it  meets  in  its  course,  and  then  retreats  again 
into  the  depths  of  the  ocean.  The  herring  and  the  haddock,  after  fre- 
quenting certain  shores,  in  vast  shoals,  for  a  series  of  years,  desert  them 
again,  and  resort  to  other  stations,  followed  by  the  species  which  prey  on 
them.  Eels  are  said  to  descend  into  the  sea  for  the  purpose  of  producing 
their  young,  which  are  seen  returning  into  the  fresh  water  by  myriads, 
extremely  small  in  size,  but  possessing  the  power  of  surmounting  every 
obstacle  which  occurs  in  the  course  of  a  river,  by  applying  their  slimy 
and  glutinous  bodies  to  the  surface  of  rocks,  or  the  gates  of  a  lock,  even 
when  dry,  and  so  climbing  over  it.f  Before  the  year  1800  there  were  no 
eels  in  Lake  Wener,  the  largest  inland  lake  in  Sweden,  which  discharges 
its  waters  by  the  celebrated  cataracts  of  Trolhattan.  But  I  am  informed 
by  Professor  Nilsson,  that  since  the  canal  was  opened  uniting  the  river 
Gotha  with  the  lake  by  a  series  of  nine  locks,  each  of  great  height,  eels 
have  been  observed  in  abundance  in  the  lake.  It  appears,  therefore,  that 
though  they  were  unable  to  ascend  the  falls,  they  have  made  their  way 
by  the  locks,  by  which  in  a  very  short  space  a  difference  of  level  of  114 
feet  is  overcome. 

Gmelin  says,  that  the  Anseres  (wild  geese,  ducks,  and  others)  subsist, 
in  their  migrations,  on  the  spawn  of  fish  ;  and  that  oftentimes,  when 
they  void  the  spawn,  two  or  three  days  afterwards,  the  eggs  retain  their 
vitality  unimpaired.];  When  there  are  many  disconnected  freshwater 
lakes  in  a  mountainous  region,  at  various  elevations,  each  remote  from 
the  other,  it  has  often  been  deemed  inconceivable  how  they  could  all 
become  stocked  with  fish  from  one  common  source  ;  but  it  has  been  sug- 
gested, that  the  minute  eggs  of  these  animals  may  sometimes  be  entan- 
gled in  the  feathers  of  water-fowl.  These,  when  they  alight  to  wash 
and  plume  themselves  in  the  water,  may  often  unconsciously  con- 
tribute to  propagate  swarms-  of  fish,  which,  in  due  season,  will  supply 
them  with  food.  Some  of  the  water-beetles,  also,  as  the  Dyticidae,  are 
amphibious,  and  in  the  evening  quit  their  lakes  and  pools,  and,  flying  in 
the  air,  transport  the  minute  ova  of  fishes  to  distant  waters.  In  this 
manner  some  naturalists  account  for  the  fry  of  fish  appearing  occasion- 


*  Sir  J.  Richardson,  ibid.  p.  190.  f  Phil.  Trans.  1747,  p.  395. 

J  Amoen.  Acad.,  Essay  75. 


CIL  XXXIX.]  MIGRATIONS   OF   TESTACEA.  649 

ally  in  small  pools  caused  by  heavy  rains ;  but  the  showers  of  small  fish, 
stated  in  so  many  accounts  to  have  fallen  from  the  atmosphere,  require 
farther  investigation. 

Geographical  Distribution  and  Migrations  of  Testacea. 

The  Testacea,  of  which  so  great  a  variety  of  species  occurs  in  the  sea, 
are  a  class  of  animals  of  peculiar  importance  to  the  geologist ;  because 
their  remains  are  found  in  strata  of  all  ages,  and  generally  in  a  higher 
state  of  preservation  than  those  of  other  organic  beings.  Climate  has 
a  decided  influence  on  the  geographical  distribution  of  species  in  this 
class ;  but  as  there  is  much  greater  uniformity  of  temperature  in  the 
waters  of  the  ocean,  than  in  the  atmosphere  which  invests  the  land,  the 
diffusion  of  marine  mollusks  is  on  the  whole  more  extensive. 

Some  forms  attain  their  fullest  development  in  warm  latitudes ;  and 
are  often  exclusively  confined  to  the  torrid  zone,  as  Nautilus,  Harpa, 
Terebellum,  Pyramidella,  Delphinula,  Aspergillum,  Tridacna,  Cucullcea, 
Crassatella,  Corbis,  Perna,  and  Plicatula.  Other  forms  are  limited  to 
one  region  of  the  sea,  as  the  Trigonia  to  parts  of  Australia,  and  the 
Concholepas  to  the  western  coast  of  South  America.  The  marine  species 
inhabiting  the  ocean  on  the  opposite  sides  of  the  narrow  isthmus  of 
Panama,  are  found  to  differ  almost  entirely,  as  we  might  have  antici- 
pated, since  a  West  Indian  mollusk  cannot  enter  the  Pacific  without 
coasting  round  South  America,  and  passing  through  the  inclement  cli- 
mate of  Cape  Horn.  The  continuity  of  the  existing  lines  of  continent 
from  north  to  south,  prevents  any  one  species  from  belting  the  globe,  or 
from  following  the  direction  of  the  isothermal  lines. 

Currents  also  flowing  permanently  in  certain  directions,  and  the  influx 
at  certain  points  of  great  bodies  of  fresh  water,  limit  the  extension  of 
many  species.  Those  which  love  deep  water  are  arrested  by  shoals ; 
others,  fitted  for  shallow  seas,  cannot  migrate  across  unfathomable  abyss- 
es. The  nature  also  of  the  ground  has  an  important  influence  on  the 
testaceous  fauna,  both  on  the  land  and  beneath  the  waters.  Certain 
species  prefer  a  sandy,  others  a  gravelly,  and  some  a  muddy  sea-bottom. 
On  the  land,  limestone  is  of  all  rocks  the  most  favourable  to  the  number 
and  propagation  of  species  of  the  genera  Helix,  Clausilia,  Bulimus,  and 
others.  Professor  E.  Forbes  has  shown  as  the  result  of  his  labours  in 
dredging  in  the  JEgean  Sea,  that  there  are  eight  well-marked  regions  of 
depth,  each  characterized  by  its  peculiar  testaceous  fauna.  The  first  of 
these,  called  the  littoral  zone,  extends  to  a  depth  of  two  fathoms  only ; 
but  this  narrow  belt  is  inhabited  by  more  than  one  hundred  species. 
The  second  region,  of  which  ten  fathoms  is  the  inferior  limit,  is  almost 
equally  populous ;  and  a  copious  list  of  species  is  given  as  characteris- 
tic of  each  region  down  to  the  seventh,  which  lies  between  the  depths 
of  80  and  105  fathoms,  all  the  inhabited  space  below  this  being  included 
in  the  eighth  province,  where  no  less  than  65  species  of  Testacea  have 
been  taken.  The  majority  of  the  shells  in  this  lowest  zone  are  white  or 


650  GEOGRAPHICAL   DISTRIBUTION   AND         [Cn.  XXXIX. 

transparent.     Only  two  species  of  Mollusca  are  common  to  all  the  eight 
regions,  namely,  Area  lactea  and  Cerithium  lima* 

Great  range  of  some  provinces  and  species. — In  Europe  conchologists 
distinguish  between  the  arctic  fauna,  the  southern  boundary  of  which 
corresponds  with  the  isothermal  line  of  32°  F.,  and  the  Celtic,  which, 
commencing  with  that  limit  as  its  northern  frontier,  extends  southwards 
to  the  mouth  of  the  English  Channel  and  Cape  Finisterre,  in  France. 
From  that  point  begins  the  Lusitanian  fauna,  which,  according  to  the 
recent  observations  of  Mr.  M'Andrew  (1852),  ranges  to  the  Canary 
Islands.  The  Mediterranean  province  is  distinct  from  all  those  above 
enumerated,  although  it  has  some  species  in  common  with  each. 

The  Indo-Pacific  region  is  by  far  the  most  extensive  of  all.  It  reaches 
from  the  Red  Sea  and  the  eastern  coast  of  Africa,  to  the  Indian  Archi- 
pelago, and  adjoining  parts  of  the  Pacific  Ocean.  To  the  geologist  it 
furnishes  a  fact  of  no  small  interest,  by  teaching  us  that  one  group  of 
living  species  of  mollusca  may  prevail  throughout  an  area  exceeding  in 
magnitude  the  utmost  limits  we  can  as  yet  assign  to  any  assemblage  of 
contemporaneous  fossil  species.  Mr.  Cuming  obtained  more  than  a 
hundred  species  of  shells  from  the  eastern  coast  of  Africa  identical  with 
those  collected  by  himself  at  the  Philippines  and  in  the  eastern  coral 
islands  of  the  Pacific  Ocean,  a  distance  equal  to  that  from  pole  to  pole.f 

Certain  species  of  the  genus  lanthina  have  a  very  wide  range,  being 
common  to  seas  north  and  south  of  the  equator.  They  are  all  provided 
with  a  beautifully  contrived  float,  which  renders  them  buoyant,  facilitating 
their  dispersion,  and  enabling  them  to  become  active  agents  in  dissemi- 
nating other  species.  Captain  King  took  a  specimen  of  lanthina  fragilis, 
alive,  a  little  north  of  the  equator,  so  loaded  with  barnacles  (Pentelasmis) 
and  their  ova  that  the  upper  part  of  its  shell  was  invisible.  The  "  Rock 
Whelk"  (Purpura  lapillus),  a  well-known  British  univalve,  inhabits 
both  the  North  Atlantic  and  North  Pacific. 

Helix  putris  (Succinea  putris,  Lam.),  so  common  in  Europe,  where  it 
reaches  from  Norway  to  Italy,  is  also  said  to  occur  in  the  United  States 
and  in  Newfoundland.  As  this  animal  inhabits  constantly  the  borders  of 
pools  and  streams  where  there  is  much  moisture,  it  is  not  impossible  that 
different  water-fowl  have  been  the  agents  of  spreading  some  of  its 
minute  eggs,  which  may  have  been  entangled  in  their  feathers.  The 
freshwater  snail,  Lymneus  palustris,  so  abundant  in  English  ponds, 
ranges  uninterruptedly  from  Europe  to  Cashmere,  and  thence  to  the 
eastern  parte  of  Asia.  Helix  aspersa,  one  of  the  commonest  of  our 
larger  land-shells,  is  found  -in  St.  Helena  and  other  distant  countries. 
Some  conchologists  have  conjectured  that  it  was  accidentally  imported  into 
St.  Helena  in  some  ship ;  for  it  is  an  eatable  species,  and  these  animals  are 
capable  of  retaining  life  during  long  voyages,  without  air  or  nourishment.  J 

*  Report  to  the  Brit.  Assoc.  1843,  p.  130. 
j  Quart.  Journ.,  Geol.  Soc.,  1846,  vol.  ii.  p.  268. 

\.  Four  individuals  of  a  large  species  of  land  shell  (Bulimus),  from  Valparaiso, 
were  brought  to  England  by  Lieutenant  Graves,  who  accompanied  Captain 


CH.  XXXIX.]  MIGRATIONS   OF   TESTACEA.  651 

Perhaps  no  species  has  a  better  claim  to  be  called  cosmopolite  than 
one  of  our  British  bivalves,  Saxicava  rugosa.  It  is  spread  over  all  the 
north-polar  seas,  and  ranges  in  one  direction  through  Europe  to  Senegal, 
occurring  on  both  sides  of  the  Atlantic  ;  while  in  another  it  finds  its  way 
into  the  North  Pacific,  and  thence  to  the  Indian  Ocean.  Nor  do  its 
migrations  cease  till  it  reaches  the  Australian  seas. 

A  British  brachiopod,  named  Terebratula  caput-serpentis,  is  common, 
according  to  Professor  E.  Forbes,  to  both  sides  of  the  North  Atlantic, 
and  to  the  South  African  and  Chinese  seas. 

Confined  range  of  other  species. — Mr.  Lowe,  in  a  memoir  published 
in  the  Cambridge  Transactions  in  1834,  enumerates  seventy-one  species 
of  land  Mollusca,  collected  by  him  in  the  islands  of  Madeira  and  Porto 
Santo,  sixty  of  which  belonged  to  the  genus  Helix  alone,  including  as 
sub-genera  Bulimus  and  Achatina,  and  excluding  Vitrina  and  Clausilia ; 
forty-four  of  these  are  new.  It  is  remarkable  that  very  few  of  the 
above-mentioned  species  are  common  to  the  neighbouring  archipelago  of 
the  Canaries  ;  but  it  is  a  still  more  striking  fact,  that  of  the  sixty  species 
of  the  three  genera  above  mentioned,  thirty-one  are  natives  of  Porto 
Santo ;  whereas,  in  Madeira,  which  contains  ten  times  the  superficies, 
were  found  but  twenty-nine.  Of  these  only  four  were  common  to  the 
two  islands,  which  are  separated  by  a  distance  of  only  twelve  leagues  ; 
and'  two  even  of  these  four  (namely  Helix  rhodostoma  and  H.  ventrosa) 
are  species  of  general  diffusion,  common  to  Madeira,  the  Canaries,  and 
the  south  of  Europe.* 

The  confined  range  of  these  mollusks  may  easily  be  explained,  if  we 
admit  that  species  have  only  one  birth-place ;  and  the  only  problem  to  be 
solved  would  relate  to  the  exceptions — to  account  for  the  dissemination 
of  some  species  throughout  several  islands,  and  the  European  continent. 
May  not  the  eggs,  when  washed  into  the  sea  by  the  undermining  of 
cliffs,  or  blown  by  a  storm  from  the  land,  float  uninjured  to  a  distant  shore  ? 

Their  mode  of  diffusion. — Notwithstanding  the  proverbially  slow 
motion  of  snails  and  mollusks  in  general,  and  although  many  aquatic 
species  adhere  constantly  to  the  same  rock  for  their  whole  lives,  they  are 
by  no  means  destitute  of  provision  for  disseminating  themselves  rapidly 
over  a  wide  area.  "  Some  Mollusca,"  says  Professor  E.  Forbes,  "  migrate 
in  their  larva  state,  for  all  of  them  undergo  a  metamorphosis  either  in  the 
egg  or  out  of  the  egg.  The  gasteropoda  commence  life  under  the  form 
of  a  small  spiral  shell,  and  an  animal' furnished  with  ciliated  wings,  or 
lobes,  like  a  pteropod,  by  means  of  which  it  can  swim  freely,  and  in  this 
form  can  migrate  with  ease  through  the  sea."f 

King  in  his  expedition  to  the  Straits  of  Magellan.  They  had  been  packed  up  in 
a  box,  and  enveloped  in  cotton  :  two  for  a  space  of  thirteen,  one  for  seventeen, 
and  a  fourth  for  upwards  of  twenty  months :  but,  on  being  exposed  by  Mr. 
Broderip  to  the  warmth  of  a  fire  in  London,  and  provided  with  tepid  water  and 
leaves,  they  revived,  and  lived  for  several  months  in  Mr.  Loddiges'  palm-house, 
till  accidentally  drowned. 

*  Camb.  Phil.  Trans.,  vol.  iv.  1831. 

f  Edin.  New  Phil.  Journ.,  April  1844. 


652  GEOGRAPHICAL  DISTRIBUTION  AND  {Cm  XXXIX. 

I 

We  are  accustomed  to  associate  in  our  minds  the  idea  of  the  greatest 
locomotive  powers  with  the  most  mature  and  perfect  state  of  each 
species  of  invertebrate  animal,  especially  when  they  undergo  a  series  of 
transformations ;  but  in  all  the  Mollusca  the  reverse  is  true.  The  young 
fry  of  the  cockle,  for  example  ( Cardium),  possess,  when  young  or  in  the 
larva  state,  an  apparatus  which  enables  them  both  to  swim  and  to  be 
carried  along  easily  by  a  marine  current.  (See  fig.  99.) 

These  small  bodies  here  represented,  which  bear  a  considerable 
resemblance  to  the  fry  of  the  univalve,  or  gasteropodous  shells  above 
mentioned,  are  so  minute  at  first  as  to  be  just  visible  to  the  naked  eye. 
They  begin  to  move  about  from  the  moment  they  are  hatched,  by  means 


Tne  young  fry  of  a  cockle  (Cardium  pygmsum,)  from  Loven's  Kongl.  Vetenskaps.    Akadem 

Handling,  1848. 

A,  The  young  just  hatched,  magnified  100  diameters.  B,  the  same  farther  advanced. 

a,  The  ciliated  organ  of  locomotion  with  its  filamentous  appendage  b. 

c,  The  rudimentary  intestine. 

d,  The  rudimentary  shell. 

of  the  long  cilia,  a,  a,  placed  on  the  edges  of  the  locomotive  disk  or 
velum.  This  disk  shrinks  up  as  they  increase  in  size,  and  gradually 
disappears,  no  trace  of  it  being  visible  in  the  perfect  animal. 

Some  species  of  shell-bearing  Mollusca  lay  their  eggs  in  a  sponge-like 
nidus,  wherein  the  young  remain  enveloped  for  a  time  after  their  birth ; 
and  this  buoyant  substance  floats  far  and  wide  as  readily  as  sea-weed. 
The  young  of  other  viviparous  tribes  are  often  borne  along  entangled  in 
sea-weed.  Sometimes  they  are  so  light,  that,  like  grains  of  sand,  they 
can  be  easily  moved  by  currents.  Balani  and  Serpulae  are  sometimes 
found  adhering  to  floating  cocoa-nuts,  and  even  to  fragments  of  pumice. 
In  rivers  and  lakes,  on  the  other  hand,  aquatic  univalves  usually  attach 
their  eggs  to  leaves  and  sticks  which  have  fallen  into  the  water,  and 
which  are  liable  to  be  swept  away  during  floods,  from  tributaries  to  the 
main  streams,  and  from  thence  to  all  parts  of  the  same  basins.  Particu- 
lar species  may  thus  migrate  during  one  season  from  the  head  waters 
of  the  Mississippi,  or  any  other  great  river,  to  countries  bordering  the 
sea,  at  the  distance  of  many  thousand  miles. 

An  illustration  of  the  mode  of  attachment  of  these  eggs  will  be  seen 
in  the  annexed  cut.  (Fig.  100.) 

The  habit  of  some  Testacea  to  adhere  to  floating  wood  is  proved  by 
their  fixing  themselves  to  the  bottoms  of  ships.  By  this  mode  of  convey- 
ance Mytilus  polymorphus,  previously  known  only  in  the  Danube  and 


On.  XXXIX.]     MIGRATIONS   OP   TESTACEA   AND   ZOOPHYTES.        653 

Wolga,  may  have  been  brought  to  the  Commercial  Docks  in  the  Thames, 
and  to  Hamburgh,  where  the  species  is  now  domiciled.  But  Mr.  Gray 
suggests  that  as  the  animal  is  known  to  have  the  faculty  of  living  for  a 
very  long  time  out  of  water,  it  is  more  probable  that  it  was  brought  in 
Russian  timber,  than  borne  uninjured  through  the  salt  water  at  the 
bottom  of  a  vessel.* 

A  lobster  (Astacus  marinusj  was  lately  taken  alive  covered  with  living 
mussels  (Mytilus  edulis)\;  and  a  large  female  crab  (Cancer  pagurus), 
covered  with  oysters,  and  bearing  also  Anomia  ephippium,  and  Actiniae, 
was  taken  in  April,  1832,  off  the  English  coast.  The  oysters,  seven  in  num- 
ber, include  individuals  of  six  years'  growth,  and  the  two  largest  are  four 
inches  long  and  three  inches  and  a  half  broad.  Both  the  crab  and 
the  oysters  were  seen  alive  by  Mr.  Robert  Brown.]; 

Fig.  100. 


Eggs  of  Freshwater  mollusks. 

Fig.  1.  Eggs  of  Jimpullaria  ovata  (a  fluviatile  species)  fixed  to  a  small  sprig  which  had  fallen  into 

the  water. 

Fig  2.  Eggs  of  Planorbis  albus,  attached  to  a  dead  leaf  lying  under  water. 
Fig.  3.  Eggs  of  the  common  Limneus  (L.  vulgaris],  adhering  to  a  dead  stick  under  water. 

From  this  example  we  learn  the  manner  in  which  oysters  may  be 
diffused  over  every  part  of  the  sea  where  the  crab  wanders ;  and  if  they 
are  at  length  carried  to  a  spot  where  there  is  nothing  but  fine  mud,  the 
foundation  of  a  new  oyster-bank  may  be  laid  on  the  death  of  the  crab. 
In  this  instance  the  oysters  survived  the  crab  many  days,  and  were 
killed  at  last  only  by  long  exposure  to  the  air. 


*  PhiL  Trans.  1835,  p.  303. 

f  The  specimen  is  preserved  in  the  Museum  of  the  Zool.  Soc.  of  London. 

\  This  specimen  is  in  the  collection  of  my  friend  Mr.  Broderip,  who  observes, 
that  this  crab,  which  was  apparently  in  perfect  health,  could  not  have  cast  her 
shell  for  six  years,  whereas  some  naturalists  have  stated  that  the  species  moults 
annually,  without  limiting  the  moulting  period  to  the  early  stages  of  the  growth 
of  the  animal. 


654  GEOGRAPHICAL   DISTRIBUTION   AND          [Cn.  XXXIX. 

Geographical  Distribution  and  Migrations  of  Zoophytes. 

Zoophytes  are  very  imperfectly  known ;  but  there  can  be  little  doubt 
that  each  maritime  region  possesses  species  peculiar  to  itself.  The 
Madrepores,  or  lamelliferous  Polyparia,  are  found  in  their  fullest  deve- 
lopment only  in  the  tropical  seas  of  Polynesia  and  the  East  and  West 
Indies ;  and  this  family  is  represented  only  by  a  few  species  in  our  seas. 
The  zoophytes  of  the  Mediterranean,  according  to  Ehrenberg,  differ 
almost  entirely  from  those  of  the  Red  Sea,  although  only  seventy  miles 
distant.  Out  of  120  species  of  Anthozoa,  only  two  are  common  to  both 
seas.*  Peron  and  Lesueur,  after  studying  the  Holothurise,  Medusce, 
and  other  congeners  of  delicate  and  changeable  forms,  came  to  the  con- 
clusion that  each  kind  has  its  place  of  residence  determined  by  the 
temperature  necessary  to  support  its  existence.  Thus,  for  example, 
they  found  the  abode  of  Pyrosoma  Atlantica,  to  be  confined  to  one 
particular  region  of  the  Atlantic  Ocean.j* 

Let  us  now  inquire  how  the  transportation  of  zoophytes  from  one 
part  of  the  globe  to  another  is  effected.  Many  of  them,  as  in  the 
families  Flustra  and  Sertularia,  attach  themselves  to  sea-weed,  and  are 
occasionally  drifted  along  with  it.  Many  fix  themselves  to  the  shells  of 
Mollusca,  and  are  thus  borne  along  by  them  to  short  distances.  Others, 
like  some  species  of  sea-pens,  float  about  in  the  ocean,  and  are  usually 
believed  to  possess  powers  of  spontaneous  motion.  But  the  most  fre- 
quent mode  of  transportation  consists  in  the  buoyancy  of  their  eggs, 
or  certain  small  vesicles,  which  are  detached,  and  are  capable  of  becom- 
ing the  foundation  of  a  new  colony.  These  gems,  as  they  are  called, 
have,  in  many  instances,  a  locomotive  power  of  their  own,  by  which 
they  proceed  in  a  determinate  direction  for  several  days  after  separation 
from  the  parent.  They  are  propelled  by  means  of  numerous  short 
threads  or  cilice,  which  are  in  constant  and  rapid  vibration ;  and,  when 
thus  supported  in  the  water,  they  may  be  borne  along  by  currents  to  a 
great  distance. 

That  some  zoophytes  adhere  to  floating  bodies,  is  proved  by  their 
being  found  attached  to  the  bottoms  of  ships,  like  certain  Testacea 
before  alluded  to. 

Geographical  Distribution  and  Migrations  of  Insects. 

Before  I  conclude  this  sketch  of  the  manner  in  which  the  habitable 
parts  of  the  earth  are  shared  out  among  particular  assemblages  of 
organic  beings,  I  must  offer  a  few  remarks  on  insects,  which,  by  their 
numbers  and  the  variety  of  their  powers  and  instincts,  exert  a  prodi- 
gious influence  in  the  economy  of  animate  nature.  As  a  large  portion 
of  these  minute  creatures  are  strictly  dependent  for  their  subsistence  on 
certain  species  of  vegetables,  the  entomological  provinces  must  coin- 
cide in  considerable  degree  with  the  botanical. 

*  Quart.  Journ.  Geol.  Soc.,  vol.  iv.  p.  336. 
f  Voy.  aux  Terres  Anstrales,  torn.  i.  p.  492. 


CH.  XXXIX.]  MIGRATIONS   OF   INSECTS.  655 

All  the  insects,  says  Latreille,  brought  from  the  eastern  parts  of  Asia 
and  China,  whatever  be  their  latitude  and  temperature,  are  distinct  from 
those  of  Europe  and  of  Africa.  The  insects  of  the  United  States, 
although  often  approaching  very  close  to  our  own,  are,  with  very  few 
exceptions,  specifically  distinguishable  by  some  characters.  In  South 
America,  the  equinoctial  lands  of  New  Granada  and  Peru  on  the  one 
side,  and  of  Guiana  on  the  other,  contain  for  the  most  part  distinct 
groups ;  the  Andes  forming  the  division,  and  interposing  a  narrow 
line  of  severe  cold  between  climates  otherwise  very  similar.* 

Migratory  instincts. — Nearly  all  the  insects  of  the  United  States 
and  Canada,  differ  specifically  from  the  European  ;  while  those  of  Green- 
land appear  to  be  in  a  great  measure  identical  with  our  own.  Some 
insects  are  very  local ;  while  a  few,  on  the  contrary,  are  common  to 
remote  countries,  between  which  the  torrid  zone  and  the  ocean  inter- 
vene. Thus  our  painted  lady  butterfly  (  Vanessa  cardui)  re-appears  at 
the  Cape  of  Good  Hope  and  in  New  Holland  and  Japan  with  scarcely 
a  varying  streak,  f  The  same  species  is  said  to  be  one  of  the  few 
insects  which  are  universally  dispersed  over  the  earth,  being  found 
in  Europe,  Asia,  Africa,  and  America ;  and  its  wide  range  is  the  more 
interesting,  because  it  seems  explained  by  its  migratory  instinct, 
seconded,  no  doubt,  by  a  capacity,  enjoyed  by  few  species,  of  enduring 
a  great  diversity  of  temperature. 

A  vast  swarm  of  this  species,  forming  a  column  from  ten  to  fifteen 
feet  broad,  was,  a  few  years  since,  observed  in  the  Canton  de  Vaud ; 
they  traversed  the  country  with  great  rapidity  from  north  to  south,  all 
flying  onwards  in  regular  order,  close  together,  and  not  turning  from 
their  course  on  the  approach  of  other  objects.  Professor  Bonelli,  of 
Turin,  observed,  in  March  of  the  same  year,  a  similar  swarm  of  the 
same  species,  also  directing  their  flight  from  north  to  south,  in  Pied- 
mont, in  such  immense  numbers  that  at  night  the  flowers  were  literally 
covered  with  them.  They  had  been  traced  from  Coni,  Raconi,  Susa,  <fec. 
A  similar  flight  at  the  end  of  the  last  century  is  recorded  by  M.  Louch  in 
the  Memoirs  of  the  Academy  of  Turin.  The  fact  is  the  more  worthy  of 
notice,  because  the  caterpillars  of  this  butterfly  are  not  gregarious,  but 
solitary  from  the  moment  that  they  are  hatched ;  and  this  instinct  remains 
dormant,  while  generation  after  generation  passes  away,  till  it  suddenly 
displays  itself  in  full  energy  when  their  numbers  happen  to  be  in  excess. 

Not  only  peculiar  species,  but  certain  types,  distinguish  particular 
countries ;  and  there  are  groups,  observes  Kirby,  which  represent  each 
other  in  distant  regions,  whether  in  their  form,  their  functions,  or  in 
both.  Thus  the  honey  and  wax  of  Europe,  Asia,  and  Africa,  are  in  each 
case  prepared  by  bees  congenerous  with  our  common  hive-bee  (Apis, 
Latr.) ;  while,  in  America,  this  genus  is  nowhere  indigenous,  but  is 
replaced  by  Melipona,  Trigona,  and  Euglossa ;  and  in  New  Holland  by 

*  Geographic  Generale  des  Insectes  et  des  Arachnides.  Mem.  du  Mus.  d'Hist. 
Nat.,  torn.  iii. 

f  Kirby  and  Spence,  vol.  iv.  p.  487  ;  and  other  authors. 


656  MIGRATIONS    OF   BIRDS.  [On.  XXXIX. 

a  still  different  but  undescribed  type.  *The  European  bee  (Apis  melli- 
fica),  although  not  a  native  of  the  new  world,  is  now  established  both 
in  North  and  South  America.  It  was  introduced  into  the  United  States 
by  some  of  the  early  settlers,  and  has  since  overspread  the  vast  forests 
of  the  interior,  building  hives  in  the  decayed  trunks  of  trees.  "  The 
Indians,"  says  Irving,  "  consider  them  as  the  harbinger  of  the  white 
man,  as  the  buffalo  is  of  the  red  man,  and  say  that  in  proportion  as  the 
bee  advances  the  Indian  and  the  buffalo  retire.  It  is  said,"  continues 
the  same  writer,  "  that  the  wild  bee  is  seldom  to  be  met  with  at  any 
great  distance  from  the  frontier,  and  that  they  have  always  been  the 
heralds  of  civilization,  preceding  it  as  it  advanced  from  the  Atlantic 
borders.  Some  of  the  ancient  settlers  of  the  west  even  pretend  to  give 
the  very  year  when  the  honey-bee  first  crossed  the  Mississippi."  f  The 
same  species  is  now  also  naturalized  in  Van  Diemen's  Land  and  New 
Zealand. 

As  almost  all  insects  are  winged,  they  can  readily  spread  themselves 
wherever  their  progress  is  not  opposed  by  uncongenial  climates,  or  by 
seas,  mountains,  and  other  physical  impediments ;  and  these  barriers 
they  can  sometimes  surmount  by  abandoning  themselves  to  violent 
winds,  which,  as  I  before  stated,  when  speaking  of  the  dispersion  of 
seeds  (p.  618.),  may  in  a  few  hours  carry  them  to  very  considerable 
distances.  On  the  Andes  some  sphinxes  and  flies  have  been  observed 
by  Humboldt,  at  the  height  of  19,180  feet  above  the  sea,  and  which 
appeared  to  him  to  have  been  involuntarily  carried  into  these  regions 
by  ascending  currents  of  air.  J 

White  mentions  a  remarkable  shower  of  aphides  which  seem  to  have 
emigrated,  with  an  east  wind,  from  the  great  hop  plantations  of  Kent 
and  Sussex,  and  blackened  the  shrubs  and  vegetables  where  they  alighted 
at  Selbourne,  spreading  at  the  same  time  in  great  clouds  all  along  the 
vale  from  Farnham  to  Alton.  These  aphides  are  sometimes  accompa- 
nied by  vast  numbers  of  the  common  lady-bird  (Coccinella  septem- 
punctata),  which  feed  upon  them.  § 

It  is  remarkable,  says  Kirby,  that  many  of  the  insects  which  are 
occasionally  observed  to  emigrate,  as,  for  instance,  the  Libellulse,  Cocci- 
nellse,  Carabi,  Cicadse,  &c.  are  not  usually  social  insects ;  but  seem  to 
congregate,  like  swallows,  merely  for  the  purpose  of  emigration.  || 
Here,  therefore,  we  have  an  example  of  an  instinct  developing  itself  on 
certain  rare  emergencies,  causing  unsocial  species  to  become  gregarious 
and  to  venture  sometimes  even  to  cross  the  ocean. 

The  armies  of  locusts  which  darken  the  air  in  Africa,  and  traverse 
the  globe  from  Turkey  to  our  southern  counties  in  England,  are  well 
known  to  all.  When  the  western  gales  sweep  over  the  Pampas  they 


*  Kirby  and  Spence,  vol.  iv.  p.  497. 

f  Washington  Irvine's  Tour  in  the  Prairies,  ch.  ix 

i  Malte-Brun,  vol.  v.  p.  379. 

8  Kirby  and  Spence,  vol.  ii.  p.  9.  1817. 

J  Kirby  and  Spence,  vol.  ii.  p.  12.  1817. 


CH.  XXXIX.]  DIFFUSION   OF   MAN.  657 

bear  along  with  them  myriads  of  insects  of  various  kinds.  As  a  proof 
of  the  manner  in  which  species  may  be  thus  diffused,  I  may  mention 
that  when  the  Creole  frigate  was  lying  in  the  outer  roads  off  Buenos 
Ayres,  in  1819,  at  the  distance  of  six  miles  from  the  land,  her  decks  and 
rigging  were  suddenly  covered  by  thousands  of  flies  and  grains  of  sand. 
The  sides  of  the  vessel  had  just  received  a  fresh  coat  of  paint,  to  which 
the  insects  adhered  in  such  numbers  as  to  spot  and  disfigure  the  vessel, 
and  to  render  it  necessary  partially  to  renew  the  paint.*  Captain  W. 
H.  Smyth  was  obliged  to  repaint  his  vessel,  the  Adventure,  in  the  Medi- 
terranean, from  the  same  cause.  He  was  on  his  way  from  Malta  to 
Tripoli,  when  a  southern  wind  blowing  from  the  coast  of  Africa,  then 
one  hundred  miles  distant,  drove  such  myriads  of  flies  upon  the  fresh 
paint,  that  not  the  smallest  point  was  left  unoccupied  by  insects. 

To  the  southward  of  the  river  Plate,  off  Cape  St.  Antonio,  and  at  the 
distance  of  fifty  miles  from  land,  several  large  dragon-flies  alighted  on  the 
Adventure  frigate,  during  Captain  King's  late  expedition  to  the  Straits  of 
Magellan.  If  the  wind  abates  when  insects  are  thus  crossing  the  sea,  the 
most  delicate  species  are  not  necessarily  drowned ;  for  many  can  repose 
without  sinking  on  the  water.  The  slender  long-legged  tipulae  have  been 
seen  standing  on  the  surface  of  the  sea,  when  driven  out  far  from  our 
coast,  and  took  wing  immediately  on  being  approached,  f  Exotic  beetles 
are  sometimes  thrown  on  OUT  shore,  which  revive  after  having  been  long 
drenched  in  salt  water ;  and  the  periodical  appearance  of  some  conspicu- 
ous butterflies  amongst  us,  after  being  unseen  some  for  five  others  for  fifty 
years,  has  been  ascribed,  not  without  probability,  to  the  agency  of  the 
winds. 

Inundations  of  rivers,  observes  Kirby,  if  they  happen  at  any  season  ex- 
cept in  the  depths  of  winter,  always  carry  down  a  number  of  insects, 
floating  on  the  surface  of  bits  of  stick,  weeds,  &c. ;  so  that  when  the  waters 
subside,  the  entomologist  may  generally  reap  a  plentiful  harvest.  In  the 
dissemination,  moreover,  of  these  minute  beings,  as  in  that  of  plants,  the 
larger  animals  play  their  part.  Insects  are,  in  numberless  instances,  borne 
along  in  the  coats  of  animals,  or  the  feathers  of  birds ;  and  the  eggs  of 
some  species  are  capable,  like  seeds,  of  resisting  the  digestive  powers  of 
the  stomach,  and  after  they  are  swallowed  with  herbage,  may  be  ejected 
again  unharmed  in  the  dung. 

Geographical  Distribution  and  Diffusion  of  Man. 

I  have  reserved  for  the  last  some  observations  on  the  range  and  diffu- 
sion of  the  human  species  over  the  earth,  and  the  influence  of  man  in 
spreading  other  animals  and  plants,  especially  the  terrestrial. 

Many  naturalists  have  amused  themselves  in  speculating  on  the  proba- 
ble birth-place  of  mankind,  the  point  from  which,  if  we  assume  the  whole 
human  race  to  have  descended  from  a  single  pair,  the  tide  of  emigration 

*  I  am  indebted  to  Liexitenant  Graves,  R.N.,  for  this  information 
f  I  state  this  fact  on  the  authority  of  my  friend,  Mr.  John  Curtis. 

42 


658  DIFFUSION   OF  MAN.  [Cn.  XXXIX. 

must  originally  have  proceeded.  It  has  been  always  a  favorite  conjec- 
ture, that  this  birth-place  was  situated  within  or  near  the  tropics,  where 
perpetual  summer  reigns,  and  where  fruits,  herbs,  and  roots  are  plentifully 
supplied  throughout  the  year.  The  climate  of  these  regions,  it  has  been 
said,  is  suited  to  a  being  born  without  any  covering,  and  who  had  not  yet 
acquired  the  arts  of  building  habitations  or  providing  clothes. 

Progress  of  Human  Population. — "  The  hunter  state,"  it  has  been  ar- 
gued, "  which  Montesquieu  placed  the  first,  was  probably  only  the  second 
stage  to  which  mankind  arrived  ;  since  so  many  arts  must  have  been  iu- 
vented  to  catch  a  salmon,  or  a  deer,  that  society  could  no  longer  have 
been  in  its  infancy  when  they  came  into  use."*  When  regions  where  the 
spontaneous  fruits  of  the  earth  abound  became  overpeopled,  men  would 
naturally  diffuse  themselves  over  the  neighboring  parts  of  the  temperate 
zone ;  but  a  considerable  time  would  probably  elapse  before  this  event  took 
place ;  and  it  is  possible,  as  a  writer  before  cited  observes,  that  in  the 
interval  before  the  multiplication  of  their  numbers  and  their  increasing 
wants  had  compelled  them  to  emigrate,  some  arts  to  take  animals  were 
invented,  but  far  inferior  to  what  we  see  practised  at  this  day  among 
savages.  As  their  habitations  gradually  advanced  into  the  temperate 
zone,  the  new  difficulties  they  had  to  encounter  would  call  forth  by 
degrees  the  spirit  of  invention,  and  the  probability  of  such  inventions 
always  rises  with  the  number  of  people  involved  in  the  same  necessity .f 

A  distinguished  modern  writer,  who  coincides  for  the  most  part  in  the 
views  above  mentioned,  has  introduced  one  of  the  persons  in  his  second 
dialogue,  as  objecting  to  the  theory  of  the  human  race  having  gradually 
advanced  from  a  savage  to  a  civilized  state,  on  the  ground  that  "  the  first 
man  must  have  inevitably  been  destroyed  by  the  elements  or  devoured  by 
savage  beasts,  so  infinitely  his  superiors  in  physical  force."!  He  then 
contends  against  the  difficulty  here  started  by  various  arguments,  all  of 
which  were,  perhaps,  superfluous  ;  for  if  a  philosopher  is  pleased  to  indulge 
in  conjectures  on  this  subject,  why  should  he  not  assign,  as  the  original 
seat  of  man,  some  one  of  those  large  islands  within  the  tropics,  which  are 
as  free  from  large  beasts  of  prey  as  Van  Diemen's  Land  or  Australia  ? 
Here  man  may  have  remained  for  a  period,  peculiar  to  a  single  island, 
just  as  some  of  the  large  anthropomorphous  species  are  now  limited  to 
one  island  within  the  tropics.  In  such  a  situation,  the  new-born  race 
might  have  lived  in  security,  though  far  more  helpless  than  the  New  Hol- 
land savages,  and  might  have  found  abundance  of  vegetable  food.  Colo- 
nies may  afterwards  have  been  sent  forth  from  this  mother  country, 
and  then  the  peopling  of  the*  earth  may  have  proceeded  according  to  the 
hypothesis  before  alluded  to. 

To  form  a  probable  conjecture  respecting  the  country  from  whence  the 
early  civilization  of  India  was  derived,  has  been  found  almost  as  difficult 
as  to  determine  the  original  birth-place  of  the  human  race.  That  the 
dawn  of  oriental  civilization  did  not  arise  within  the  limits  of  the  tropics, 

*  Brand's  Select  Dissert,  from  the  Amcen.  Acad.,  vol.  i.  p.  118.  f  Ibid 

\  Sir  H.  Davy,  Consolations  in  Travel,  p.  74. 


CH.  XXXIX.]  ANCIENT   CHRONOLOGY.  659 

is  the  conclusion  to  which  Baron  William  von  Humboldt  has  come  after 
much  patient  research  into  "  the  diversities  of  the  structure  of  language 
and  their  influence  on  the  mental  development  of  the  human  race."  Ac- 
cording to  him  the  ancient  Zend  country  from  whence  the  spread  of 
knowledge  and  the  arts  has  been  traced  in  a  south-easterly  direction,  lay 
to  the  north-west  of  the  upper  Indus.* 

As  to  the  time  of  the  first  appearance  of  man  upon  the  earth,  if  we 
are  to  judge  from  the  discordance  of  opinion  amongst  celebrated  chro- 
nologers,  not  even  a  rude  approximation  has  yet  been  made  towards 
determining  a  point  of  so  much  interest.  The  problem  seems  hitherto  to 
have  baffled  the  curiosity  of  the  antiquary,  if  possible,  more  completely 
than  the  fixing  on  a  geographical  site  for  the  original  habitation  of  the 
ancestors  of  the  human  race.  The  Chevalier  Bunsen,  in  his  elaborate 
and  philosophical  work  on  Ancient  Egypt,f  has  satisfied  not  a  few  of  the 
learned,  by  an  appeal  to  monumental  inscriptions  still  extant,  that  the 
successive  dynasties  of  kings  may  be  traced  back  without  a  break,  to 
Menes,  and  that  the  date  of  his  reign  would  correspond  with  the  year 
3640  B.  c.  He  supposes  at  the  same  time,  what  is  most  reasonable,  that 
the  Egyptian  people  must  have  existed  for  a  long  period  (probably  at 
least  for  five  centuries),  in  their  earlier  and  less  settled  state,  before  they 
reached  the  point  of  civilization  at  which  Menes  consolidated  them  into 
a  great  and  united  empire.  This  would  carry  us  back  to  upwards  of 
4000  years  B.  c.,  or  to  an  epoch  coincident  with  that  commonly  set  down 
for  the  creation  of  the  world  in  accordance  with  computations  founded  on 
the  combined  ages  of  the  successive  antediluvian  patriarchs.  It  follows 
that  the  same  epoch  of  Menes  is  anterior  by  a  great  many  centuries  to 
the  most  ancient  of  the  dates  usually  fixed  upon  for  the  Mosaic  deluge. 
The  fact  that  no  record  or  tradition  of  any  great  and  overwhelming  flood 
has  been  detected  in  the  mythology,  or  monumental  annals  of  the  Egyp- 
tians, will  suggest  many  reflections  to  a  geologist  who  has  weighed  well 
the  evidence  we  possess  of  a  variety  of  partial  deluges  which  have  hap- 
pened in  districts  not  free  like  Egypt,  for  the  last  3000  years,  from  earth- 
quakes and  other  causes  of  great  aqueous  catastrophes.  .  The  tales  and 
legends  of  calamitous  floods  preserved  in  Greece,  Asia  Minor,  the  southern 
shores  of  the  Baltic,  China,  Peru,  and  Chili,  have,  as  we  have  seen,  been 
all  of  them  handed  down  to  us  by  the  inhabitants  of  regions  in  which 
the  operation  of  natural  causes  in  modern  times,  and  the  recurrence  of  a 
succession  of  disastrous  floods,  afford  us  data  for  interpreting  the  meaning 
of  the  obscure  traditions  of  an  illiterate  age.J 

In  his  learned  treatise  on  ancient  chronology,  Dr.  Hales  has  selected, 
from  a  much  greater  number,  a  list  of  no  less  than  120  authors,  all  of 
whom  give  a  different  period  for  the  epoch  of  the  creation  of  the  world, 

*  W.  von  Humboldt,  "  On  the  Kawi  Language,"  <fec.  cited  in  Cosmos.  Intro- 
duction. 

f  Egypten's  Stelle,  <fec.  Egypt  restored  to  her  Place  in  Universal  History,  by 
C.  C.  J.  Bunsen.  1845. 

^  For  Grecian  and  Asiatic  deluges,  see  above,  p.  356.;  Cimbrian,  p.  331.  , 
Chinese,  p.  7.  •  Peruvian,  T>.  502. ;  Chilian  or  Araucanian  deluge,  p.  500. 


660  GEOGRAPHICAL   DISTRIBUTION   AND          [On.  XXXIX. 

the  extreme  range  of  difference  between  them  amounting  to  no  less  than 
3268  years.  It  appears  that  even  amongst  authorities,  who  in  England 
are  generally  regarded .  as  orthodox,  there  is  a  variance,  not  of  years  or 
of  one  or  two  centuries,  but  of  upwards  of  a  millennium,  according  as  they 
have  preferred  to  follow  the  Hebrew,  or  the  Samaritan,  or  the  Greek  ver- 
sions of  the  Mosaic  writings.  Can  we  then  wonder  that  they  who  de- 
cipher the  monuments  of  Egypt,  or  the  geologist  who  interprets  the 
earth's  autobiography,  should  arrive  at  views  respecting  the  date  of  an 
ancient  empire,  or  the  age  of  our  planet,  irreconcileable  with  every  one 
of  these  numerous  and  conflicting  chronologies  ?  The  want  of  agree- 
ment amongst  the  learned  in  regard  to  the  probable  date  of  the  deluge 
of  Noah  is  a  source  of  far  greater  perplexity  and  confusion  than  our  ex- 
treme uncertainty  as  to  the  epoch  of  the  creation, — the  deluge  being  a 
comparatively  modern  event,  from  which  the  repeopling  of  the  earth  and 
the  history  of  the  present  races  of  mankind  is  made  to  begin. 

Naturalists  have  long  felt  that  to  render  probable  the  received  opinion 
that  all  the  leading  varieties  of  the  human  family  have  originally  sprung 
from  a  single  pair,  (a  doctrine  against  which  there  appears  to  me  to  be 
no  sound  objection,)  a  much  greater  lapse  of  time  is  required  for  the 
slow  and  gradual  formation  of  races,  (such  as  the  Caucasian,  Mongolian, 
and  Negro,)  than  is  embraced  in  any  of  the  popular  systems  of  chro- 
nology. The  existence  of  two  of  those  marked  varieties  above  mentioned 
can  be  traced  back  3000  years  before  the  present  time,  or  to  the  painting 
of  pictures,  preserved  in  the  tombs  or  on  the  walls  of  buried  temples  in 
Egypt.  In  these  we  behold  the  Negro  and  Caucasian  physiognomies 
portrayed  as  faithfully  and  in  as  strong  contrast  as  if  the  likenesses  of  those 
races  had  been  taken  yesterday.  When  we  consider  therefore  the  ex- 
treme slowness  of  the  changes,  which  climate  and  other  modifying 
causes  have  produced  in  modern  times,  we  must  allow  for  a  vast  series  of 
antecedent  ages,  in  the  course  of  which  the  long-continued  influence  of  simi- 
lar external  circumstances  gave  rise  to  peculiarities,  probably  increased  in 
many  successive  generations,  until  they  were  fixed  by  hereditary  trans- 
mission. The  characteristic  forms  and  features  thus  acquired  by  certain 
tribes,  may  have  been  afterwards  diffused  by  migration  from  a  few  cen- 
tres over  wide  continental  spaces.  The  theory,  therefore,  that  all  the 
races  of  man  have  come  from  one  common  stock  receives  support  from 
every  investigation  which  forces  us  to  expand  our  ideas  of  the  duration 
of  past  time,  or  which  multiplies  the  number  of  years  that  have  passed 
away  since  the  origin  of  man.  Hitherto,  geology  has  neither  enlarged 
nor  circumscribed  the  "  human  period  ;"  but  simply  proved  that  in  the 
history  of  animated  nature  it  is  comparatively  modern,  or  the  last  of  a 
long  series  of  antecedent  epochs,  in  each  of  which  the  earth  has  been 
successively  peopled  by  distinct  species  of  animals  and  plants. 

In  an  early  stage  of  society  the  necessity  of  hunting  acts  as  a  principle 
of  repulsion,  causing  men  to  spread  with  the  greatest  rapidity  over  a 
country,  until  the  whole  is  covered  with  scattered  settlements.  It  has 
been  calculated  that  eight  hundred  acres  of  hunting-ground  produce  only 


CH.  XXXIX.]  DIFFUSION   OF  MAN.  661 

as  much  food  as  half  an  acre  of  arable  land.  When  the  game  has  been 
in  a  great  measure  exhausted,  and  a  state  of  pasturage  succeeds,  the 
several  hunter  tribes,  being  already  scattered,  may  multiply  in  a  short 
time  into  the  greatest  number  which  the  pastoral  state  is  capable  of  sus- 
taining. The  necessity,  says  Brand,  thus  imposed  upon  the  two  savage 
states,  of  dispersing  themselves  far  and  wide  over  the  country,  affords  a 
reason  why,  at  a  very  early  period,  the  worst  parts  of  the  earth  may  have 
become  inhabited. 

But  this  reason,  it  may  be  said,  is  only  applicable  in  as  far  as  regards 
the  peopling  of  a  continuous  continent ;  whereas  the  smallest  islands, 
however  remote  from  continents,  have  almost  always  been  found  inha- 
bited by  man.  St.  Helena,  it  is  true,  afforded  an  exception  ;  for  when 
that  island  was  discovered  in  1501,  it  was  only  inhabited  by  sea-fowl, 
and  occasionally  by  seals  and  turtles,  and  was  covered  with  a  forest  of 
trees  and  shrubs,  all  of  species  peculiar  to  it,  with  one  or  two  exceptions, 
and  which  seem  to  have  been  expressly  created  for  this  remote  and 
insulated  spot.* 

The  islands  also  of  Mauritius,  Bourbon,  Pitcairns,  and  Juan  Fernan- 
dez, and  those  of  the  Galapagos  archipelago,  one  of  which  is  seventy 
miles  long,  were  inhabited  when  first  discovered,  and,  what  is  more 
remarkable  than  all,  the  Falkland  Islands,  which  together  are  120  miles 
in  length  by  60  in  breadth,  and  abounding  in  food  fit  for  the  support 
of  man. 

Drifting  of  canoes  to  vast  distances. — But  very  few  of  the  numerous 
coral  islets  and  volcanoes  of  the  vast  Pacific,  capable  of  sustaining  a 
few  families  of  men,  have  been  found  untenanted  ;  and  we  have,  there- 
fore, to  inquire  whence  and  by  what  means,  if  all  the  members  of  the 
great  human  family  have  had  one  common  source,  could  those  savages 
have  migrated.  Cook,  Forster,  and  others,  have  remarked  that  parties 
of  savages  in  their  canoes  must  have  often  lost  their  way,  and  must 
have  been  driven  on  distant  shores,  where  they  were  forced  to  remain, 
deprived  both  of  the  means  and  of  the  requisite  intelligence  for  return- 
ing to  their  own  country.  Thus  Captain  Cook  found  on  the  island  of 
Wateoo  three  inhabitants  of  Otaheite,  who  had  been  drifted  thither  in 
a  canoe,  although  the  distance  between  the  two  isles  is  550  miles.  In 
1696,  two  canoes,  containing  thirty  persons,  who  had  left  Ancorso,  were 
thrown  by  contrary  winds  and  storms  on  the  island  of  Samar,  one  of 
the  Philippines,  at  a  distance  of  800  miles.  In  1721,  two  canoes,  one 
of  which  contained  twenty-four,  and  the  other  six  persons,  men,  women, 
and  children,  were  drifted  from  an  island  called  Farroilep  to  the  island 
of  Guaham,  one  of  the  Marians,  a  distance  of  200  miles,  f 

Kotzebue,  when  investigating  the  Coral  Isles  of  Radack,  at  the  east- 
ern extremity  of  the  Caroline  Isles,  became  acquainted  with  a  person  of 
the  name  of  Kadu,  who  was  a  native  of  Ulea,  an  isle  1500  miles  distant, 
from  which  he  had  been  drifted  with  a  party.  Kadu  and  three  of  his 

*See  p.  615.  f  Malte-Brun's  Geography,  vol.  iii.  p.  419. 


662  DIFFUSION   OF   MAN.  [On.  XXXIX. 

countrymen  one  day  left  Ulea  in  a  sailing  boat,  when  a  violent  storm 
arose,  and  drove  them  out  of  their  course :  they  drifted  about  the  open 
sea  for  eight  months,  according  to  their  reckoning  by  the  moon,  mak- 
ing a  knot  on  a  cord  at  every  new  moon.  Being  expert  fishermen,  they 
subsisted  entirely  on  the  produce  of  the  sea ;  and  when  the  rain  fell,  laid 
in  as  much  fresh  water  as  they  had  vessels  to  contain  it.  "  Kadu," 
says  Kotzebue,  "  who  was  the  best  diver,  frequently  went  down  to  the 
bottom  of  the  sea,  where  it  is  well  known  that  the  water  is  not  so  salt, 
with  a  cocoa-nut  shell,  with  only  a  small  opening."  *  When  these 
unfortunate  men  reached  the  isles  of  Radack,  every  hope  and  almost 
every  feeling  had  died  within  them  ;  their  sail  had  long  been  destroyed, 
their  canoe  had  long  been  the  sport  of  winds  and  waves,  and  they 
were  picked  up  by  the  inhabitants  of  Aur  in  a  state  of  insensibility ; 
but  by  the  hospitable  care  of  those  islanders  they  soon  recovered,  and 
were  restored  to  perfect  health,  f 

Captain  Beechey,  in  his  voyage  to  the  Pacific,  fell  in  with  some  natives 
cf  the  Coral  Islands,  who  had  in  a  similar  manner  been  carried  to  a 
great  distance  from  their  native  country.  They  had  embarked,  to  the 
number  of  150  souls,  in  three  double  canoes,  from  Anaa,  or  Chain 
Island,  situated  about  three  hundred  miles  to  the  eastward  of  Otaheite. 
They  were  overtaken  by  the  monsoon,  which  dispersed  the  canoes ;  and 
after  driving  them  about  the  ocean,  left  them  becalmed,  so  that  a  great 
number  of  persons  perished.  Two  of  the  canoes  were  never  heard  of; 
but  the  other  was  drifted  from  one  uninhabited  island  to  another,  at 
each  of  which  the  voyagers  obtained  a  few  provisions  ;  and  at  length, 
after  having  wandered  for  a,  distance  of  600  miles,  they  were  found  and 
carried  to  their  home  in  the  Blossom.  J 

Mr.  Crawfurd  informs  me  that  there  are  several  well-authenticated 
accounts  of  canoes  having  been  drifted  from  Sumatra  to  Madagascar, 
and  by  such  causes  a  portion  of  the  Malayan  language,  with  some 
useful  plants,  have  been  transferred  to  that  island,  which  is  principally 
peopled  by  negroes. 

The  space  traversed  in  some  of  these  instances  was  so  great,  that 
similar  accidents  might  suffice  to  transport  canoes  from  various  parts  of 
Africa  to  the  shores  of  South  America,  or  from  Spain  to  the  Azores, 
and  thence  to  North  America ;  so  that  man,  even  in  a  rude  state  of 
society,  is  liable  to  be  scattered  involuntarily  by  the  winds  and  waves 
ovtr  the  globe,  in  a  manner  singularly  analogous  to  that  in  which  many 
plants  and  animals  are  diffused.  We  ought  not,  then,  to  wonder,  that 
during  the  ages  required  for  some  tribes  of  the  human  race  to  attain 
that  advanced  stage  of  civilization  which  empowers  the  navigator  to 
cross  the  ocean  in  all  directions  with  security,  the  whole  earth  should 


I     It: 


*  Chamisso  states  that  the  water  which  they  brought  up  was  cooler,  and  i, 
their  opinion,  less  salt.     It  is  difficult  to  conceive  its  being  fresher  near  the  bot- 
tom, except  where  submarine  springs  may  happen  to  rise. 

f  Kotzebue's  Voyage,  1815-1818.     Quarterly  Review,  vol.  xxyi.  p.  361. 

\  Nanutive  of  a  Voyage  to  the  Pacific,  <fce.,  in  the  years  1825,  1826,  1827, 1828, 
p.  170. 


CH.  XXXIX.]          DISPERSION   OP   ANIMALS   BY   MAN.  663 

have  become  the  abode  of  rude  tribes  of  hunters  and  fishers.  "Were 
the  whole  of  mankind  now  cut  off,  with  the  exception  of  one  family, 
inhabiting  the  old  or  new  continent,  or  Australia,  or  even  some  coral 
islet  of  the  Pacific,  we  might  expect  their  descendants,  though  they 
should  never  become  more  enlightened  than  the  South  Sea  Islanders  or 
the  Esquimaux,  to  spread  in  the  course  of  ages  over  the  whole  earth, 
diffused  partly  by  the  tendency  of  population  to  increase,  in  a  limited 
district,  beyond  the  means  of  subsistence,  and  partly  by  the  accidental 
drifting  of  canoes  by  tides  and  currents  to  distant  shores. 

Involuntary  Influence  of  Man  in  diffusing  Animals  and  Plants. 

Many  of  the  general  remarks  which  have  been  made  respecting  the 
influence  of  man  in  spreading  or  in  checking  the  diffusion  of  plants 
apply  equally  to  his  relations  with  the  animal  kingdom.  On  a  future 
occasion  I  shall  be  led  to  speak  of  the  instrumentality  of  our  species  in 
naturalizing  useful  animals  and  plants  in  new  regions,  when  explaining 
my  views  of  the  effects  which  the  spreading  and  increase  of  certain 
species  exert  in  the  extirpation  of  others.  At  present  I  shall  confine 
myself  to  a  few  remarks  on  the  involuntary  aid  which  man  lends  to  the 
dissemination  of  species. 

In  the  mammiferous  class  our  influence  is  chiefly  displayed  in  in- 
creasing the  number  of  quadrupeds  which  are  serviceable  to  us,  and  in 
exterminating  or  reducing  the  number  of  those  which  are  noxious. 

Sometimes,  however,  we  unintentionally  promote  the  multiplication  of 
inimical  species,  as  when  we  introduced  the  rat,  which  was  not  indigenous 
in  the  new  world,  into  all  parts  of  America.  They  have  been  conveyed 
over  in  ships,  and  now  infest  a  great  multitude  of  islands  and  parts  of 
that  continent.  In  like  manner  the  Norway  rat  (Mus  decumanus) 
has  been  imported  into  England,  where  it  plunders  our  property  in  ships 
and  houses. 

Among  birds,  the  house  sparrow  may  be  cited  as  a  species  known  to 
have  extended  its  range  with  the  tillage  of  the  soil.  During  the  last 
century  it  has  spread  gradually  over  Asiatic  Russia  towards  the  north 
and  east,  always  following  the  progress  of  cultivation.  It  made  its  first 
appearance  on  the  Irtisch  in  Tobolsk,  soon  after  the  Russians  had 
ploughed  the  land.  It  came  in  1735  up  the  Obi  to  Beresow,  and  four 
years  after  to  Naryn,  about  fifteen  degrees  of  longitude  farther  east.  In 
1710,  it  had  been  seen  in  the  higher  parts  of  the  coast  of  the  Lena,  in  the 
government  of  Irkutzk.  In  all  these  places  it  is  now  common,  but  is  not 
yet  found  in  the  uncultivated  regions  of  Kamtschatka.* 

The  great  viper  (Fer  de  lance),  a  species  no  less  venomous  than  the 
rattlesnake,  which  now  ravages  Martinique  and  St.  Lucia,  was  accident- 
ally introduced  by  man,  and  exists  in  no  other  part  of  the  West  Indies. 

Many  parasitic  insects  which  attack  our  persons,  and  some  of  which 
are  supposed  to  be  peculiar  to  our  species,  have  been  carried  into  all  parts 

*  Glogef,  Abiiiid.  der  Vogel,  p.  103. ;  Pallas,  Zoog.  Rosso-Asiat.,  torn.  ii.  p.  197. 


664  DISPERSION   OP   ANIMALS   BY  MAN.          [On.  XXXIX. 

of  the  earth,  and  have  as  high  a  claim  as  man  to  a  universal  geographi- 
cal distribution. 

A  great  variety  of  insects  have  been  transported  in  ships  from  one 
country  to  another,  especially  in  warmer  latitudes.  The  European  house- 
fly has  been  introduced  in  this  way  into  all  the  South  Sea  Islands. 
Notwithstanding  the  coldness  of  our  climate  in  England  we  have  been 
unable  to  prevent  the  cockroach  (JBlatta  orientalis)  from  entering  and 
diffusing  itself  in  our  ovens  and  kneading  troughs,  and  availing  itself 
of  the  artificial  warmth  which  we  afford.  It  is  well  known  also,  that 
beetles,  and  many  other  kinds  of  ligniperdous  insects,  have  been  intro- 
duced into  Great  Britain  in  timber  ;  especially  several  North  American 
species.  "The  commercial  relations,"  says  Mai  te-Brun*,  "between  France 
and  India  have  transported  from  the  latter  country  the  aphis,  which 
destroys  the  apple  tree,  and  two  sorts  of  Neuroptera,  the  Lucifuga  and 
Flavicola,  mostly  confined  to  Provence  and  the  neighbourhood  of  Bour- 
deaux,  where  they  devour  the  timber  in  the  houses  and  naval  arsenals." 

Among  mollusks  we  may  mention  the  Teredo  navalis,  which  is  a 
native  of  equatorial  seas,  but  which,  by  adhering  to  the  bottom  of  ships, 
was  transported  to  Holland,  where  it  has  been  most  destructive  to  vessels 
and  piles.  The  same  species  has  also  become  naturalized  in  England, 
and  other  countries  enjoying  an  extensive  commerce.  Bulimus  undatus, 
a  land  species  of  considerable  size,  native  of  Jamaica  and  other  West  In- 
dian islands,  has  been  imported,  adhering  to  tropical  timber,  into  Liver- 
pool ;  and,  as  I  learn  from  Mr.  Broderip,  is  now  naturalized  in  the  woods 
near  that  town. 

In  all  these  and  innumerable  other  instances  we  may  regard  the  invo- 
luntary agency  of  man  as  strictly  analogous  to  that  of  the  inferior  ani- 
mals. Like  them,  we  unconsciously  contribute  to  extend  or  limit  the 
geographical  range  and  numbers  of  certain  species,  in  obedience  to  gene- 
ral rules  in  the  economy  of  nature,  which  are  for  the  most  part  bevond 
our  control. 

*  Syst.  of  Geog.,  vol.  viii.  p.  169. 


CHAPTER    XL. 

THEORIES    RESPECTING    THE    ORIGINAL    INTRODUCTION    OF    SPECIES. 

Proposal  of  an  hypothesis  on  this  subject — Supposed  centres  or  foci  of  creation — 
Why  distinct,  provinces  of  animals  and  plants  have  not  become  more  blended 
together — Brocchi's  speculations  on  the  loss  of  species — Stations  of  plants  and 
animals — Causes  on  which  they  depend — Stations  of  plants  how  affected 
by  animals — Equilibrium  in  the  number  of  species  how  preserved — Peculiar 
efficacy  of  insects  in  this  task — Rapidity  with  which  certain  insects  multiply 
or  decrease  in  numbers — Effect  of  omnivorous  animals  in  preserving  the 
equilibrium  of  species — Reciprocal  influence  of  aquatic  and  terrestrial  species 
on  each  other. 

Theory  of  Linnaeus. — IT  would  be  superfluous  to  examine  the  various 
attempts  which  were  made  to  explain  the  phenomena  of  the  distri- 
bution of  species  alluded  to  in  the  preceding  chapters,  in  the  infancy 
of  the  sciences  of  botany,  zoology,  and  physical  geography.  The 
theories  or  rather  conjectures  then  indulged  now  stand  refuted  by  a 
simple  statement  of  facts ;  and  if  Linnaeus  were  living  he  would  be  the 
first  to  renounce  the  notions  which  he  promulgated.  For  he  imagined 
the  habitable  world  to  have  been  for  a  certain  time  limited  to  one  small 
tract,  the  only  portion  of  the  earth's  surface  that  was  as  yet  laid  bare 
by  the  subsidence  of  the  primaeval  ocean.  In  this  fertile  spot  he  sup- 
posed the  originals  of  all  the  species  of  plants  which  exist  on  this  globe 
to  have  been  congregated  together  with  the  first  ancestors  of  all  ani- 
mals and  of  the  human  race.  "  In  qua  commode  habitaverint  animalia 
omnia,  et  vegetabilia  laete  germinaverint."  In  order  to  accommodate  the 
various  habitudes  of  so  many  creatures,  and  to  provide  a  diversity  of 
climate  suited  to  their  several  natures,  the  tract  in  which  the  creation 
took  place  was  supposed  to  have  been  situated  in  some  warm  region  of 
the  earth,  but  to  have  contained  a  lofty  mountain  range,  on  the  heights 
and  in  the  declivities  of  which  were  to  be  found  all  temperatures  and 
every  climate,  from  that  of  the  torrid  to  that  of  the  frozen  zone.* 

That  there  never  was  a  universal  ocean  since  the  planet  was  inhabited, 
or,  rather,  since  the  oldest  groups  of  strata  yet  known  to  contain  organic 
remains  were  formed,  is  proved  by  the  presence  of  terrestrial  plants  or 
bv  indications  of  shores  in  all  the  older  formations ;  and  if  this  con- 
clusion was  not  established,  yet  no  geologist  could  deny  that,  since  the 
first  small  portion  of  the  earth  was  laid  dry,  there  have  been  many 
entire  changes  in  the  species  of  plants  and  animals  inhabiting  the  land. 

But,  without  dwelling  on  the  above  and  other  refuted  theories,  let 
us  inquire  whether  some  hypothesis  cannot  be  substituted  as  simple  as 
that  of  Linnaeus,  to  which  the  phenomena  now  ascertained  in  regard  to 
the  distribution  both  of  aquatic  and  terrestrial  species  may  be  referred. 

*  De  terra  habitabili  increment© ;  also  Prichard,  Phys.  Hist,  of  Mankind,  vol. 
i.  p.  17.,  where  the  hypotheses  of  different  naturalists  are  enumerated. 


666  INTRODUCTION   OF   SPECIES.  [Ca  XL. 

The  following  may,  perhaps,  be  reconcileable  with  known  facts  : — Each 
species  may  have  had  its  origin  in  a  single  pair,  or  individual,  where  an 
individual  was  sufficient,  and  species  may  have  been  created  in  succession 
at  such  times  and  in  such  places  as  to  enable  them  to  multiply  and  endure 
for  an  appointed  period,  and  occupy  an  appointed  space  on  the  globe. 

In  order  to  explain  this  theory,  let  us  suppose  every  living  thing  to 
be  destroyed  in  the  western  hemisphere,  both  on  the  land  and  in  the 
ocean,  and  permission  to  be  given  to  man  to  people  this  great  desert, 
by  transporting  into  it  animals  and  plants  from  the  eastern  hemisphere, 
a  strict  prohibition  being  enforced  against  introducing  two  original 
stocks  of  the  same  species. 

Now  it  is  easy  to  show  that  the  result  of  such  a  mode  of  colonizing 
would  correspond  exactly,  so  far  as  regards  the  grouping  of  animals  and 
plants,  with  that  now  observed  throughout  the  globe.  In  the  first  place, 
it  would  be  necessary  for  naturalists,  before  they  imported  species  into 
particular  localities,  to  study  attentively  the  climate  and  other  physical 
conditions  of  each  spot.  It  would  be  no  less  requisite  to  introduce  the 
different  species  in  succession,  so  that  each  plant  and  animal  might 
have  time  and  opportunity  to  multiply  before  the  species  destined  to 
prey  upon  it  was  admitted.  Many  herbs  and  shrubs,  for  example,  must 
spread  far  and  wide  before  the  sheep,  the  deer,  and  the  goat  could  be 
allowed  to  enter,  lest  they  should  devour  and  annihilate  the  original 
stocks  of  many  plants,  and  then  perish  themselves  for  want  of  food. 
The  above-mentioned  herbivorous  animals  in  their  turn  must  be  per- 
mitted to  make  considerable  progress  before  the  entrance  of  the  first 
pair  of  wolves  or  lions.  Insects  must  be  allowed  to  swarm  before  the 
swallow  could  be  permitted  to  skim  through  the  air,  and  feast  on 
thousands  at  one  repast. 

It  is  evident  that,  however  equally  in  this  case  our  original  stocks 
were  distributed  over  the  whole  surface  of  land  and  water,  there  would 
nevertheless  arise  distinct  botanical  and  zoological  provinces,  for  there 
are  a  great  many  natural  barriers  which  oppose  common  obstacles  to 
the  advance  of  a  variety  of  species.  Thus,  for  example,  almost  all  the 
animals  and  plants  naturalized  by  us,  towards  the  extremity  of  South 
America,  would  be  unable  to  spread  beyond  a  certain  limit,  towards  the 
east,  west,  and  south ;  because  they  would  be  stopped  by  the  ocean, 
and  a  few  of  them  only  would  succeed  in  reaching  the  cooler  latitudes 
of  the  northern  hemisphere,  because  they  would  be  incapable  of  bear- 
ing the  heat  of  the  tropics,  through  which  they  must  pass.  In  the 
course  of  ages,  undoubtedly,  exceptions  would  arise,  and  some  species 
might  become  common  to  the  temperate  and  polar  regions,  or  both 
sides  of  the  equator ;  for  I  have  before  shown  that  the  powers  of  diffu- 
sion conferred  on  some  classes  are  very  great.  But  we  might  confi- 
dently predict  that  these  exceptions  would  never  become  so  numerous 
as  to  invalidate  the  general  rule. 

Some  of  the  plants  and  animals  transplanted  by  us  to  the  coast  of 
Chili  and  Peru  would  never  be  able  to  cross  the  Andes,  so  as  to  reach 


OH.  XL.]  SUPPOSED    CENTRES   OP    CREATION.  667 

the  eastern  plains ;  nor,  for  a  similar  reason,  would  those  first  established 
in  the  Pampas,  or  the  valleys  of  the  Amazon  and  the  Orinoco,  ever 
arrive  at  the  shores  of  the  Pacific. 

In  the  ocean  an  analogous  state  of  things  would  prevail ;  for  there, 
also,  climate  would  exert  a  great  influence  in  limiting  the  range  of  spe- 
cies, and  the  land  would  stop  the  migrations  of  aquatic  tribes  as  effectually 
as  the  sea  arrests  the  dispersion  of  the  terrestrial.  As  certain  birds,  in- 
sects, and  the  seeds  of  plants,  can  never  cross  the  direction  of  prevailing 
winds,  so  currents  form  natural  barriers  to  the  dissemination  of  many 
oceanic  races.  A  line  of  shoals  may  be  as  impassable  to  deep-water 
species,  as  are  the  Alps  and  the  Andes  to  plants  and  animals  peculiar  to 
plains  ;  while  deep  abysses  may  prove  insuperable  obstacles  to  the  migra- 
tions of  the  inhabitants  of  shallow  waters. 

Supposed  centres,  or  foci,  of  creation. — It  is  worthy  of  observation, 
that  one  effect  of  the  introduction  of  single  pairs  of  each  species  must  be 
the  confined  range  of  certain  groups  in  spots,  which,  like  small  islands, 
or  solitary  inland  lakes,  have  few  means  of  interchanging  their  inhabit- 
ants with  adjoining  regions.  Now  this  congregating  in  a  small  space 
of  many  peculiar  species,  would  give  an  appearance  of  centres  or  foci  of 
creation,  as  they  have  been  termed,  as  if  they  were  favourite  points 
where  the  creative  energy  has  been  in  greater  action  than  in  others,  and 
where  the  numbers  of  peculiar  organic  beings  have  consequently  become 
more  considerable. 

I  do  not  mean  to  call  in  question  the  soundness  of  the  inferences  of 
some  botanists,  as  to  the  former  existence  of  certain  limited  spots  whence 
species  of  plants  have  been  propagated,  radiating,  as  it  were,  in  all  direc- 
tions from  a  common  centre.  On  the  contrary,  I  conceive  these  pheno- 
mena to  be  the  necessary  consequences  of  the  plan  of  nature  before  sug- 
gested, operating  during  the  successive  mutations  of  the  surface,  some  of 
which  the  geologist  can  prove  to  have  taken  place  subsequently  to  the 
period  when  many  species  now  existing  were  created.  In  order  to  ex- 
emplify how  this  arrangement  of  plants  may  have  been  produced,  let  us 
imagine  that,  about  three  centuries  before  the  discovery  of  St.  Helena 
(itself  of  submarine  volcanic  origin),  a  multitude  of  new  islands  had 
been  thrown  up  in  the  surrounding  sea,  and  that  these  had  each  become 
clothed  with  plants  emigrating  from  St.  Helena,  in  the  same  manner  as 
the  wild  plants  of  Campania  have  diffused  themselves  over  Monte  Nuovo. 
Whenever  the  first  botanist  investigated  the  new  archipelago,  he  would, 
in  all  probability,  find  a  different  assemblage  of  plants  in  each  of  the 
islands  of  recent  formation ;  but  in  St.  Helena  itself,  he  would  meet  with 
individuals  of  every  species,  belonging  to  all  parts  of  the  archipelago, 
and  some,  in  addition,  peculiar  to  itself,  viz.,  those  which  had  not  been 
able  to  obtain  a  passage  into  any  one  of  the  surrounding  new-formed 
lands.  In  this  case  it  might  be  truly  said  that  the  original  island  was 
the  primitive  focus,  or  centre,  of  a  certain  type  of  vegetation ;  whereas, 
in  the  surrounding  islands,  there  would  be  a  smaller  number  of  species, 
yet  all  belonging  to  the  same  group. 


668  BROCCHI   ON  LOSS   OF   SPECIES.  [Cn.  XL. 

But  this  peculiar  distribution  of  plants  would  not  warrant  the  conclu- 
sion that,  in  the  space  occupied  by  St.  Helena,  there  had  been  a  greater 
exertion  of  creative  power  than  in  the  spaces  of  equal  area  occupied  by 
the  new  adjacent  lands  ;  because,  within  the  period  in  which  St.  Helena 
had  acquired  its  peculiar  vegetation,  each  of  the  spots  supposed  to  be 
subsequently  converted  into  land  may  have  been  the  birth-place  of  a  great 
number  of  marine  animals  and  plants,  which  may  have  had  time  to 
scatter  themselves  far  and  wide  over  the  southern  Atlantic. 

Why  distinct  provinces  not  more  blended. — Perhaps  it  may  be  ob- 
jected to  some  parts  of  the  foregoing  train  of  reasoning,  that  during  the 
lapse  of  past  ages,  especially  during  many  partial  revolutions  of  the 
globe  of  comparatively  modern  date,  different  zoological  and  botanical 
provinces  ought  to  have  become  more  confounded  and  blended  together 
— that  the  distribution  of  species  approaches  too  nearly  to  what  might 
have  been  expected,  if  animals  and  plants  had  been  introduced  into  the 
globe  when  its  physical  geography  had  already  assumed  the  features 
which  it  now  wears ;  whereas  we  know  that,  in  certain  districts,  conside- 
rable geographical  changes  have  taken  place  since  species  identical  with 
those  now  in  being  were  created. 

BrocchVs  speculations  on  loss  of  species. — These  and  many  kindred 
topics  cannot  be  fully  discussed  until  we  have  considered,  not  merely  the 
general  laws  which  may  regulate  the  first  introduction  of  species,  but 
those  which  may  limit  their  duration  on  the  earth.  Brocchi  remarked, 
when  hazarding  some  interesting  conjectures  respecting  "the  loss  of 
species,"  that  a  modern  naturalist  had  no  small  assurance,  who  declared 
"  that  individuals  alone  were  capable  of  destruction,  and  that  species 
were  so  perpetuated  that  nature  could  not  annihilate  them,  so  long  as 
the  planet  lasted,  or  at  least  that  nothing  less  than  the  shock  of  a  comet, 
or  some  similar  disaster,  could  put  an  end  to  their  existence."*  The 
Italian  geologist,  on  the  contrary,  had  satisfied  himself  that  many  species 
of  Testacea,  which  formerly  inhabited  the  Mediterranean,  had  become 
extinct,  although  a  great  number  of  others,  which  had  been  the  contem- 
poraries of  those  lost  races,  still  survived.  He  came  to  the  opinion  that 
about  half  the  species  which  peopled  the  waters  when  the  Subapennine 
strata  were  deposited  had  gone  out  of  existence ;  and  in  this  inference  he 
does  not  appear  to  have  been  far  wrong. 

But,  instead  of  seeking  a  solution  of  this  problem,  like  some  other 
geologists  of  his  time,  in  a  violent  and  general  catastrophe,  Brocchi  en- 
deavoured to  imagine  some  regular  and  constant  law  by  which  species 
might  be  made  to  disappear  from  the  earth  gradually  and  in  succession. 
The  death,  he  suggested,  of  a  species  might  depend,  like  that  of  indivi- 
duals, on  certain  peculiarities  of  constitution  conferred  upon  them  at 
their  birth ;  and  as  the  longevity  of  the  one  depends  on  a  certain  force 
of  vitality,  which,  after  a  period,  grows  weaker  and  weaker,  so  the  dura- 
tion of  the  other  may  be  governed  by  the  quantity  of  prolific  power 

*  Necker,  Phytozool.  Philosoph.  p.  21.;  Brocchi,  Conch.  Foss.  Subap.,  tome 
i.  p.  229. 


CH.  XL.]  STATIONS   OF   PLANTS   AND    ANIMALS.  669 

bestowed  upon  the  species  which,  after  a  season,  may  decline  in  energy, 
so  that  the  fecundity  and  multiplication  of  individuals  may  be  gradually 
lessened  from  century  to  century,  "  until  that  fatal  term  arrives  when  the 
embryo,  incapable  of  extending  and  developing  itself,  abandons,  almost 
at  the  instant  of  its  formation,  the  slender  principle  of  life  by  which  it 
was  scarcely  animated, — and  so  all  dies  with  it." 

Now  we  may  coincide  in  opinion  with  the  Italian  naturalist,  as  to  the 
gradual  extinction  of  species  one  after  another,  by  the  operation  of  regular 
and  constant  causes,  without  admitting  an  inherent  principle  of  deteriora- 
tion in  their  physiological  attributes.  We  might  concede,  "  that  many 
species  are  on  the  decline,  and  that  the  day  is  not  far  distant  when  they 
will  cease  to  exist ;"  yet  deem  it  consistent  with  what  we  know  of  the 
nature  of  organic  beings,  to  believe  that  the  last  individuals  of  each  species 
retain  their  prolific  powers  in  their  full  intensity. 

Brocchi  has  himself  speculated  on  the  share  which  a  change  of  climate 
may  have  had  in  rendering  the  Mediterranean  unfit  for  the  habitation  of 
certain  Testacea,  which  still  continued  to  thrive  in  the  Indian  Ocean,  and 
of  others  which  were  now  only  represented  by  analogous  forms  within 
the  tropics.  He  must  also  have  been  aware  that  other  extrinsic  causes, 
such  as  the  progress  of  human  population,  or  the  increase  of  some  one 
of  the  inferior  animals,  might  gradually  lead  to  the  extirpation  of  a  par- 
ticular species,  although  its  fecundity  might  remain  to  the  last  unimpaired. 
If,  therefore,  amid  the  vicissitudes  of  the  animate  and  inanimate  world, 
there  are  known  causes  capable  of  bringing  about  the  decline  and  extir- 
pation of  species,  it  became  him  thoroughly  to  investigate  the  full  extent 
to  which  these  might  operate,  before  he  speculated  on  any  cause  of  so 
purely  hypothetical  a  kind  as  "  the  diminution  of  the  prolific  virtue." 

If  it  could  have  been  shown  that  some  wild  plant  had  insensibly  dwin- 
dled away  and  died  out,  as  sometimes  happens  to  cultivated  varieties  pro- 
pagated by  cuttings,  even  though  climate,  soil,  and  every  other  circum- 
stance, should  continue  identically  the  same — if  any  animal  had  perished 
while  the  physical  condition  of  the  earth,  and  the  number  and  force  of 
its  foes,  with  every  other  extrinsic  cause,  remain  unaltered,  then  might  we 
have  some  ground  for  suspecting  that  the  infirmities  of  age  creep  on  as 
naturally  on  species  as  upon  individuals.  But,  in  the  absence  of  such  ob- 
servations, let  us  turn  to  another  class  of  facts,  and  examine  attentively 
the  circumstances  which  determine  the  stations  of  particular  animals  and 
plants,  and  perhaps  we  shall  discover,  in  the  vicissitudes  to  which  these 
stations  are  exposed,  a  cause  fully  adequate  to  explain  the  phenomena 
under  consideration. 

Stations  of  plants  and  animals. — Stations  comprehend  all  the  cir- 
cumstances, whether  relating  to  the  animate  or  inanimate  world,  which 
determine  whether  a  given  plant  or  animal  can  exist  in  a  given  place ; 
so  that  if  it  be  shown  that  stations  can  become  essentially  modified  by 
the  influence  of  known  causes,  it  will  follow  that  species,  as  well  as  indi- 
viduals, are  mortal. 

Every  naturalist  is  familiar  with  the  fact,  that  although  in  a  particular 


670  EQUILIBRIUM   OF   SPECIES  [Cfl.  XL- 

country,  such  as  Great  Britain,  there  may  be  more  than  three  thousand 
species  of  plants,  ten  thousand  insects,  and  a  great  variety  in  each  of  the 
other  classes ;  yet  there  will  not  be  more  than  a  hundred,  perhaps  not 
half  that  number,  inhabiting  any  given  locality.  There  may  be  no  want 
of  space  in  the  supposed  tract :  it  may  be  a  large  mountain,  or  an  exten- 
sive moor,  or  a  great  river  plain,  containing  room  enough  for  individuals 
of  every  species  in  our  island  ;  yet  the  spot  will  be  occupied  by  a  few  to 
the  exclusion  of  many,  and  these  few  are  enabled,  throughout  long  periods, 
to  maintain  their  ground  successfully  against  every  intruder,  notwith- 
standing the  facilities  which  species  enjoy,  by  virtue  of  their  power  of  dif- 
fusion, of  invading  adjacent  territories. 

The  principal  causes  which  enable  a  certain  assemblage  of  plants  thus 
to  maintain  their  ground  against  all  others  depend,  as  is  well  known,  on 
the  relations  between  the  physiological  nature  of  each  species,  and  the 
climate,  exposure,  soil,  and  other  physical  conditions  of  the  locality.  Some 
plants  live  only  on  rocks,  others  in  meadows,  a  third  class  in  marshes. 
Of  the  latter,  some  delight  in  a  fresh-water  morass, — others  in  salt  marshes, 
where  their  roots  may  copiously  absorb  saline  particles.  Some  prefer  an 
alpine  region  in  a  warm  latitude,  where,  during  the  heat  of  summer, 
they  are  constantly  irrigated  by  the  cool  waters  of  melting  snows.  To 
others  loose  sand,  so  fatal  to  the  generality  of  species,  affords  the  most 
proper  station.  The  Carex  arenaria  and  the  Elymus  arenarius  acquire 
their  full  vigor  on  a  sandy  dune,  obtaining  an  ascendancy  over  the  very 
plants  which  in  a  stiff  clay  would  immediately  stifle  them. 

Where  the  soil  of  a  district  is  of  so  peculiar  a  nature  that  it  is  extremely 
favorable  to  certain  species,  and  agrees  ill  with  every  other,  the  former 
get  exclusive  possession  of  the  ground,  and,  as  in  the  case  of  heaths,  live 
in  societies.  In  like  manner  the  bog  moss  (Sphagnum)  is  fully  developed 
in  peaty  swamps,  and  becomes,  like  the  heath,  in  the  language  of  bota- 
nists, a  social  plant.  Such  monopolies,  however,  are  not  common,  for  they 
are  checked  by  various  causes.  Not  only  are  many  species  endowed  with 
equal  powers  to  obtain  and  keep  possession  of  similar  stations,  but  each 
plant,  for  reasons  not  fully  explained  by  the  physiologist,  has  the  property 
of  rendering  the  soil  where  it  has  grown  less  fitted  for  the  support  of 
other  individuals  of  its  own  species,  or  even  other  species  of  the  same 
family.  Yet  the  same  spot,  so  far  from  being  impoverished,  is  improved, 
for  plants  of  another  family.  Oaks,  for  example,  render  the  soil  more 
fertile  for  the  fir  tribe,  and  firs  prepare  the  soil  for  oaks.  Every  agricul- 
turist feels  the  force  of  this  law  of  the  organic  world,  and  regulates  ac- 
cordingly the  rotation  of  his  crops. 

Equilibrium  in  the  number  of  species,  how  preserved. — "  All  the  plants 
of  a  given  country,"  says  De  Candolle,  in  his  usual  spirited  style,  "  are  at 
war  one  with  another.  The  first  which  establish  themselves  by  chance 
in  a  particular  spot  tend,  by  the  mere  occupancy  of  space,  to  exclude 
other  species — the  greater  choke  the  smaller ;  the  longest  livers  replace 
those  which  last  for  a  shorter  period  ;  the  more  prolific  gradually  make 


CH.  XL.]  PRESERVED    BY   INSECTS.  671 

themselves  masters  of  the  ground,  which  species  multiplying  more  slowly 
would  otherwise  fill." 

In  this  continual  strife  it  is  not  always  the  resources  of  the  plant  itself 
which  enable  it  to  maintain  or  extend  its  ground.  Its  success  depends, 
in  a  great  measure,  on  the  number  of  its  foes  or  allies  among  the  animals 
and  plants  inhabiting  the  same  region.  Thus,  for  example,  a  herb 
which  loves  the  shade  may  multiply,  if  some  tree  with  spreading  boughs 
and  dense  foliage  flourish  in  the  neighborhood.  Another,  which,  if  un  • 
assisted,  would  be  overpowered  by  the  rank  growth  of  some  hardy  com- 
petitor, is  secure  because  its  leaves  are  unpalatable  to  cattle ;  which,  on 
the  other  hand,  annually  crop  down  its  antagonist,  and  rarely  suffer  it  to 
ripen  its  seed. 

•  Oftentimes  we  see  some  herb  which  has  flowered  in  the  midst  of  a 
thorny  shrub,  when  all  the  other  individuals  of  the  same  species,  in  the 
open  fields  around,  are  eaten  down,  and  cannot  bring  their  seed  to 
maturity.  In  this  case,  the  shrub  has  lent  his  armor  of  spines  and 
prickles  to  protect  the  defenceless  herb  against  the  mouths  of  the  cattle, 
and  thus  a  few  individuals  which  occupied,  perhaps,  the  most  unfavor- 
able station  in  regard  to  exposure,  soil,  and  other  circumstances,  may, 
nevertheless,  by  the  aid  of  an  ally,  become  the  principal  source  whereby 
the  winds  are  supplied  with  seeds  which  perpetuate  the  species  through- 
out the  surrounding  tract.  Thus,  in  the  New  Forest  in  Hampshire,  the 
young  oaks  which  are  not  consumed  by  the  deer,  or  uprooted  by  the 
swine,  are  indebted  to  the  holly  for  their  escape. 

In  the  above  examples  we  see  one  plant  shielding  another  from  the 
attacks  of  animals ;  but  instances  are,  perhaps,  still  more  numerous, 
where  some  animal  defends  a  plant  against  the  enmity  of  some  other 
subject  of  the  vegetable  kingdom. 

Scarcely  any  beast,  observes  a  Swedish  naturalist,  will  touch  the 
nettle,  but  fifty  different  kinds  of  insects  are  fed  by  it*  Some  of  these 
seize  upon  the  root,  others  upon  the  stem  ;  some  eat  the  leaves,  others 
devour  the  seeds  and  flowers ;  but  for  this  multitude  of  enemies,  the 
nettle  (  Urtica  dioica\  which  is  now  found  in  all  the  four  quarters  of  the 
globe,  would  annihilate  a  great  number  of  plants.  LinnaBiis  tells  us,  in 
his  "  Tour  in  Scania,"  that  goats  were  turned  into  an  island  which 
abounded  with  the  Agrostis  arundinacea,  where  they  perished  by  famine  ; 
but  horses  which  followed  them  grew  fat  on  the  same  plant.  The  goat, 
also,  he  says,  thrives  on  the  meadow-sweet  and  water-hemlock,  plants 
which  are  injurious  to  cattle.f 

Agency  of  insects. — Every  plant,  observes  Wilcke,  has  its  proper  in- 
sect allotted  to  it  to  curb  its  luxuriancy,  and  to  prevent  it  from  multiply- 
ing to  the  exclusion  of  others.  "Thus  grass  in  meadows  sometimes 
flourishes  so  as  to  exclude  all  other  plants  ;  here  the  Phalsena  graminis 
(Bombyx  gram^,  with  her  numerous  progeny,  finds  a  well-spread  table ; 

*  Amoen.  Acad.  vol.  vi.  p.  17.  §  12.  f  Ibid.  vol.  vii.  p.  409. 


672  EQUILIBRIUM   OF   SPECIES  [Cn.  XL. 

they  multiply  m  immense  numbers,  and  the  farmer,  for  some  years, 
laments  the  failure  of  his  crop ;  but  the  grass  being  consumed,  the 
moths  die  with  hunger,  or  remove  to  another  place.  Now  the  quantity 
of  grass  being  greatly  diminished,  the  other  plants,  which  were  before 
choked  by  it,  spring  up,  and  the  ground'  becomes  variegated  with  a  mul- 
titude of  different  species  of  flowers.  Had  not  nature  given  a  commis- 
sion to  this  minister  for  that  purpose,  the  grass  would  destroy  a  great 
number  of  species  of  vegetables,  of  which  the  equilibrium  is  now  kept 
up."* 

In  the  above  passage  allusion  is  made  to  the  ravages  committed  in 
1740,  and  the  two  following  years,  in  many  provinces  of  Sweden,  by  a 
most  destructive  insect.  The  same  moth  is  said  never  to  touch  the  fox- 
tail grass,  so  that  it  may  be  classed  as  a  most  active  ally  and  benefactor 
of  that  species,  and  as  peculiarly  instrumental  in  preserving  it  in  its 
present  abundance.f  A  discovery  of  Rolander,  cited  in  the  treatise  of 
Wilcke  above  mentioned,  affords  a  good  illustration  of  the  checks  and 
counter-checks  which  nature  has  appointed  to  preserve  the  balance  of 
power  among  species.  "The  Phalcena  strobilella  has  the  fir  cone 
assigned  to  it  to  deposit  its  eggs  upon  ;  the  young  caterpillars  coming 
out  of  the  shell  consume  the  cone  and  superfluous  seed ;  but,  lest  the 
destruction  should  be  too  general,  the  Ichneumon  strobilellce  lays  its  eggs 
in  the  caterpillar,  inserting  its  long  tail  in  the  openings  of  the  cone  till  it 
touches  the  included  insect,  for  its  body  is  too  large  to  enter.  Thus  it 
fixes  its  minute  egg  upon  the  caterpillar,  which  being  hatched,  destroys 
it."t 

Entomologists  enumerate  many  parallel  cases  where  insects,  appropri- 
ated to  certain  plants,  are  kept  down  by  other  insects,  and  these  again 
by  parasites  expressly  appointed  to  prey  on  them.§  Few  perhaps  are  in 
the  habit  of  duly  appreciating  the  extent  to  which  insects  are  active  in 
preserving  the  balance  of  species  among  plants,  and  thus  regulating  in- 
directly the  relative  numbers  of  many  of  the  higher  orders  of  terrestrial 
animals. 

The  peculiarity  of  their  agency  consists  in  their  power  of  suddenly 
multiplying  their  numbers  to  a  degree  which  could  only  be  accomplished 
in  a  considerable  lapse  of  time  in  any  of  the  larger  animals,  and  then  as 
instantaneously  relapsing,  without  the  intervention  of  any  violent  disturb- 
ing cause,  into  their  former  insignificance. 

If,  for  the  sake  of  employing,  on  different  but  rare  occasions,  a  power 
of  many  hundred  horses,  we  were  under  the  necessity  of  feeding  all  these 
animals  at  great  cost  in  the  intervals  when  their  services  were  not  re- 
quired, we  should  greatly  admire  the  invention  of  a  machine,  such  as  the 
steam-engine,  which  was  capable  at  any  moment  of  exerting  the  same 
degree  of  strength  without  any  consumption  of  food  during  periods  of 
inaction.  The  .same  kind  of  admiration  is  strongly  excited  when  we 
contemplate  the  powers  of  insect  life,  in  the  creation  of  which  the  Author 

*  Amcen.  Acad.,  vol.  vi.  p.  17.  §  11,  12.     f  Kirby  and  Spence,  vol.  i.  p.  178. 
J  Amoen.  Acad.,  vol.  vi.  p.  26.  §  14.          §  Kirby  and  Spence,  vol.  iv.  p.  218. 


CH.  XL.]  PRESERVED   BY  INSECTS.  673 

of  nature  nas  been  so  prodigal.  A  scanty  number  of  minute  individuals, 
to  be  detected  only  by  careful  research,  are  ready  in  a  few  days,  weeks, 
or  months,  to  give  birth  to  myriads,  which  may  repress  any  degree  ot 
monopoly  in  another  species,  or  remove  nuisances,  such  as  dead  carcases, 
which  might  taint  the  air.  But  no  sooner  has  the  destroying  commis- 
sion been  executed  than  the  gigantic  power  becomes  dormant — each  of 
the  mighty  host  soon  reaches  the  term  of  its  transient  existence,  and  the 
season  arrives  when  the  whole  species  passes  naturally  into  the  egg,  and 
thence  into  the  larva  and  pupa  state.  In  this  defenceless  condition  it 
may  be  destroyed  either  by  the  elements,  or  by  the  augmentation  of 
some  of  its  numerous  foes  which  may  prey  upon  it  in  the  early  stages  of 
its  transformation :  or  it  often  happens  that  in  the  following  year  the 
season  proves  unfavorable  to  the  hatching  of  the  eggs  or  the  develop- 
ment of  the  pupae. 

Thus  the  swarming  myriads  depart  which  may  have  covered  the  vege- 
tation like  the  aphides,  or  darkened  the  air  like  locusts.  In  almost  every 
season  there  are  some  species  which  in  this  manner  put  forth  their 
strength,  and  then,  like  Milton's  spirits,  which  thronged  the  spacious 
hall,  "  reduce  to  smallest  forms  their  shapes  immense" — 

So  thick  the  aery  crowd 

Swarm'd  and  were  straiten'd ;  till  the  signal  given, 
Behold  a  wonder!  they  but  now  who  seem'd 
In  bigness  to  surpass  earth's  giant  sons, 
Now  less  than  smallest  dwarfs. 

A  few  examples  will  illustrate  the  mode  in  which  this  force  operates. 
It  is  well  known  that,  among  the  countless  species  of  the  insect  creation, 
some  feed  on  animal,  others  on  vegetable  matter ;  and  upon  considering 
a  catalogue  of  eight  thousand  British  Insects  and  Arachnidse,  Mr.  Kirby 
found  that  these  two  divisions  were  nearly  a  counterpoise  to  each  other, 
the  carnivorous  being  somewhat  preponderant.  There  are  also  distinct 
species,  some  appointed  to  consume  living,  others  dead  or  putrid  animal 
and  vegetable  substances.  One  female,  of  Musca  carnaria,  will  give  birth 
to  twenty  thousand  young ;  and  the  larvse  of  many  flesh-flies  devour  so 
much  food  in  twenty-four  hours,  and  grow  so  quickly,  as  to  increase  their 
weight  two  hundred-fold !  In  five  days  after  being  hatched  they  arrive 
at  their  full  growth  and  size,  so  that  there  was  ground,  says  Kirby,  for  the 
assertion  of  Linnaeus,  that  three  flies  of  M.  vomitoria  could  devour  a  dead 
horse  as  quickly  as  a  lion*;  and  another  Swedish  naturalist  remarks,  that  so 
great  are  the  powers  of  propagation  of  a  single  species  even  of  the 
smallest  insects,  that  each  can  commit,  when  required,  more  ravages  than 
the  elephant.f 

Next  to  locusts,  the  aphides,  perhaps,  exert  the  greatest  power  over 
the  vegetable  world,  and,  like  them,  are  so  metimes  so  numerous  as  to 
darken  the  air.  The  multiplication  of  these  little  creatures  is  without 

*  Kirby  and  Spence,  vol.  i.  p.  250.  f  Wilcke,  Amoan,  Acad.  c.  LL 

43 


6T4  EQUILIBRIUM   OP   SPECIES.  [On.  XL. 

parallel,  and  almost  every  plant  has  its  peculiar  species.  Reaumur  has 
proved  that  in  five  generations  one  aphis  may  be  the  progenitor  of 
5,904,900,000  descendants ;  and  it  is  supposed  that  in  one  year  there 
may  be  twenty  generations.*  Mr.  Curtis  observes  that,  as  among  cater- 
pillars we  find  some  that  are  constantly  and  unalterably  attached  to  one 
or  more  particular  species  of  plants,  and  others  that  feed  indiscriminately 
on  most  sorts  of  herbage,  so  it  is  precisely  with  the  aphides :  some  are 
particular,  others  more  general  feeders  ;  and  as  they  resemble  other  insects 
in  this  respect,  so  they  do  also  in  being  more  abundant  in  some  years 
than  in  others.f  In  1793  they  were  the  chief,  and  in  1798  the  sole, 
cause  of  the  failure  of  the  hops.  In  1794,  a  season  almost  unparalleled 
for  drought,  the  hop  was  perfectly  free  from  them  ;  while  peas  and  beans, 
especially  the  former,  suffered  very  much  from  their  depredations. 

The  ravages  of  the  caterpillars  of  some  of  our  smaller  moths  afford  a 
good  illustration  of  the  temporary  increase  of  a  species.  The  oak-trees 
of  a  considerable  wood  have  been  stripped  of  their  leaves  as  bare  as  in 
winter  by  the  caterpillars  of  a  small  green  moth  (Tortrix  viridana), 
which  has  been  observed  the  year  following  not  to  abound  .J  The  silver 
Y  moth  (Plusia  gamma),  although  one  of  our  common  species,  is  not 
dreaded  by  us  for  its  devastations ;  but  legions  of  their  caterpillars  have 
at  times  created  alarm  in  France,  as  in  1735.  Reaumur  observes  that 
the  female  moth  lays  aboutffour  hundred  eggs;  so  that  if  twenty  cater- 
pillars were  distributed  in  a  garden,  and  all  lived  through  the  winter  and 
became  moths  in  the  succeeding  May,  the  eggs  laid  by  these,  if  half  of 
them  were  female  and  all  fertile,  would  in  the  next  generation  produce 
800,000  caterpillars.§  A  modern  writer,  therefore,  justly  observes  that, 
did  not  Providence  put  causes  in  operation  to  keep  them  in  due  bounds, 
the  caterpillars  of  this  moth  alone,  leaving  out  of  consideration  the  two 
thousand  other  British  species,  might  soon  destroy  more  than  half  of  our 
vegetation.|| 

In  the  latter  part  of  the  last  century  an  ant  most  destructive  to  the 
sugar-cane  (Formica  saccharivora),  appeared  in  such  infinite  hosts  in  the 
island  of  Granada,  as  to  put  a  stop  to  the  cultivation  of  that  vegetable. 
Their  numbers  were  incredible.  The  plantations  and  roads  were  filled 
with  them ;  many  domestic  quadrupeds,  together  with  rats,  mice,  and 
reptiles,  and  even  birds,  perished  in  consequence  of  this  plague.  It  was 
not  till  1780  that  they  were  at  length  annihilated  by  torrents  of  rain, 
which  accompanied  a  dreadful  hurricane.^" 

Devastations  caused  by  locusts. — We  may  conclude  by  mentioning 
some  instances  of  the  devastations  of  locusts  in  various  countries.  Among 
other  parts  of  Africa,  Cyrenaica  has  been  at  different  periods  infested  by 
myriads  of  these  creatures,  which  have  consumed  nearly  every  green 
thing.  The  effect  of  the  havoc  committed  by  them  may  be  estimated 

*  Kirby  and  Spence,  vol.  i.  p.  174.  f  Trans.  Linn.  Soc.,  vol.  vi. 

±  Lib.  Ent.  Know.,  Insect  Trans.,  p.  203.     See  Haworth,  Lep. 
§  Reaumur,  ii.  337.  ||  Lib.  Ent.   Know.,  Insect  Trans.,  p.   212. 

IT  Kirby  and  Spence,  vol.  i.  p.  183.     Castle,  Phil.  Trans.,  xxx.  346. 


CH.XL.]  DEVASTATIONS    CAUSED   BY   LOCUSTS.  675 

by  the  famine  they  occasioned.  St.  Augustin  mentions  a  plague  of  this 
kind  in  Africa,  which  destroyed  no  less  than  800,000  men  in  the  king- 
dom of  Massinissa  alone,  and  many  more  upon  the  territories  bordering 
upon  the  sea.  It  is  also  related,  that  in  the  year  591  an  infinite  army 
of  locusts  migrated  from  Africa  into  Italy ;  and,  after  grievously  ravaging 
the  country,  were  cast  into  the  sea,  when  there  arose  a  pestilence  from 
their  stench,  which  carried  off  nearly  a  million  of  men  and  beasts. 

In  the  Venetian  territory,  also,  in  1748,  more  than  thirty  thousand 
persons  are  said  to  have  perished  in  a  famine  occasioned  by  this  scourge ; 
and  other  instances  are  recorded  of  their  devastations  in  France,  Spain, 
Italy,  Germany,  &c.  In  different  parts  of  Russia  also,  Hungary,  and 
Poland,  in  Arabia  and  India,  and  other  countries,  their  visitations  have 
been  periodically  experienced.  Although  they  have  a  preference  for 
certain  plants,  yet,  when  these  are  consumed,  they  will  attack  almost  all 
the  remainder.  In  the  accounts  of  the  invasion  of  locusts,  the  state- 
ments which  appear  most  marvellous  relate  to  the  prodigious  mass  of 
matter  which  encumbers  the  sea  wherever  they  are  blown  into  it,  and  the 
pestilence  arising  from  its  putrefaction.  Their  dead  bodies  are  said  to 
have  been,  in  some  places,  heaped  one  upon  another,  to  the  depth  of  four 
feet,  in  Russia,  Poland  and  Lithuania ;  and  when,  in  Southern  Africa, 
they  were  driven  into  the  sea,  by  a  north-west  wind,  they  formed,  says 
Barrow,  along  the  shore,  for  fifty  miles,  a  bank  three  or  four  feet  high.* 
But  when  we  consider  that  forests  are  stripped  of  their  foliage,  and  the 
earth  of  its  green  garment  for  thousands  of  square  miles,  it  may  well  be 
supposed  that  the  volume  of  animal  matter  produced  may  equal  that  of 
great  herds  of  quadrupeds  and  flights  of  large  birds  suddenly  precipitated 
into  the  sea. 

The  occurrence  of  such  events,  at  certain  intervals,  in  hot  countries, 
like  the  severe  winters  and  damp  summers  returning  after  a  series  of 
years  in  the  temperate  zone,  may  affect  the  proportional  numbers  of 
almost  all  classes  of  animals  and  plants,  and  probably  prove  fatal  to  the 
existence  of  many  which  would  otherwise  thrive  there ;  while,  on  the 
contrary,  the  same  occurrences  can  scarcely  fail  to  be  favorable  to 
certain  species  which,  if  deprived  of  such  aid,  might  not  maintain  their 
ground. 

Although  it  may  usually  be  remarked  that  the  extraordinary  increase 
of  some  one  species  is  immediately  followed  and  checked  by  the  multi- 
plication of  another,  yet  this  does  not  always  happen ;  partly  because 
many  species  feed  in  common  on  the  same  kinds  of  food,  and  partly  be- 
cause many  kinds  of  food  are  often  consumed  indifferently  by  one  and 
the  same  species.  In  the  former  case,  where  a  variety  of  different  ani- 
mals have  precisely  the  same  taste,  as,  for  example,  when  many  insec- 
tivorous birds  and  reptiles  devour  alike  some  particular  fly  or  beetle,  the 
unusual  numbers  of  these  insects  may  cause  only  a  slight  and  almost 
imperceptible  augmentation  of  each  of  these  species  of  bird  and  reptile. 

*  Travels  in  Africa,  p.  257.     Kirby  and  Spence,  voL  i.  p.  216. 


676  RECIPROCAL   INFLUENCE   OF   SPECIES.  [Cu.  XL. 

In  the  other  instances,  where  one  animal  preys  on  others  of  almost  every 
class,  as  for  example,  where  our  English  buzzards  devour  not  only  small 
quadrupeds,  as  rabbits  and  field-mice,  but  also  birds,  frogs,  lizards,  and 
insects,  the  profusion  of  any  one  of  these  last  may  cause  all  such  general 
feeders  to  subsist  more  exclusively  upon  the  species  thus  in  excess,  by 
which  means  the  balance  may  be  restored. 

Agency  of  omnivorous  animals. — The  number  of  species  which  are 
nearly  omnivorous  is  considerable ;  and  although  every  animal  has,  per- 
haps, a  predilection  for  some  one  description  of  food  rather  than  another, 
yet  some  are  not  even  confined  to  one  of  the  great  kingdoms  of  the  or- 
ganic world.  Thus,  when  the  raccoon  of  the  West  Indies  can  procure 
neither  fowls,  fish,  snails,  nor  insects,  it  will  attack  the  sugar-canes,  and 
devour  various  kinds  of  grain.  The  civets,  when  animal  food  is  scarce, 
maintain  themselves  on  fruits  and  roots. 

Numerous  birds,  which  feed  indiscriminately  on  insects  and  plants, 
are  perhaps  more  instrumental  than  any  other  of  the  terrestrial  tribes  in 
preserving  a  constant  equilibrium  between  the  relative  numbers  of  differ- 
ent classes  of  animals  and  vegetables.  If  the  insects  become  very  nu- 
merous and  devour  the  plants,  these  birds  will  immediately  derive  a 
larger  portion  of  their  subsistence  from  insects,  just  as  the  Arabians, 
Syrians,  and  Hottentots  feed  on  locusts,  when  the  locusts  devour  their 
crops. 

Reciprocal  influence  of  aquatic  and  terrestrial  species. — The  intimate 
relation  of  the  inhabitants  of  the  water  to  those  of  the  land,  and  the  in- 
fluence exerted  by  each  on  the  relative  number  of  species,  must  not  be 
overlooked  amongst  the  complicated  causes  which  determine  the  exist- 
ence of  animals  and  plants  in  certain  regions.  A  large  portion  of  the 
amphibious  quadrupeds  and  reptiles  prey  partly  on  aquatic  plants  and 
animals,  and  in  part  on  terrestrial ;  and  a  deficiency  of  one  kind  of  prey 
causes  them  to  have  immediate  recourse  to  the  other.  The  voracity  of 
certain  insects,  as  the  dragon-fly,  for  example,  is  confined  to  the  water 
during  one  stage  of  their  transformations,  and  in  their  perfect  state  to  the 
air.  Innumerable  water-birds,  both  of  rivers  and  seas,  derive  in  like 
manner  their  food  indifferently  from  either  element ;  so  that  the  abun- 
dance or  scarcity  of  prey  in  one  induces  them  either  to  forsake  or  more 
constantly  to  haunt  the  other.  Thus  an  intimate  connection  between 
the  state  of  the  animate  creation  in  a  lake  or  river,  and  in  the  adjoining 
dry  land,  is  maintained ;  or  between  a  continent,  with  its  lakes  and  riv- 
ers, and  the  ocean.  It  is  well  known  that  many  birds  migrate,  during 
stormy  seasons,  from  the  sea-shore  into  the  interior,  in  search  of  food ; 
while  others,  on  the  contrary,  urged  by  like  wants,  forsake  their  inland 
haunts,  and  live  on  substances  rejected  by  the  tide. 

The  migration  of  fish  into  rivers  during  the  spawning  season  supplies 
another  link  of  the  same  kind.  Suppose  the  salmon  to  be  reduced  in 
numbers  by  some  marine  foes,  as  by  seals  and  grampuses,  the  consequence 
must  often  be,  that  in  the  course  of  a  few  years  the  otters  at  the  distance 
of  several  hundred  miles  inland  will  be  lessened  in  number  from  the 


CH.  XLL]  THE   EANGE   OF   SPECIES.  077 

scarcity  of  lish.  On  the  other  hand,  if  there  be  a  dearth  of  food  for  the 
young  fry  of  the  salmon  in  rivers  and  estuaries,  so  that  few  return  to  the 
sea,  the  sand  eels  and  other  marine  species,  which  are  usually  kept  down 
by  the  salmon,  will  swarm  in  greater  profusion. 

It  is  unnecessary  to  accumulate  a  greater  number  of  illustrations 
in  order  to  prove  that  the  stations  of  different  plants  and  animals 
depend  on  a  great  complication  of  circumstances, — on  an  immense 
variety  of  relations  in  the  state  of  the  inanimate  worlds.  Every  plant 
requires  a  certain  climate,  soil,  and  other  conditions,  and  often  the  aid 
of  many  animals,  in  order  to  maintain  its  ground.  Many  animals  feed 
on  certain  plants,  being  often  restricted  to  a  small  number,  and  some- 
times to  one  only;  other  members  of  the  animal  kingdom  feed  on 
plant-eating  species,  and  thus  become  dependent  on  the  conditions  of 
the  stations  not  only  of  their  prey,  but  of  the  plants  consumed  by  them. 

Having  duly  reflected  on  the  nature  and  extent  of  these  mutual 
relations  in  the  different  parts  of  the  organic  and  inorganic  worlds,  we 
may  next  proceed  to  examine  the  results  which  may  be  anticipated 
from  the  fluctuations  now  continually  in  progress  in  the  state  of  the 
earth's  surface,  and  in  the  geographical  distribution  of  its  living  pro- 
ductions. 


CHAPTER    XLI. 

EXTINCTION    OF    SPECIES. CHANGES    IN    THE    STATIONS    OF    ANIMALS. 

Extension  of  the  range  of  one  species  alters  the  condition  of  many  others — The 
first  appearance  of  a  new  specie8  causes  the  chief  disturbance — Changes 
known  to  have  resulted  from  the  advance  of  human  population — Whether 
man  increases  the  productive  powers  of  the  earth — Indigenous  quadrupeds 
and  birds  extirpated  in  Great  Britain — Extinction  of  the  dodo — Rapid  propa- 
gation of  domestic  quadrupeds  in  America — Power  of  exterminating  species 
no  prerogative  of  man — Concluding  remarks 

WE  have  seen  that  the  stations  of  animals  and  plants  depend  not 
merely  on  the  influence  of  external  agents  in  the  inanimate  world,  and 
the  relations  of  that  influence  to  the  structure  and  habits  of  each  spe- 
cies, but  also  on  the  state  of  the  contemporary  living  beings  which 
inhabit  the  same  part  of  the  globe.  In  other  words,  the  possibility  of 
the  existence  of  a  certain  species  in  a  given  place,  or  of  its  thriving 
more  or  less  therein,  is  determined  not  merely  by  temperature,  humi- 
dity, soil,  elevation,  and  other  circumstances  of  the  like  kind ;  but  also 
by  the  existence  or  non-existence,  the  abundance  or  scarcity,  of  a  parti- 
cular assemblage  of  other  plants  and  animals  in  the  same  region. 

If  it  be  shown  that  both  these  classes  of  circumstances,  whether 
relating  to  the  animate  or  inanimate  creation,  are  perpetually  changing, 
it  will  follow  that  species  are  subject  to  incessant  vicissitudes ;  and  if 


678  EFFECT  OF  THE  EXTENSION          [On.  XH 

the  result  of  these  mutations,  in  the  course  of  ages,  be  so  great  as 
materially  to  affect  the  general  condition  of  stations,  it  will  follow  that 
the  successive  destruction  of  species  must  now  be  part  of  the  regular 
and  constant  order  of  nature. 

Extension  of  the  range  of  one  species  alters  the  condition  of  the  others. 
— It  will  be  desirable,  first,  to  consider  the  effects  which  every  extension 
of  the  numbers  or  geographical  range  of  one  species  must  produce  on 
the  condition  of  others  inhabiting  the  same  regions.  When  the  neces- 
sary consequences  of  such  extensions  have  been  fully  explained,  the 
reader  will  be  prepared  to  appreciate  the  important  influence  which 
slight  modifications  in  the  physical  geography  of  the  globe  may  exert 
on  the  condition  of  organic  beings. 

In  the  first  place,  it  is  clear  that  when  any  region  is  stocked  with  as 
great  a  variety  of  animals  and  plants  as  the  productive  powers  of  that 
region  will  enable  it  to  support,  the  addition  of  any  new  species,  or  the 
permanent  numerical  increase  of  one  previously  established,  must  always 
be  attended  either  by  the  local  extermination  or  the  numerical  decrease 
of  some  other  species, 

There  may  undoubtedly  be  considerable  fluctuations  from  year  to 
year,  and  the  equilibrium  may  be  again  restored  without  any  permanent 
alteration  ;  for,  in  particular  seasons,  a  greater  supply  of  heat,  humidity, 
or  other  causes,  may  augment  the  total  quantity  of  vegetable  produce, 
in  which  case  all  the  animals  subsisting  on  vegetable  food,  and  others 
which  prey  on  them,  may  multiply  without  any  one  species  giving  way  : 
but  whilst  the  aggregate  quantity  of  vegetable  produce  remains  unaltered, 
the  progressive  increase  of  one  animal  or  plant  implies  the  decline  of 
another. 

All  agriculturists  and  gardeners  are  familiar  with  the  fact  that  when 
weeds  intrude  themselves  into  the  space  appropriated  to  cultivated  spe- 
cies, the  latter  are  starved  in  their  growth,  or. stifled.  If  we  abandon 
for  a  short  time  a  field  or  garden,  a  host  of  indigenous  plants, 

The  darnel,  hemlock,  and  rank  fumitory, 

pour  in  and  obtain  the  mastery,  extirpating  the  exotics,  or  putting  an 
end  to  the  monopoly  of  some  native  plants. 

If  we  inclose  a  park,  and  stock  it  with  as  many  deer  as  the  herbage 
will  support,  we  cannot  add  sheep  without  lessening  the  number  of  the 
deer ;  nor  can  other  herbivorous  species  be  subsequently  introduced,  unless 
the  individuals  of  each  species  in  the  park  become  fewer  in  proportion. 

So,  if  there  be  an  island  where  leopards  are  the  only  beasts  of  prey, 
and  the  lion,  tiger,  and  hyaena  afterwards  enter,  the  leopards,  if  they 
stand  their  ground,  will  be  reduced  in  number.  If  the  locusts  then 
arrive  and  swarm  greatly,  they  may  deprive  a  large  number  of  plant- 
eating  animals  of  their  food,  and  thereby  cause  a  famine,  not  only 
among  them,  but  among  the  beasts  of  prey :  certain  species  perhaps, 
which  had  the  weakest  footing  in  the  island,  may  thus  be  annihilated. 


On.  XLL]  OF   THE   RANGE   OP   SPECIES.  679 

We  have  seen  how  many  distinct  geographical  provinces  there  are  of 
aquatic  and  terrestrial  species,  and  how  great  are  the  powers  of  migra- 
tion conferred  on  different  classes,  whereby  the  inhabitants  of  one  region 
may  be  enabled  from  time  to  time  to  invade  another,  and  do  actually  so 
migrate  and  diffuse  themselves  over  new  countries.  Now,  although  our 
knowledge  of  the  history  of  the  animate  creation  dates  from  so  recent  a 
period,  that  we  can  scarcely  trace  the  advance  or  decline  of  any  animal 
or  plant,  except  in  those  cases  where  the  influence  of  man  has  intervened ; 
yet  we  can  easily  conceive  what  must  happen  when  some  new  colony  of 
wild  animals  or  plants  enters  a  region  for  the  first  time,  and  succeeds  in 
establishing  itself. 

Supposed  effects  of  the  first  entrance  of  the  polar  bear  into  Iceland. — 
Let  us  consider  how  great  are  the  devastations  committed  at  certain 
periods  by  the  Greenland  bears,  when  they  are  drifted  to  the  shores  of 
Iceland  in  considerable  numbers  on  the  ice.  These  periodical  invasions 
are  formidable  even  to  man ;  so  that  when  the  bears  arrive,  the  inhabit- 
ants collect  together,  and  go  in  pursuit  of  them  with  fire-arms — each 
native  who  slays  one  being  rewarded  by  the  King  of  Denmark.  The 
Danes  of  old,  when  they  landed  in  their  marauding  expeditions  upon  our 
coast,  hardly  excited  more  alarm,  nor  did  our  islanders  muster  more 
promptly  for  the  defence  of  their  lives  and  property  against  the  common 
enemy,  than  the  modern  Icelanders  against  these  formidable  brutes.  It 
often  happens,  says  Henderson,  that  the  natives  are  pursued  by  the  bear 
when  he  has  been  long  at  sea,  and  when  his  natural  ferocity  has  been 
heightened  by  the  keenness  of  hunger  ;  if  unarmed,  it  is  frequently  by 
stratagem  only  that  they  make  their  escape.* 

Let  us  cast  our  thoughts  back  to  the  period  when  the  first  polar  bears 
reached  Iceland,  before  it  was  colonized  by  the  Norwegians  in  874  :  we 
may  imagine  the  breaking  up  of  an  immense  barrier  of  ice  like  that 
which,  in  1816  and  the  following  year,  disappeared  from  the  east  coast 
of  Greenland,  which  it  had  surrounded  for  four  centuries.  By  the  aid  of 
such  means  of  transportation  a  great  number  of  these  quadrupeds  might 
effect  a  landing  at  the  same  time,  and  the  havoc  which  they  would  make 
among  the  species  previously  settled  in  the  island  would  be  terrific.  The 
deer,  foxes,  seals,  and  even  birds,  on  which  these  animals  sometimes  prey, 
would  be  soon  thinned  down. 

But  this  would  be  a  part  only,  and  probably  an  insignificant  portion, 
of  the  aggregate  amount  of  change  brought  about  by  the  new  invader. 
The  plants  on  which  the  deer  fed,  being  less  consumed  in  consequence  of 
the  lessened  numbers  of  that  herbivorous  species,  would  soon  supply  more 
food  to  several  insects,  and  probably  to  some  terrestrial  testacea,  so  that 
the  latter  would  gain  ground.  The  increase  of  these  would  furnish  other 
insects  and  birds  with  food,  so  that  the  numbers  of  these  last  would  b« 
augmented.  The  diminution  of  the  seals  would  afford  a  respite  to  soms 
fish  which  they  had  persecuted  ;  and  these  fish,  in  their  turn,  would  then 

*  Journal  of  a  Residence  in  Iceland,  p.  276. 


680  DISTURBANCE   CAUSED   BY   NEW  SPECIES.  [On.  XLL 

multiply  and  press  upon  their  peculiar  prey.  Many  water-fowls,  the  eggs 
and  young  of  which  are  devoured  by  foxes,  would  increase  when  the  foxes 
were  thinned  down  by  the  bears ;  and  the  fish  on  which  the  water-fowls 
subsisted  would  then,  in  their  turn,  be  less  numerous.  Thus  the  numeri- 
cal proportions  of  a  great  number  of  the  inhabitants,  both  of  the  land  and 
sea,  might  be  permanently  altered  by  the  settling  of  one  new  species  in 
the  region ;  and  the  changes  caused  indirectly  would  ramify  through  all 
classes  of  the  living  creation,  and  be  almost  endless. 

An  actual  illustration  of  what  we  have  here  only  proposed  hypotheti- 
cally,  is  in  some  degree  afforded  by  the  selection  of  small  islands  by  the 
eider  duck  for  its  residence  during  the  season  of  incubation,  its  nest  being 
seldom  if  ever  found  on  the  shores  of  the  main  land,  or  even  of  a  large 
island.  The  Icelanders  are  so  well  aware  of  this,  that  they  have  expended 
a  great  deal  of  labor  in  forming  artificial  islands,  by  separating  from  the 
main  land  certain  promontories,  joined  to  it  by  narrow  isthmuses.  This 
insular  position  is  necessary  to  guard  against  the  destruction  of  the  eggs 
and  young  birds,  by  foxes,  dogs,  and  other  animals.  One  year,  says 
Hooker,  it  happened  that,  in  the  small  island  of  Vidoe,  adjoining  the  coast 
of  Iceland,  a  fox  got  over  upon  the  ice,  and  caused  great  alarm,  as  an  im- 
mense number  of  ducks  were  then  sitting  on  their  eggs  or  young  ones. 
It  was  long  before  he  was  taken,  which  was  at  last,  however,  effected  by 
bringing  another  fox  to  the  island,  and  fastening  it  by  a  string  near  the 
haunt  of  the  former,  by  which  he  was  allured  within  shot  of  the  hunter.* 

The  first  appearance  of  a  new  species  causes  the  chief  disturbance. — It 
is  usually  the  first  appearance  of  an  animal  or  plant,  in  a  region  to  which 
it  was  previously  a  stranger,  that  gives  rise  to  the  chief  alteration  ;  since, 
after  a  time,  an  equilibrium  is  again  established.  But  it  must  require 
ages  before  such  a  new  adjustment  of  the  relative  forces  of  so  many  con- 
flicting agents  can  be  definitely  settled.  The  causes  in  simultaneous 
action  are  so  numerous,  that  they  admit  of  an  almost  infinite  number  of 
combinations ;  and  it  is  necessary  that  all  these  should  have  occurred  once 
before  the  total  amount  of  change,  capable  of  flowing  from  any  new  dis- 
turbing force,  can  be  estimated. 

Thus,  for  example,  suppose  that  once  in  two  centuries  a  frost  of  un- 
usual intensity,  or  a  volcanic  eruption  of  great  violence  accompanied  by 
floods  from  the  melting  of  glaciers,  should  occur  in  Iceland ;  or  an  epi- 
demic disease,  fatal  to  the  larger  number  of  individuals  of  some  one  species, 
and  not  affecting  others, — these,  and  a  variety  of  other  contingencies,  all 
of  which  may  occur  at  once,  or  at  periods  separated  by  different  intervals 
of  time,  ought  to  happen  before  it  would  be  possible  for  us  to  declare  what 
ultimate  alteration  the  presence  of  any  new  comer,  such  as  the  bear  before 
mentioned,  might  occasion  in  the  animal  population  of  the  isle. 

Every  new  condition  in  the  state  of  the  organic  or  inorganic  creation, 
a  new  animal  or  plant,  an  additional  snow-clad  mountain,  any  perma- 
nent change,  however  slight  in  comparison  to  the  whole,  gives  rise  to  a 

*  Tour  in  Iceland,  vol.  i.  p.  64,  2nd  edit. 


CH.  XLL]  CHANGES    CAUSED   BY   MAN.  681 

new  order  of  things,  and  may  make  a  material  change  in  regard  to  some 
one  or  more  species.  Yet  a  swarm  of  locusts,  or  a  frost  of  extreme 
intensity,  or  an  epidemic  disease,  may  pass  away  without  any  great 
apparent  derangement;  no  species  may  be  lost,  and  all  may  soon 
recover  their  former  relative  numbers,  because  the  same  scourges  may 
have  visited  the  region  again  and  again,  at  preceding  periods.  Every 
plant  that  was  incapable  of  resisting  such  a  degree  of  cold,  every  animal 
which  was  exposed  to  be  entirely  cut  off  by  an  epidemic  or  by  famine 
caused  by  the  consumption  of  vegetation  by  the  locusts,  may  have 
perished  already,  so  that  the  subsequent  recurrence  of  similar  catastro- 
phes is  attended  only  by  a  temporary  change. 

Changes  caused  by  Man 

We  are  best  acquainted  with  the  mutations  brought  about  by  the 
progress  of  human  population,  and  the  growth  of  plants  and  animals 
favored  by  man.  To  these,  therefore,  we  should  in  the  first  instance 
turn  our  attention.  If  we  conclude,  from  the  concurrent  testimony  of 
history  and  of  the  evidence  yielded  by  geological  data,  that  man  is, 
comparatively  speaking,  of  very  modern  origin,  we  must  at  once  perceive 
how  great  a  revolution  in  the  state  of  the  animate  world  the  increase 
of  the  human  race,  considered  merely  as  consumers  of  a  certain  quantity 
of  organic  matter,  must  necessarily  cause. 

Whether  man  increases  the  productive  powers  of  the  earth. — It  may 
perhaps,  be  said,  that  man  has,  in  some  degree,  compensated  for  the 
appropriation  to  himself  of  so  much  food,  by  artificially  improving  the 
natural  productiveness  of  soils,  by  irrigation,  manure,  and  a  judicious 
intermixture  of  mineral  ingredients  conveyed  from  different  localities. 
But  it  admits  of  reasonable  doubt  whether,  upon  the  whole,  we  fertilize 
or  impoverish  the  lands  which  we  occupy.  This  assertion  may  seem 
startling  to  many ;  because  they  are  so  much  in  the  habit  of  regarding 
the  sterility  or  productiveness  of  land  in  relation  to  the  wants  of  man, 
and  not  as  regards  the  organic  world  generally.  It  is  difficult,  at  first, 
to  conceive,  if  a  morass  is  converted  into  arable  land,  and  made  to  yield 
a  crop  of  grain,  even  of  moderate  abundance,  that  we  have  not  improved 
the  capabilities  of  the  habitable  surface — that  we  have  not  empowered 
it  to  support  a  larger  quantity  of  organic  life.  In  such  cases,  however, 
a  tract,  before  of  no  utility  to  man,  may  be  reclaimed,  and  become  of 
high  agricultural  importance,  though  it  may,  nevertheless,  yield  a 
scantier  vegetation.  If  a  lake  be  drained,  and  turned  into  a  meadow, 
the  space  will  provide  sustenance  to  man,  and  many  terrestrial  animals 
serviceable  to  him,  but  not,  perhaps,  so  much  food  as  it  previously  yielded 
to  the  aquatic  races. 

If  the  pestiferous  Pontine  marshes  were  drained,  and  covered  with 
corn,  like  the  plains  of  the  Po,  they  might,  perhaps,  feed  a  smaller 
number  of  animals  than  they  do  now  ;  for  these  morasses  are  filled  with 
herds  of  buffaloes  and  swine,  and  they  swarm  with  birds,  reptiles,  and 
insects. 


682  CHANGES   CAUSED   BY  MAN.  [On.  XLL 

The  felling  of  dense  and  lofty  forests,  which  covered,  even  within  the 
records  of  history,  a  considerable  space  on  the  globe,  now  tenanted  by 
civilized  man,  must  generally  have  lessened  the  amount  of  vegetable 
food  throughout  the  space  where  these  woods  grew.  We  must  also 
take  into  our  account  the  area  covered  by  towns,  and  a  still  larger  sur- 
face occupied  by  roads. 

If  we  force  the  soil  to  bear  extraordinary  crops  one  year,  we  are, 
perhaps,  compelled  to  let  it  lie  fallow  the  next.  But  nothing  so  much 
counterbalances  the  fertilizing  effects  of  human  art  as  the  extensive 
cultivation  of  foreign  herbs  and  shrubs,  which,  although  they  are  often 
more  nutritious  to  man,  seldom  thrive  with  the  same  rank  luxuriance  as 
the  native  plants  of  a  district.  Man  is,  in  truth,  continually  striving  to 
diminish  the  natural  diversity  of  the  stations  of  animals  and  plants  in 
every  country,  and  to  reduce  them  all  to  a  small  number  fitted  for 
species  of  economical  use.  He  may  succeed  perfectly  in  attaining  his 
object,  even  though  the  vegetation  be  comparatively  meagre,  and  the 
total  amount  of  animal  life  be  greatly  lessened. 

Spix  and  Martius  have  given  a  lively  description  of  the  incredible 
number  of  insects  which  lay  waste  the  crops  in  Brazil,  besides  swarms 
of  monkeys,  flocks  of  parrots,  and  other  birds,  as  well  as  the  paca, 
agouti,  and  wild  swine.  They  describe  the  torment  which  the  planter 
and  the  naturalist  suffer  from  the  musquitoes,  and  the  devastation  of 
the  ants  and  blattas ;  they  speak  of  the  dangers  to  which  they  were 
exposed  from  the  jaguar,  the  poisonous  serpents,  crocodiles,  scorpions, 
centipedes,  and  spiders.  But  with  the  increasing  population  and  culti- 
vation of  the  country,  say  these  naturalists,  these  evils  will  gradually 
diminish ;  when  the  inhabitants  have  cut  down  the  woods,  drained  the 
marshes,  made  roads  in  all  directions,  and  founded  villages  and  towns, 
man  will,  by  degrees,  triumph  over  the  rank  vegetation  and  the  noxious 
animals,  and  all  the  elements  will  second  and  amply  recompense  his 
activity.* 

The  number  of  human  beings  now  peopling  the  earth  is  supposed  to 
amount  to  eight  hundred  millions,  so  that  we  may  easily  understand 
how  great  a  number  of  beasts  of  prey,  birds,  and  animals  of  every  class, 
this  prodigious  population  must  have  displaced,  independently  of  the 
still  more  important  consequences  which  have  followed  from  the 
derangement  brought  about  by  man  in  the  relative  numerical  strength 
of  particular  species. 

Indigenous  quadrupeds  and  birds  extirpated  in  Great  Britain. — Let 
us  make  some  inquiries  into  the  extent  of  the  influence  which  the  pro- 
gress of  society  has  exerted  during  the  last  seven  or  eight  centuries,  in 
altering  the  distribution  of  indigenous  British  animals.  Dr.  Fleming 
has  prosecuted  this  inquiry  with  his  usual  zeal  and  ability ;  and  in  a 
memoir  on  the  subject  has  enumerated  the  best-authenticated  examples 
of  the  decrease  or  extirpation  of  certain  species  during  a  period  when 

*  Travels  in  Brazil,  vol.  i.  p.  260. 


CH.  XLL]  CHANGES   CAUSED   BY   MAN.  683 

our  population  has  made  the  most  rapid  advances.     I  shall  offer  a  brief 
outline  of  his  results.* 

The  stag,  as  well  as  the  fallow  deer  and  the  roe,  were  formerly  so 
abundant  in  our  island,  that,  according  to  Lesley,  from  five  hundred  to 
a  thousand  were  sometimes  slain  at  a  hunting  match ;  but  the  native 
races  would  already  have  been  extinguished,  had  they  not  been  care- 
fully preserved  in  certain  forests.  The  otter,  the  marten,  and  the 
polecat,  were  also  in  sufficient  numbers  to  be  pursued  for  the  sake  of 
their  fur ;  but  they  have  now  been  reduced  within  very  narrow  bounds. 
The  wild  cat  and  fox  have  also  been  sacrificed  throughout  the  greater 
part  of  the  country,  for  the  security  of  the  poultry-yard  or  the  fold. 
Badgers  have  been  expelled  from  nearly  every  district,  which  at  former 
periods  they  inhabited. 

Besides  these,  which  have  been  driven  out  from  their  favorite  haunts, 
and  everywhere  reduced  in  number,  there  are  some  which  have  been 
wholly  extirpated  ;  such  as  the  ancient  breed  of  indigenous  horses,  and 
the  wild  boar ;  of  the  wild  oxen  a  few  remains  are  still  preserved  in 
some  of  the  old  English  parks.  The  beaver,  which  is  eagerly  sought 
after  for  its  fur,  had  become  scarce  at  the  close  of  the  ninth  century ; 
and,  by  the  twelfth  century,  was  only  to  be  met  with,  according  to 
Giraldus  de  Barri,  in  one  river  in  Wales,  and  another  in  Scotland.  The 
wolf,  once  so  much  dreaded  by  our  ancestors,  is  said  to  have  maintained 
its  ground  in  Ireland  so  late  as  the  beginning  of  the  eighteenth  century 
(17 10),  though  it  had  been  extirpated  in  Scotland  thirty  years  before, 
and  in  England  at  a  much  earlier  period.  The  bear,  which,  in  Wales, 
was  regarded  as  a  beast  of  the  chase  equal  to  the  hare  or  the  boarf, 
only  perished,  as  a  native  of  Scotland,  in  the  year  1057/t 

Many  native  birds  of  prey  have  also  been  the  subjects  of  unremitting 
persecution.  The  eagles,  larger  hawks,  and  ravens,  have  disappeared 
from  the  more  cultivated  districts.  The  haunts  of  the  mallard,  the  snipe, 
the  redshank,  and  the  bittern,  have  been  drained  equally  with  the 
summer  dwellings  of  the  lapwing  and  the  curlew.  But  these  species  still 
linger  in  some  portion  of  the  British  isles ;  whereas  the  larger  capercailzies 
or  wood  grouse,  formerly  natives  of  the  pine-forests  of  Ireland  and  Scot- 
land, have  been  destroyed  within  the  last  sixty  years.  The  egret  and 
the  crane,  which  appear  to  have  been  formerly  very  common  in  Scot- 
land, are  now  only  occasional  visitants.^ 

The  bustard  (Otis  tarda),  observes  Graves,  in  his  British  Ornitholo- 
gy ||,  "  was  formerly  seen  in  the  downs  and  heaths  of  various  parts  of 
our  island,  in  flocks  of  forty  or  fifty  birds ;  whereas  it  is  now  a  circum- 
stance of  rare  occurrence  to  meet  with  a  single  individual."  Bewick 
also  remarks,  "  that  they  were  formerly  more  common  in  this  island 
than  at  present ;  they  are  now  found  only  in  the  open  counties  of  the 


Ed.  Phil.  Journ.,  No.  xxii.  p.  287.  Oct.  1824.         f  Ray.  Syn.  Quad.,  p.  214. 
Fleming,  Ed.  Phil.  Journ.,  No.  xxii.  p.  295.  §  Fleming,  ibid.,  p.  292. 

Vol.  iil  London,  1821. 


684  EXTINCTION  OF  THE  DODO.  [Ca  XLI. 

south  and  east — in  the  plains  of  Wiltshire,  Dorsetshire,  and  some  parts 
of  Yorkshire."*  In  the  few  years  that  have  elapsed  since  Bewick 
wrote,  this  bird  has  entirely  disappeared  from  Wiltshire  and  Dorsetshire. 

These  changes,  it  may  be  observed,  are  derived  from  very  imperfect 
memorials,  and  relate  only  to  the  larger  and  more  conspicuous  animals 
inhabiting  a  small  spot  on  the  globe  ;  but  they  cannot  fail  to  exalt  our 
conception  of  the  enormous  revolutions  which,  in  the  course  of  several 
thousand  years,  the  whole  human  species  must  have  effected. 

Extinction  of  the  dodo. — The  kangaroo  and  the  emu  are  retreating 
rapidly  before  the  progress  of  colonization  in  Australia ;  and  it  scarcely 
admits  of  doubt,  that  the  general  cultivation  of  that  country  must  lead 
to  the  extirpation  of  both.  The  most  striking  example  of  the  loss, 
even  within  the  last  two  centuries,  of  a  remarkable  species,  is  that  of 
the  dodo — a  bird  first  seen  by  the  Dutch,  when  they  landed  on  the  Isle 
of  France,  at  that  time  uninhabited,  immediately  after  the  discovery  of 
the  passage  to  the  East  Indies  by  the  Cape  of  Good  Hope.  It  was  of 
a  large  size,  and  singular  form  ;  its  wings  short,  like  those  of  an  ostrich, 
and  wholly  incapable  of  sustaining  its  heavy  body,  even  for  a  short 
flight.  In  its  general  appearance  it  differed  from  the  ostrich,  cassowary, 
or  any  known  bird.f 

Many  naturalists  gave  figures  of  the  dodo  after  the  commencement 
of  the  seventeenth  century ;  and  there  is  a  painting  of  it  in  the  British 
Museum,  which  is  said  to  have  been  taken  from  a  living  individual. 
Beneath  the  painting  is  a  leg,  in  a  fine  state  of  preservation,  which  orni- 
thologists are  agreed  cannot  belong  to  any  other  known  bird.  In  the 
museum  at  Oxford,  also,  there  is  a  foot  and  a  head  in  an  imperfect  state. 

In  spite  of  the  most  active  search,  during  the  last  century,  no  infor- 
mation respecting  the  dodo  was  obtained,  and  some  authors  have  gone 
so  far  as  to  pretend  that  it  never  existed;  but  a  great  mass  of  satis- 
factory evidence  in  favor  of  its  recent  existence  has  now  been  collected 
by  Mr.  BroderipJ  and  by  Mr.  Strickland  and  Dr.  Melville.  Mr.  Strick- 
land, agreeing  with  Professor  Reinhardt,  of  Copenhagen,  in  referring 
the  dodo  to  the  Columbida3,  calls  it  a  "vulture-like  frugivorous  pigeon." 
It  appears,  also,  that  another  short-winged  bird  of  the  same  order,  called 
"  The  Solitaire,"  inhabited  the  small  island  of  Rodrigues,  300  miles  east 
of  the  Mauritius,  and  has  been  exterminated  by  man,  as  have  one  or 
two  different  but  allied  birds  of  the  Isle  of  Bourbon. § 

*  Land  Birds,  vol.  i.  p.  316.  ed.  1821. 

f  Some  have  complained  that  inscriptions  on  tomb-stones  convey  no  general 
information,  except  that  individuals  were  born  and  died,  accidents  which  must 
happen  alike  to  all  men.  But  the  death  of  a  species  is  so  remarkable  an  event 
in  natural  history  that  it  deserves  commemoration,  and  it  is  with  no  small 
interest  that  we  learn,  from  the  archives  of  the  University  of  Oxford,  the  exact 
day  and  year  when  the  remains  of  the  last  specimen  of  the  dodo,  which  had 
been  permitted  to  rot  in  the  Ashmolean  Museum,  were  cast  away.  The  relics, 
we  are  told,  were  "  a  musaeo  subducta,  annuente  vice-cancellario  aliisque  cura- 
toribus,  ad  ea  lustranda  convocatis,  die  Januarii  8vo,  A.D.  1755."  Zool.  Journ. 
No.  12.  p.  559.^1828.  {  Penny  Cyclopaedia,  "Dodo."  1837. 

§  Messrs.  Strickland  and  Melville  on  "  the  Dodo  and  its  Kindred."  London,  1848. 


CH.  XLL]  DOMESTIC    QUADRUPEDS   IN   AMERICA.  685 

JRapid  propagation  of  domestic  quadrupeds  over  the  American  conti- 
nent.-^Next  to  the  direct  agency  of  man,  his  indirect  influence  in 
multiplying  the  numbers  of  large  herbivorous  quadrupeds  of  domesti- 
cated races  may  be  regarded  as  one  of  the  most  obvious  causes  of  the 
extermination  of  species.  On  this,  and  on  several  other  grounds,  the 
introduction  of  the  horse,  ox,  and  other  mammalia,  into  America,  and 
their  rapid  propagation  over  that  continent  within  the  last  three  centu- 
ries, is  a  fact  of  great  importance  in  natural  history.  The  extraordi- 
nary herds  of  wild  cattle  and  horses  which  overran  the  plains  of  South 
America  sprung  from  a  very  few  pairs  first  carried  over  by  the  Spaniards ; 
and  they  prove  that  the  wide  geographical  range  of  large  species  in 
great  continents  does  not  necessarily  imply  that  they  have  existed  there 
from  remote  periods. 

Humboldt  observes,  in  his  Travels,  on  the  authority  of  Azzara,  that 
it  is  believed  there  exist,  in  the  Pampas  of  Buenos  Ayres,  twelve  million 
cows  and  three  million  horses,  without  comprising,  in  this  enumeration, 
the  cattle  that  have  no  acknowledged  proprietor.  In  the  Llanos  of  Carac- 
cas,  the  rich  hateros,  or  proprietors  of  pastoral  farms,  are  entirely  igno- 
rant of  the  number  of  cattle  they  possess.  The  young  are  branded 
with  a  mark  peculiar  to  each  herd,  and  some  of  the  most  wealthy 
owners  mark  as  many  as  fourteen  thousand  a  year.*  In  the  northern 
plains,  from  the  Orinoco  to  the  lake  of  Maraycabo,  M.  Depons  reckoned 
that  1,200,000  oxen,  180,000  horses,  and  90,000  mules,  wandered  at 
large,  f  In  some  parts  of  the  valley  of  the  Mississippi,  especially  in  the 
country  of  the  Osage  Indians,  wild  horses  are  immensely  numerous. 

The  establishment  of  black  cattle  in  America  dates  from  Columbus's 
second  voyage  to  St.  Domingo.  They  there  multiplied  rapidly ;  and 
that  island  presently  became  a  kind  of  nursery  from  which  these  ani- 
mals were  successively  transported  to  various  parts  of  the  continental 
coast,  and  from  thence  into  the  interior.  Notwithstanding  these 
numerous  exportations,  in  twenty-seven  years  after  the  discovery  of  the 
island,  herds  of  four  thousand  head,  as  we  learn  from  Oviedo,  were  not 
uncommon,  and  there  were  even  some  that  amounted  to  eight  thousand. 
In  1587,  the  number  of  hides  exported  from  St.  Domingo  alone,  accord- 
ing to  Acosta's  report,  was  35,444 ;  and  in  the  same  year  there  were 
exported  64,350  from  the  ports  of  New  Spain.  This  was  in  the  sixty- 
fifth  year  after  the  taking  of  Mexico,  previous  to  which  event  the 
Spaniards,  who  came  into  that  country,  had  not  been  able  to  engage  in 
anything  else  than  war.  J  Every  one  is  aware  that  these  animals  are 
now  established  throughout  the  American  continent  from  Canada  to 
the  Straits  of  Magellan. 

The  ass  has  thriven  very  generally  in  the  New  World  ;  and  we  learn 
from  Ulloa,  that  in  Quito  they  ran  wild,  and  multiplied  in  amazing 
numbers,  so  as  to  become  a  nuisance.  They  grazed  together  in  herds, 

*  Pers.  Na,r.  vol.  iv. 

f  Quarterly  Review,  vol.  xxi.  p.  335.  \  Ibid. 


686  DOMESTIC   QUADRUPEDS   IN   AMERICA.  [Ca  XLI 

and  when  attacked  defended  themselves  with  their  mouths.  If  a  horse 
happened  to  stray  into  the  places  where  they  fed,  they  all  fell  upon  him, 
and  did  not  cease  biting  and  kicking  till  they  left  him  dead.* 

The  first  hogs  were  carried  to  America  by  Columbus,  and  established 
in  the  Island  of  St.  Domingo  the  year  following  its  discovery,  in 
November,  1493.  In  succeeding  years  they  were  introduced  into  other 
places  where  the  Spaniards  settled ;  and,  in  the  space  of  half  a  century, 
they  were  found  established  in  the  New  World,  from  the  latitude  of 
25°  north,  to  the  40th  degree  of  south  latitude.  Sheep,  also,  and 
goats  have  multiplied  enormously  in  the  New  World,  as  have  also  the 
cat  and  the  rat;  which  last,  as  before  stated,  has  been  imported  unin- 
tentionally in  ships.  The  dogs  introduced  by  man  which  have  at 
different  periods  become  wild  in  America,  hunted  in  packs,  like  the 
wolf  and  the  jackall,  destroying  not  only  hogs,  but  the  calves  and 
foals  of  the  wild  cattle  and  horses. 

Ulloa  in  his  voyage,  and  Buffon  on  the  authority  of  old  writers,  relate 
a  fact  which  illustrates  very  clearly  the  principle  before  explained,  of 
the  check  which  the  increase  of  one  animal  necessarily  offers  to  that  of 
another.  The  Spaniards  had  introduced  goats  into  the  Island  of  Juan 
Fernandez,  where  they  became  so  prolific  as  to  furnish  the  pirates  who 
infested  those  seas  with  provisions.  In  order  to  cut  off  this  resource 
from  the  buccaneers,  a  number  of  dogs  were  turned  loose  into  the  island ; 
and  so  numerous  did  they  become  in  their  turn,  that  they  destroyed  the 
goats  in  every  accessible  part,  after  which  the  number  of  the  wild  dogs 
again  decreased,  f 

Increase  of  rein-deer  imported  into  Iceland. — As  an  example  of  the 
rapidity  with  which  a  large  tract  may  become  peopled  by  the  offspring 
of  a  single  pair  of  quadrupeds,  it  may  be  mentioned  that  in  the  year 
1773  thirteen  rein-deer  were  exported  from  Norway,  only  three  of  which 
reached  Iceland.  These  were  turned  loose  into  the  mountains  of  Guld- 
bringe  Syssel,  where  they  multiplied  so  greatly,  in  the  course  of  forty 
years,  that  it  was  not  uncommon  to  meet  with  herds,  consisting  of  from 
forty  to  one  hundred,  in  various  districts. 

The  rein-deer,  observes  a  modern  writer,  is  in  Lapland  a  loser  by  his 
connexion  with  man,  but  Iceland  will  be  this  creature's  paradise. 
There  is,  in  the  interior,  a  tract  which  Sir.  G.  Mackenzie  computes  at 
not  less  than  forty  thousand  square  miles,  without  a  single  human  habi- 
tation, and  almost  entirely  unknown  to  the  natives  themselves.  There 
are  no  wolves :  the  Icelanders  will  keep  out  the  bears ;  and  the  rein- 
deer, being  almost  unmolested  by  man,  will  have  no  enemy  whatever, 
unless  it  has  brought  with  it  its  own  tormenting  gad-fly.  J 

Besides  the  quadrupeds  before  enumerated,  our  domestic  fowls  have 
also  succeeded  in  the  West  Indies  and  America,  where  they  have  the 

*  Ulloa's  Voyage.     Wood's  Zoog.  vol.  i.  p.  9. 

f  Buffon,  vol.  v.  p.  100.     Ulloa's  Voyage,  vol.  ii.  p.  220. 

±  Travels  in  Iceland  in  1810,  p.  342. 


CH.  XLI]  CHANGES    CAUSED   BY  MAN.  687 

common  fowl,  the  goose,  the  duck,  the  peacock,  the  pigeon,  and  the 
guinea-fowl.  As  these  were  often  taken  suddenly  from  the  temperate 
to  very  hot  regions,  they  were  not  reared  at  first  without  much  difficulty : 
but  after  a  few  generations,  they  became  familiarized  to  the  climate, 
which,  in  many  cases,  approached  much  nearer  than  that  of  Europe  to 
the  temperature  of  their  original  native  countries. 

The  fact  of  so  many  millions  of  wild  and  tame  individuals  of  our  do 
mestic  species,  almost  all  of  them  the  largest  quadrupeds  and  birds, 
having  been  propagated  throughout  the  new  continent  within  the  short 
period  that  has  elapsed  since  the  discovery  of  America,  while  no  appre- 
ciable improvement  can  have  been  made  in  the  productive  powers  of 
that  vast  continent,  affords  abundant  evidence  of  the  extraordinary 
changes  which  accompany  the  diffusion  and  progressive  advancement  of 
the  human  race  over  the  globe.  That  it  should  have  remained  for  us  to 
witness  such  mighty  revolutions  is  a  proof,  even  if  there  was  no  other 
evidence,  that  the  entrance  of  man  into  the  planet  is,  comparatively 
speaking,  of  extremely  modern  date,  and  that  the  effects  of  his  agency 
are  only  beginning  to  be  felt. 

Population  which  the  globe  is  capable  of  supporting. — A  modern 
writer  has  estimated,  that  there  are  in  America  upwards  of  four  million 
square  miles  of  useful  soil,  each  capable  of  supporting  200  persons  ;  and 
nearly  six  million,  each  mile  capable  of  supporting  490  persons.*  If  this 
conjecture  be  true,  it  will  follow,  as  that  author  observes,  that  if  the 
natural  resources  of  America  were  fully  developed,  it  would  afford  suste- 
nance to  five  times  as  great  a  number  of  inhabitants  as  the  entire  mass 
of  human  beings  existing  at  present  upon  the  globe.  The  new  continent, 
he  thinks,  though  less  than  half  the  size  of  the  old,  contains  an  equal 
quantity  of  useful  soil,  and  much  more  than  an  equal  amount  of  produc- 
tive power.  Be  this  as  it  may,  we  may  safely  conclude  that  the  amount 
of  human  population  now  existing  constitutes  but  a  small  proportion  of 
that  which  the  globe  is  capable  of  supporting,  or  which  it  is  destined  to 
sustain  at  no  distant  period,  by  the  rapid  progress  of  society,  especially 
in  America,  Australia,  and  certain  parts  of  the  old  continent. 

Power  of  exterminating  species  no  prerogative  of  man. — But  if  we  re- 
flect that  many  millions  of  square  miles  of  the  most  fertile  land,  occupied 
originally  by  a  boundless  variety  of  animal  and  vegetable  forms,  have 
been  already  brought  under  the  dominion  of  man,  and  compelled,  in  a 
great  measure,  to  yield  nourishment  to  him,  and  to  a  limited  number  of 
plants  and  animals  which  he  has  caused  to  increase,  we  must  at  once  be 
convinced,  that  the  annihilation  of  a  multitude  of  species  has  already  been 
effected,  and  will  continue  to  go  on  hereafter,  in  certain  regions,  in  a  still 
more  rapid  ratio,  as  the  colonies  of  highly  civilized  nations  spread  them- 
selves over  unoccupied  lands. 

Yet,  if  we  wield  the  sword  of  extermination  as  we  advance,  we  have  no 
reason  to  repine  at  the  havoc  committed,  nor  to  fancy,  with  the  Scottish 

*  Maclaren,  art.  America,  Encyc.  Brit 


688  CHANGES   CAUSED   BY   MAN.  [Co.  XLI. 

poet,  that  "  we  violate  the  social  union  of  nature  ;"  or,  complain,  with  the 
melancholy  Jacques,  that  we 

Are  mere  usurpers,  tyrants,  and  what's  worse. 
To  fright  the  animals  and  to  kill  them  up 
In  their  assign'd  and  native  dwelling-place. 

We  have  only  to  reflect,  that  in  thus  obtaining  possession  of  the  earth 
by  conquest,  and  defending  our  acquisitions  by  force,  we  exercise  no  ex- 
clusive prerogative.  Every  species  which  has  spread  itself  from  a  small 
point  over  a  wide  area  must,  in  like  manner,  have  marked  its  progress 
by  the  diminution  or  the  entire  extirpation  of  some  other,  and  must 
maintain  its  ground  by  a  successful  struggle  against  the  encroachments  of 
other  plants  and  animals.  That  minute  parasitic  plant,  called  "  the  rust"  in 
wheat,  has,  like  the  Hessian  fly,  the  locust,  and  the  aphis,  caused  famines 
ere  now  amongst  the  "  lords  of  the  creation."  The  most  insignificant  and 
diminutive  species,  whether  in  the  animal  or  vegetable  kingdom,  have 
each  slaughtered  their  thousands,  as  they  disseminated  themselves  over 
the  globe,  as  well  as  the  lion,  when  first  it  spread  itself  over  the  tropical 
regions  of  Africa. 

Concluding  remarks. — Although  we  have  as  yet  considered  one  class 
only  of  the  causes  (the  organic)  by  which  species  may  become  extermi- 
nated, yet  it  cannot  but  appear  evident  that  the  continued  action  of  these 
alone,  throughout  myriads  of  future  ages,  must  work  an  entire  change 
in  the  state  of  the  organic  creation,  not  merely  on  the  continents  and 
islands,  where  the  power  of  man  is  chiefly  exerted,  but  in  the  great 
ocean,  where  his  control  is  almost  unknown.  The  mind  is  prepared  by 
the  contemplation  of  such  future  revolutions  to  look  for  the  signs  of 
others,  of  an  analogous  nature,  in  the  monuments  of  the  past.  Instead 
of  being  astonished  at  the  proofs  there  manifested  of  endless  mutations 
in  the  animate  world,  they  will  appear  to  one  who  has  thought  profound- 
ly on  the  fluctuations  now  in  progress,  to  afford  evidence  in  favor  of  the 
uniformity  of  the  system,  unless,  indeed,  we  are  precluded  from  speaking 
of  uniformity  when  we  characterize  a  principle  of  endless  variation. 


CHAPTER  XLII. 

EXTINCTION    OF    SPECIES. INFLUENCE    OF    INORGANIC    CAUSES. 

Powers  of  diffusion  indispensable,  that  each  species  may  maintain  its  ground — 
How  changes  in  physical  geography  affect  the  distribution  of  species — Rate 
of  the  change  of  species  due  to  this  cause  cannot  be  uniform — Every  change 
in  the  physical  geography  of  large  regions  tends  to  the  extinction  of  species 
— Effects  of  a  general  alteration  of  climate  on  the  migration  of  species — 
Gradual  refrigeration  would  cause  species  in  the  northern  and  southern 
hemispheres  to  become  distinct — Elevation  of  temperature  the  reverse — 
Effects  on  the  condition  of  species  which  must  result  from  inorganic  changes 
inconsistent  with  the  theory  of  transmutation. 

Powers  of  diffusion  indispensable,  that  each  species  may  maintain  its 
ground. — HAVING  shown  in  the  last  chapter,  how  considerably  the 
numerical  increase  or  the  extension  of  the  geographical  range  of  any 
one  species  must  derange  the  numbers  and  distribution  of  others,  let  us 
now  direct  our  attention  to  the  influence  which  the  inorganic  causes 
described  in  the  second  book  are  continually  exerting  on  the  habitations 
of  species. 

So  great  is  the  instability  of  the  earth's  surface,  that  if  nature  were 
not  continually  engaged  in  the  task  of  sowing  seeds  and  colonizing 
animals,  the  depopulation  of  a  certain  portion  of  the  habitable  sea  and 
land  w£>uld  in  a  few  years  be  considerable.  Whenever  a  river  transports 
sediment  into  a  lake  or  sea,  so  as  materially  to  diminish  its  depth,  the 
aquatic  animals  and  plants  which  delight  in  deep  water  are  expelled : 
the  tract,  however,  is  not  allowed  to  remain  useless ;  but  is  soon  peopled 
by  species  which  require  more  light  and  heat,  and  thrive  where  the 
water  is  shallow.  Every  addition  made  to  the  land  by  the  encroach- 
ment of  the  delta  of  a  river  banishes  many  subaqueous  species  from 
their  native  abodes ;  but  the  new-formed  plain  is  not  permitted  to  lie 
unoccupied,  being  instantly  covered  with  terrestrial  vegetation.  The 
ocean  devours  continuous  lines  of  sea-coasts,  and  precipitates  forests  or 
rich  pasture  land  into  the  waves:  but  this  space  is  not  lost  to  the 
animate  creation ;  for  shells  and  sea-weeds  soon  adhere  to  the  new- 
made  cliffs,  and  numerous  fish  people  the  channel  which  the  current  has 
scooped  out  for  itself.  No  sooner  has  a  volcanic  island  been  thrown 
up  than  some  lichens  begin  to  grow  upon  it,  and  it  is  sometimes  clothed 
with  verdure  while  smoke  and  ashes  are  still  occasionally  thrown  from 
the  crater.  The  cocoa,  pandanus,  and  mangrove  take  root  upon  the 
coral  reef  before  it  has  fairly  risen  above  the  waves.  The  burning 
stream  of  lava  that  descends  from  Etna  rolls  through  the  stately  forest, 
and  converts  to  ashes  every  tree  and  herb  which  stands  in  its  way ;  but 
the  black  strip  of  land  thus  desolated  is  covered  again  in  the  course  of 
time,  with  oaks,  pines,  and  chestnuts,  as  luxuriant  as  those  which  the 
fiery  torrent  swept  away. 

44 


690  EXTINCTION    OP   SPECIES.  [CiL  XLII. 

Every  flood  and  landslip,  every  wave  which  a  hurricane  or  earth- 
quake throws  upon  the  shore,  every  sKower  of  volcanic  dust  and  ashes 
which  buries  a  country  far  and  wide  to  the  depth  of  many  feet,  every 
advance  of  the  sand-flood,  every  conversion  of  salt  water  into  fresh 
when  rivers  alter  their  main  channel  of  discharge,  every  permanent 
variation  in  the  rise  or  fall  of  tides  in  an  estuary — these  and  countless 
other  causes  displace,  in  the  course  of  a  few  centuries,  certain  plart-r 
and  animals  from  stations  which  they  previously  occupied.  If,  there- 
fore, the  Author  of  nature  had  not  been  prodigal  of  those  numerous 
contrivances,  before  alluded  to,  for  spreading  all  classes  of  organic 
beings  over  the  earth — if  he  had  not  ordained  that  the  fluctuations  of 
the  animate  and  inanimate  creation  should  be  in  perfect  harmony  with 
each  other,  it  is  evident  that  considerable  spaces,  now  the  most  habi- 
table on  the  globe,  would  soon  be  as  devoid  of  life  as  are  the  Alpine 
snows,  or  the  dark  abysses  of  the  ocean,  or  the  moving  sands  of  the 
Sahara. 

The  powers,  then,  of  migraiion  and  diffusion  conferred  on  animals 
and  plants  are  indispensable  to  enable  them  to  maintain  their  ground, 
and  would  be  necessary,  even  though  it  were  never  intended  that  a 
species  should  gradually  extend  its  geographical  range.  But  a  facility 
of  shifting  their  quarters  being  once  given,  it  cannot  fail  to  happen  that 
the  inhabitants  of  one  province  should  occasionally  penetrate  into  some 
other ;  since  the  strongest  of  those  barriers  which  I  before  described  as 
separating  distinct  regions  are  all  liable  to  be  thrown  down,  one  after 
the  other,  during  the  vicissitudes  of  the  earth's  surface. 

How  changes  in  physical  Geography  affect  the  distribution  of  species. 
— The  numbers  and  distribution  of  particular  species  are  affected  in 
two  ways,  by  changes  in  the  physical  geography  of  the  earth  : — First, 
these  changes  promote  or  retard  the  migrations  of  species  ;  secondly, 
they  alter  the  physical  conditions  of  the  localities  which  sp'ecies  inhabit. 
If  the  ocean  should  gradually  wear  its  way  through  an  isthmus,  like 
that  of  Suez,  it  would  open  a  passage  for  the  intermixture  of  the  aquatic 
tribes  of  two  seas  previously  disjoined,  and  would,  at  the  same  time, 
close  a  free  communication  which  the  terrestrial  plants  and  animals  of 
two  continents  had  before  enjoyed.  These  would  be,  perhaps,  the  most 
important  consequences,  in  regard  to  the  distribution  of  species,  which 
would  result  from  the  breach  made  by  the  sea  in  such  a  spot ;  but 
there  would  be  others  of  a  distinct  nature,  such  as. the  conversion  of  a 
certain  tract  of  land,  which  formed  the  isthmus,  into  sea.  This  space, 
previously  occupied  by  terrestrial  plants  and  animals,  would  be  imme- 
diately delivered  over  to  the  aquatic ;  a  local  revolution  which  might 
have  happened  in  innumerable  other  parts  of  the  globe,  without  being 
attended  by  any  alteration  in  the  blending  together  of  species  of  two 
distinct  provinces. 

Rate  of  change  of  species  cannot  be  uniform. — This  observation  leads 
me  to  point  out  one  of  the  most  interesting  conclusions  to  which  we 
are  led  by  the  contemplation  of  the  vicissitudes  of  the  inanimate  world 


Cii.  XLIL]  EFFECT   OF   GEOGRAPHICAL   CHANGES.  691 

in  relation  to  those  of  the  animate.  It  is  clear  that,  if  the  agency  of 
inorganic  causes  be  uniform,  as  I  have  supposed,  they  must  operate 
very  irregularly  on  the  state  of  organic  beings,  so  that  the  rate  accord- 
ing to  which  these  will  change  in  particular  regions  will  not  be  equal  in 
equal  periods  of  time. 

I  am  not  about  to  advocate  the  doctrine  of  general  catastrophes 
recurring  at  certain  intervals,  as  in  the  ancient  Oriental  cosmogonies,  nor 
do  I  doubt  that,  if  very  considerable  periods  of  equal  duration  could  be 
compared  one  with  another,  the  rate  of  change  in  the  living,  as  well  as 
in  the  inorganic  world,  might  be  nearly  uniform ;  but  if  we  regard  each 
of  the  causes  separately,  which  we  know  to  be  at  present  the  most 
instrumental  in  remodelling  the  state  of  the  surface,  we  shall  find  that  we 
must  expect  each  to  be  in  action  for  thousands  of  years,  without  producing 
any  extensive  alterations  in  the  habitable  surface,  and  then  to  give  rise, 
during  a  very  brief  period,  to  important  revolutions. 

Illustration  derived  from  subsidences. — I  shall  illustrate  this  principle 
by  a  few  of  the  most  remarkable  examples  which  present  themselves.  In 
the  course  of  the  last  century,  as  we  have  seen,  a  considerable  number  of 
instances  are  recorded  of  the  solid  surface,  whether  covered  by  water  or 
not,  having  been  permanently  sunk  or  upraised  by  subterranean  move- 
ments. Most  of  these  convulsions  are  only  accompanied  by  temporary 
fluctuations  in  the  state  of  limited  districts,  and  a  continued  repetition  of 
these  events  for  thousands  of  years  might  not  produce  any  decided  change 
in  the  state  of  many  of  those  great  zoological  or  botanical  provinces  of 
which  I  have  sketched  the  boundaries. 

When,  for  example,  large  parts  of  the  ocean  and  even  of  inland  seas 
are  a  thousand  fathoms  or  upwards  in  depth,  it  is  a  matter  of  no  moment 
to  the  animate  creation  that  vast  tracts  should  be  heaved  up  many  fathoms 
at  certain  intervals,  or  should  subside  to  the  same  amount.  Neither  can 
any  material  revolution  be  produced  in  South  America  either  in  the  ter- 
restrial or  the  marine  plants  or  animals  by  a  series  of  shocks  on  the  coast 
ofi  Chili,  each  of  which,  like  that  of  Penco,  in  1751,  should  uplift  the 
coast  about  twenty-five  feet.  Nor  if  the  ground  sinks  fifty  feet  at  a  time, 
as  in  the  harbor  of  Port  Royal,  in  Jamaica,  in  1692,  will  such  alterations 
of  level  work  any  general  fluctuations  in  the  state  of  opganic  beings 
inhabiting  the  West  Indian  Islands,  or  the  Carribean  Sea. 

It  is  only  when  the  subterranean  powers,  by  shifting  gradually  the 
points  where  their  principal  force  is  developed,  happen  to  strike  upon 
some  particular  region  where  a  slight  change  of  level  immediately  affects 
the  distribution  of  land  and  water,  or  the  state  of  the  climate,  or  the 
barriers  between  distinct  groups  of  species  over  extensive  areas,  that  the 
rate  of  fluctuation  becomes  accelerated,  and  may,  in  the  course  of  a  few 
years  or  centuries,  work  mightier  changes  than  had  been  experienced  in 
myriads  of  antecedent  years. 

Thus,  for  example,  a  repetition  of  subsidences  causing  the  narrow 
isthmus  of  Panama  to  sink  down  a  few  hundred  feet,  would,  in  a  few 
centuries,  bring  about  a  great  revolution  in  the  state  of  the  animate  crea- 


692  EFFECT   OF   GEOGRAPHICAL    CHANGES          [Cii.  XLIL 

tion  in  the  western  hemisphere.  Thousands  of  aquatic  species  would  pass, 
for  the  first  time,  from  the  Caribbean  Sea  into  the  Pacific ;  and  thousands 
of  others,  before  peculiar  to  the  Pacific  Ocean,  would  make  their  way 
into  the  Caribbean  Sea,  the  Gulf  of  Mexico,  and  the  Atlantic.  A  con- 
siderable modification  would  probably  be  occasioned  by  the  same  event 
in  the  direction  or  volume  of  the  Gulf  stream,  and  thereby  the  tempera- 
ture of  the  sea  and  the  contiguous  lands  might  be  altered  as  far  as  the 
influence  of  that  current  extends.  A  change  of  climate  might  thus  be 
produced  in  the  ocean  from  Florida  to  Spitzbergen,  and  in  many  countries 
of  North  America,  Europe,  and  Greenland.  Not  merely  the  heat,  but 
the  quantity  of  rain  which  falls,  would  be  altered  in  certain  districts,  so 
that  many  species  would  be  excluded  from  tracts  where  they  before 
flourished :  others  would  be  reduced  in  number ;  and  some  would  thrive 
more  and  multiply.  The  seeds  also  and  the  fruits  of  plants  would  no 
longer  be  drifted  in  precisely  the  same  directions,  nor  the  eggs  of  aquatic 
animals ;  neither  would  species  be  any  longer  impeded  in  their  migrations 
towards  particular  stations  before  shut  out  from  them  by  their  inability 
to  cross  the  mighty  current. 

Let  us  take  another  example  from  a  part  of  the  globe  which  is  at 
present  liable  to  suffer  by  earthquakes,  namely,  the  low  sandy  tract  which 
intervenes  between  the  sea  of  Azof  and  the  Caspian.  If  there  should 
occur  a  sinking  down  to  a  trifling  amount,  and  such  ravines  should  be 
formed  as  might  be  produced  by  a  few  earthquakes,  not  more  consider- 
able than  have  fallen  within  our  limited  observation  during  the  last  150 
years,  the  waters  of  the  Sea  of  Azof  would  pour  rapidly  into  the  Caspian, 
which,  according  to  the  measurements  lately  made  by  the  Academy  of 
St.  Petersburg,  is  84  feet  below  the  level  of  the  Black  Sea.*  The  Sea 
of  Azof  would  immediately  borrow  from  the  Black  Sea,  that  sea  again 
from  the  Mediterranean,  and  the  Mediterranean  from  the  Atlantic,  so  that 
an  inexhaustible  current  would  pour  down  into  the  low  tracts  of  Asia 
bordering  the  Caspian,  by  which  all  the  Bandy  salt  steppes  adjacent  to 
that  sea  would  be  inundated.  An  area  of  several  thousand  square  leagues, 
now  below  the  level  of  the  Mediterranean,  would  be  converted  from  land 
into  sea. 

Illustration  derived  from  the  elevation  of  land. — Let  us  next  imagine 
a  few  cases  of  the  elevation  of  land  of  small  extent  at  certain  critical 
points,  as,  for  example,  in  the  shallowest  part  of  the  Straits  of  Gibraltar, 
where  the  deepest  soundings  from  the  African  to  the  European  side  give 
only  220  fathoms.  In  proportion  as  this  submarine  barrier  of  rock  was 
upheaved,  the  whole  channel  ^ould  be  contracted  in  width  and  depth, 
and  the  volume  of  water  which  the  current  constantly  flowing  from  the 
Atlantic  pours  into  the  Mediterranean  would  be  lessened.  But  the  loss 
of  the  inland  sea  by  evaporation  would  remain  the  same ;  so  that  being 
no  longer  able  to  draw  on  the  ocean  for  a  supply  sufficient  to  restore  its 
equilibrium,  it  must  sink,  and  leave  dry  a  certain  portion  of  land  around 

*  See  a  note  on  this  subject,  chap.  x.  p.  157. 


CH.  XLIL]  ON   THE    DISTRIBUTION   OF   SPECIES.  693 

its  borders.  The  current  which  now  flows  constantly  out  of  the  Black 
Sea  into  the  Mediterranean  would  then  rush  in  more  rapidly,  and  the 
level  of  the  Mediterranean  would  be  thereby  prevented  from  falling  so 
low ;  but  the  level  of  the  Black  Sea  would,  for  the  same  reason,  sink ;  so 
that  when,  by  a  continued  series  of  elevatory  movements,  the  Straits  of 
Gibraltar  had  become  completely  closed  up,  we  might  expect  large  and 
level  sandy  steppes  to  surround  both  the  Black  Sea  and  Mediterranean, 
like  those  occurring  at  present  on  the  skirts  of  the  Caspian  and  the  Lake 
of  Aral.  The  geographical  range  of  hundreds  of  aquatic  species  would  be 
thereby  circumscribed,  and  that  of  hundreds  of  terrestrial  plants  and 
animals  extended. 

A  line  of  submarine  volcanos  crossing  the  channel  of  some  strait,  and 
gradually  choking  it  up  with  ashes  and  lava,  might  produce  a  new  bar- 
rier as  effectually  as  a  series  of  earthquakes ;  especially  if  thermal  springs, 
charged  with  carbonate  of  lime,  silica,  and  other  mineral  ingredients, 
should  promote  the  rapid  multiplication  of  corals  and  shells,  and  cement 
them  together  with  solid  matter  precipitated  during  the  intervals  between 
eruptions.  Suppose  in  this  manner  a  stoppage  to  be  caused  of  the  Ba- 
hama channel  between  the  bank  of  that  name  and  the  coast  of  Florida. 
This  insignificant  revolution,  confined  to  a  mere  spot  in  the  bottom  of 
the  ocean,  would,  by  diverting  the  main  current  of  the  Gulf  stream,  give 
rise  to  extensive  changes  in  the  climate  and  distribution  of  animals  and 
plants  inhabiting  the  northern  hemisphere. 

Illustration  from  the  formation  of  new  islands. — A  repetition  of  ele- 
vatory movements  of  earthquakes  might  continue  over  an  area  as  exten- 
sive as  Europe,  for  thousands  of  ages,  at  the  bottom  of  the  ocean,  in  cer- 
tain regions,  and  produce  no  visible  effects ;  whereas,  if  they  should  ope- 
rate in  some  shallow  parts  of  the  Pacific,  amid  the  coral  archipelagos, 
they  would  soon  give  birth  to  a  new  continent.  Hundreds  of  volcanic 
islands  may  be  thrown  up,  and  become  covered  with  vegetation,  without 
causing  more  than  local  fluctuations  in  the  animate  world  ;  but  if  a  chain 
like  the  Aleutian  archipelago,  or  the  Kurile  Isles,  run  for  a  distance  of 
many  hundred  miles,  so  as  to  form  an  almost  uninterrupted  communica- 
tion between  two  continents,  or  two  distant  islands,  the  migrations  of 
plants,  birds,  insects,  and  even  of  some  quadrupeds,  may  cause,  in  a  short 
time,  an  extraordinary  series  of  revolutions  tending  to  augment  the  range 
of  some  animals  and  plants,  and  to  limit  that  of  others.  A  new  archi- 
pelago might  be  formed  in  the  Mediterranean,  the  Bay  of  Biscay,  and  a 
thousand  other  places,  and  might  produce  less  important  events  than  one 
rock  which  should  rise  up  between  Australia  and  Java,  so  placed  that 
winds  and  currents  might  cause  an  interchange  of  the  plants,  insects, 
and  birds. 

From  the  wearing  through  of  an  isthmus. — If  we  turn  from  the  ig- 
neous to  the  aqueous  agents,  we  find  the  same  tendency  to  an  irregular 
rate  of  change,  naturally  connected  with  the  strictest  uniformity  in  the 
energy  of  those  causes.  When  the  sea,  for  example,  gradually  encroaches 
upon  both  sides  of  a  narrow  isthmus,  as  that  of  Sleswick,  separating  the 


694  EFFECT   OF   GEOGRAPHICAL   CHANGES  [Cn.  XLIL 

North  Sea  from  the  Baltic,  where,  as  before  stated,  the  cliffs  on  both  the 
opposite  coasts  are  wasting  away*,  no  material  alteration  results  for 
thousands  of  years,  save  only  that  there  is  a  progressive  conversion  of  a 
small  strip  of  land  into  water.  A  few  feet  only,  or  a  few  yards,  are  an- 
nually removed  ;  but  if,  at  last,  the  partition  should  be  broken  down,  and 
the  tides  of  the  ocean  should  enter  by  a  direct  passage  into  the  inland  sea, 
instead  of  going  by  a  circuitous  route  through  the  Cattegat,  a  body  of 
salt  water  would  sweep  up  as  for  as  the  Gulfs  of  Bothnia  and  Finland, 
the  waters  of  which  are  now  brackish,  or  almost  fresh ;  and  this  revolu- 
tion would  be  attended  by  the  local  annihilation  of  many  species. 

Similar  consequences  must  have  resulted  on  a  small  scale,  when  the 
sea  opened  its  way  through  the  Isthmus  of  Staveren  in  the  thirteenth 
century,  forming  a  union  between  an  inland  lake  and  the  ocean,  and 
opening,  in  the  course  of  one  century,  a  shallow  strait,  more  than  half  as 
wide  as  the  narrowest  part  of  that  which  divides  England  from  France. 

Changes  in  physical  geography  which  must  occasion  extinction  of  species. 
— It  will  almost  seem  superfluous,  after  I  have  thus  traced  the  important 
modifications  in  the  condition  of  living  beings  which  flow  from  changes 
of  trifling  extent,  to  argue  that  entire  revolutions  might  be  brought 
about,  if  the  climate  and  physical  geography  of  the  whole  globe  were 
greatly  altered.  It  has  been  stated,  that  species  are  in  general  local,  some 
being  confined  to  extremely  small  spots,  and  depending  for  their  existence 
on  a  combination  of  causes,  which,  if  they  are  to  be  met  with  elsewhere, 
occur  only  in  some  very  remote  region.  Hence  it  must  happen  that, 
when  the  nature  of  these  localities  is  changed,  the  species  will  perish ; 
for  it  will  rarely  happen  that  the  cause  which  alters  the  character 
of  the  district  will  afford  new  facilities  to  the  species  to  establish  itself 
elsewhere. 

African  deserts. — If  we  attribute  the  origin  of  a  great  part  of  the  desert 
of  Africa  to  the  gradual  progress  of  moving  sands  driven  eastward  by  the 
westerly  winds,  we  may  safely  infer  that  a  variety  of  species  must  have  been 
annihilated  by  this  cause  alone.  The  sand-flood  has  been  inundating,  from 
time  immemorial,  some  of  the  rich  lands  on  the  west  of  the  Nile  ;  and 
we  have  only  to  multiply  this  effect  a  sufficient  number  of  times  in  order 
to  understand  how,  in  the  lapse  of  ages,  a  whole  group  of  terrestrial  ani- 
mals and  plants  may  become  extinct. 

The  African  desert,  without  including  Bornou  and  Darfour,  extends, 
according  to  the  calculation  of  Humboldt,  over  194,000  square  leagues; 
an  area  nearly  three  times  as  great  as  that  of  France,  In  a  small  por- 
tion of  so  vast  a  space,  we  may  infer  from  analogy  that  there  were  many 
peculiar  species  of  plants  and  animals  which  must  have  been  banished  by 
the  sand,  and  their  habitations  invaded  by  the  camel,  and  by  birds  and 
insects  formed  for  the  arid  sands. 

There  is  evidently  nothing  in  the  nature  of  the  catastrophe  to  favor 
the  escape  of  the  former  inhabitants  to  some  adjoining  province  ;  nothing 

*  See  above,  p.  317. 


CH.  XLIL]  ON   THE   DISTRIBUTION    OF   SPECIES.  695 

to  weaken,  in  the  bordering  lands,  that  powerful  barrier  against  emigra- 
tion— pre-occupancy.  Nor,  even  if  the  exclusion  of  a  certain  group  of 
species  from  a  j^iven  tract  were  compensated  by  an  extension  of  their 
range  over  a  new  country,  would  that  circumstance  tend  to  the  conserva- 
tion of  species  in  general ;  for  the  extirpation  would  merely  then  be 
transferred  to  the  region  so  invaded.  If  it  be  imagined,  for  example,  that 
the  aboriginal  quadrupeds,  birds,  and  other  animals  of  Africa,  emigrated 
in  consequence  of  the  advance  of  drift-sand,  and  colonized  Arabia,  the 
indigenous  Arabian  species  must  have  given  way  before  them,  and  have 
been  reduced  in  number  or  destroyed. 

Let  us  next  suppose  that,  in  some  central  or  more  elevated  parts  of  the 
great  African  desert,  the  upheaving  power  of  subterranean  movements 
should  be  exerted  throughout  an  immense  series  of  ages,  accompanied,  at 
certain  intervals,  by  volcanic  eruptions,  such  as  gave  rise  at  once,  in  1755, 
to  a  mountain  1600  feet  high,  on  the  Mexican  plateau.  When  the  con- 
tinued repetition  of  these  events  had  caused  a  mountain-chain,  it  is 
obvious  that  a  complete  transformation  in  the  state  of  the  climate  would 
be  brought  about  throughout  a  vast  area. 

We  may  imagine  the  summits  of  the  new  chain  to  rise  so  high  as  to 
be  covered,  like  Mount  Atlas,  for  several  thousand  feet,  with  snow,  during 
a  great  part  of  the  year.  The  melting  of  these  snows,  during  the  great- 
est heat,  would  cause  the  rivers  to  swell  in  the  season  when  the  greatest 
drought  now  prevails ;  the  waters,  moreover,  derived  from  this  source, 
would  always  be  of  lower  temperature  than  the  surrounding  atmosphere, 
and  would  thus  contribute  to  cool  the  climate.  During  the  numerous 
earthquakes  and  volcanic  eruptions  supposed  to  accompany  the  gradual 
formation  of  the  chain,  there  would  be  many  floods  caused  by  the  burst- 
ing of  temporary  lakes,  and  by  the  melting  of  snows  by  lava.  These 
inundations  might  deposit  alluvial  matter  far  and  wide  over  the  original 
sands,  as  the  country  assumed  varied  shapes,  and  was  modified  again  and 
again  by  the  moving  power  from  below,  and  the  aqueous  erosion  of  the 
surface  above.  At  length  the  Sahara  might  be  fertilized,  irrigated  by  rivers 
and  streamlets  intersecting  it  in  every  direction,  and  covered  by  jungle 
and  morasses  ;  so  that  the  animals  and  plants  which  now  people  Northern 
Africa  would  disappear,  and  the  region  would  gradually  become  fitted 
for  the  reception  of  a  population  of  species  perfectly  dissimilar  in  their 
forms,  habits,  and  organization. 

There  are  always  some  peculiar  and  characteristic  features  in  the  phy- 
sical geography  of  each  large  division  of  the  globe ;  and  on  these 
peculiarities  the  state  of  animal  and  vegetable  life  is  dependent.  If, 
therefore,  we  admit  incessant  fluctuations  in  the  physical  geography,  we 
must,  at  the  same  time,  concede  the  successive  extinction  of  terrestrial 
and  aquatic  species  to  be  part  of  the  economy  of  our  system.  When 
some  great  class  of  stations  is  in  excess  in  certain  latitudes,  as,  for  example, 
in  wide  savannahs,  arid  sands,  lofty  mountains,  or  inland  seas,  we  find  a 
corresponding  development  of  species  adapted  for  such  circumstances. 
In  North  America,  where  there  is  a  chain  of  vast  inland  lakes  of  fiesh 


696  EFFECT   OF   GEOGRAPHICAL    CHANGES.  [Cn.  XLIL 

water,  we  find  an  extraordinary  abundance  and  variety  of  aquatic  birds, 
fresh-water  fish,  testacea,  and  small  amphibious  reptiles,  fitted  for  such  a 
climate.  The  greater  part  of  these  would  perish  if  the  lakes  were 
destroyed, — an  event  that  might  be  brought  about  by  some  of  the  least 
of  those  important  revolutions  contemplated  in  geology.  It  might 
happen  that  no  fresh-water  lakes  of  corresponding  magnitude  might  then 
exist  011  the  globe ;  or  that,  if  they  occurred  elsewhere,  they  might  be 
situated  in  New  Holland,  Southern  Africa.  Eastern  Asia,  or  some  region 
so  distant  as  to  be  quite  inaccessible  to  the  North  American  species ;  or 
they  might  be  situated  within  the  tropics,  in  a  climate  uninhabitable  by 
creatures  fitted  for  a  temperate  zone ;  or,  finally,  we  may  presume  that 
they  would  be  pre-occupied  by  indigenous  tribes. 

A  vivid  description  has  been  given  by  Mr.  Darwin  and  Sir  W.  Parish 
of  the  great  droughts  which  have  sometimes  visited  the  Pampas  of  South 
America,  for  three  or  four  years  in  succession,  during  which  an  incredible 
number  of  wild  animals,  cattle,  horses,  and  birds,  have  perished  from 
want  of  food  and  water.  Several  hundred  thousand  animals  were  drown- 
ed in  the  Parana  alone,  having  rushed  into  the  river  to  drink,  and  being 
too  much  exhausted  by  hunger  to  escape.*  Such  droughts  are  often 
attended  in  South  America  and  other  hot  climates  by  wide-spreading 
conflagrations,  caused  by  lightning,  which  fires  the  dried  grass  and  brush- 
wood. Thus  quadrupeds,  birds,  insects,  and  other  creatures,  are  destroyed 
by  myriads.  How  many  species,  both  of  the  animal  and  vegetable  world, 
which  once  flourished  in  the  country  between  the  valley  of  the  Parana 
and  the  Straits  of  Magellan,  may  not  have  been  annihilated,  since  the  first 
drought  or  first  conflagration  began ! 

To  pursue  this  train  of  reasoning  farther  is  unnecessary ;  the  geologist 
has  only  to  reflect  on  what  has  been  said  of  the  habitations  and  stations 
of  organic  beings  in  general,  and  to  consider  them  in  relation  to  those 
effects  which  were  contemplated  in  the  second  book,  as  resulting  from 
the  igneous  and  aqueous  causes  now  in  action,  and  he  will  immediately 
perceive  that,  amidst  the  vicissitudes  of  the  earth's  surface,  species  cannot 
be  immortal,  but  must  perish,  one  after  the  other,  like  the  individuals 
which  compose  them.  There  is  no  possibility  of  escaping  from  this  con- 
clusion, without  resorting  to  some  hypothesis  as  violent  as  that  of 
Lamarck,  who  imagined,  as  we  have  before  seen,  that  species  are  each  of 
them  endowed  with  indefinite  powers  of  modifying  their  organization,  in 
conformity  to  the  endless  changes  of  circumstances  to  which  they  are 
exposed. 

Effects  of  a,  general  Alteration  in  Climate  on  the  Distribution  of  Species. 

Some  of  the  effects  which  must  attend  every  general  alteration  of  cli- 
mate are  sufficiently  peculiar  to  claim  a  separate  consideration  before 
concluding  the  present  chapter. 

*  Darwin's  Journal,  p.  156.,  2d  ed.  p.  133.  Sir  "W.  Parish,  Buenos  Ayres,  <fec. 
p.  371.  and  151. 


CH.  XLIL]  EFFECTS    OF    CHANGES   IN    CLIMATE.  697 

I  have  before  stated  that,  during  seasons  of  extraordinary  severity, 
many  northern  birds,  and  in  some  countries  many  quadrupeds,  migrate 
southwards.  If  these  cold  seasons  were  to  become  frequent,  in  conse- 
quence of  a  gradual  and  general  refrigeration  of  the  atmosphere,  such 
migrations  would  be  more  and  more  regular,  until,  at  -length,  many 
animals,  now  confined  to  the  arctic  regions,  would  become  the  tenants 
of  the  temperate  zone;  while  the  inhabitants  of  the  temperate  zone  would 
approach  nearer  to  the  equator.  At  the  same  time,  many  species  pre- 
viously established  on  high  mountains  would  begin  to  descend,  in  every 
latitude,  towards  the  middle  regions;  and  those  which  were  confined  to 
the  flanks  of  mountains  would  make  their  way  into  the  plains.  Analo- 
gous changes  would  also  take  place  in  the  vegetable  kingdom. 

If,  on  the  contrary,  the  heat  of  the  atmosphere  be  on  the  increase,  the 
plants  and  animals  of  low  grounds  would  ascend  to  higher  levels,  the 
equatorial  species  would  migrate  into  the  temperate  zone,  and  those  of 
the  temperate  into  the  arctic  circle. 

But  although  some  species  might  thus  be  preserved,  every  great  change 
of  climate  must  be  fatal  to  many  which  can  find  no  place  of  retreat  when 
their  original  habitations  become  unfit  for  them.  For  if  the  general  tem- 
perature be  on  the  rise,  then  there  is  no  cooler  region  whither  the  polar 
species  can  take  refuge;  if  it  be  on  the  decline,  then  the  animals  and 
plants  previously  established  between  the  tropics  have  no  resource.  Sup- 
pose the  general  heat  of  the  atmosphere  to  increase,  so  that  even  the 
arctic  region  became  too  warm  for  the  musk-ox  and  rein-deer,  it  is  clear 
that  they  must  perish ;  so  if  the  torrid  zone  should  lose  so  much  of  its 
heat,  by  the  progressive  refrigeration  of  the  earth's  surface,  as  to  be  an 
unfit  habitation  for  apes,  boas,  bamboos,  and  palms,  these  tribes  of  ani- 
mals and  plants,  or,  at  least}  most  of  the  species  now  belonging  to  them, 
would  become  extinct,  for  there  would  be  no  warmer  latitudes  for  their 
reception. 

It  will  follow,  therefore,  that  as  often  as  the  climates  of  the  globe  are 
passing  from  the  extreme  of  heat  to  that  of  cold — from  the  summer  to 
the  winter  of  the  great  year  before  alluded  to* — the  migratory  movement 
will  be  directed  constantly  from  the  poles  towards  the  equator ;  and  for 
this  reason  the  species  inhabiting  parallel  latitudes,  in  the  northern  and 
southern  hemispheres,  must  become  widely  different.  For  I  assume,  on 
grounds  before  explained,  that  the  original  stock  of  each  species  is  intro- 
duced into  one  spot  of  the  earth  only,  and,  consequently,  no  species  can 
be  at  once  indigenous  in  the  arctic  and  antarctic  circles. 

But  when,  on  the  contrary,  a  series  of  changes  in  the  physical  geogra- 
phy of  the  globe,  or  any  other  supposed  cause,  occasions  an  elevation  of 
the  general  temperature, — when  there  is  a  passage  from  the  winter  to  one 
of  the  vernal  or  summer  seasons  of  the  great  cycle  of  climate, — then  the 
order  of  the  migratory  movement  is  inverted.  The  different  species  of 
animals  and  plants  direct  their  course  from  the  equator  towards  the  poles; 

*  See  above,  chap.  vii.  p.  112. 


698  EFFECTS    OF    CHANGES   IN    CLIMATE  [CH.  XLIL 

and  the  northern  and  southern  hemispheres  may  become  peopled  to  a 
certain  limited  extent  by  identical  species. 

I  say  limited,  because  we  cannot  speculate  on  the  entire  transposition 
of  a  group  of  animals  and  plants  from  tropical  to  polar  latitudes,  or  the 
reverse,  as  a  probable  or  even  possible  event.  We  may  believe  the  mean 
annual  temperature  of  one  zone  to  be  transferable  to  another,  but  we 
know  that  the  same  climate  cannot  be  so  transferred.  Whatever  be  the 
general  temperature  of  the  earth's  surface,  comparative  equability  of  heat 
will  characterize  the  tropical  regions;  while  great  periodical  variations 
will  belong  to  the  temperate,  and  still  more  to  the  polar  latitudes.  These, 
and  many  other  peculiarities  connected  with  heat  and  light,  depend  on 
fixed  astronomical  causes,  such  as  the  motion  of  the  earth  and  its  position 
in  relation  to  the  sun,  and  not  on  those  fluctuations  of  its  surface  which 
may  influence  the  general  temperature. 

Among  many  obstacles  to  such  extensive  transference  of  habitations, 
we  must  not  forget  the  immense  lapse  of  time  required,  according  to  the 
hypothesis  before  suggested,  to  bring  about  a  considerable  change  in 
climate.  During  a  period  so  vast,  the  other  cause  of  extirpation,  before 
enumerated,  would  exert  so  powerful  an  influence  as  to  prevent  all,  save 
a  very  few  hardy  species,  from  passing  from  equatorial  to  polar  regions, 
or  from  the  tropics  to  the  pole.* 

But  the  power  of  accommodation  to  new  circumstances  is  great  in 
certain  species,  and  might  enable  many  to  pass  from  one  zone  to  another, 
if  the  mean  annual  heat  of  the  atmosphere  and  the  ocean  were  greatly 
altered.  To  the  marine  tribes,  especially,  such  a  passage  would  be  possi- 
ble; for  they  are  less  impeded  in  their  migrations  by  barriers  of  land, 
than  are  the  terrestrial  by  the  ocean.  Add  to  this,  that  the  temperature 
of  the  ocean  is  much  more  uniform  than  that  of  the  atmosphere  investing 
the  land;  so  that  we  may  easily  suppose  that  most  oif  the  testacea,  fish, 
and  other  classes,  might  pass  from  the  equatorial  into  the  temperate 
regions,  if  the  mean  temperature  of  those  regions  were  transposed,  although 
a  second  expatriation  of  these  species  of  tropical  origin  into  the  arctic  and 
antarctic  circles  would  probably  be  impossible. 

Let  us  now  consider  more  particularly  the  effect  of  vicissitudes  of 
climate  in  causing  one  species  to  give  way  before  the  increasing  numbers 
of  some  other. 

When  temperature  forms  the  barrier  which  arrests  the  progress  of  an 
animal  or  plant  in  a  particular  direction,  the  individuals  are  fewer  and 
less  vigorous  as  they  approach  the  extreme  confines  of  the  geographical 
range  of  the  species.  But  these  stragglers  are  ready  to  multiply  rapidly 
on  the  slightest  increase  or  diminution  of  heat  that  may  be  favorable 
to  them,  just  as  particular  insects  increase  during  a  hot  summer,  and 
certain  plants  and  animals  gain  ground  after  a  series  of  congenial 
seasons. 

In  almost  every  district,  especially  if  it  be  mountainous,  there  are  a 

*  See  above,  chaps,  vi.  vii.  and  viii 


CH.  XLII.]  ON   THE    DISTRIBUTION    OF    SPECIES.  699 

variety  of  species  the  limits  of  whose  habitations  are  conterminous,  some 
being  unable  to  proceed  farther  without  encountering  too  much  heat, 
others  too  much  cold.  Individuals,  which  are  thus  on  the  borders  of  the 
regions  proper  to  their  respective  species,  are  like  the  outposts  of  hostile 
armies,  ready  to  profit  by  every  slight  change  of  circumstances  in  their 
favor,  and  to  advance  upon  the  ground  occupied  by  their  neighbors 
and  opponents. 

The  proximity  of  distinct  climates  produced  by  the  inequalities  of  the 
earth's  surface,  brings  species  possessing  very  different  constitutions  into 
such  immediate  contact,  that  their  naturalizations  are  very  speedy  when- 
ever opportunities  of  advancing  present  themselves.  Many  insects  and 
plants,  for  example,  are  common  to  low  plains  within  the  arctic  circle, 
and  to  lofty  mountains  in  Scotland  and  other  parts  of  Europe.  If  the 
climate,  therefore,  of  the  polar  regions  were  transferred  to  our  own  lati- 
tudes, the  species  in  question  would  immediately  descend  from  these  ele- 
vated stations  to  overrun  the  low  grounds.  Invasions  of  this  kind,  at- 
tended by  the  expulsion  of  the  pre-occupants,  are  almost  instantaneous, 
because  the  change  of  temperature  not  only  places  the  one  species  in  a 
more  favorable  position,  but  renders  the  others  sickly  and  almost  inca- 
pable of  defence. 

These  changes  inconsistent  with  the  theory  of  transmutation. — Lamarck, 
when  speculating  on  the  transmutation  of  species,  supposed  every  modifi- 
cation in  organization  and  instinct  to  be  brought  about  slowly  and  insen- 
sibly in  an  indefinite  lapse  of  ages.  But  he  does  not  appear  to  have 
sufficiently  considered  how  much  every  alteration  in  the  physical  condition 
of  the  habitable  surface  changes  the  relations  of  a  great  number  of  co- 
existing species,  and  that  some  of  these  would  be  ready  instantly  to  avail 
themselves  of  the  slightest  change  in  their  favor,  and  to  multiply  to  the 
injury  of  others.  Even  if  we  thought  it  possible  that  the  palm  or  the 
elephant,  which  now  flourish  in  equatorial  regions,  could  ever  learn  to 
bear  the  variable  seasons  of  our  temperate  zone,  or  the  rigors  of  an 
arctic  winter,  we  might  with  no  less  confidence  affirm,  that  they  must 
perish  before  they  had  time  to  become  habituated  to  such  new  circum- 
stances. That  they  would  be  displaced  by  other  species  as  often  as  the 
climate  varied,  may  be  inferred  from  the  data  before  explained  respect- 
ing the  local  extermination  of  species  produced  by  the  multiplication  of 
others. 

Suppose  the  climate  of  the  highest  part  of  the  woody  zone  of  Etna  to 
be  transferred  to  the  sea-shore  of  the  base  of  the  mountain',  no  botanist 
would  anticipate  that  the  olive,  lemon-tree,  and  prickly  pear  (Cactus 
Opuntia)  would  be  able  to  contend  with  the  oak  and  chestnut,  which 
would  begin  forthwith  to  descend  to  a  lower  level ;  or  that  these  last 
would  be  able  to  stand  their  ground  against  the  pine,  which  would  also, 
in  the  space  of  a  few  years,  begin  to  occupy  a  lower  position.  We  might 
form  some  kind  of  estimate  of  the  time  which  might  be  required  for  the 
migrations  of  these  plants ;  whereas  we  have  no  data  for  concluding  that 
any  number  of  thousands  of  years  would  be  sufficient  for  one  step  in  the 


TOO  EFFECTS   OF    CHANGES    OF    CLIMATE.  [Cn.  XLII. 

pretended  metamorphosis  of  one  species  into  another,  possessing  distinct 
attributes  and  qualities. 

This  argument  is  applicable  not  merely  to  climate,  but  to  any  other 
cause  of  mutation.  However  slowly  a  lake  may  be  converted  into  a 
marsh,  or  a  marsh  into  a  meadow,  it  is  evident  that  before  the  lacustrine 
plants  can  acquire  the  power  of  living  in  marshes,  or  the  marsh-plants 
of  living  in  a  less  humid  soil,  other  species,  already  existing  in  the  region, 
and  fitted  for  these  several  stations,  will  intrude  and  keep  possession  of 
the  ground.  So,  if  a  tract  of  salt  water  becomes  fresh  by  passing  through 
every  intermediate  degree  of  brackishness,  still  the  marine  mollusks  will 
never  be  permitted  to  be  gradually  metamorphosed  into  fluviatile  species ; 
because  long  before  any  such  transformation  can  take  place  by  slow  and 
insensible  degrees,  other  tribes,  already  formed  to  delight  in  brackish  or 
fresh  water,  will  avail  themselves  of  the  change  in  the  fluid,  and  will, 
each  in  their  turn,  monopolize  the  space. 

It  is  idle,  therefore,  to  dispute  about  the  abstract  possibility  of  the 
conversion  of  one  species  into  another,  when  there  are  known  causes  so 
much  more  active  in  their  nature,  which  must  always  intervene  and  pre- 
vent the  actual  accomplishment  of  such  conversions.  A  faint  image  of 
the  certain  doom  of  a  species  less  fitted  to  struggle  with  some  new  con- 
dition in  a  region  which  it  previously  inhabited,  and  where  it  has  to  con- 
tend with  a  more  vigorous  species,  is  presented  by  the  extirpation  of  sav- 
age tribes  of  men  by  the  advancing  colony  of  some  civilized  nation.  In 
this  case  the  contest  is  merely  between  two  different  races — two  varieties, 
moreover,  of  a  species  which  exceeds  all  others  in  its  aptitude  to  accom- 
modate its  habits  to  the  most  extraordinary  variations  of  circumstances. 
Yet  few  future  events  are  more  certain  than  the  speedy  extermination  of 
the  Indians  of  North  America  and  the  savages  of  New  Holland  in  the 
course  of  a  few  centuries,  when  these  tribes  will  be  remembered  only  in 
poetry  or  history. 

Concluding  remarks. — We  often  hear  astonishment  expressed  at  the 
disappearance  from  the  earth  in  times  comparatively  modern  of  many 
small  as  well  as  large  animals,  the  remains  of  which  have  been  found  in 
a  fossil  state,  under  circumstances  implying  that  neither  any  great  geo- 
graphical revolution,  nor  the  exterminating  influence  of  man  has  inter- 
vened to  account  for  their  extinction.  But  in  all  such  cases  we  should 
inquire  whether  we  are  sufficiently  acquainted  with  the  numerous  and 
complicated  conditions  on  which  the  perpetuation  of  each  species  depends, 
to  entitle  us  to  wonder  if  it  should  be  suddenly  cut  off. 

Mr.  Darwin,  when  calling  attention  to  the  fact  that  the  horse,  mega- 
therium, megalonyx,  and  many  contemporary  Mammalia,  had  perished 
in  South  America  after  that  continent  had  acquired  its  present  confi- 
guration, and  when,  if  we  may  judge  by  the  Testacea,  the  climate  very 
nearly  resembled  the  present,  observes,  "  that  in  the  living  creation  one 
species  is  often  extremely  rare  in  a  given  region,  while  another  of  the 
same  genus  and  with  closely  allied  habits  is  exceedingly  common.  A 


CH.  XLIII.J  SUCCESSIVE   EXTINCTION   OF   SPECIES.  701 

zoologist  familiar  with  such  phenomena,  if  asked  to  explain  them,  usu- 
ally replies,  that  some  slight  difference  in  climate,  food,  or  the  number 
of  its  enemies,  must  determine  the  relative  strength  of  the  two  species 
in  question,  although  we  may  be  unable  to  point  out  the  precise  man- 
ner of  the  action  of  the  check.  We  are,  therefore,  driven  to  the  con- 
clusion, that  causes  generally  quite  inappreciable  by  us  determine  whe- 
ther a  given  species  shall  be  abundant  or  scanty  in  numbers.  Why, 
then,  should  we  feel  astonishment  if  the  rarity  is  occasionally  carried  a 
step  farther, — to  extinction  ?"  * 


CHAPTER  XLIII. 

EXTINCTION    AND    CREATION    OF    SPECIES. 

Theory  of  the  successive  extinction  of  species  consistent  with  a  limited  geogra- 
phical distribution — Opinions  of  botanists  respecting  the  centres  from  which 
plants  have  been  diffused — Whether  there  are  grounds  for  inferring  that  the 
loss,  from  time  to  time,  of  certain  animals  and  plants,  is  compensated  by  the 
introduction  of  new  species? — Whether  any  evidence  of  such  new  creations 
could  be  expected  within  the  historical  era  \ — The  question  whether  the  exist- 
ing species  have  been  created  in  succession  must  be  decided  by  geological 
monuments. 

Successive  Extinction  of  Species  consistent  with  their  limited  Geogra- 
phical Distribution. 

IN  the  preceding  chapters  I  have  pointed  out  the  strict  dependence 
of  each  species  of  animal  and  plant  on  certain  physical  conditions  in 
the  state  of  the  earth's  surface,  and  on  the  number  and  attributes  of 
other  organic  beings  inhabiting  the  same  region.  I  have  also  endea- 
vored to  show  that  all  these  conditions  are  in  a  state  of  continual 
fluctuation,  the  igneous  and  aqueous  agents  remodelling,  from  time 
to  time,  the  physical  geography  of  the  globe,  and  the  .migrations  of 
species  causing  new  relations  to  spring  up  successively  between  different 
organic  beings.  I  have  deduced  as  a  corollary,  that  the  species  existing 
at  any  particular  period,  must,  in  the  course  of  ages,  become  extinct 
one  after  the  other.  "  They  must  die  out,"  to  borrow  an  emphatical 
expression  from  BufFon,  "because  Time  fights  against  them." 

If  the  views  which  I  have  taken  are  just,  there  will  be  no  difficulty  in 
explaining  why  the  habitations  of  so  many  species  are  now  restrained 
within  exceedingly  narrow  limits.  Every  local  revolution,  such  as 
those  contemplated  in  the  preceding  chapter,  tends  to  circumscribe  the 
range  of  some  species,  while  it  enlarges  that  of  others ;  and  if  we  are 

*  Journ.  of  Nat.  Hist.  <fec.  2d  edit.,  1845,  p.  175;  also  Lyell's  2d  Visit  to  the 
United  States,  vol.  i.  p.  351. 


702  DISTRIBUTION   OF    SPECIES.  [Cn.  XLIIL 

led  to  infer  that  new  species  originate  in  one  spot  only,  each  must 
require  time  to  diffuse  itself  over  a  wide  area.  It  will  follow,  there- 
fore, from  the  adoption  of  this  hypothesis,  that  the  recent  origin  of 
some  species,  and  the  high  antiquity  of  others,  are  equally  consistent 
with  the  general  fact  of  their  limited  distribution;  some  being  local, 
because  they  have  not  existed  long  enough  to  admit  of  their  wide 
dissemination  ;  others,  because  circumstances  in  the  animate  or  inani- 
mate world  have  occurred  to  restrict  the  range  which  they  may  once 
have  obtained.  As  a  general  rule,  however,  species,  common  to  many 
distant  provinces,  or  those  now  found  to  inhabit  very  distant  parts  of 
the  globe,  are  to  be  regarded  as  the  most  ancient.  Numerically  speak- 
ing, they  may  not  perhaps  be  largely  represented,  but  their  wide  diffu- 
sion .shows  that  they  have  had  a  long  time  to  spread  themselves,  and 
have  been  able  to  survive  many  important  revolutions  in  physical 
geography. 

After  so  much  evidence  has  been  brought  to  light  by  the  geologist, 
of  land  and  sea  having  changed  places  in  various  regions  since  the 
existing  species  were  in  being,  we  can  feel  no  surprise  that  the  zoologist 
and  .botanist  have  hitherto  found  it  difficult  to  refer  the  geographical 
distribution  of  species  to  any  clear  and  determinate  principles,  since 
they  have  usually  speculated  on  the  phenomena,  upon  the  assumption 
that  the  physical  geography  of  the  globe  had  undergone  no  material 
alteration  since  the  introduction  of  the  species  now  living.  So  long  as 
this  assumption  was  made,  the  facts  relating  to  the  geography  of  plants 
and  animals  appeared  capricious  in  the  extreme,  and  by  many  the  sub- 
ject was  pronounced  to  be  so  full  of  mystery  and  anomalies,  that  the 
establishment  of  a  satisfactory  theory  was  hopeless.* 

Centres  from  which  plants  have  been  diffused. — Some  botanists  con- 
ceived, ic  accordance  with  the  hypothesis  of  Wildenow,  that  mountains 
were  the  centres  of  creation  from  which  the  plants  now  inhabiting  large 
continents  have  radiated ;  to  which  De  Candolle  and  others,  with  much 
reason,  objected,  that  mountains,  on  the  contrary,  are  often  the  barriers 
between  two  provinces  of  distinct  vegetation.  The  geologist  who  is 
acquainted  with  the  extensive  modifications  which  the  surface  of  the 

*  This  and  the  preceding  chapter,  on  the  causes  of  extinction  of  species  and 
their  present  geographical  distribution,  are  reprinted  almost  verbatim  from  the 
original  edition  of  the  second  volume  of  "  The  Principles,"  published  in  January, 
1832.  It  was  I  believe  the  first  attempt  to  point  out  how  former  changes  in  the 
geography -and  local  climate  of  many  parts  of  the  globe  must  be  taken  into 
account  when  we  endeavor  to"  explain  the  actual  provinces  of  plants  and  ani- 
mals, the  changes  alluded  to  having  been  proved  by  geological  evidence  to  be 
subsequent  to  the  creation  of  a  great  proportion  of  the  species  now  living,  and 
these  having  been,  according  to  the  view  which  I  advocated,  introduced  in  succes- 
sion, and  not  all  at  one  geological  epoch.  In  my  third  volume,  published  in 
May,  1833, 1  announced  my  conviction  that  the  greater  part  of  the  existing  Fauna 
and  Flora  of  Sicily  were  older  than  the  mountains,  plains,  and  rivers,  which  the 
eame  species  of  animals  and  plants  now  inhabit.  (Prin.  of  Geol.,  vol.  iii.  ch.  ix. ; 
repeated  in  Elements  of  Geol.,  2d  edit.,  vol.  i.  p.  297.)  This  line  of  reasoning 
Las  since  been  ably  followed  up  and  elucidated  by  Professor  E.  Forbes  in  an 
excellent  paper  (published  in  1846)  already  alluded  to.  (See  page  86.) 


CH.  XLIIL]  CENTRES   OF   VEGETATION.  703 

earth  has  undergone  in  very  recent  geological  epochs,  may  be  able,  per- 
haps, to  reconcile  both  these  theories  in  their  application  to  different 
regions. 

A  lofty  range  of  mountains,  which  is  so  ancient  as  to  date  from  a 
period  when  the  species  of  animals  and  plants  differed  from  those  now 
living,  will  naturally  form  a  barrier  between  contiguous  provinces ;  but  a 
chain  which  has  been  raised,  in  great  part,  within  the  epoch  of  existing 
species,  and  around  which  new  lands  have  arisen  from  the  sea  within 
that  period,  will  be  a  centre  of  peculiar  vegetation. 

"  In  France,"  observes  De  Candolle,  "  the  Alps  and  Cevennes  prevent 
a  great  number  of  the  plants  of  the  south  from  spreading  themselves  to 
the  northward ;  but  it  has  been,  remarked  that  some  species  have  made 
their  way  through  the  gorges  of  these  chains,  and  are  found  on  their 
northern  sides,  principally  in  those  places  where  they  are  lower  and  more 
interrupted."*  Now  the  chains  here  alluded  to  have  probably  been  of 
considerable  height  ever  since  the  era  when  the  existing  vegetation  began 
to  appear,  and  were  it  not  for  the  deep  fissures  which  divide  them,  they 
might  have  caused  much  more  abrupt  terminations  to  the  extension  of 
distinct  assemblages  of  species. 

Parts  of  the  Italian  peninsula,  on  the  other  hand,  have  gained  a  con- 
siderable portion  of  their  present  height  since  a  majority  of  the  marine 
species  now  inhabiting  the  Mediterranean,  and  probably,  also,  since  the 
terrestrial  plants  of  the  same  region  were  in  being.  Large  tracts  of  land 
have  been  added,  both  on  the  Adriatic  and  Mediterranean  side,  to  what 
originally  constituted  a  much  narrower  range  of  mountains,  if  not  a  chain 
of  islands  running  nearly  north  and  south,  like  Corsica  and  Sardinia.  It 
may  therefore  be  presumed  that  the  Apennines  have  been  a  centre  whence 
species  have  diffused  themselves  over  the  contiguous  lower  and  newer 
regions.  In  this  and  all  analogous  situations,  the  doctrine  of  Wildenow, 
that  species  have  radiated  from  the  mountains  as  from  centres,  may  be 
well  founded. 

Introduction  of  New  Species. 

If  the  reader  should  infer,  from  the  facts  laid  before  him  in  the  pre- 
ceding chapters,  that  the  successive  extinction  of  animals  and  plants  may 
be  part  of  the  constant  and  regular  course  of  nature,  he  will  naturally 
inquire  whether  there  are  any  means  provided  for  the  repair  of  these 
losses  ?  Is  it  part  of  the  economy  of  our  system  that  the  habitable  globe 
should,  to  a  certain  extent,  become  depopulated  both  in  the  ocean  and 
on  the  land ;  or  that  the  variety  of  species  should  diminish  until  some 
new  era  arrives  when  a  new  and  extraordinary  effort  of  creative  energy 
is  to  be  displayed  ?  Or  is  it  possible  that  new  species  can  be  called  into 
being  from  time  to  time,  and  yet  that  so  astonishing  a  phenomenon  can 
escape  the  observation  of  naturalists  ? 

*  Essai  Etementaire,  <fcc.  p.  46. 


704  INTRODUCTION   OP   NEW   SPECIES.  [Cn.  XLIII. 

Humboldt  has  characterized  these  subjects  as  among  the  mysteries 
which  natural  science  cannot  reach ;  and  he  observes  that  the  investiga- 
tion of  the  origin  of  beings  does  not  belong  to  zoological  or  botanical 
geography.  To  geology,  however,  these  topics  do  strictly  appertain ;  and 
this  science  is  chiefly  interested  in  inquiries  into  the  state  of  the  animate 
creation  as  it  now  exists,  with  a  view  of  pointing  out  its  relations  to  ante- 
cedent periods  when  its  condition  was  different. 

Before  offering  any  hypothesis  towards  the  solution  of  so  difficult  a 
problem,  let  us  consider  what  kind  of  evidence  we  ought  to  expect,  in 
the  present  state  of  science,  of  the  first  appearance  of  new  animals  or 
plants,  if  we  could  imagine  the  successive  creation  of  species  to  constitute, 
like  their  gradual  extinction,  a  regular  part  of  the  economy  of  nature. 

In  the  first  place  it  is  obviously  more  easy  to  prove  that  a  species, 
once  numerously  represented  in  a  given  district,  has  ceased  to  be,  than 
that  some  other  which  did  not  pre-exist  has  made  its  appearance — 
assuming  always,  for  reasons  before  stated,  that  single  stocks  only  of  each 
animal  and  plant  are  originally  created,  and  that  individuals  of  new 
species  do  not  suddenly  start  up  in  many  different  places  at  once. 

So  imperfect  has  the  science  of  natural  history  remained  down  to  our 
own  times,  that,  within  the  memory  of  persons  now  living,  the  numbers 
of  known  animals  and  plants  have  been  doubled,  or  even  quadrupled,  in 
many  classes.  New  and  often  conspicuous  species  are  annually  discover- 
ed in  parts  of  the  old  continent,  long  inhabited  by  the  most  civilized 
nations.  Conscious,  therefore,  of  the  limited  extent  of  our  information, 
we  always  infer,  when  such  discoveries  are  made,  that  the  beings  in 
question  had  previously  eluded  our  research  ;  or  had  at  least  existed  else- 
where, and  only  migrated  at  a  recent  period  into  the  territories  where  we 
now  find  them.  It  is  difficult,  even  in  contemplation,  to  anticipate  the 
time  when  we  shall  be  entitled  to  make  any  other  hypothesis  in  regard 
to  all  the  marine  tribes,  and  to  by  far  the  greater  number  of  the  terres- 
trial ] — such  as  birds,  which  possess  such  unlimited  powers  of  migration ; 
insects,  which,  besides  the  variability  of  each  species  in  number,  are  also 
so  capable  of  being  diffused  to  vast  distances ;  and  cryptogamous  plants, 
to  which,  as  to  many  other  classes,  both  of  the  animal  and  vegetable 
kingdom,  similar  observations  are  applicable. 

What  kind  of  evidence  of  new  creations  could  be  expected? — What  kind 
of  proofs,  therefore,  could  we  reasonably  expect  to  find  of  the  origin  at  a 
particular  period  of  a  new  species? 

Perhaps  it  may  be  said  in  reply  that,  within  the  last  two  or  three  cen- 
turies, some  forest  tree  or  new  quadruped  might  have  been  observed  to 
appear  suddenly  in  those  parts  of  England  or  France  which  had  been 
most  thoroughly  investigated ; — that  naturalists  might  have  been  able  to 
show  that  no  such  living  being  inhabited  any  other  region  of  the  globe, 
and  that  there  was  no  tradition  of  anything  similar  having  before  been 
observed  in  the  district  where  it  had  made  its  appearance. 

Now,  although  this  objection  may  seem  plausible,  yet  its  force  will  be 
found  to  depend  entirely  on  the  rate  of  fluctuation  which  we  suppose  to 


Cu.  XLIIL]  APPEARANCE   OP   NEW   SPECIES.  705 

prevail  in  the  animate  world,  and  on  the  proportion  which  such  conspicu- 
ous subjects  of  the  animal  and  vegetable  kingdoms  bear  to  those  which 
are  less  known  and  escape  our  observation.  There  are,  perhaps,  more  than 
a  million  species  of  plants  and  animals,  exclusive  of  the  microscopic  and 
infusory  animalcules,  now  inhabiting  the  terraqueous  globe.  The  terres- 
trial plants  may  amount,  says  De  Candolle,  to  somewhere  between  110,000 
and  120,000;*  but  the  data  on  which  this  conjecture  is  founded  are  con- 
sidered by  many  botanists  to  be  vague  and  unsatisfactory.  Sprengel  only 
enumerated,  in  1827,  about  31,000  known  phaenogamous,  and  6000 
cryptogamous  plants ;  but  that  naturalist  omitted  many,  perhaps  7000 
phaenogamous,  and  1000  cryptogamous  species.  Mr.  Lindley,  in  a  letter 
to  the  author  in  1836,  expressed  his  opinion  that  it  would  be  rash  to 
speculate  on  the  existence  of  more  than  80,000  phaenogamous,  and  10,000 
cryptogamous  plants.  "  If  we  take,"  he  says,  in  a  letter  to  the  author  on 
this  subject,  "37,000  as  the  number  of  published  phaenogamous  species, 
and  then  add,  for  the  undiscovered  species  in  Asia  and  New  Holland, 
15,000,  in  Africa  10,000,  and  in  America  18,000,  we  have  80,000  spe- 
cies ;  and  if  7000  be  the  number  of  published  cryptogamous  plants,  and 
we  allow  3000  for  the  undiscovered  species  (making  10,000),  there  would 
then  be,  on  the  whole,  90,000  species."  But  since  that  period  one  cata- 
logue, as  I  learn  from  Dr.  J.  Hooker,  contains  a  list  of  the  names  of  78,000 
phaenogamous  plants  which  had  been  published  before  1841. 

It  was  supposed  by  Linnaeus  that  there  were  four  or  five  species  of 
insects  in  the  world  for  each  phaenogamous  plant :  but  if  we  may  judge  from 
the  relative  proportion  of  the  two  classes  in  Great  Britain,  the  number  of 
insects  must  be  still  greater;  for  the  total  number  of  British  insects, 
"according  to  the  last  census,"  is  about  1 2,500 ;f  whereas  there  are  only 
1500  phaenogamous  plants  indigenous  to  our  island.  As  the  insects  are 
much  more  numerous  in  hot  countries  than  in  our  temperate  latitudes,  it 
seems  difficult  to  avoid  the  conclusion  that  there  are  more  than  half  a 
million  species  in  the  world. 

The  number  of  known  mammifers,  when  Temminck  wrote,  exceeded 
800,  and  Mr.  Waterhouse  informs  me  that  more  than  1200  are  now 
(1850)  ascertained  to  exist.  Baron  Cuvier  estimated  the  amount  of  known 
fishes  at  6000;  and  Mr.  G.  Gray,  in  his  "Genera  of  Birds,"  enumerates 
8000  species.  We  have  still  to  add  the  reptiles,  and  all  the  invertebrated 
animals,  exclusive  of  insects.  It  remains,  in  a  great  degree,  mere  matter 
of  conjecture  what  proportion  the  aquatic  tribes  may -bear  to  the  denizens 
of  the  land ;  but  the  habitable  surface  beneath  the  waters  can  hardly  be 
estimated  at  less  than  double  that  of  the  continents  and  islands,  even 
admitting  that  a  very  considerable  area  is  destitute  of  life,  in  consequence 
of  great  depth,  cold,  darkness,  and  other  circumstances.  In  the  late  polar 
expedition  it  was  found  that,  in  some  regions,  as  in  Baffin's  Bay,  there 
were  marine  animals  inhabiting  the  bottom  at  great  depths,  where  the 
temperature  of  the  water  was  below  the  freezing  point.  That  there  is 

*  Geog.  des  Plantes.     Diet,  des  Sci. 
f  See  Catalogue  of  Brit  Insects,  by  John  Curtis,  Esq. 
45 


706  SPECULATIONS    ON   THE  [Cu.  XL1II. 

life  at  much  greater  profundities  in  warmer  regions  may  be  confidently 
inferred. 

The  ocean  teems  with  life — the  class  of  Polyps  alone  are  conjectured 
by  Lamarck  to  be  as  strong  in  individuals  as  insects.  Every  tropical  reef 
is  described  as  covered  with  Corals  and  Sponges,  and  swarming  with 
Crustacea,  Echini,  and  Testacea ;  while  almost  every  tide-washed  rock  in 
the  world  is  carpeted  with  Fuci,  and  supports  some  Corallines,  Actiniae, 
and  Mollusca.  There  are  innumerable  forms  in  the  seas  of  the  warmer 
zones,  which  have  scarcely  begun  to  attract  the  attention  of  the  naturalist ; 
and  there  are  parasitic  animals  without  number,  three  or  four  of  which 
are  sometimes  appropriated  to  one  genus,  as  to  the  whale  (Balcena),  for 
example.  Even  though  we  concede,  therefore,  that  the  geographical  range 
of  marine  species  is  more  extensive  in  general  than  that  of  the  terrestrial  (the 
temperature  of  the  sea  being  more  uniform,  and  the  land  impeding  less 
the  migrations  of  the  oceanic  than  the  ocean  those  of  the  terrestrial  spe- 
cies), yet  it  seems  probable  that  the  aquatic  tribes  far  exceed  in  number 
the  inhabitants  of  the  land. 

Without  insisting  on  this  point,  it  may  be  safe  to  assume,  that,  exclu- 
sive of  microscopic  beings,  there  are  between  one  and  two  millions  of 
species  now  inhabiting  the  terraqueous  globe ;  so  that  if  only  one  of  these 
were  to  become  extinct  annually,  and  one  new  one  were  to  be  every  year 
called  into  being,  much  more  than  a  million  of  years  might  be  required 
to  bring  about  a  complete  revolution  in  organic  life. 

I  am  not  hazarding  at  present  any  hypothesis  as  to  the  probable  rate 
of  change ;  but  none  will  deny  that  when  the  annual  birth  and  the  annual 
death  of  one  species  on  the  globe  is  proposed  as  a  mere  speculation,  this 
at  least  is  to  imagine  no  slight  degree  of  instability  in  the  animate  crea- 
tion. If  we  divide  the  surface  of  the  earth  into  twenty  regions  of  equal 
area,  one  of  these  might  comprehend  a  space  of  land  and  water  about 
equal  in  dimensions  to  Europe,  and  might  contain  a  twentieth  part  of  the 
million  of  species  which  may  be  assumed  to  exist  in  the  animal  kingdom. 
In  this  region  one  species  only  would,  according  to  the  rate  of  mortality 
before  assumed,  perish  in  twenty  years,  or  only  five  out  of  fifty  thousand 
in  the  course  of  a  century.  But  as  a  considerable  proportion  of  the  whole 
would  belong  to  the  aquatic  classes,  with  which  we  have  a  very  imperfect 
acquaintance,  we  must  exclude  them  from  our 'consideration;  and  if  they 
constitute  half  of  the  entire  number,  then  one  species  only  might  be  lost 
in  forty  years  among  the  terrestrial  tribes.  Now  the  Mammalia,  whether 
terrestrial  or  aquatic,  bear  so  small  a  proportion  to  other  classes  of  ani- 
mals, forming  less,  perhaps,  than  one  thousandth  part  of  the  whole,  that 
if  the  longevity  of  species  in  the  different  orders  were  equal,  a  vast  period 
must  elapse  before  it  would  come  to  the  turn  of  this  conspicuous  class  to 
lose  one  of  their  number.  If  one  species  only  of  the  whole  animal  king- 
dom died  out  in  forty  years,  no  more  than  one  mammifer  might  disappear 
in  40,000  years  in  a  region  of  the  dimensions  of  Europe. 

It  is  easy,  therefore,  to  see,  that  in  a  small  portion  of  such  an  area, 
in  countries,  for  example,  of  the  size  of  England  and  France,  periods  of 


CH.  XLIIL]  APPEARANCE   OF   NEW   SPECIES.  707 

much  greater  duration  must  elapse  before  it  would  be  possible  to  authen- 
ticate the  first  appearance  of  one  of  the  larger  plants  and  animals,  assum- 
ing the  annual  birth  and  death  of  one  species  to  be  the  rate  of  vicissi- 
tude in  the  animate  creation  throughout  the  world. 

The  observations  of  naturalists  upon  living  species  may,  in  the  course 
of  future  centuries,  accumulate  positive  data,  from  which  an  insight  into 
the  laws  which  govern  this  part  of  our  terrestrial  system  may  be  derived; 
but,  in  the  present  deficiency  of  historical  records,  we  have  traced  up  the 
subject  to  that  point  where  geological  monuments  alone  are  capable  of 
leading  us  on  to  the  discovery  of  ulterior  truths.  To  these,  therefore,  we 
must  appeal,  carefully  examining  the  strata  of  recent  formation  wherein 
the  remains  of  living  species,  both  animal  and  vegetable,  are  known  to 
occur.  We  must  study  these  strata  in  strict  reference  to  their  chronologi- 
cal order,  as  deduced  from  their  superposition,  and  other  relations.  From 
these  sources  we  may  learn  which  of  the  species,  now  our  contemporaries, 
have  survived  the  greatest  revolutions  of  the  earth's  surface ;  which  of 
them  have  co-existed  with  the  greatest  number  of  animals  and  plants 
now  extinct ;  and  which  have  made  their  appearance  only  when  the  ani- 
mate world  had  nearly  attained  its  present  condition. 

From  such  data  we  may  be  enabled  to  infer,  whether  species  have  been 
called  into  existence  in  succession,  or  all  at  one  period  ;  whether  singly, 
or  by  groups  simultaneously;  whether  the  antiquity  of  man  be  as  high 
as  that  of  any  of  the  inferior  beings  which  now  share  the  planet 
with  him,  or  whether  the  human  species  is  one  of  the  most  recent  of  the 
whole. 

To  some  of  these  questions  we  can  even  now  return  a  satisfactory 
answer  ;  and  with  regard  to  the  rest,  we  have  some  data  to  guide  conjec- 
ture, and  to  enable  us  to  speculate  with  advantage :  but  in  order  to  be 
fully  qualified  to  enter  upon  such  discussions  the  reader  must  study  the 
ample  body  of  materials  amassed  by  the  industry  of  modern  geologists. 


CHAPTER  XLIV. 


EFFECTS  PRODUCED  BY  THE  POWERS  OF  VITALITY  ON  THE  STATE 
OF  THE  EARTH'S  SURFACE. 

Modifications  in  physical  geography  caused  by  organic  beings — "Why  the  vege- 
table soil  does  not  augment  in  thickness — The  theory,  that  vegetation  is  an 
antagonist  power  counterbalancing  the  degradation  caused  by  running  water 
untenable — Conservative  influence  of  vegetation — Rain  diminished  by  felling 
of  forests — Distribution  of  American  forests  dependent  on  direction  of  pre- 
dominant winds — Influence  of  man  in  modifying  the  physical  geography  of 
the  globe. 

THE  second  branch  of  our  inquiry,  respecting  changes  of  the  organic 
world,  relates  to  the  processes  by  which  the  remains  of  animals  and 
plants  become  fossil,  or,  to  speak  still  more  generally,  to  all  the  effects 
produced  by  the  powers  of  vitality  on  the  surface  and  shell  of  the 
earth. 

Before  entering  on  the  principal  division  of  this  subject,  the  imbedding 
and  preservation  of  animal  and  vegetable  remains,  I  shall  offer  a  few  re- 
marks on  the  superficial  modifications  caused  directly  by  the  agency  of 
organic  beings,  as  when  the  growth  of  certain  plants  covers  the  slope  of 
a  mountain  with  peat,  or  converts  a  swamp  into  dry  land  ;  or  when  vege- 
tation prevents  the  soil,  in  certain  localities,  from  being  washed  away  by 
running  water. 

In  considering  alterations  of  this  kind,  brought  about  in  the  physical 
geography  of  particular  tracts,  we  are  too  apt  to  think  exclusively  of  that 
part  of  the  earth's  surface  which  has  emerged  from  beneath  the  waters, 
and  with  which  alone,  as  terrestrial  beings,  we  are  familiar.  Here  the 
direct  power  of  animals  and  plants  to  cause  any  important  variation  is, 
of  necessity,  very  limited,  except  in  checking  the  progress  of  that  decay 
of  which  the  land  is  the  chief  theatre.  But  if  we  extend  our  views,  and 
instead  of  contemplating  the  dry  land,  consider  that  larger  portion  which 
is  assigned  to  the  aquatic  tribes,  we  discover  the  great  influence  of  the 
living  creation,  in  imparting  varieties  of  conformation  to  the  solid  exterior 
which  the  agency  of  inanimate  causes  alone  could  not  produce. 

Thus,  when  timber  is  floated  into  the  sea,  it  is  often  drifted  to  vast 
distances,  and  subsides  in  spots  where  there  might  have  been  no  deposit, 
at  that  time  and  place,  if  the  earth  had  not  been  tenanted  by  living 
beings.  If,  therefore,  in  the  course  of  ages,  a  hill  of  wood,  or  lignite, 
be  thus  formed  in  the  subaqueous  regions,  a  change  in  the  submarine 
geography  may  be  said  to  have  resulted  from  the  action  of  organic  pow- 
ers. So  in  regard  to  the  growth  of  coral  reefs ;  it  is  probable  that  a  large 


CH.  XLIV.]        INCREASE   ON   THE   SURFACE   OF   TJIE   LAND.         709 

portion  of  the  matter  of  which  they  are  composed  is  supplied  by  mineral 
springs,  which  often  rise  up  at  the  bottom  of  the  sea,  and  which,  on  land, 
abound  throughout  volcanic  regions  hundreds  of  leagues  in  extent.  The 
matter  thus  constantly  given  out  could  not  go  on  accumulating  for  ever 
in  the  waters,  but  would  be  precipitated  in  the  abysses  of  the  sea,  even 
if  there  were  no  polyps  and  testacea ;  but  these  animals  arrest  and  secrete 
the  carbonate  of  lime  on  the  summits  of  submarine  mountains,  and  form 
reefs  many  hundred  feet  in  thickness,  and  hundreds  of  miles  in  length, 
where,  but  for  them,  none  might  ever  have  existed. 

Why  the  vegetable  soil  does  not  augment  in  thickness. — If  no  such 
voluminous  masses  are  formed  on  the  land,  it  is  not  from  the  want  of 
solid  matter  in  the  structure  of  terrestrial  animals  and  plants  ;  but  merely 
because,  as  I  have  so  often  stated,  the  continents  are  those  parts  of  the 
globe  where  accessions  of  matter  can  scarcely  ever  take  place — where, 
on  the  contrary,  the  most  solid  parts  already  formed  are,  each  in  their 
turn,  exposed  to  gradual  degradation.  The  quantity  of  timber  and 
vegetable  matter  which  grows  in  a  tropical  forest  in  the  course  of  a 
century  is  enormous,  and  multitudes  of  animal  skeletons  are  scattered 
there  during  the  same  period,  besides  innumerable  land  shells  and  other 
organic  substances.  The  aggregate  of  these  materials,  therefore,  might 
constitute  a  mass  greater  in  volume  than  that  which  is  produced  in  any 
coral-reef  during  the  same  lapse  of  years ;  but,  although  this  process 
should  continue  on  the  land  for  ever,  no  mountains  of  wood  or  bone 
would  be  seen  stretching  far  and  wide  over  the  country,  or  pushing  out 
bold  promontories  into  the  sea.  The  whole  solid  mass  is  either  devoured 
by  animals,  or  decomposes,  as  does  a  portion  of  the  rock  and  soil  on 
which  the  animals  and  plants  are  supported. 

The  waste  of  the  strata  themselves,  accompanied  by  the  decomposition 
of  their  organic  remains,  and  the  setting  free  of  their  alkaline  ingredients, 
is  one  source  from  whence  running  water  and  the  atmosphere  may  derive 
the  materials  which  are  absorbed  by  the  roots  and  leaves  of  plants. 
Another  source  is  the  passage  into  a  gaseous  form  of  even  the  hardest 
parts  of  animals  and  plants  which  die  and  putrefy  in  the  air,  where  they 
are  soon  resolved  into  the  elements  of  which  .they  are  composed  :  and 
while  a  portion  of  these  constituents  is  volatilized,  the  rest  is  taken  up 
by  rain-water,  and  sinks  into  the  earth,  or  flows  towards  the  sea ;  so  that 
they  enter  again  and  again  into  the  composition  of  different  organic 
beings. 

The  principal  elements  found  in  plants  are  hydrogen,  carbon,  and 
oxygen ;  so  that  water  and  the  atmosphere  contain  all  of  them,  either 
in  their  own  composition  or  in  solution.*  The  constant  supply  of 
these  elements  is  maintained  not  only  by  the  putrefaction  of  animal 
and  vegetable  substances,  and  the  decay  of  rocks,  but  also  by  the 
copious  evolution  of  carbonic  acid  and  other  gases  from  volcanoes  and 

*  See  some  good  remarks  on  the  Formation  of  Soils,  Bakewell's  Geology,  chap, 
xviii 


710  VEGETATION  NO  COUNTERPOISE       [Cm  XLIV. 

mineral  springs,  and  by  the  effects  of  ordinary  evaporation,  whereby 
aqueous  vapors  are  made  to  rise  from  the  ocean,  and  to  circulate  round 
the  globe. 

It  is  well  known,  that  when  two  gases  of  different  specific  gravity  are 
brought  into  contact,  even  though  the  heavier  be  the  lowermost,  they  soon 
become  uniformly  diffused  by  mutual  absorption  through  the  whole  space 
which  they  occupy.  By  virtue  of  this  law,  the  heavy  carbonic  acid  finds 
its  way  upwards  through  the  lighter  air  of  the  atmosphere,  and  conveys 
nourishment  to  the  lichen  which  covers  the  mountain  top. 

If  the  quantity  of  food  consumed  by  terrestrial  animals,  and  the 
elements  imbibed  by  the  roots  and  leaves  of  plants,  were  derived  entirely 
from  that  supply  of  hydrogen,  carbon,  oxygen,  nitrogen,  and  other 
elements,  given  out  into  the  atmosphere  and  the  waters  by  the  putres- 
cence of  organic  substances,  then  we  might  imagine  that  the  vegetable 
mould  would,  after  a  series  of  years,  neither  gain  nor  lose  a  single  particle 
by  the  action  of  organic  beings ;  and  this  conclusion  is  not  far  from  the 
truth ;  but  the  operation  which  renovates  the  vegetable  and  animal  mould 
is  by  no  means  so  simple  as  that  here  supposed.  Thousands  of  carcases 
of  terrestrial  animals  are  floated  down,  every  century,  into  the  sea ;  and, 
together  with  forests  of  drift-timber,  are  imbedded  in  subaqueous  deposits, 
where  their  elements  are  imprisoned  in  solid  strata,  and  may  there  remain 
locked  up  throughout  whole  geological  epochs  before  they  again  become 
Mibservient  to  the  purposes  of  life. 

On  the  other  hand,  fresh  supplies  are  derived  by  the  atmosphere  and 
by  running'  water,  as  before  stated,  from  the  disintegration  of  rocks  and 
their  organic  contents,  and  through  the  agency  of  mineral  springs  from  the 
interior  of  the  earth,  from  whence  all  the  elements  before  mentioned,  which 
enter  principally  into  the  composition  of  animals  and  vegetables,  are  con- 
tinually evolved.  Even  nitrogen  is  found,  by  chemists,  to  be  contained 
very  generally  in  the  waters  of  mineral  springs. 

Vegetation  not  an  antagonist  power  counterbalancing  the  action  of 
running  water. — If  we  suppose  that  the  copious  supply  from  the  nether 
regions,  by  springs  and  volcanic  vents,  of  carbonic  acid  and  other  gases, 
together  with  the  decomposition  of  rocks,  may  be  just  sufficient  to  coun- 
terbalance that  loss  of  matter  which,  having  already  served  for  the  nour- 
ishment of  animals  and  plants,  is  annually  carried  down  in  organized 
forms,  and  buried  in  subaqueous  strata,  we  concede  the  utmost  that  is 
consistent  with  probability.  An  opinion,  however,  has  been  expressed, 
that  the  processes  of  vegetable  life,  by  absorbing  various  gases  from  the 
atmosphere,  cause  so  large  a  mass  of  solid  matter  to  accumulate  on 
the  surface  of  the  land,  that  this  mass  alone  may  constitute  a  great  coun- 
terpoise to  all  the  matter  transported  to  lower  levels  by  the  aqueous 
agents  of  decay.  "  Torrents  and  rivers,"  it  is  said — "  the  waves  of  the 
sea  and  marine  currents — act  upon  lines  only ;  but  the  power  of  vegeta- 
tion to  absorb  the  elastic  and  non-elastic  fluids  circulating  round  the 
earth,  extends  over  the  whole  surface  of  the  continents.  By  the  silent 
but  universal  action  of  this  great  antagonist  power,  the  spoliation  and 


Cfl.  XLIV.]        TO   THE   LEVELLING   POWER   OF   WATER.  711 

waste  caused  by  running  water  on  the  land,  and  by  the  movements  of  the 
ocean,  are  neutralized,  and  even  counterbalanced."* 

In  opposition  to  these  views,  I  conceive  that  we  shall  form  a  juster 
estimate  of  the  influence  of  vegetation,  if  we  consider  it  as  being  in  a 
slight  degree  conservative,  and  capable  of  retarding  the  waste  of  land, 
but  not  of  acting  as  an  antagonist  power.  The  vegetable  mould  is 
seldom  more  than  a  few  feet  in  thickness,  and  frequently  does  not  exceed 
a  few  inches  ;  and  we  by  no  means  find  that  its  volume  is  more  consi- 
derable on  those  parts  of  our  continents  which  we  can  prove,  by  geo- 
logical data,  to  have  been  elevated  at  more  ancient  periods,  and  where, 
consequently,  there  has  been  the  greatest  time  for  the  accumulation  of 
vegetable  matter,  produced  throughout  successive  zoological  epochs.  On 
the  contrary,  these  higher  and  older  regions  are  more  frequently  denuded, 
so  as  to  expose  the  bare  rock  to  the  action  of  the  sun  and  air. 

We  find  in  the  torrid  zone,  where  the  growth  of  plants  is  most  rank 
and  luxurious,  that  accessions  of  matter  due  to  their  agency  are  by  no 
means  the  most  conspicuous.  Indeed  it  is  in  these  latitudes,  where  the 
vegetation  is  most  active,  that,  for  reasons  to  be  explained  in  the  next 
chapter,  even  those  superficial  peat  mosses  are  unknown  which  cover  a 
large  area  in  some  parts  of  our  temperate  zone.  If  the  operation  of 
animal  and  vegetable  life  could  restore  to  the  general  surface  of  the 
continents  a  portion  of  the  elements  of  those  disintegrated  rocks  of 
which  such  enormous  masses  are  swept  down  annually  into  the  sea,  the 
effects  would  long  ere  this  have  constituted  one  of  the  most  striking 
features  in  the  structure  and  composition  of  our  continents.  All  the 
great  steppes  and  table-lands  of  the  world,  where  the  action  of  running 
water  is  feeble,  would  have  become  the  grand  repositories  of  organic 
matter,  accumulated  without  that  intermixture  of  earthy  sediment 
which  so  generally  characterizes  the  subaqueous  strata. 

I  have  already  stated  that,  in  the  known  operation  of  the  igneous  causes, 
a  real  antagonist  power  is  found,  which  may  counterbalance  the  level- 
ling action  of  running  water  (p.  563) ;  and  there  seems  no  good  reason 
for  presuming  that  the  upheaving  and  depressing  force  of  earthquakes, 
together  with  the  ejection  of  matter  by  volcanoes,  may  not  be  fully  ade- 
quate to  restore  that  inequality  of  the  surface  which  rivers  and  the  waves 
and  currents  of  the  ocean  annually  tend  to  lessen.  If  a  counterpoise  bo 
derived  from  this  source,  the  quantity  and  elevation  of  land  above  the 
sea  may  for  ever  remain  the  same,  in  spite  of  the  action  of  the  aqueous 
causes,  which,  if  thus  counteracted,  may  never  be  able  to  reduce  the 
surface  of  the  earth  more  nearly  to  a  state  of  equilibrium  than  that  which 
it  has  now  attained  ;  and,  on  the  other  hand,  the  force  of  the  aqueous 
agents  themselves  might  thus  continue  for  ever  unimpaired. 

Conservative  influence  of  vegetation. — If,  then,  vegetation  cannot  act 
as  an  antagonist  power  amid  the  mighty  agents  of  change  which  are 
always  modifying  the  surface  of  the  globe,  let  us  next  inquire  how  far 

*  See  Professor  Sedgwick's  Anniversary  Address  to  the  Geological  Society, 
Feb.  1831,  p.  24. 


712          CONSERVATIVE   INFLUENCE    OP   VEGETATION.       [Cn.  XLIV. 

its  influence  is  conservative, — how  far  it  may  retard  the  levelling  effects 
of  running  water,  which  it  cannot  oppose,  much  less  counterbalance. 

It  is  well  known  that  a  covering  of  herbage  and  shrubs  may  protect  a 
loose  soil  from  being  carried  away  by  rain,  or  even  by  the  ordinary 
action  of  a  river,  and  may  prevent  hills  of  loose  sand  from  being  blown 
away  by  the  wind ;  for  the  roots  bind  together  the  separate  particles 
into  a  firm  mass,  and  the  leaves  intercept  the  rain-water,  so  that  it  dries 
up  gradually,  instead  of  flowing  off  in  a  mass  and  with  great  velocity. 
The  old  Italian  hydrographers  make  frequent  mention  of  the  increased 
degradation  which  has  followed  the  clearing  away  of  natural  woods  in 
several  parts  of  Italy.  A  remarkable  example  was  afforded  in  the 
Upper  Val  d'  Arno,  in  Tuscany,  on  the  removal  of  the  woods  clothing 
the  steep  declivities  of  the  hills  by  which  that  valley  is  bounded. 
When  the  ancient  forest  laws  were  abolished  by  the  Grand  Duke  Joseph, 
during  the  last  century,  a  considerable  tract  of  surface  in  the  Cassentina 
(the  Clausentinium  of  the  Romans)  was  denuded,  and  immediately  the 
quantity  of  sand  and  soil  washed  down  into  the  Arno  increased  enor- 
mously. Frisi,  alluding  to  such  occurrences,  observes,  that  as  soon  as 
the  bushes  and  plants  were  removed,  the  waters  flowed  off  more  rapid- 
ly, and,  in  the  manner  of  floods,  swept  away  the  vegetable  soil.* 

This  effect  of  vegetation  is  of  high  interest  to  the  geologist,  when  he 
is  considering  the  formation  of  those  valleys  which  have  been  princi- 
pally due  to  the  action  of  rivers.  The  spaces  intervening  between  val- 
leys, whether  they  be  flat  or  ridgy,  when  covered  with  vegetation,  may 
scarcely  undergo  the  slightest  waste,  as  the  surface  may  be  protected  by 
the  green  sward  of  grass ;  and  this  may  be  renewed,  in  the  manner 
before  described,  from  elements  derived  from  rain-water  and  the  atmo- 
sphere. Hence,  while  the  river  is  continually  bearing  down  matter  in 
the  alluvial  plain,  and  undermining  the  cliffs  on  each  side  of  every  valley, 
the  height  of  the  intervening  rising  grounds  may  remain  stationary. 

In  this  manner,  a  cone  of  loose  scoria?,  sand,  and  ashes,  such  as  Monte 
Nuovo,  may,  when  it  has  once  become  densely  clothed  with  herbage 
and  shrubs,  suffer  scarcely  any  further  dilapidation  ;  and  the  perfect 
state  of  the  cones  of  hundreds  of  extinct  volcanoes  in  France,  the  Nea- 
politan territory,  Sicily,  and  elsewhere,  may  prove  nothing  whatever, 
either  as  to  their  relative  or  absolute  antiquity.  We  may  be  enabled 
to  infer,  from  the  integrity  of  such  conical  hills  of  incoherent  materials, 
that  no  flood  can  have  passed  over  the  countries  where  they  are  situated, 
since  their  formation  ;  but  the  atmospheric  action  alone,  in  spots  where 
there  happen  to  be  no  torrents,  and  where  the  surface  was  clothed  with 
vegetation,  could  scarcely  in  any  lapse  of  ages  have  destroyed  them. 

During  a  tour  in  Spain,  in  1830,  I  was  surprised  to  see  a  district  of 
gently  undulating  ground  in  Catalonia,  consisting  of  red  and  gray  sand- 
stone, and  in  some  parts  of  red  marl,  almost  entirely  denuded  of  herbage ; 
•while  the  roots  of  the  pines,  holm  oaks,  and  some  other  trees,  were  half 

*  Treatise  011  Rivers  and  Torrents,  p.  5.     Garston's  translation. 


CH.  XLIV.]  INFLUENCE   OP   MAN.  718 

exposed,  as  if  the  soil  had  been  washed  away  by  a  flood.  Such  is  the 
state  of  the  forests,  for  example,  between  Oristo  and  Vich,  and  near  San 
Lorenzo.  But,  being  overtaken  by  a  violent  thunder-storm,  in  the  month 
of  August,  I  saw  the  whole  surface,  even  the  highest  levels  of  some  flatr 
topped  hills,  streaming  with  mud,  while  on  every  declivity  the  devasta- 
tion of  torrents  was  terrific.  The  peculiarities  in  the  physiognomy  of 
the  district  were  at  once  explained  ;  and  I  was  taught  that,  in  speculating 
on  the  greater  effects  which  the  direct  action  of  rain  may  once  have  pro- 
duced on  the  surface  of  certain  parts  of  England,  we  need  not  revert  to 
periods  when  the  heat  of  the  climate  was  tropical. 

In  the  torrid  zone  the  degradation  of  land  is  generally  more  rapid ; 
but  the  waste  is  by  no  means  proportioned  to  the  superior  quantity  of 
rain  or  the  suddenness  of  its  fall,  the  transporting  power  of  water  being 
counteracted  by  a  greater  luxuriance  of  vegetation.  A  geologist  who  is 
no  stranger  to  tropical  countries  observes,  that  the  softer  rocks  would 
speedily  be  washed  away  in  such  regions,  if  the  numerous  roots  of  plants 
were  not  matted  together  in  such  a  manner  as  to  produce  considerable 
resistance  to  the  destructive  power  of  the  rains.  The  parasitical  and 
creeping  plants  also  entwine  in  every  possible  direction,  so  as  to  render 
the  forests  nearly  impervious,  and  the  trees  possess  forms  and  leaves  best 
calculated  to  shoot  off  the  heavy  rains ;  which,  when  they  have  thus 
been  broken  in  their  fall,  are  quickly  absorbed  by  the  ground  beneath, 
or,  when  thrown  into  the  drainage  depressions,  give  rise  to  furious 
torrents.* 


Influence  of  Man  in  modifying  the  Physical  Geography  of  the 

Globe. 

Before  concluding  this  chapter,  I  shall  offer  a  few  observations  on  the 
influence  of  man  in  modifying  the  physical  geography  of  the  globe ;  for 
we  must  class  his  agency  among  the  powers  of  organic  nature. 

Felling  of  forests. — The  felling  of -forests  has  been  attended,  in  many 
countries,  by  a  diminution  of  rain,  as  in  Barbadoes  and  Jamaica.f  For 
in  tropical  countries,  where  the  quantity  of  aqueous  vapor  in  the  atmo- 
sphere is  great,  but  where,  on  the  other  hand,  the  direct  rays  of  the  sun 
are  most  powerful,  any  impediment  to  the  free  circulation  of  air,  or  any 
screen  which  shades  the  earth  from  the  solar  rays,  becomes  a  source  of 
humidity ;  and  wherever  dampness  and  cold  have  begun  to  be  generated 
by  such  causes,  the  condensation  of  vapor  continues.  The  leaves,  more- 
over, of  all  plants  are  alembics,  and  some  of  those  in  the  torrid  zone  have 
the  remarkable  property  of  distilling  water,  thus  contributing  to  prevent 
the  earth  from  becoming  parched  up. 

Distribution  of  the  American  forests. — There  can  be  no  doubt  then, 
that  the  state  of  the  climate,  especially  the  humidity  of  the  atmosphere, 
influences  vegetation,  and  that,  in  its  turn,  vegetation  re-acts  upon  the 

*  De  la  Beche,  Geol.  Man.,  p.  184.,  1st  ed.        f  Phil.  Trans.,  voL  iL  p.  294. 


714  INFLUENCE   OP  MAN  [On.  XLIV. 

climate :  but  some  writers  seem  to  liave  attributed  too  much  importance 
to  the  influence  of  forests,  particularly  those  of  America,  as  if  they  were 
the  primary  cause  of  the  moisture  of  the  climate. 

The  theory  of  a  modern  author  on  this  subject  "  that  forests  exist  in 
those  parts  of  America  only  where  the  predominant  winds  carry  with  them  a 
considerable  quantity  of  moisture  from  the  ocean,"  seems  far  more  rational. 
In  all  countries,  he  says,  "  having  a  summer  heat  exceeding  70°,  the 
presence  or  absence  of  natural  woods,  and  their  greater  or  less  luxuriance, 
may  be  taken  as  a  measure  of  the  amount  of  humidity,  and  of  the  fer- 
tility of  the  soil.  Short  and  heavy  rains  in  a  warm  country  will  produce 
grass,  which,  having  its  roots  near  to  the  surface,  springs  up  in  a  few  days, 
and  withers  when  the  moisture  is  exhausted ;  but  transitory  rains,  how- 
ever heavy,  will  not  nourish  trees ;  because,  after  the  surface  is  saturated, 
the  remainder  of  the  water  runs  off,  and  the  moisture  lodged  in  the  soil 
neither  sinks  deep  enough,  nor  is  in  sufficient  quantity,  to  furnish  the 
giants  of  the  forests  with  the  necessary  sustenance.  It  may  be  assumed 
that  twenty  inches  of  rain  falling  moderately  or  at  intervals,  will  leave  a 
greater  permanent  supply  in  the  soil  than  forty  inches  falling,  as  it  some- 
times does  in  the  torrid  zone,  in  as  many  hours."* 

"  In  all  regions,"  he  continues,  "  where  ranges  of  mountains  intercept 
the  course  of  the  constant  or  predominant  winds,  the  country  on  the 
windward  side  of  the  mountains  will  be  moist,  and  that  on  the  leeward 
dry ;  and  hence  parched  deserts  will  generally  be  found  on  the  west  side 
of  countries  within  the  tropics,  and  on  the  east  side  of  those  beyond 
them,  the  prevailing  winds  in  these  cases  being  generally  in  opposite  di- 
rections. On  this  principle,  the  position  of  forests  in  North  and  South 
America  may  be  explained.  Thus,  for  example,  in  the  region  within  the 
thirtieth  parallel,  the  moisture  swept  up  by  the  trade-wind  from  the  At- 
lantic is  precipitated  in  part  upon  the  mountains  of  Brazil,  which  are  but 
low,  and  so  distributed  as  to  extend  far  into  the  interior.  The  portion 
which  remains  is  borne  westward,  and,  losing  a  little  as  it  proceeds,  is 
at  length  arrested  by  the  Andes,  where  it  falls  down  in  showers  on  their 
summits.  The  aerial  current,  now  deprived  of  all  the  humidity  with 
which  it  can  part,  arrives  in  a  state  of  complete  exsiccation  at  Peru,  where 
consequently  no  rain  falls.  But  in  the  region  of  America,  beyond  the 
thirtieth  parallel,  the  Andes  serve  as  a  screen  to  intercept  the  moisture 
brought  by  the  prevailing  winds  from  the  Pacific  Ocean  :  rains  are  copi- 
ous on  their  summits,  and  in  Chili  on  their  western  declivities ;  but  none 
falls  on  the  plains  to  the  eastward,  except  occasionally  when  the  wind 
blows  from  the  Atlantic."!  - 

I  have  been  more  particular  in  explaining  these  views,  because  they 
appear  to  place  in  a  true  light  the  dependence  of  vegetation  on  climate, 
the  humidity  being  increased,  and  more  uniformly  diffused  throughout 
the  year,  by  the  gradual  spreading  of  wood. 

*  Maclaren,  art.  America,  Encyc.  Britannica. 

f  Maclaren,  art.  America,  Encyc.  Britannica,  where  the  position  of  the  Ame- 
rican forests,  in  accordance  with  this  theory,  is  laid  down  in  a  map. 


CH.  XLIV.]         IN   MODIFYING   PHYSICAL   GEOGRAPHY.  715 

It  has  been  affirmed,  that  formerly,  when  France  and  England  were 
covered  with  wood,  Europe  was  much  colder  than  at  present;  that  the 
winters  in  Italy  were  longer,  and  that  the  Seine,  and  many  other  rivers, 
froze  more  regularly  every  winter  than  now.  M.  Arago,  in  an  essay  on 
this  subject,  has  endeavored  to  show,  by  tables  of  observations  on  the 
congelation  of  the  Rhine,  Danube,  Rhone,  Po,  Seine,  and  other  rivers,  at 
different  periods,  that  there  is  no  reason  to  believe  the  cold  to  have  been 
in  general  more  intense  in  ancient  times.*  He  admits,  however,  that  the 
climate  of  Tuscany  has  been  so  far  modified,  by  the  removal  of  wood,  as 
that  the  winters  are  less  cold;  but  the  summers  also,  he  contends,  are 
less  hot  than  of  old;  and  the  summers,  according  to  him,  were  formerly 
hotter  in  France  than  in  our  own  times.  His  evidence  is  derived  chiefly 
from  documents  showing  that  wine  was  made  three  centuries  ago  in 
the  Vivarais  and  several  other  provinces,  at  an  earlier  season,  at  greater 
elevations,  and  in  higher  latitudes,  than  are  now  found  suitable  to  the  vine. 

There  seems  little  doubt  that  in  the  United  States  of  North  America 
the  rapid  clearing  of  the  country  has  rendered  the  winters  less  severe  and 
the  summers  less  hot;  in  other  words,  the  extreme  temperatures  of 
January  and  July  have  been  observed  from  year  to  year  to  approach 
somewhat  nearer  to  each  other.  Whether  in  this  case,  or  in  France,  the 
mean  temperature  has  been  raised,  seems  by  no  means  as  yet  decided; 
but  there  is  no  doubt  that  the  climate  has  become,  as  Buifon  would  have 
said,  "less  excessive." 

I  have  before  shown,  when  treating  of  the  excavation  of  new  estuaries 
in  Holland  by  inroads  of  the  ocean,  as  also  of  the  changes  on  our  own 
coasts,  that  although  the  conversion  of  sea  into  land  by  artificial  labors 
may  be  great,  yet  it  must  always  be  in  subordination  to  the  power  of  the 
tides  and  currents,  or  to  the  great  movements  which  alter  the  relative 
level  of  the  land  and  sea,  (Chap.  XX.)  If,  in  addition  to  the  assistance 
obtained  by  parliamentary  grants  for  defending  Dunwich  from  the  waves, 
all  the  resources  of  Europe  had  been  directed  to  the  same  end,  the  exist- 
ence of  that  port  might  perhaps  have  been  prolonged  for  several  centuries 
(p.  310.)  But  in  the  mean  time,  the  current  would  have  continued  to 
sweep  away  portions  from  the  adjoining  cliffs  on  each  side,  giving  to  the 
whole  line  of  coast  its  present  form,  until  at  length  the  town,  projecting  as 
a  narrow  promontory,  must  have  become  exposed  to  the  irresistible  fury 
of  the  waves. 

It  is  scarcely  necessary  to  observe,  that  the  control  which  man  can 
obtain  over  the  igneous  agents  is  less  even  than  that  which  he  may  exert 
over  the  aqueous.  He  cannot  modify  the  upheaving  or  depressing  force 
of  earthquakes,  or  the  periods  or  degree  of  violence  of  volcanic  eruptions; 
and  on  these  causes  the  inequalities  of  the  earth's  surface,  and,  conse- 
quently, the  shape  of  the  sea  and  land,  appear  mainly  to  depend.  The 
utmost  that  man  can  hope  to  effect  in  this  respect  is  occasionally  to 
divert  the  course  of  a  lava-stream,  and  to  prevent  the  burning  matter,  for 

*  Annuaire  du  Bureau  des  Long.     1884. 


T16  INFLUENCE   OF   MAN  [Ca  XLIV. 

a  season,  from  overwhelming  a  city,  or  some  other  of  the  proudest  works 
of  human  industry. 

If  all  the  nations  of  the  earth  should  attempt  to  quarry  away  the  lava 
which  flowed  during  one  eruption  from  the  Icelandic  volcanoes  in  1783, 
and  the  two  following  years,  and  should  attempt  to  consign  it  to  the 
deepest  abysses  of  the  ocean,  they  might  toil  for  thousands  of  years  and 
not  accomplish  their  task.  Yet  the  matter  borne  down  to  the  sea  by  two 
great  rivers,  the  Ganges  and  Burrampooter,  in  each  quarter  of  a  century, 
probably  equals  in  weight  and  volume  the  mass  of  Icelandic  lava  pro- 
duced by  that  great  eruption  (p.  282).  So  insignificant  is  the  aggregate 
force  exerted  by  man,  when  contrasted  with  the  ordinary  operations  of 
aqueous  or  igneous  agents  in  the  natural  world. 

No  application,  perhaps,  of  human  skill  and  labor  tends  so  greatly  to 
vary  the  state  of  the  nabitable  surface,  as  that  employed  in  the  drainage 
of  lakes  and  marshes,  since  not  only  the  stations  of  many  animals  and 
plants,  but  the  general  climate  of  a  district,  may  thus  be  modified.  'It  is 
also  a  kind  of  alteration  to  which  it  is  difficult  to  find  anything  analogous 
in  the  agency  of  inferior  beings;  for  we  ought  always,  before  we  decide 
that  any  part  of  the  influence  of  man  is  novel  and  anomalous,  carefully  to 
consider  the  powers  of  all  other  animated  agents  which  may  be  limited 
or  superseded  by  him.*  Many  who  have  reasoned  on  these  subjects  seem 
to  have  forgotten  that  the  human  race  often  succeeds  to  the  discharge  of 
functions  previously  fulfilled  by  other  species.  Suppose  the  growth  of  some 
of  the  larger  terrestrial  plants,  or,  in  other  words,  the  extent  of  forest,  to 
be  diminished  by  man,  and  the  climate  to  be  thereby  modified,  it  does 
not  follow  that  this  kind  of  innovation  is  unprecedented.  It  is  a  change 
in  the  state  of  vegetation,  and  such  may  often  have  been  the  result  of 
the  appearance  of  new  species  upon  the  earth.  The  multiplication,  for 
example,  of  certain  insects  in  parts  of  Germany,  during  the  last  century, 
destroyed  more  trees  than  man,  perhaps,  could  have  felled  during  an 
equal  period. 

It  would  be  rash,  however,  to  affirm  that  the  power  of  man  to  modify 
the  surface  may  not  differ  in  kind  or  degree  from  that  of  other  living 
beings  ;  although  the  problem  is  certainly  more  complex  than  many 
who  have  speculated  on  such  topics  have  imagined.  If  land  be  raised 
from  the  sea,  the  greatest  alteration  in  its  physical  condition,  which 
could  ever  arise  from  the  influence  of  organic  beings,  would  probably 
be  produced  by  the  first  immigration  of  terrestrial  plants,  whereby 
the  new  tract  would  become  covered  with  vegetation.  The  change 
next  in  importance  would  seem  to  be  when  animals  first  enter,  and 
modify  the  proportionate  numbers  of  certain  species  of  plants.  If  there 
be  any  anomaly  in  the  intervention  of  man,  in  farther  varying  the  rela- 

*  Since  this  was  written  I  have  seen  in  New  Brunswick  (1852)  a  lake  formed 
by  beavers  who  had  thrown  a  dam,  consisting  of  stakes,  stones,  and  mud,  across 
the  course  of  a  small  streamlet,  between  Dorchester  and  the  Portage  south  of  the 
Peticodiac  river.  The  beavers  have  since  been  extirpated  by  man,  but  the 
lake  remains,  and  musk  rats  have  taken  possession  of  the  shallow  parts  of  the 
lake  to  build  their  habitations  in  them. 


CH.  XLIV.]       IN   MODIFYING   PHYSICAL   GEOGRAPHY.  717 

tive  numbers  in  the  vegetable  kingdom,  it  may  not  so  much  consist  in 
the  kind  or  absolute  quantity  of  alteration,  as  in  the  circumstance  that 
a  single  species,  in  this  case,  would  exert,  by  its  superior  power  and  uni- 
versal distribution,  an  influence  equal  to  that  of  hundreds  of  other  ter- 
restrial animals. 

If  we  inquire  whether  man,  by  his  direct  power,  or  by  the  changes 
which  he  may  give  rise  to  indirectly,  tends,  upon  the  whole,  to  lessen  or 
increase  the  inequalities  of  the  earth's  surface,  we  shall  incline,  perhaps, 
to  the  opinion  that  he  is  a  levelling  agent.  In  mining  operations  he 
conveys  upwards  a  certain  quantity  of  materials  from  the  bowels  of  the 
earth  ;  but,  on  the  other  hand,  much  rock  is  taken  annually  from  the 
land,  in  the  shape  of  ballast,  and  afterwards  thrown  into  the  sea,  and 
by  this  means,  in  spite  of  prohibitory  laws,  many  harbors,  in  various 
parts  of  the  world,  have  been  blocked  up.  We  rarely  transport  heavy 
materials  to  higher  levels,  and  our  pyramids  and  cities  are  chiefly  con- 
structed of  stone  brought  down  from  more  elevated  situations.  By 
ploughing  up  thousands  of  square  miles,  and  exposing  a  surface  for 
part  of  the  year  to  the  action  of  the  elements,  we  assist  the  abrading 
force  of  rain,  and  diminish  the  conservative  effects  of  vegetation. 


CHAPTER  XLV. 

. . 

INCLOSING    OF    FOSSILS    IN    PEAT,    BROWN    SAND,    AND   VOLCANIC 
EJECTIONS. 

Division  of  the  subject — Imbedding  of  organic  remains  in  deposits  on  emerged 
land — Growth  of  peat — Site  of  ancient  forests  in  Europe  now  occupied  by 
peat — Bog  iron-ore — Preservation  of  animal  substances  in  peat — Miring  of 
quadrupeds — Bursting  of  the  Sol  way  moss — Great  Dismal  Swamp — Imbed- 
ding of  organic  bodies  and  human  remains  in  blown  sand — Moving  sands  of 
African  deserts — De  Luc  on  their  recent  origin — Buried  temple  of  Ipsambul 
— Dried  carcases  in  the  sands — Towns  overwhelmed  by  sand-floods — Imbed- 
ding of  organic  and  other  remains  in  volcanic  formations  on  the  land. 

Division  of  the  subject. — THE  next  subject  of  inquiry  is  the  mode  in 
which  the  remains  of  animals  and  plants  become  fossil,  or  are  buried 
in  the  earth  by  natural  causes.  M.  Constant  Prevost  has  observed, 
that  the  effects  of  geological  causes  are  divisible  into  two  great  classes ; 
those  produced  during  the  submersion  of  land  beneath  the  waters, 
and  those  which  take  place  after  its  emersion.  Agreeably  to  this  classi- 
fication, I  shall  consider,  first,  in  what  manner  animal  and  vegetable 
remains  become  included  and  preserved  in  deposits  on  emerged  land,  or 
that  part  of  the  surface  which  is  not  permanently  covered  by  water, 
whether  of  seas  or  lakes  ;  secondly,  the  manner  in  which  organic  remains 
become  imbedded  in  subaqueous  deposits. 

Under  the  first  division.  I  shall  treat  of  the  following  topics : — 1st,  the 
growth  of  peat,  and  the  preservation  of  vegetable  and  animal  remains 
therein ; — 2dly,  the  burying  of  organic  remains  in  blown  sand  ; — 3dly, 
of  the  same  in  the  ejections  and  alluviums  of  volcanoes; — 4thly,  in 
alluviums  generally,  and  in  the  ruins  of  landslips ; — Sthly,  in  the  mud 
and  stalagmite  of  caves  and  fissures. 

Growth  of  Peat,  and  Preservation  of  Vegetable  and  Animal  Remains 

therein. 

The  generation  of  peat,  when  not  completely  under  water,  is  confined 
to  moist  situations,  where  the  temperature  is  low,  and  where  vegetables 
may  decompose  without  putrefying.  It  may  consist  of  any  of  the 
numerous  plants  which  are  capable  of  growing  in  such  stations  ;  but  a 
species  of  moss  (Sphagnum)  constitutes  a  considerable  part  of  the  peat 
found  in  marshes  of  the  north  of  Europe ;  this  plant  having  the  pro- 
perty of  throwing  up  new  shoots  in  its  upper  part,  while  its  lower 
extremities  are  decaying.*  Reeds,  rushes,  and  other  aquatic  plants 
may  usually  be  traced  in  peat ;  and  their  organization  is  often  so  entire 
that  there  is  no  difficulty  in  discriminating  the  distinct  species. 

*  For  a  catalogue  of  plants  which  form  peat,  see  Rev.  Dr.  Rennie's  Essays  on 
Peat,  p.  171 ;  and  Dr.  MacCulloch's  Western  Isles,  vol.  i.  p.  129. 


CH.  XLV.]  FORMATION   OF   PEAT.  719 

Analysis  of  peat.  —  In  general,  says  Sir  H.  Davy,  one  hundred  parts 
of  dry  peat  contain  from  sixty  to  ninety-nine  parts  of  matter  destructi- 
ble by  fire  ;  and  the  residuum  consists  of  earths  usually  of  the  same 
kind  as  the  substratum  of  clay,  marl,  gravel,  or  rock,  on  which  they  are 
found,  together  with  oxide  of  iron.  "  The  peat  of  the  chalk  counties 
of  England,"  observes  the  same  writer,  "contains  much  gypsum:  but  I 
have  found  very  little  in  any  specimens  from  Ireland  or  Scotland,  and 
in  general  these  peats  contain  very  little  saline  matter."  *  From  the 
researches  of  Dr.  MacCulloch,  it  appears  that  peat  is  intermediate 
between  simple  vegetable  matter  and  lignite,  the  conversion  of  peat  to 
lignite  being  gradual,  and  being  brought  about  by  a  prolonged  action 
of  water,  f 

Peat  abundant  in  cold  and  humid  climates.  —  Peat  is  sometimes 
formed  on  a  declivity  in  mountainous  regions,  where  there  is  much 
moisture  ;  but  in  such  situations  it  rarely,  if  ever,  exceeds  four  feet  in 
thickness.  In  bogs,  and  in  low  grounds  into  which  alluvial  peat  is 
drifted,  it  is  found  forty  feet  thick,  and  upwards;  but  in  such  cases  it 
generally  owes  one  half  of  its  volume  to  the  water  which  it  contains. 
It  has  seldom,  if  ever,  been  discovered  within  the  tropics  ;  and  it  rarely 
occurs  in  the  valleys,  even  in  the  south  of  France  and  Spain.  It 
abounds  more  and  more,  in  proportion  as  we  advance  farther  from  the 
equator,  and  becomes  not  only  more  frequent  but  more  inflammable  in 
northern  latitudes.^ 

The  same  phenomenon  is  repeated  in  the  southern  hemisphere.  No 
peat  is  found  in  Brazil,  nor  even  in  the  swampy  parts  of  the  country 
drained  by  the  La  Plata  on  the  east  side  of  -South  America,  or  in  the 
island  of  Chiloe  on  the  west  ;  yet  when  we  reach  the  45th  degree  of 
latitude  and  examine  the  Chonos  Archipelago  or  the  Falkland  Islands, 
and  Tierra  del  Fuego,  we  meet  with  an  abundant  growth  of  this  sub- 
stance. Almost  all  plants  contribute  here  by  their  decay  to  the  pro- 
duction of  peat,  even  the  grasses  ;  but  it  is  a  singular  fact,  says  Mr. 
Darwin,  as  contrasted  with  what  occurs  in  Europe,  that  no  kind  of 
moss  enters  into  the  composition  of  the  South  American  peat,  which 
is  formed  by  many  plants,  but  chiefly  by  that  called  by  Brown  Astelia 


I  learn  from  Dr.  Forchhammer  (1849)  that  water  charged  with  vege- 
table matter  in  solution  does  not  throw  down  a  deposit  of  peat  in 
countries  where  the  mean  temperature  of  the  year  is  above  48°  or  44° 
Fahrenheit.  Frost  causes  the  precipitation  of  such  peaty  matter,  but 
in  warm  climates  the  attraction  of  the  carbon  for  the  oxygen  of  the  air 
mechanically  mixed  with  the  water  increases  with  the  increasing  tem- 
perature, and  the  dissolved  vegetable  matter  or  humic  acid  (which  is 
organic  matter  in  a  progressive  state  of  decomposition)  being  converted 
into  carbonic  acid,  rises  and  is  absorbed  into  the  atmosphere,  and  thus 
disappears. 

*  Irish  Bog  Reports,  p.  209.  f  System  of  Geology,  vol.  ii.  p.  353. 

\  Rev.  Dr.  Rennie  on  Peat,  p.  260.     §  Darwin's  Journal,  p.  349.  ;  2d  ed.  p.  287. 


720  FORMATION   OF  PEAT.  [Cn.  XLV. 

Extent  of  surf  ace  covered  by  peat. —  There  is  a  vast  extent  of  surface 
in  Europe  covered  with  peat,  which,  in  Ireland,  is  said  to  extend  over  a 
tenth  of  the  whole  island.  One  of  the  mosses  on  the  Shannon  is 
described  as  being  fifty  miles  long,  by  two  or  three  broad  ;  and  the  great 
marsh  of  Montoire,  near  the  mouth  of  the  Loire,  is  mentioned,  by 
Blavier,  as  being  more  than  fifty  leagues  in  circumference.  It  is  a 
curious  and  well-ascertained  fact,  that  many  of  these  mosses  of  the  north 
of  Europe  occupy  the  place  of  forests  of  pine  and  oak,  which  have,  many 
of  them,  disappeared  within  the  historical  era.  Such  changes  are 
brought  about  by  the  fall  of  trees  and  the  stagnation  of  water,  caused 
by  their  trunks  and  branches  obstructing  the  free  drainage  of  the 
atmospheric  waters,  and  giving  rise  to  a  marsh.  In  a  warm  climate, 
such  decayed  timber  would  immediately  be  removed  by  insects,  or  by 
putrefaction ;  but,  in  the  cold  temperature  now  prevailing  in  our 
latitudes,  many  examples  are  recorded  of  marshes  originating  in  this 
source.  Thus,  in  Mar  forest,  in  Aberdeenshire,  large  trunks  of  Scotch 
fir,  which  had  fallen  from  age  and  decay,  were  soon  immured  in  peat, 
formed  partly  out  of  their  perishing  leaves  and  branches,  and  in  part 
from  the  growth  of  other  plants.  We  also  learn,  that  the  overthrow  of 
a  forest  by  a  storm,  about  the  middle  of  the  seventeenth  century,  gave 
rise  to  a  peat-moss  near  Lochbroom,  in  Ross-shire,  where,  in  less  than 
half  a  century  after  the  fall  of  the  trees,  the  inhabitants  dug  peat.*  Dr. 
Walker  mentions  a  similar  change,  when,  in  the  year  1756,  the  whole 
wood  of  Drumlaurig  in  Dumfries-shire  was  overset  by  the  wind.  Such 
events  explain  the  occurrence,  both  in  Britain  and  on  the  Continent,  of 
mosses  where  the  trees  are  all  broken  within  two  or  three  feet  of  the 
original  surface,  and  where  their  trunks  all  lie  in  the  same  direction.f 

It  may  however  be  suggested  in  these  cases,  that  the  soil  had  become 
exhausted  for  trees,  and  that,  on  the  principle  of  that  natural  rotation 
which  prevails  in  the  vegetable  world,  one  set  of  plants  died  out  and 
another  succeeded.  It  is  certainly  a  remarkable  fact  that  in  the 
Danish  islands,  and  in  Jutland  and  Holstein,  fir  wood  of  various  species, 
especially  Scotch  fir,  is  found  at  the  bottom  of  the  peat-mosses,  although 
it  is  well  ascertained  that  for  the  last  five  centuries  no  Coniferae  have 
grown  wild  in  thesfe  countries ;  the  coniferous  trees  which  now  flourish 
there  having  been  all  planted  towards  the  close  of  the  last  century. 

Nothing  is  more  common  than  the  occurrence  of  buried  trees  at  the 
bottom  of  the  Irish  peat-mosses,  as  also  in  most  of  those  of  England, 
France,  and  Holland ;  and  they  have  been  so  often  observed  with  parts 
of  their  trunks  standing  erect,  and  with  their  roots  fixed  to  the  subsoil, 
that  no  doubt  can  be  entertained  of  their  having  generally  grown  on 
the  spot.  They  consist,  for  the  most  part,  of  the  fir,  the  oak,  and  the 
birch  :  where  the  subsoil  is  clay,  the  remains  of  oak  are  the  most  abun- 
dant; where  sand  is  the  substratum,  fir  prevails.  In  the  marsh  of 
Curragh,  in  the  Isle  of  Man,  vast  trees  are  discovered  standing  firm  on 

*  Rennie's  Essays  on  Peat,  p.  65.  f  Ibid.  p.  30. 


CH.  XLV.]  FORESTS   CONVERTED   INTO   PEAT.  721 

their  roots,  though  at  the  depth  of  eighteen  or  twenty  feet  below  the 
surface.  Some  naturalists  have  desired  to  refer  the  imbedding  of  timber 
in  peat-mosses  to  aqueous  transportation,  since  rivers  are  well  known 
to  float  wood  into  lakes ;  but  the  facts  above  mentioned  show  that,  in 
numerous  instances,  such  an  hypothesis  is  inadmissible.  It  has,  more- 
over, been  observed,  that  in  Scotland,  as  also  in  many  parts  of  the  Con- 
tinent, the  largest  trees  are  found  in  those  peat-mosses  which  lie  in  the 
least  elevated  regions,  and  that  the  trees  are  proportionally  smaller  in 
those  which  lie  at  higher  levels ;  from  which  fact  De  Luc  and  Walker 
have  both  inferred  that  the  trees  grew  on  the  spot,  for  they  would 
naturally  attain  a  greater  size  in  lower  and  warmer  levels.  The  leaves, 
also,  and  fruits  of  each  species,  are  continually  found  immersed  in  the 
moss  along  with  the  parent  trees ;  as,  for  example,  the  leaves  and  acorns 
of  the  oak,  the  cones  and  leaves  of  the  fir,  and  the  nuts  of  the  hazel. 

Recent  origin  of  some  peat-mosses* — In  Hatfield  moss,  in  Yorkshire, 
which  appears  clearly  to  have  been  a  forest  eighteen  hundred  years 
ago,  fir-trees  have  been  found  ninety  feet  long,  and  sold  for  masts  and 
keels  of  ships ;  oaks  have  also  been  discovered  there  above  one  hundred 
feet  long.  The  dimensions  of  an  oak  from  this  moss  are  given  in  the 
Philosophical  Transactions,  No.  275,  which  must  have  been  larger  than 
any  tree  now  existing  in  the  British  dominions. 

In  the  same  moss  of  Hatfield,  as  well  as  in  that  of  Kincardine,  in 
Scotland,  and  several  others,  Roman  roads  have  been  found  covered  to  the 
depth  of  eight  feet  by  peat.  All  the  coins,  axes,  arms,  and  other  uten- 
sils found  in  British  and  French  mosses,  are  also  Roman ;  so  that  a 
considerable  portion  of  the  peat  in  European  peat-bogs  is  evidently  not 
more  ancient  than  the  age  of  Julius  Caesar.  Nor  can  any  vestiges  of 
the  ancient  forests  described  by  that  general,  along  the  line  of  the  great 
Roman  way  in  Britain,  be  discovered,  except  in  the  ruined  trunks  of 
trees  in  peat. 

De  Luc  ascertained  that  the  very  sites  of  the  aboriginal  forests  of  Her- 
cinia,  Semana,  Ardennes,  and  several  others,  are  now  occupied  by  mosses 
and  fens ;  and  a  great  part  of  these  changes  have,  with  much  probability, 
been  attributed  to  the  strict  orders  given  by  Severus,  and  other  emperors, 
to  destroy  all  the  wood  in  the  conquered  provinces.  Several  of  the 
British  forests,  however,  which  are  now  mosses,  were  cut  at  different 
periods,  by  order  of  the  English  parliament,  because  they  harbored  wolves 
or  outlaws.  Thus  the  Welsh  woods  were  cut  and  burned,  in  the  reign 
of  Edward  I. ;  as  were  many  of  those  in  Ireland,  by  Henry  II.,  to  pre- 
vent the  natives  from  harboring  in  them,  and  harassing  his  troops. 

It  is  curious  to  reflect  that  considerable  tracts  have,  by  these  acci- 
dents, been  permanently  sterilized,  and  that,  during  a  period  when  civi- 
lization has  been  making  great  progress,  large  areas  in  Europe  have,  by 
human  agency,  been  rendered  less  capable  of  administering  to  the 
wants  of  man.  Rennie  observes,*  with  truth,  that  in  those  regions 

*  Essays  on  Peat,  <fcc.,  p.  74. 
46 


722  HUMAN  REMAINS  IN  PEAT.  [Cn.  XLV. 

alone  which  the  Roman  eagle  never  reached  —  in  the  remote  circles  of 
the  German  empire,  in  Poland  and  Prussia,  and  still  more  in  Norway, 
Sweden,  and  the  vast  empire  of  Russia  —  can  we  see  what  Europe  was 
before  it  yielded  to  the  power  of  Rome.  Desolation  now  reigns  where 
stately  forests  of  pine  and  oak  once  flourished,  such  as  might  now  have 
supplied  all  the  navies  of  Europe  with  timber. 

Sources  of  bog  iron-ore.  —  At  the  bottom  of  peat-mosses  there  is 
sometimes  found  a  cake,  or  "pan,"  as  it  is  termed,  of  oxide  of  iron, 
and  the  frequency  of  bog  iron-ore  is  familiar  to  the  mineralogist.  The 
oak,  which  is  so  often  dyed  black  in  peat,  owes  its  color  to  the  same 
metal.  From  what  source  the  iron  is  derived  has  often  been  a  subject 
of  discussion,  until  the  discoveries  of  Ehrenberg  seem  at  length  to 
have  removed  the  difficulty.  He  had  observed  in  the  marshes  about 
Berlin  a  substance  of  a  deep  ochre  yellow  passing  into  red,  which 
covered  the  bottom  of  the  ditches,  and  which,  where  it  had  become  dry 
after  the  evaporation  of  the  water,  appeared  exactly 
10L  like  oxide  of  iron.  But  under  the  microscope  it  was 

found  to  consist  of  slender  articulated  threads  or 
plates,  partly  siliceous  and  partly  ferruginous,  of 
what  he  considered  an  animalcule,  Gaillonella  fer- 


teiia  fermginea.    ruginea,  but  which  most  naturalists  now  regard  as 

a.   2000  times  inaguifie  * 


bog  iron-ore  consists  of  an  aggregate  of  millions  of  these  organic  bodies 
invisible  to  the  naked  eye.f 

Preservation  of  animal  substances  in  peat.  —  One  interesting  circum- 
stance attending  the  history  of  peat  mosses  is  the  high  state  of  preser- 
vation of  animal  substances  buried  in  them  for  periods  of  many  years. 
In  June,  1747,  the  body  of  a  woman  was  found  six  feet  deep,  in  a  peat- 
moor  in  the  Isle  of  Axholm,  in  Lincolnshire.  The  antique  sandals  on 
her  feet  afforded  evidence  of  her  having  been  buried  there  for  many  ages  : 
yet  her  nails,  hair,  and  skin,  are  described  as  having  shown  hardly  any 
marks  of  decay.  On  the  estate  of  the  Earl  of  Moira,  in  Ireland,  a  human 
body  was  dug  up,  a  foot  deep  in  gravel,  covered  with  eleven  feet  of 
moss  ;  the  body  was  completely  clothed  and  the  garments  seemed  all  to 
be  made  of  hair.  Before  the  use  of  wool  was  known  in  that  country 
the  clothing  of  the  inhabitants  was  made  of  hair,  so  that  it  would  appear 
that  this  body  had  been  buried  at  that  early  period  ;  yet  it  was  fresh  and 
unimpaired.];  In  the  Philosophical  Transactions  we  find  an  example 
recorded  of  the  bodies  of  two  persons  having  been  buried  in  moist  peat, 
in  Derbyshire,  in  1674,  about  'a  yard  deep,  which  were  examined  twenty- 
eight  years  and  nine  months  afterwards  ;  "  the  color  of  their  skin  was 
fair  and  natural,  their  flesh  soft  as  that  of  persons  newly  dead."§ 

Among  other  analogous  facts  we  may  mention,  that  in  digging  a  pit 

*  See  above,  p.  388,  note. 

f  Ehrenberg,  Taylor's  Scientific  Mem.  vol.  i.  part  iii.  p.  402. 

jj.  Dr.  Rennie,  on  Peat,  p.  521  ;  where  several  other  instances  are  referred  to. 

§  Phil.  Trans.,  vol.  xxxviii.  1734. 


CH.  XLV.]  SOLWAY   MOSS.  *723 

for  a  well  near  Dulverton,  in  Somersetshire,  many  pigs  were  found  in 
various  postures,  still  entire.  Their  shape  was  well  preserved,  the  skin, 
which  retained  the  hair,  having  assumed  a  dry,  membranous  appearance. 
Their  whole  substance  was  converted  into  a  white,  friable,  laminated, 
inodorous,  and  tasteless  substance;  but  which,  when  exposed  to  heat, 
emitted  an  odor  precisely  similar  to  broiled  bacon.* 

Cause  of  the  antiseptic  property  of  peat. — We  naturally  ask  whence 
peat  derives  this  antiseptic  property  ?  It  has  been  attributed  by  some  to 
the  carbonic  and  gallic  acids  which  issue  from  decayed  wood,  as  also  to 
the  presence  of  charred  wood  in  the  lowest  strata  of  many  peat-mosses, 
for  charcoal  is  a  powerful  antiseptic,  and  capable  of  purifying  water 
already  putrid.  Vegetable  gums  and  resins  also  may  operate  in  the 
same  way.f 

The  tannin  occasionally  present  in  peat  is  the  produce,  says  Dr.  Mac- 
Culloch,  of  tormentilla,  and  some  other  plants ;  but  the  quantity  he 
thinks  too  small,  and  its  occurrence  too  casual,  to  give  rise  to  effects  of 
any  importance.  He  hints  that  the  soft  parts  of  animal  bodies,  preserved 
in  peat-bogs,  may  have  been  converted  into  adipocire  by  the  action  of 
water  merely  ;  an  explanation  which  appears  clearly  applicable  to  some 
of  the  cases  above  enumerated.]; 

Miring  of  quadrupeds. — The  manner,  however,  in  which  peat  con- 
tributes to  preserve,  for  indefinite  periods,  the  harder  parts  of  terrestrial 
animals,  is  a  subject  of  more  immediate  interest  to  the  geologist.  There 
are  two  ways  in  which  animals  become  occasionally  buried  in  the  peat 
of  marshy  grounds ;  they  either  sink  down  into  the  semifluid  mud,  un- 
derlying a  turfy  surface  upon  which  they  have  rashly  ventured,  or,  at 
other  times,  as  we  shall  see  in  the  sequel,  a  bog  "  bursts,"  and  animals 
may  be  involved  in  the  peaty  alluvium. 

In  the  extensive  bogs  of  Newfoundland,  cattle  are  sometimes  found 
buried  with  only  their  heads  and  necks  above  ground  ;  and  after  having 
remained  for  days  in  this  situation,  they  .have  been  drawn  out  by  ropes 
and  saved.  In  Scotland,  also,  cattle  venturing  on  the  "  quaking  moss" 
are  often  mired,  or  "  laired,"  as  it  is  termed ;  and  in  Ireland,  Mr.  King 
asserts  that  the  number  of  cattle  which  are  lost  in  sloughs  is  quite 
incredible.§ 

Solway  moss. — The  description  given  of  the  Sol  way  moss  will  serve 
to  illustrate  the  general  character  of  these  boggy  grounds.  That  moss, 
observes  Gilpin,  is  a  flat  area,  about  seven  miles  in  circumference,  situated 
on  the  western  confines  of  England  and  Scotland.  Its  surface  is  covered 
with  grass  and  rushes,  presenting  a  dry  crust  and  a  fair  appearance ; 
but  it  shakes  under  the  least  pressure,  the  bottom  being  unsound  and 
semifluid.  The  adventurous  passenger,  therefore,  who  sometimes  in  dry 
seasons  traverses  this  perilous  waste,  to  save  a  few  miles,  picks  his  cautious 
way  over  the  rushy  tussocks  as  they  appear  before  him,  for  here  the  soil 

*  Dr.  Rennie,  on  Peat,  <fec.,  p.  521.          t  Syst.  of  Geol.  vol.  ii.  pp.  340—346. 
f  Ibid.  p.  531.  §  Phil.  Trans,  vol.  xv.  p.  949. 


724  GREAT   DISMAL  SWAMP.  [Cfl.  XLV. 

is  firmest.  If  his  foot  slip,  or  if  he  venture  to  desert  this  mark  of  secu- 
rity, it  is  possible  he  may  never  more  be  heard  of. 

"At  the  battle  of  Solway,  in  the  time  of  Henry  VIII.  (1542),  when 
the  Scotch  army,  commanded  by  Oliver  Sinclair,  was  routed,  an  unfortu- 
nate troop  of  horse,  driven  by  their  fears,  plunged  into  this  morass,  which 
instantly  closed  upon  them.  The  tale  was  traditional,  but  it  is  now 
authenticated ;  a  man  and  horse,  in  complete  armor,  having  been 
found  by  peat-diggers,  in  the  place  where  it  was  always  supposed  the 
affair  had  happened.  The  skeleton  of  each  was  well  preserved,  and  the 
different  parts  of  the  armor  easily  distinguished."* 

The  same  moss,  on  the  16th  of  December,  1772,  having  been  filled 
like  a  great  sponge  with  water  during  heavy  rains,  swelled  to  an  unusual 
height  above  the  surrounding  country,  and  then  burst.  The  turfy  cover- 
ing seemed  for  a  time  to  act  like  the  skin  of  a  bladder  retaining  the 
fluid  within,  till  it  forced  a  passage  for  itself,  when  a  stream  of  black 
half-consolidated  mud  began  at  first  to  creep  over  the  plain,  resembling, 
in  the  rate  of  its  progress,  an  ordinary  lava-current.  No  lives  were  lost, 
but  the  deluge  totally  overwhelmed  some  cottages,  and  covered  400  acres. 
The  highest  parts  of  the  original  moss  subsided  to  the  depth  of  about 
twenty-five  feet ;  and  the  height  of  the  moss,  on  the  lowest  parts  of  the 
country  which  it  invaded,  was  at  least  fifteen  feet. 

Bursting  of  a  peat-moss  in  Ireland. — A  recent  inundation  in  Sligo 
(January,  1831),  affords  another  example  of  this  phenomenon.  After  a 
sudden  thaw  of  snow,  the  bog  between  Bloomfield  and  Geevah  gave  way ; 
and  a  black  deluge,  carrying  with  it  the  contents  of  a  hundred  acres  of 
bog,  took  the  direction  of  a  small  stream  and  rolled  on  with  the  violence 
of  a  torrent,  sweeping  along  heath,  timber,  mud,  and  stones,  and  over- 
whelming many  meadows  and  arable  land.  On  passing  through  some 
boggy  land,  the  flood  swept  out  a  wide  and  deep  ravine,  and  part  of  the 
road  leading  from  Bloomfield  to  St.  James's  Well  was  completely 
carried  away  from  below  the  foundation  for  the  breadth  of  200  yards. 

Great  Dismal  Swamp. — I  have  described,  in  my  Travels  in  North 
America,!  an  extensive  swamp  or  morass,  forty  miles  long  from  north 
to  south,  and  twenty-five  wide,  between  the  towns  of  Norfolk  in  Virginia, 
and  Weldon  in  North  Carolina.  It  is  called  the  "  Great  Dismal,"  and 
has  somewhat  the  appearance  of  an  inundated  river-plain  covered  with 
aquatic  trees  and  shrubs,  the  soil  being  as  black  as  that  of  a  peat  bog. 
It  is  higher  on  all  sides  except  one  than  the  surrounding  country,  towards 
which  it  sends  forth  streams  of  water  to  the  north,  east,  and  south,  re- 
ceiving a  supply  from  the  west  only.  In  its  centre  it  rises  12  feet  above 
the  flat  region  which  bounds  it.  The  soil,  to  the  depth  of  15  feet,  is 
formed  of  vegetable  matter  without  any  admixture  of  earthy  particles, 
and  offers  an  exception  to  a  general  rule  before  alluded  to,  namely,  that 
such  peaty  accumulations  scarcely  ever  occur  so  far  south  as  lat.  36°,  or 
in  any  region  where  the  summer  heat  is  so  great  as  in  Virginia.  In  dig- 

*  Gilpin,  Observ.  on  Picturesque  Beauty,  &c.,  1772. 
f  Travels,  Ac.,  in  1841,  1842,  vol.  i.  p.  143. 


CH.  XLV.]  FOSSILS  IN  PEAT  MOSSES.  725 

ging  canals  through  the  morass  for  the  purpose  of  obtaining  timber, 
much  of  the  black  soil  has  been  thrown  out  from  time  to  time,  and  ex- 
posed to  the  sun  and  air,  in  which  case  it  soon  rots  away  so  that 
nothing  remains  behind,  showing  clearly  that  it  owes  its  preservation  to 
the  shade  afforded  by  a  luxuriant  vegetation  and  to  the  constant  evapo- 
ration of  the  spongy  soil  by  which  the  air  is  cooled  during  the  hot 
months.  The  surface  of  the  bog  is  carpeted  with  mosses,  and  densely 
covered  with  ferns  and  reeds,  above  which  many  evergreen  shrubs  and 
trees  flourish,  especially  the  White  Cedar  (Cupressus  thyoides),  which 
stands  firmly  supported  by  its  long  tap  roots  in  the  softest  parts  of  the 
quagmire.  Over  the  whole  the  deciduous  cypress  (Taxodium  distichum) 
is  seen  to  tower  with  its  spreading  top,  in  full  leaf  in  the  season  when 
the  sun's  rays  are  hottest,  and  when,  if  not  intercepted  by  a  screen  of 
foliage,  they  might  soon  cause  the  fallen  leaves  and  dead  plants  of  the 
preceding  autumn  to  decompose,  instead  of  adding  their  contributions  to 
the  peaty  mass.  On  the  surface  of  the  wide  morass  lie  innumerable  trunks 
of  large  and  tall  trees,  while  thousands  of  others,  blown  down  by  the 
winds,  are  buried  at  various  depths  in  the  black  mire  below.  Thev  re- 
mind the  geologist  of  the  prostrate  position  of  large  stems  of  Sigillaria 
and  Lepidodendron,  converted  into  coal  in  ancient  carboniferous  rocks. 

Bones  of  herbivorous  quadrupeds  in  peat. — The  antlers  of  large  and 
full-grown  stags  are  amongst  the  most  common  and  conspicuous  remains 
of  animals  in  peat.  They  are  not  horns  which  have  been  shed ;  foi 
portions  of  the  skull  are  found  attached,  proving  that  the  whole  animal 
perished.  Bones  of  the  ox,  hog,  horse,  sheep,  and  other  herbivorous 
animals,  also  occur.  M.  Morren  has  discovered  in  the  peat  of  Flanders 
the  bones  of  otters  and  beavers*  ;  but  no  remains  have  been  met  with 
belonging  to  those  extinct  -quadrupeds,  of  which  the  living  congeners 
inhabit  warmer  latitudes,  such  as  the  elephant,  rhinoceros,  hippopota- 
mus, hyaena,  and  tiger,  though  these  are  so  common  in  superficial 
deposits  of  silt,  mud,  sand,  or  stalactite,  in  various  districts  throughout 
Great  Britain.  Their  absence  seems  to  imply  that  they  had  ceased  to 
live  before  the  atmosphere  of  this  part  of  the  world  acquired  that  cold 
and  humid  character  which  favors  the  growth  of  peat. 

Remains  of  ships,  &c.,  in  peat  mosses. — From  the  facts  before  men- 
tioned, that  mosses  occasionally  burst,  and  descend  in  a  fluid  state  to 
lower  levels,  it  will  readily  be  seen  that  lakes  and  arms  of  the  sea  may 
occasionally  become  the  receptacles  of  drift  peat.  Of  this,  accordingly, 
there  are  numerous  examples ;  and  hence  the  alternations  of  clay  and 
sand  with  different  deposits  of  peat  so  frequent  on  some  coasts,  as  on 
those  of  the  Baltic  and  German  Ocean.  We  are  informed  by  Deguer, 
that  remains  of  ships,  nautical  instruments,  and  oars,  have  been  found 
in  many  of  the  Dutch  mosses ;  and  Gerard,  in  his  History  of  the  Valley 
of  the  Somme,  mentions  that  in  the  lowest  tier  of  that  moss  was  found 
a  boat  loaded  with  bricks,  proving  that  these  mosses  were  at  one  period 

*  Bulletin  de  la  Soc.  Geol.  de  France,  torn.  ii.  p.  26. 


726  PRESERVATION  OF   ORGANIC   REMAINS,         [Ca  XLV. 

navigable  lakes  and  arms  of  the  sea,  as  were  also  many  mosses  on  the 
coast  of  Picardy,  Zealand,  and  Friesland,  from  which  soda  and  salt  are 
procured.*  The  canoes,  stone  hatchets,  and  stone  arrow-heads  found 
in  peat  in  different  parts  of  Great  Britain,  lead  to  similar  conclusions. 

Imbedding  of  human  and  other  remains,  and  works  of  Art,  in 
Blown  Sand. 

The  drifting  of  sand  may  next  be  considered  among  the  causes 
capable  of  preserving  organic  remains  and  works  of  art  on  the  emerged 
land. 

African  Sands. — The  sands  of  the  African  deserts  have  been  driven 
by  the  west  winds  over  part  of  the  arable  land  of  Egypt,  on  the  west- 
ern bank  of  the  Nile,  in  those  places  where  valleys  open  into  the  plain, 
or  where  there  are  gorges  through  the  Libyan  mountains.  By  similar 
sand-drifts  the  ruins  of  ancient  cities  have  been  buried  between  the 
temple  of  Jupiter  Ammon  and  Nubia.  M.  G.  A.  De  Luc  attempted  to 
infer  the  recent  origin  of  our  continents,  from  the  fact  that  these  moving 
sands  have  arrived  only  in  modern  times  at  the  fertile  plains  of  the  Nile. 
The  same  scourge,  he  said,  would  have  afflicted  Egypt  for  ages  anterior 
to  the  times  of  history,  had  the  continents  risen  above  the  level  of  the 
sea  several  hundred  centuries  before  our  era.f  But  the  author  proceeded 
in  this,  as  in  all  his  other  chronological  computations,  on  a  multitude  of 
gratuitous  assumptions.  He  ought,  in  the  first  place,  to  have  demon- 
strated that  the  whole  continent  of  Africa  was  raised  above  the  level  of 
the  sea  at  one  period ;  for  unless  this  point  was  established,  the  region 
from  whence  the  sands  began  to  move  might  have  been  the  last  addition 
made  to  Africa,  and  the  commencement  of  the  sand-flood  might  have 
been  long  posterior  to  the  laying  dry  of  the  greater  portion  of  that  con- 
tinent. That  the  different  parts  of  Europe  were  not  all  elevated  at  one 
time  is  now  generally  admitted.  De  Luc  should  also  have  pointed  out 
the  depth'  of  drift  sand  in  various  parts  of  the  great  Libyan  deserts,  and 
have  shown  whether  any  valleys  of  large  dimensions  had  been  filled  up — 
how  long  these  may  have  arrested  the  progress  of  the  sands,  and  how  far 
the  flood  had  upon  the  whole  advanced  since  the  times  of  history. 

We  have  seen  that  Sir  J.  G.  Wilkinson  is  of  opinion  that,  while  the 
sand-drift  is  making  aggressions  at  certain  points  upon  the  fertile  soil  of 
Egypt,  the  alluvial  deposit  of  the  Nile  is  advancing  very  generally  upon 
the  desert ;  and  that,  upon  the  whole,  the  balance  is  greatly  in  favor  of 
the  fertilizing  mud.J; 

No  mode  of  interment  can  be  conceived,  more  favorable  to  the  conser- 
vation of  monuments  for  indefinite  periods  than  that  now  so  common  in 
the  region  immediately  westward  of  the  Nile.  The  sand  which  sur- 
rounded and  filled  the  great  temple  of  Ipsambul,  first  discovered  by 

*  Dr.  Rennie,  Essays  on  Peat  Moss,  p.  205. 

f  M.  G.  A.  De  Luc,  Mercure  de  France,  Sept.  1809. 

;  See  p.  262. 


CH.  XLV.]          AND   WORKS   OF   ART,   IN   BLOWN   SAND.  727 

Burckhardt,  and  afterwards  partially  uncovered  by  Belzoni  and  Beechey, 
was  so  fine  as  to  resemble  a  fluid  when  put  in  motion.  Neither  the 
features  of  the  colossal  figures,  nor  the  color  of  the  stucco  with  which 
some  were  covered,  nor  the  paintings  on  the  walls,  had  received  any 
injury  from  being  enveloped  for  ages  in  this  dry  impalpable  dust.* 

At  some  future  period,  perhaps  when  the  pyramids  shall  have  perished, 
the  action  of  the  sea,  or  an  earthquake,  may  lay  open  to  the  day  some  of 
these  buried  temples.  Or  we  may  suppose  the  desert  to  remain  undis- 
turbed, and  changes  in  the  surrounding  sea  and  land  to  modify  the 
climate  and  the  direction  of  the  prevailing  winds,  so  that  these  may  then 
waft  away  the  Libyan  sands  as  gradually  as  they  once  brought  them  to 
those  regions.  Thus,  many  a  town  and  temple  of  higher  antiquity  than 
Thebes  or  Memphis  may  reappear  in  their  original  antiquity,  and  a 
part  of  the  gloom  which  overhangs  the  history  of  the  earlier  nations  be 
dispelled. 

Whole  caravans  are  said  to  have  been  overwhelmed  by  the  Libyan 
sands ;  and  Burckhardt  informs  us  that  "  after  passing  the  Akaba  near 
the  head  of  the  Red  Sea,  the  bones  of  dead  camels  are  the  only  guides  of 
the  pilgrim  through  the  wastes  of  sand." — "  We  did  not  see,"  says  Cap- 
tain Lyon,  speaking  of  a  plain  near  the  Soudah  mountains,  in  Northern 
Africa,  "  the  least  appearance  of  vegetation ;  but  observed  many  skele- 
tons of  animals,  which  had  died  of  fatigue  on  the  desert,  and  occasionally 
the  grave  of  some  human  being.  All  these  bodies  were  so  dried  by  the 
heat  of  the  sun,  that  putrefaction  appears  not  to  have  taken  place  after 
death.  In  recently  expired  animals  I  could  not  perceive  the  slightest 
offensive  smell ;  and  in  those  long  dead,  the  skin  with  the  hair  on  it 
remained  unbroken  and  perfect,  although  so  brittle  as  to  break  with  a 
slight  blow.  The  sand-winds  never  cause  these  carcases  to  change  their 
places ;  for,  in  a  short  time,  a  slight  mound  is  formed  round  them,  and 
they  become  stationary ."f 

Towns  ovenvhelmed  by  sand  floods. — The  burying  of  several  towns  and 
villages  in  England,  France,  and  Jutland,  by  blown  sand,  is  on  record ; 
thus,  for  example,  near  St.  Pol  de  Leon,  in  Brittany,  a  whole  village  was 
completely  buried  beneath  drift  sand,  so  that  nothing  was  seen  but  the 
spire  of  the  church/];  In  Jutland  marine  shells  adhering  to  sea-weed  are 
sometimes  blown  by  the  violence  of  the  wind  to  the  height  of  100  feet, 
and  buried  in  similar  hills  of  sand. 

In  Suffolk,  in  the  year  1688,  part  of  Downham  was  overwhelmed  by 
sands  which  had  broken  loose  about  100  years  before,  from  a  warren 
five  miles  to  the  south-west.  This  sand  had,  in  the  course  of  a  century, 
travelled  five  miles,  and  covered  more  than  1000  acres  of  land.§  A  con- 
siderable tract  of  cultivated  land  on  the  north  coast  of  Cornwall  has  been 
inundated  by  drift  sand,  forming  hills  several  hundred  feet  above  the 

*  Stratton,  Ed.  Phil.  Journ.,  No.  v.  p.  62. 

f  Travels  in  North  Africa  in  the  Years  1818,  1819,  and  1820,  p.  83. 
\  Mem.  de  1'Acad  des  Sci.  de  Paris,  1772.     See  also  the  case  of  the  buried 
church  of  Eccles,  above,  p.  306. 
§  Phil.  Trans.,  vol.  ii.  p.  722. 


728  FOSSILS  IN  VOLCANIC   FORMATIONS.  [dr.  XLV. 

level  of  the  sea,  and  composed  of  comminuted  marine  shells,  in  which  some 
terrestrial  shells  are  enclosed  entire.  By  the  shifting  of  these  sands  the 
ruins  of  ancient  buildings  have  been  discovered ;  and  in  some  cases  where 
wells  have  been  bored  to  a  great  depth,  distinct  strata,  separated  by  a 
vegetable  crust,  are  visible.  In  some  places,  as  at  New  Quay,  large  masses 
have  become  sufficiently  indurated  to  be  used  for  architectural  purposes. 
The  lapidification,  which  is  still  in  progress,  appears  to  be  due  to  oxide  of 
iron  held  in  solution  by  the  water  which  percolates  the  sand.* 

Imbedding  of  Organic  and  other  Remains  in  Volcanic  Formations  on 

the  Land. 

1  have  in  some  degree  anticipated  the  subject  of  this  section  in  former 
chapters,  when  speaking  of  the  buried  cities  around  Naples,  and  those 
on  the  flanks  of  Etna  (pp.  385.  400.).  From  the  facts  referred  to,  it 
appeared  that  the  preservation  of  human  remains  and  works  of  art  is 
frequently  due  to  the  descent  of  floods  caused  by  the  copious  rains  which 
accompany  eruptions.  These  aqueous  lavas,  as  they  are  called  in  Cam- 
pania, flow  with  great  rapidity,  and  in  1822  surprised  and  suffocated,  as 
was  stated,  seven  persons  in  the  villages  of  St.  Sebastian  and  Massa,  on 
the  flanks  of  Vesuvius. 

In  the  tufts,  moreover,  or  solidified  mud,  deposited  by  these  aqueous 
lavas,  impressions  of  leaves  and  of  trees  have  been  observed.  Some  of 
those,  formed  after  the  eruption  of  Vesuvius  in  1822,  are  now  preserved 
in  the  museum  at  Naples. 

Lava  itself  may  become  indirectly  the  means  of  preserving  terrestrial 
remains,  by  overflowing  beds  of  ashes,  pumice,  and  ejected  matter,  which 
may  have  been  showered  down  upon  animals  and  plants,  or  upon  human 
remains.  Few  substances  are  better  non-conductors  of  heat  than  volcanic 
dust  and  scoria,  so  that  a  bed  of  such  materials  is  rarely  melted  by  a 
superimposed  lava-current.  After  consolidation,  the  lava  affords  secure 
protection  to  the  lighter  and  more  removable  mass  below,  in  which  the 
organic  relics  may  be  enveloped.  The  Herculanean  tuffs  containing  the 
rolls  of  papyrus,  of  which  the  characters  are  still  legible,  have,  as  was 
before  remarked,  been  for  ages  covered  by  lava. 

Another  mode  by  which  lava  may  tend  to  the  conservation  of  imbedded 
remains,  at  least  of  works  of  human  art,  is  by  its  overflowing  them  when 
it  is  not  intensely  heated,  in  which  case  they  sometimes  suffer  little  or  no 
injury. 

Thus  when  the  Etnean  lava-current  of  1669  covered  fourteen  towns 
and  villages,  and  part  of  the  city  of  Catania,  it  did  not  melt  down  a  great 
number  of  statues  and  other  articles  in  the  vaults  of  Catania ;  and  at  the 
depth  of  thirty-five  feet  in  the  same  current,  on  the  site  of  Mompiliere,  one 
of  the  buried  towns,  the  bell  of  a  church  and  some  statues  were  found 
uninjured  (p.  401.). 

*  Boase  on  Submersion  of  Part  of  the  Mount's  Bay,  <fec.,  Trans.  Roy.  Geol. 
Soc.  of  Cornwall,  vol.  ii.  p.  140. 


CH.  XLV.]  BURIED   CITIES  IN  INDIA.  729 

We  read  of  several  buried  cities  in  Central  India,  ana  among  others 
of  Oujein  (or  Oojain)  which  about  fifty  years  before  the  Christian  era 
was  the  seat  of  empire,  of  art,  and  of  learning ;  but  which  in  the  time 
of  the  Rajah  Vicramaditya,  was  overwhelmed,  according  to  tradition, 
together  with  more  than  eighty  other  large  towns  in  the  provinces  of 
Malwa  and  Bagur,  "  by  a  shower  of  earth."  The  city  which  now  bears 
the  name  is  situated  a  mile  to  the  southward  of  the  ancient  town.  On 
digging  on  the  spot  where  the  latter  is  supposed  to  have  stood,  to  the 
depth  of  fifteen  or  eighteen  feet,  there  are  frequently  discovered,  says  Mr. 
Hunter,  entire  brick  walls,  pillars  of  stone,  and  pieces  of  wood  of  an 
extraordinary  hardness,  besides  utensils  of  various  kinds,  ancient  coins, 
and  occasionally  buried  wheat  in  a  state  resembling  charcoal.* 

The  soil  which  covers  Oujein  is  described  as  "  being  of  an  ash-gray 
color,  with  minute  specks  of  black  sand."f  And  the  "  shower  of  earth," 
said  to  have  "  fallen  from  heaven,"  has  been  attributed  by  some  travellers 
to  volcanic  agency.  There  are,  however,  no  active  volcanoes  in  Central 
India,  the  nearest  to  Oujein  being  Denodur  hill  near  Bhooj,  the  capital 
of  Cutch,  300  geographical  miles  distant,  if  indeed  that  hill  has  ever 
poured  out  lava  in  historical  times,  which  is  doubted  by  many.J  The 
latest  writers  on  Oujein  avow  their  suspicion  that  the  supposed  "  cata- 
strophe" was  nothing  more  than  the  political  decline  and  final  abandon- 
ment of  a  great  city  which,  like  Nineveh  or  Babylon,  and  many  an 
ancient  seat  of  empire  in  the  East,  after  losing  its  importance  as  a  me- 
tropolis, became  a  heap  of  ruins.  The  rapidity  with  which  the  sun-dried 
bricks,  of  which  even  the  most  splendid  oriental  palaces  are  often  con- 
structed, crumble  down  when  exposed  to  rain  and  sun,  and  are  converted 
into  mounds  of  ordinary  earth  and  clay,  is  well  known.  According  to 
Captain  Dangerfield,  trap  tuff  and  columnar  basalt  constitute  the  rocks 
in  the  environs  of  Oujein§,  and  the  volcanic  nature  of  these  formations, 
from  which  the  materials  of  the  bricks  were  originally  derived,  may 
have  led  to  the  idea  of  the  city  having  been  overwhelmed  by  a  volcanic 
eruption. 

*  Narrative  of  Journey  from  Agra  to  Oujein,  Asiatic  Researches,  vol.  vi.  p.  8d. 
f  Asiatic  Journal,  vol.  ix.  p.  35.  \  See  above,  p.  460. 

£  Sir  J.  Malcolm's  Central  India.    Appendix,  No.  2.  p.  824. 


CHAPTER  XLVI. 

BURYING    OF    FOSSILS    IN    ALLUVIAL   DEPOSITS    AND    IN    CAVES. 

Fossils  in  alluvium — Effects  of  sudden  inundations — Ttrerres-crial  animals  most 
abundantly  preserved  in  alluvium  where  earthquakes  prevail — Marine  allu- 
vium— Buried  town — Effects  of  Landslips — Organic  remains  in  fissures  and 
caves — Form  and  dimensions  of  caverns — their  probable  origin — Closed  basins 
and  subterranean  rivers  of  the  Morea — Katavothra — Formation  of  breccias 
with  red  cement — Human  remains  imbedded  in  Morea — Intermixture,  in  caves 
of  South  of  France  and  elsewhere,  of  human  remains  and  bones  of  extinct 
quadrupeds,  no  proof  of  former  co-existence  of  man  with  those  lost  species. 

Fossils  in  alluvium. — THE  next  subject  for  our  consideration,  accord- 
ing to  the  division  before  proposed,  is  the  embedding  of  organic  bodies 
in  alluvium. 

The  gravel,  sand,  and  mud  in  the  bed  of  a  river  does  not  often  con- 
tain any  animal  or  vegetable  remains ;  for  the  whole  mass  is  so  continu- 
ally shifting  its  place,  and  the  attrition  of  the  various  parts  is  so  great, 
that  even  the  hardest  rocks  contained  in  it  are,  at  length,  ground  down 
to  powder.  But  when  sand  and  sediment  are  suddenly  swept  by  a  flood, 
and  then  let  fall  upon  the  land,  such  an  alluvium  may  envelop  trees  or 
the  remains  of  animals,  which,  in  this  manner,  are  often  permanently 
preserved.  In  the  mud  and  sand  produced  by  the  floods  in  Scotland,  in 
1829,  the  dead  and  mutilated  bodies  of  hares,  rabbits,  moles,  mice,  par- 
tridges, and  even  the  bodies  of  men,  were  found  partially  buried.*  But 
in  these  and  similar  cases  one  flood  usually  effaces  the  memorials  left  by 
another,  and  there  is  rarely  a  sufficient  depth  of  undisturbed  transported 
matter,  in  any  one  spot,  to  preserve  the  organic  remains  for  ages  from 
destruction. 

Where  earthquakes  prevail,  and  the  levels  of  a  country  are  changed 
from  time  to  time,  the  remains  of  animals  may  more  easily  be  inhumed 
and  protected  from  disintegration.  Portions  of  plains,  loaded  with  allu- 
vial accumulations  by  transient  floods,  may  be  gradually  upraised  ;  and, 
if  any  organic  remains  have  been  imbedded  in  the  transported  materials, 
they  may,  after  such  elevation,  be  placed  beyond  the  reach  of  the  erosive 
power  of  streams.  In  districts  where  the  drainage  is  repeatedly  deranged 
by  subterranean  movements,  every  fissure,  every  hollow  caused  by  the 
sinking  in  of  land,  becomes  a  depository  of  organic  and  inorganic  sub- 
stances, hurried  along  by  transient  floods. 

Marine  alluvium. — In  May,  1787,  a  dreadful  inundation  of  the  sea 
was  caused  at  Coringa,  Ingeram,  and  other  places,  on  the  coast  of  Coro- 
mandel,  in  the  East  Indies,  by  a  hurricane  blowing  from  the  N.  E.,  which 
raised  the  waters  so  that  they  rolled  inland  to  the  distance  of  about 
twenty  miles  from  the  shore,  swept  away  many  villages,  drowned  more 

*  Sir  T.  D.  Lauder,  Bart.,  on  Floods  in  Morayshire,  Aug.  1839,  p.  177. 


CH.  XLVL]  BURIED   TOWN.  Y31 

than  10,000  people,  and  left  the  country  covered  with  marine  mud,  on 
which  the  carcasses  of  about  100,000  head  of  cattle  were  strewed.  An  old 
tradition  of  the  natives  of  a  similar  flood,  said  to  have  happened  about  a 
century  before,  was,  till  this  event,  regarded  as  fabulous  by  the  European 
settlers.*  The  same  coast  of  Coromandel  was,  so  late  as  May,  1832,  the 
scene  of  another  catastrophe  of  the  same  kind ;  and  when  the  inunda- 
tion subsided,  several  vessels  were  seen  grounded  in  the  fields  of  the  low 
country  about  Coringa. 

Many  of  the  storms  termed  hurricanes  have  evidently  been  connected 
with  submarine  earthquakes,  as  is  shown  by  the  atmospheric  phenomena 
attendant  on  them,  and  by  the  sounds  heard  in  the  ground  and  the  odors 
emitted.  Such  were  the  circumstances  which  accompanied  the  swell  of 
the  sea  in  Jamaica,  in  1780,  when  a  great  wave  desolated  the  western 
coast,  and  bursting  upon  Savanna  la  Mar,  swept  away  the  whole  town  in 
an  instant,  so  that  not  a  vestige  of  man,  beast,  or  habitation,  was  seen 
upon  the  surface,  f 

Houses  and  works  of  art  in  alluvial  deposits. — A  very  ancient  sub- 
terranean town,  apparently  of  Hindoo  origin,  was  discovered  in  India  in 
1833,  in  digging  the  Doab  canal.  Its  site  is  north  of  Saharunpore,  near 
the  town  of  Behat,  and  seventeen  feet  below  the  present  surface  of  the 
country.  More  than  170  coins  of  silver  and  copper  have  already  been 
found,  and  many  articles  in  metal  and  earthenware.  The  overlying 
deposit  consisted  of  about  five  feet  of  river  sand,  with  a  substratum  about 
twelve  feet  thick  of  red  alluvial  clay.  In  the  neighborhood  are  several 
rivers  and  torrents,  which  descend  from  the  mountains  charged  with  vast 
quantities  of  mud,  sand,  and  shingle  ;  and  within  the  memory  of  persons 
now  living  the  modern  Behat  has  been  threatened  by  an  inundation, 
which,  after  retreating,  left  the  neighboring  country  strewed  over  with 
a  superficial  covering  of  sand  several  feet  thick.  In  sinking  wells  in  the 
environs,  masses  of  shingle  and  boulders  have  been  reached  resembling 
those  now  in  the  river-channels  of  the  same  district,  under  a  deposit  of 
thirty  feet  of  reddish  loam.  Captain  Cautley,  therefore,  who  directed  the 
excavations,  supposes  that  the  matter  discharged  by  torrents  has  gradually 
raised  the  whole  country  skirting  the  base  of  the  lower  hills ;  and  that  the 
ancient  town,  having  been  originally  built  in  a  hollow,  was  submerged  by 
floods,  and  covered  over  with  sediment  seventeen  feet  in  thickness.  J 

We  are  informed,  by  M.  Boblaye,  that  in  the  Morea,  the  formation 
termed  ceramique,  consisting  of  pottery,  tiles,  and  bricks,  intermixed 
with  various  works  of  art,  enters  so  largely  into  the  alluvium  and  vege- 
table soil  upon  the  plains  of  Greece,  and  into  hard  and  crystalline  brec- 
cias which  have  been  formed  at  the  foot  of  declivities,  that  it  constitutes 
an  important  stratum  which  might,  in  the  absence  of  zoological  cha- 
racters, serve  to  mark  our  epoch  in  a  most  indestructible  manner.§ 

*  Dodsley's  Ann.  Regist ,  1788. 

f  Edwards,  Hist,  of  West  Indies,  vol.  i.  p.  235,  ed.  1801 
t  Journ.  of  Asiat.  Soc.,  Nos.  xxv.  and  xxix.,  1834. 
§  Ann.  des  Sci.  Nat.  torn.  xxii.  p.  117,  Feb.  1831. 


732  LANDSLIPS.  [On.  XL VI, 

Landslips. — The  landslip,  by  suddenly  precipitating  large  masses  of 
rock  and  soil  into  a  valley,  overwhelms  a  multitude  of  animals,  and 
sometimes  buries  permanently  whole  villages,  with  their  inhabitants  and 
large  herds  of  cattle.  Thus  three  villages,  with  their  entire  population, 
were  covered,  when  the  mountain  of  Piz  fell  in  1772,  in  the  district  of 
Treviso,  in  the  state  of  Venice,*  and  part  of  Mount  Grenier,  south  of 
Chambery,  in  Savoy,  which  fell  down  in  the  year  1248,  buried  five 
parishes,  including  the  town  and  church  of  St.  Andre,  the  ruins  occu- 
pying an  extent  of  about  nine  square  miles,  f 

The  number  of  lives  lost  by  the  slide  of  the  Rossberg,  in  Switzerland, 
in  1806,  was  estimated  at  more  than  800,  a  great  number  of  the  bodies, 
as  well  as  several  villages  and  scattered  houses,  being  buried  deep  under 
mud  and  rock.  In  the  same  country,  several  hundred  cottages,  with 
eighteen  of  their  inhabitants  and  a  great  number  of  cows,  goats,  and 
sheep,  were  victims  to  the  sudden  fall  of  a  bed  of  stones,  thirty  yards 
deep,  which  descended  from  the  summits  of  the  Diablerets  in  Vallais. 
In  the  year  1618,  a  portion  of  Mount  Conto  fell,  in  the  county  of  Chia- 
venna,  in  Switzerland,  and  buried  the  town  of  Pleurs  with  all  its  inhabit- 
ants, to  the  number  of  2430. 

It  is  unnecessary  to  multiply  examples  of  similar  local  catastrophes, 
which  however  numerous  they  may  have  been  in  mountainous  parts  of 
Europe,  within  the  historical  period,  have  been,  nevertheless,  of  rare  occur- 
rence when  compared  to  events  of  the  same  kind  which  have  taken  place 
in  regions  convulsed  by  earthquakes.  It  is  then  that  enormous  masses 
of  rock  and  earth,  even  in  comparatively  low  and  level  countries,  are 
detached  from  the  sides  of  valleys,  and  cast  down  into  the  river  courses, 
and  often  so  unexpectedly  that  they  overwhelm,  even  in  the  daytime, 
every  living  thing  upon  the  plains. 

Preservation  of  Organic  Remains  in  Fissures  and  Caves. 

In  the  history  of  earthquakes  it  was  shown  that  many  hundreds  of 
new  fissures  and  chasms  had  opened  in  certain  regions  during  the  last 
150  years,  some  of  which  are  described  as  being  of  unfathomable  depth. 
We  also  perceive  that  mountain  masses  have  been  violently  fractured  and 
dislocated,  during  their  rise  above  the  level  of  the  sea ;  and  thus  we  may 
account  for  the  existence  of  many  cavities  in  the  interior  of  the  earth  by 
the  simple  agency  of  earthquakes;  but  there  are  some  caverns,  especially 
in  limestone  rocks,  which,  .although  usually,  if  not  always,  connected 
with  rents,  are  nevertheless  of  such  forms,  and  dimensions,  alternately 
expanding  into  spacious  chambers,  and  then  contracting  again  into  nar- 
row passages,  that  it  is  difficult  to  conceive  that  they  can  owe  their  origin 
to  the  mere  fracturing  and  displacement  of  solid  masses. 

In  the  limestone  of  Kentucky,  in  the  basin  of  Green  River,  one  of  the 

*  Malte-Brun's  Geog.,  vol.  i.  p.  435. 

f  Bake  well,  Travels  iu  the  Tarentaise,  vol.  i.  p.  201. 


CH.  XLVL]  FOSSILS   IN   CAVES.  733 

tributaries  of  the  Ohio,  a  line  of  underground  cavities  has  been  traced 
in  one  direction  for  a  distance  of  ten  miles,  without  any  termination ;  and 
one  of  the  chambers,  of  which  there  are  many,  all  connected  by  narrow 
tunnels,  is  no  less  than  ten  acres  in  area  and  150  feet  in  its  greatest 
height.  Besides  the  principal  series  of  "  antres  vast,"  there  are  a  great 
many  lateral  embranchments  not  yet  explored.* 

The  cavernous  structure  here  alluded  to  is  not  altogether  confined  to 
calcareous  rocks ;  for  it  has  lately  been  observed  in  micaceous  and  argilla- 
ceous schist  in  the  Grecian  island  of  Thermia  (Cythnos  of  the  ancients), 
one  of  the  Cyclades.  Here  also  spacious  halls,  with  rounded  and  irregu- 
lar walls,  are  connected  together  by  narrow  passages  or  tunnels,  and 
there  are  many  lateral  branches  which  have  no  outlet.  A  current  of 
water  has  evidently  at  some  period  flowed  through  the  whole,  and  left  a 
muddy  deposit  of  bluish  clay  upon  the  floor ;  but  the  erosive  action  of 
the  stream  cannot  be  supposed  to  have  given  rise  to  the  excavations  in 
the  first  instance.  M.  Virlet  suggests  that  fissures  were  first  caused  by 
earthquakes,  and  that  these  fissures  became  the  chimneys  or  vents  for 
the  disengagement  of  gas,  generated  below  by  volcanic  heat.  Gases,  he 
observes,  such  as  the  muriatic,  sulphuric,  fluoric,  and  others,  might,  if 
raised  to  a  high  temperature,  alter  and  decompose  the  rocks  which  they 
traverse.  There  are  signs  of  the  former  action  of  such  vapors  in  rents 
of  the  micaceous  schist  of  Thermia,  and  thermal  springs  now  issue  from 
the  grottoes  of  that  island.  We  may  suppose  that  afterwards  the  elements 
of  the  decomposed  rocks  were  gradually  removed  in  a  state  of  solution 
by  mineral  waters ;  a  theory  which,  according  to  M.  Virlet,  is  confirmed 
by  the  effect  of  heated  gases  which  escape  from  rents  in  the  isthmus  of 
Corinth,  and  which  have  greatly  altered  and  corroded  the  hard  siliceous 
and  jaspideous  rocks.f 

When  we  reflect  on  the  quantity  of  carbonate  of  lime  annually  poured 
out  by  mineral  waters,  we  are  prepared  to  admit  that  large  cavities  must, 
in  the  course  of  ages,  be  formed  at  considerable  depths  below  the  surface 
in  calcareous  rocks.J  These  rocks,  it  will  be  remembered,  are  at  once 
more  soluble,  more  permeable,  and  more  fragile,  than  any  others,  at  least 
all  the  compact  varieties  are  very  easily  broken  by  the  movements  of 
earthquakes,  which  would  produce  only  flexures  in  argillaceous  strata. 
Fissures  once  formed  in  limestone  are  not  liable,  as  in  many  other  forma- 
tions, to  become  closed  up  by  impervious  clayey  matter,  and  hence  a 
stream  of  acidulous  water  might  for  ages  obtain  a  free  and  unobstructed 
passage.§ 

Morea. — Nothing  is  more  common  in  limestone  districts  than  the 
engulfment  of  rivers,  which  after  holding  a  subterranean  course  for  many 
miles  escape  again  by  some  new  outlet.  As  they  are  usually  charged 

*  Nahum  Ward,  Trans,  of  Antiq.  Soc.  of  Massachusetts.  Holmes's  United 
States,  p.  438. 

f  Bull,  de  la  Soc.  Geol.  de  France,  torn.  ii.  p.  329. 

±  See  above,  p.  240. 

§  See  remarks  by  M.  Boblaye,  Ann.  des  Mines,  Sine  serie,  torn,  iv 


734  PRESERVATION   OF   FOSSILS  [On.  XLVI. 

with  fine  sediment,  and  often  with  sand  and  pebbles  where  they  enter, 
whereas  they  are  usually  pure  and  limpid  where  they  flow  out  again, 
they  must  deposit  much  matter  in  empty  spaces  in  the  interior  of  the 
earth.  In  addition  to  the  materials  thus  introduced,  stalagmite,  or  car- 
bonate of  lime,  drops  from  the  roofs  of  caverns,  and  in  this  mixture  the 
bones  of  animals  washed  in  by  rivers  are  often  entombed.  In  this  manner 
we  may  account  for  those  bony  breccias  which  we  often  find  in  caves, 
some  of  which  are  of  high  antiquity  while  others  are  very  recent  and 
in  daily  progress.  In  no  district  are  engulfed  streams  more  conspicuous 
than  in  the  Morea,  where  the  phenomena  attending  them  have  been 
lately  studied  and  described  in  great  detail  by  M.  Boblaye  and  his  fellow- 
laborers  of  the  French  expedition  to  Greece.*  Their  account  is  pecu- 
liarly interesting  to  geologists,  because  it  throws  light  on  the  red  osseous 
breccias  containing  the  bones  of  extinct  quadrupeds  which  are  so  common 
in  almost  all  the  countries  bordering  the  Mediterranean.  It  appears  that 
the  numerous  caverns  of  the  Morea  occur  in  a  compact  limestone,  of  the 
age  of  the  English  chalk,  immediately  below  which  are  arenaceous  strata 
referred  to  the  period  of  our  greensand.  In  the  more  elevated  districts 
of  that  peninsula  there  are  many  deep  land-locked  valleys,  or  basins, 
closed  round  on  all  sides  by  mountains  of  fissured  and  cavernous  lime- 
stone. The  year  is  divided  almost  as  distinctly  as  between  the  tropics 
into  a  rainy  season,  which  lasts  upwards  of  four  months,  and  a  season  of 
drought  of  nearly  eight  months'  duration.  When  the  torrents  are 
swollen  by  the  rains,  they  rush  from  surrounding  heights  into  the  inclosed 
basins ;  but,  instead  of  giving  rise  to  lakes,  as  would  be  the  case  in  most 
other  countries,  they  are  received  into  gulfs  or  chasms,  called  by  the 
Greeks  "  Katavothra,"  and  which  correspond  to  what  are  termed  "  swal- 
low-holes" in  the  north  of  England.  The  water  of  these  torrents  is 
charged  with  pebbles  and  red  ochreous  earth,  resembling  precisely  the 
well-known  cement  of  the  osseous  breccias  of  the  Mediterranean.  It 
dissolves  in  acids  with  effervescence,  and  leaves  a  residue  of  hydrated 
oxide  of  iron,  granular  iron,  impalpable  grains  of  silex,  and  small  crystals 
of  quartz.  Soil  of  the  same  description  abounds  everywhere  on  the 
surface  of  the  decomposing  limestone  in  Greece,  that  rock  containing  in 
it  much  siliceous  and  ferruginous  matter. 

Many  of  the  Katavothra  being  insufficient  to  give  passage  to  all  the 
water  in  the  rainy  season,  a  temporary  lake  is  formed  round  the  mouth 
of  the  chasm,  which  then  becomes  still  farther  obstructed  by  pebbles, 
sand,  and  red  mud,  thrown  down  from  the  turbid  waters.  The  lake 
being  thus  raised,  its  waters  generally  escape  through  other  openings,  at 
higher  levels,  around  the  borders  of  the  plain,  constituting  the  bottom  of 
the  closed  basin. 

In  some  places,  as  at  Kavaros  and  Tripolitza,  where  the  principal  dis- 
charge is  by  a  gulf  in  the  middle  of  the  plain,  nothing  can  be  seen  over 
the  opening  in  summer,  when  the  lake  dries  up,  but  a  deposit  of  red 

*  Ann.  des  Mines,  3me  serie,  torn,  iv.,  1833. 


CH.  XL VI]  IN   FISSURES   AND    CAVES.  735 

mud,  cracked  in  all  directions.  But  the  Katavothron  is  more  commonly 
situated  at  the  foot  of  the  surrounding  escarpment  of  limestone ;  and  in 
that  case  there  is  sometimes  room  enough  to  allow  a  person  to  enter,  in 
summer,  and  even  to  penetrate  far  into  the  interior.  Within  is  seen  a 
suite  of  chambers,  communicating  with  each  other  by  narrow  passages ; 
and  M.  Virlet  relates,  that  in  one  instance  he  observed,  near  the  entrance, 
human  bones  imbedded  in  recent  red  mud,  mingled  with  the  remains  of 
plants  and  animals  of  species  now  inhabiting  the  Morea.  It  is  not 
wonderful,  he  says,  that  the  bones  of  man  should  be  met  with  in  such 
receptacles ;  for  so  murderous  have  been  the  late  wars  in  Greece,  that 
skeletons  are  often  seen  lying  exposed  on  the  surface  of  the  country.* 

In  summer,  when  no  water  is  flowing  into  the  Katavothron,  its  mouth, 
half  closed  up  with  red  mud,  is  masked  by  a  vigorous  vegetation,  which 
is  cherished  by  the  moisture  of  the  place.  It  is  then  the  favorite  hiding- 
place  and  den  of  foxes  and  jackals ;  so  that  the  same  cavity  serves  at  one 
season  of  the  year  for  the  habitation  of  carnivorous  beasts,  and  at  another 
as  the  channel  of  an  engulfed  river.  Near  the  mouth  of  one  chasm,  M. 
Boblaye  and  his  companions  saw  the  carcass  of  a  horse,  in  part  devoured, 
the  size  of  which  seemed  to  have  prevented  the  jackals  from  dragging  it 
in:  the  marks  of  their  teeth  were  observed  on  the  bones,  and  it  was 
evident  that  the  floods  of  the  ensuing  winter  would  wash  in  whatsoever 
might  remain  of  the  skeleton. 

It  has  been  stated  that  the  waters  of  all  these  torrents  of  the  Morea  are 
turbid  where  they  are  engulfed ;  but  when  they  come  out  again,  often  at 
the  distance  of  many  leagues,  they  are  perfectly  clear  and  limpid,  being 
only  charged  occasionally  with  a  slight  quantity  of  calcareous  sand.  The 
points  of  efflux  are  usually  near  the  sea-shores  of  the  Morea,  but  some- 
times they  are  submarine ;  and  when  this  is  the  case,  the  sands  are  seen 
to  boil  up  for  a  considerable  space,  and  the  surface  of  the  sea,  in  calm 
weather,  swells  in  large  convex  waves.  It  is  curious  to  reflect,  that  when 
this  discharge  fails  in  seasons  of  drought,  the  pressure  of  the  sea  may 
force  its  salt  waters  into  subterraneous  caverns,  and  carry  in  marine  sand 
and  shells,  to  be  mingled  with  ossiferous  mud,  and  the  remains  of  terres- 
trial animals. 

In  general,  however,  the  efflux  of  water  at  these  inferior  openings  is 
surprisingly  uniform.  It  seems,  therefore,  that  the  large  caverns  in  the 
interior  must  serve  as  reservoirs,  and  that  the  water  escapes  gradually 
from  them,  in  consequence  of  the  smallness  of  the  rents  and  passages  by 
which  they  communicate  with  the  surface. 

The  phenomena  above  described  are  not  confined  to  the  Morea,  but 
occur  in  Greece  generally,  and  in  those  parts  of  Italy,  Spain,  Asia  Minor, 
and  Syria,  where  the  formations  of  the  Morea  extend.  The  Copaic  lake 
in  Boeotia  has  no  outlet,  except  by  underground  channels ;  and  hence 
we  can  explain  those  traditional  and  historical  accounts  of  its  having 
gained  on  the  surrounding  plains  and  overflowed  towns,  as  such  floods 

*  Bull,  de  la  Soc.  Geol.  de  France,  torn.  iii.  p.  223. 


736  PRESERVATION   OF   FOSSILS  [Cn.  XLVI. 

must  have  happened  whenever  the  outlet  was  partially  choked  up  by  mud, 
gravel,  or  the  subsidence  of  rocks,  caused  by  earthquakes.  When  speak- 
ing of  the  numerous  fissures  in  the  limestone  of  Greece,  M.  Boblaye 
reminds  us  of  the  famous  earthquake  of  469  B.  c.,  when,  as  we  learn  from 
Cicero,  Plutarch,  Strabo,  and  Pliny,  Sparta  was  laid  in  ruins,  part  of  the 
summit  of  Mount  Taygetus  torn  off,  and  numerous  gulfs  and  fissures 
caused  in  the  rocks  of  Laconia. 

During  the  great  earthquake  of  1693,  in  Sicily,  several  thousand  people 
were  at  once  entombed  in  the  ruins  of  caverns  in  limestone,  at  Sortino 
Vecchio ;  and,  at  the  same  time,  a  large  stream,  which  had  issued  for 
ages  from  one  of  the  grottoes  below  that  town,  changed  suddenly  its  sub- 
terranean course,  and  came  out  from  the  mouth  of  a  cave  lower  down 
the  valley,  where  no  water  had  previously  flowed.  To  this  new  point 
the  ancient  water-mills  were  transferred,  as  I  learnt  when  I  visited  the 
spot  in  1829. 

When  the  courses  of  engulfed  rivers  are,  thus  liable  to  change,  from 
time  to  time,  by  alterations  in  the  levels  of  a  country,  and  by  the  rending 
and  shattering  of  mountain  masses,  we  must  suppose  that  the  dens  of 
wild  beasts  will  sometimes  be  inundated  by  subterranean  floods,  and  their 
carcasses  buried  under  heaps  of  alluvium.  The  bones,  moreover,  of  indi- 
viduals which  have  died  in  the  recesses  of  caves,  or  of  animals  which  have 
been  carried  in  for  prey,  may  be  drifted  along,  and  mixed  up  with  mud, 
sand,  and  fragments  of  rocks,  so  as  to  form  osseous  breccias. 

In  1833  I  had  an  opportunity  of  examining  the  celebrated  caves  of 
Franconia,  and  among  others  that  of  Rabenstein,  newly  discovered.  Their 
general  form,  and  the  nature  and  arrangement  of  their  contents,  appeared 
to  me  to  agree  perfectly  with  the  notion  of  their  having  once  served  as 
the  channels  of  subterranean  rivers.  This  mode  of  accounting  for  the 
introduction  of  transported  matter  into  the  Franconian  and  other  caves, 
filled  up  as  they  often  are  even  to  their  roofs  with  osseous  breccia,  was 
long  ago  proposed  by  M.  C.  Prevost,*  and  seems  at  length  to  be  very 
generally  adopted.  But  I  do  not  doubt  that  bears  inhabited  some  of  the 
German  caves,  or  that  the  cavern  of  Kirkdale,  in  Yorkshire,  was  once  the 
den  of  hyaenas.  The  abundance  of  bony  dung,  associated  with  hyaenas' 
bones,  has  been  pointed  out  by  Dr.  Buckland,  and  with  reason,  as  con- 
firmatory of  this  opinion. 

The  same  author  observed  in  every  cave  examined  by  him  in  Germany, 
that  deposits  of  mud  and  sand,  with  or  without  rolled  pebbles  and  angu- 
lar fragments  of  rock,  were  covered  over  with  a  single  crust  of  stalagmite.f 
In  the  English  caves  he  remarked  a  similar  absence  of  alterations  of  allu- 
vium and  stalagmite.  But  Dr.  Schmerling  has  discovered  in  a  cavern  at 
Chockier,  about  two  leagues  from  Liege,  three  distinct  beds  of  stalagmite, 
and  between  each  of  them  a  mass  of  breccia,  and  mud  mixed  with  quartz 
pebbles,  and  in  the  three  deposits  the  bones  of  extinct  quadrupeds.  J 

*  M6m.  de  la  ftoc.  d'Hist.  Nat.  de  Paris,  torn.  iv. 

f  Reliquiae  Diluvianse,  p.  108. 

i  Journ.  de  Ge"ol.,  torn.  i.  p.  286.     July,  1830. 


CH.  XLVL]  IN   FISSURES   AND    CAVES.  737 

This  exception  does  not  invalidate  the  generality  of  the  phenomenon 
pointed  out  by  Dr.  Buckland,  one  cause  of  which  may  perhaps  be  this, 
that  if  several  floods  pass  at  different  intervals  of  time  through  a  subter- 
ranean passage,  the  last,  if  it  has  power  to  drift  along  fragments  of  rock, 
will  also  tear  up  any  alternating  stalagmitic  and  alluvial  beds  that  may 
have  been  previously  formed.  Another  cause  may  be,  that  a  particular 
line  of  caverns  will  rarely  be  so  situated,  in  relation  to  the  lowest  levels 
of  a  country,  as  to  become,  at  two  distinct  epochs,  the  receptacle  of  en- 
gulfed rivers ;  and  if  this  should  happen,  some  of  the  caves,  or  at  least 
the  tunnels  of  communication,  may  at  the  first  period  be  entirely  choked 
up  with  transported  matter,  so  as  not  to  allow  the  subsequent  passage  of 
water  in  the  same  direction. 

As  the  same  chasms  may  remain  open  throughout  periods  of  indefinite 
duration,  the  species  inhabiting  a  country  may  in  the  meantime  be  greatly 
changed,  and  thus  the  remains  of  animals  belonging  to  very  different 
epochs  may  become  mingled  together  in  a  common  tomb.  For  this 
reason  it  is  often  difficult  to  separate  the  monuments  of  the  human  epoch 
from  those  relating  to  periods  long  antecedent,  and  it  was  not  without 
great  care  and  skill  that  Dr.  Buckland  was  enabled  to  guard  against  such 
anachronisms  in  his  investigations  of  several  of  the  English  caves.  He 
mentions  that  human  skeletons  were  found  in  the  cave  of  Wokey  Hole, 
near  Wells,  in  the  Mendips,  dispersed  through  reddish  mud  and  clay, 
and  some  of  them  united  by  stalagmite  into  a  firm  osseous  breccia. 
"  The  spot  on  which  they  lie  is  within  reach  of  the  highest  floods  of  the 
adjacent  river,  and  the  mud  in  which  they  are  buried  is  evidently 
fluviatile."  * 

In  speaking  of  the  cave  of  Paviland  on  the  coast  of  Glamorganshire 
the  same  author  states  that  the  entire  mass  through  which  bones  were 
dispersed  appeared  to  have  been  disturbed  by  ancient  diggings,  so  that 
the  remains  of  extinct  animals  had  become  mixed  with  recent  bones  and 
shells.  In  the  same  cave  was  a  human  skeleton,  and  the  remains  of  recent 
testacea  of  eatable  species,  which  may  have  been  carried  in  by  man. 

In  several  caverns  on  the  banks  of  the  Meuse,  near  Liege,  Dr.  Schmer- 
ling  has  found  human  bones  in  the  same  mud  and  breccia  with  those  of 
the  elephant,  rhinoceros,  bear,  and  other  quadrupeds  of  extinct  species. 
He  has  observed  none  of  the  dung  of  any  of  these  animals :  and  from 
this  circumstance,  and  the  appearance  of  the  mud  and  pebbles,  he  con- 
cludes that  these  caverns  were  never  inhabited  by  wild  beasts,  but  washed 
in  by  a  current  of  water.  As  the  human  skulls  and  bones  were  in  frag- 
ments, and  no  entire  skeleton  had  been  found,  he  does  not  believe  that 
these  caves  were  places  of  sepulture,  but  that  the  human  remains  were 
washed  in  at  the  same  time  as  the  bones  of  extinct  quadrupeds,  and  that 
these  lost  species  of  mammalia  co-existed  on  the  earth  with  man. 

Caverns  in  the  south  of  France. — Similar  associations  in  the  south 
of  France,  of  human  bones  and  works  of  art,  with  remains  of  extinct 
quadrupeds,  have  induced  other  geologists  to  maintain  that  man  was  an 

*  Reliquite  Diluviance,  p.  165. 
47 


738  PRESERVATION   OF   FOSSILS  [Cn.  XLVL 

inhabitant  of  that  part  of  Europe  before  the  rhinoceros,  hyaena,  tiger, 
and  many  fossil  species  disappeared.  I  may  first  mention  the  cavern  of 
Bize,  in  the  department  of  Aude,  where  M.  Marcel  de  Serres  met  with  a 
small  number  of  human  bones  mixed  with  those  of  extinct  animals  and 
with  land  shells.  They  occur  in  a  calcareous  stony  mass,  bound  together 
by  a  cement  of  stalagmite.  On  examining  the  same  caverns,  M.  Tournal 
found  not  only  in  these  calcareous  beds,  but  also  in  a  black  mud  which 
overlies  a  red  osseous  mud,  several  human  teeth,  together  with  broken 
angular  fragments  of  a  rude  kind  of  pottery,  and  also  recent  marine  and 
terrestrial  shells.  The  teeth  preserve  their  enamel ;  but  the  fangs  are  so 
much  altered  as  to  adhere  strongly  when  applied  to  the  tongue.  Of  the 
terrestrial  shells  thus  associated  with  the  bones  and  pottery,  the  most 
common  are  Cyclostoma  elegans,  Bulimus  decollatus,  Helix  nemoralis, 
and  H.  nitida.  Among  the  marine  are  found  Pecten  jacobceus,  Mytilus 
edulis,  and  Natica  mille-punctata,  all  of  them  eatable  kinds,  and  which 
may  have  been  brought  there  for  food.  Bones  were  found  in  the  same 
mass  belonging  to  three  new  species  of  deer,  the  brown  bear  ( Ursus 
arctdideus),  and  the  wild  bull  (Bos  urus),  formerly  a  native  of 
Germany.* 

In  the  same  parts  of  France,  M.  de  Christol  has  found  in  caverns  in  a 
tertiary  limestone  at  Pondres  and  Souvignargues,  two  leagues  north  of 
Lunel-viel,  in  the  department  of  Herault,  human  bones  and  pottery  con- 
fusedly mixed  with  remains  of  the  rhinoceros,  bear,  hyaena,  and  other 
terrestrial  mammifers.  They  were  imbedded  in  alluvial  mud,  of  the  so- 
lidity of  calcareous  tufa,  and  containing  some  flint  pebbles  and  fragments 
of  the  limestone  of  the  country.  Beneath  this  mixed  accumulation, 
which  sometimes  attained  a  thickness  of  thirteen  feet,  is  the  original 
floor  of  the  cavern,  about  a  foot  thick,  covered  with  bones  and  the  dung 
of  animals  (album  grcecum),  in  a  sandy  and  tufaceous  cement. 

The  human  bones  in  these  caverns  of  Pondres  and  Souvignargues 
were  found,  upon  a  careful  analysis,  to  have  parted  with  their  animal 
matter  to  as  great  a  degree  as  those  of  the  hyaena  which  accompany 
them,  and  are  equally  brittle,  and  adhere  as  strongly  to  the  tongue. 

In  order  to  compare  the  degree  of  alteration  of  these  bones  with  those 
known  to  be  of  high  antiquity,  M.  Marcel  de  Serres  and  M.  Ballard, 
chemists  of  Montpelier,  procured  some  from  a  Gaulish  sarcophagus,  in 
the  plain  of  Lunel,  supposed  to  have  been  buried  for  fourteen  or  fifteen 
centuries  at  least.  In  these  the  cellular  tissue  was  empty,  but  they  were 
more  solid  than  fresh  bones.  They  did  not  adhere  to  the  tongue  in  the 
same  manner  as  those  of  the  caverns  of  Bize  and  Pondres,  yet  they 
had  lost  at  least  three  fourths  of  their  original  animal  matter. 

The  superior  solidity  of  the  Gaulish  bones  to  those  in  a  fresh  skeleton 
is  a  fact  in  perfect  accordance  with  the  observations  made  by  Dr.  Mantell 
on  bones  taken  from  a  Saxon  tumulus  near  Lewes. 

M.  Tessier  has  also  described  a  cavern  near  Mialet,  in  the  department 

*  M.  Marcel  de  Serres,  Gdognosie  des  Terrains  Tertiaires,  p.  64.     Introduction. 


CH.  XLVL]  IN   FISSURES  AND   CAVES.  739 

of  Gard,  where  the  remains  of  the  bear  and  other  animals  were  mingled 
confusedly  with  human  bones,  coarse  pottery,  teeth  pierced  for  amulets, 
pointed  fragments  of  bone,  bracelets  of  bronze,  and  a  Roman  urn.  Part 
of  this  deposit  reached  to  the  roof  of  the  cavity,  and  adhered  firmly  to  it. 
The  author  suggests  that  the  exterior  portion  of  the  grotto  may  at  one 
period  have  been  a  den  of  bears,  and  that  afterwards  the  aboriginal  inha- 
bitants of  the  country  took  possession  of  it  either  for  a  dwelling  or  a  burial- 
place,  and  left  there  the  coarse  pottery,  amulets,  and  pointed  pieces  of 
bone.  At  a  third  period  the  Romans  may  have  used  the  cavern  as  a 
place  of  sepulture  or  concealment,  and  to  them  may  have  belonged  the 
urn  and  bracelets  of  metal.  If  we  then  suppose  the  course  of  the  neigh- 
boring river  to  be  impeded  by  some  temporary  cause,  a  flood  would  be 
occasioned,  which,  rushing  into  the  open  grotto,  may  have  washed  all 
the  remains  into  the  interior  caves  and  tunnels,  heaping  the  whole  con- 
fusedly together.* 

In  the  controversy  which  has  arisen  on  this  subject,  MM.  Marcel  de 
Serres,  De  Christol,  Tournal,  and  others,  have  contended,  that  the  pheno- 
mena of  this  and  other  caverns  in  the  south  of  France  prove  that  the 
fossil  rhinoceros,  hyaena,  bear,  and  several  other  lost  species,  were  once 
contemporaneous  inhabitants  of  the  country,  together  with  man ;  while 
M.  Desnoyers  has  supported  the  opposite  opinion.  The  flint  hatchets  and 
arrow-heads,  he  says,  and  the  pointed  bones  and  coarse  pottery  of  many 
French  and  English  caves,  agree  precisely  in  character  with  those  found 
in  the  tumuli,  and  under  the  dolmens  (rude  altars  of  unhewn  stone)  of 
the  primitive  inhabitants  of  Gaul,  Britain,  and  Germany.  The  human 
bones,  therefore,  in  the  caves  which  are  associated  with  such  fabricated 
objects,  must  belong  not  to  antediluvian  periods,  but  to  a  people  in  the 
same  stage  of  civilization  as  those  who  constructed  the  tumuli  and 
altars. 

In  the  Gaulish  monuments  we  find,  together  with  the  objects  of  indus- 
try above  mentioned,  the  bones  of  wild  and  domestic  animals  of  species 
now  inhabiting  Europe,  particularly  of  deer,  sheep,  wild-boars,  dogs, 
horses,  and  oxen.  This  fact  has  been  ascertained  in  Quercy,  and  other 
provinces ;  and  it  is  supposed  by  antiquaries  that  the  animals  in  question 
were  placed  beneath  the  Celtic  altars  in  memory  of  sacrifices  offered  to 
the  Gaulish  divinity  Hesus,  and  in  the  tombs  to  commemorate  funeral 
repasts,  and  also  from  a  supposition  prevalent  among  savage  nations, 
which  induces  them  to  lay  up  provisions  for  the  manes  of  the  dead  in  a 
future  life.  But  in  none  of  these  ancient  monuments  have  any  bones 
been  found  of  the  elephant,  rhinoceros,  hyaena,  tiger,  and  other  quadru- 
peds, such  as  are  found  in  caves,  as  might  certainly  have  been  expected 
had  these  species  continued  to  flourish  at  the  time  that  this  part  of  Gaul 
was  inhabited  by  man.  f 

We  are  also  reminded  by  M.  Desnoyers  of  a  passage  in  Florus,  in  which 
it  is  related  that  Caesar  ordered  the  caves  into  which  the  Aquitanian 

*  Bull,  de  la  Soc.  Geol.  de  France,  torn.  ii.  pp.  56 — 63. 

f  Desnoyers,  Bull,  de  la  Soc.  Ge"ol.  de  France,  torn.  ii.  p.  252. 


740  PRESERVATION   OF   FOSSILS  [Cn.  XL VI. 

Gauls  had  retreated  to  be  closed  up.*  It  is  also  on  record,  that  so  late 
as  the  eighth  century,  the  Aquitanians  defended  themselves  in  caverns 
against  King  Pepin.  As  many  of  these  caverns,  therefore,  may  have 
served  in  succession  as  temples  and  habitations,  as  places  of  sepulture, 
concealment,  or  defence,  it  is  easy  to  conceive  that  human  bones,  and 
those  of  animals,  in  osseous  breccias  of  much  older  date,  may  have  been 
swept  away  together,  by  inundations,  and  then  buried  in  one  promiscuous 
heap. 

It  is  not  on  the  evidence  of  such  intermixtures  that  we  ought  readily 
to  admit  either  the  high  antiquity  of  the  human  race,  or  the  recent  date 
of  certain  lost  species  of  quadrupeds. 

Among  the  various  modes  in  which  the  bones  of  animals  become  pre- 
served, independently  of  the  agency  of  land  floods  and  engulfed  rivers,  I 
may  mention  that  open  fissures  often  serve  as  natural  pitfalls  in  which 
herbivorous  animals  perish.  This  may  happen  the  more  readily  when 
they  are  chased  by  beasts  of  prey,  or  when  surprised  while  carelessly 
browsing  on  the  shrubs  which  so  often  overgrow  and  conceal  the  edges 
of  fissures.f 

During  the  excavations  recently  made  near  Behat  in  India,  the  bones 
of  two  deer  were  found  at  the  bottom  of  an  ancient  well  which  had 
been  filled  up  with  alluvial  loam.  Their  horns  were  broken  to  pieces, 
but  the  jaw  bones  and  other  parts  of  the  skeleton  remained  tolerably 
perfect.  "  Their  presence,"  says  Captain  Cautley,  "  is  easily  accounted 
for,  as  a  great  number  of  these  and  other  animals  are  constantly  lost  in 
galloping  over  the  jungles  and  among  the  high  grass  by  falling  into 
deserted  wells."}; 

Above  the  village  of  Selside,  near  Ingleborough  in  Yorkshire,  a 
chasm  of  enormous  but  unknown  depth  occurs  in  the  scar-limestone,  a 
member  of  the  carboniferous  series.  "  The  chasm,"  says  Professor  Sedg- 
wick,  "is  surrounded  by  grassy  shelving  banks,  and  many  animals, 
tempted  towards  its  brink,  have  fallen  down  and  perished  in  it.  The 
approach  of  cattle  is  now  prevented  by  a  strong  lofty  wall ;  but  there 
can  be  no  doubt  that,  during  the  last  two  or  three  thousand  years,  great 
masses  of  bony  breccia  must  have  accumulated  in  the  lower  parts  of  the 
great  fissure,  which  probably  descends  through  the  whole  thickness  of  the 
scar-limestone,  to  the  depth  of  perhaps  five  or  six  hundred  feet."§ 

When  any  of  these  natural  pit-falls  happen  to  communicate  with  lines 
of  subterranean  caverns,  the  bones,  earth,  and  breccia,  may  sink  by 
their  own  weight,  or  be  washed  into  the  vaults  below. 

At  the  north  extremity  of  the  rock  of  Gibraltar  are  perpendicular 
fissures,  on  the  ledges  of  which  a  number  of  hawks  nestle  and  rear  their 
young  in  the  breeding  season.  They  throw  down  from  their  nests  the 
bones  of  small  birds,  mice,  and  other  animals,  on  which  they  feed,  and 

*  Hist  Rom.  Epit,  lib.  iii.  c.  10. 

f  Buckland,  Reliquiae  Diluvianse,  p.  25. 

±  See  above,  pp.  730,  781. 

fc  On  the  Lake  Mountains  of  North  of  England,  Geol.Soc.  Jan.  5,  1831. 


CH.  XLVL]  IN   FISSURES   AND    CAVES.  741 

these  are  gradually  united  into  a  breccia  of  angular  fragments  of  the 
decomposing  limestone  with  a  cement  of  red  earth. 

At  the  pass  of  Escrinet  in  France,  on  the  northern  escarpment  of  the 
Coiron  hills,  near  Aubenas,  I  have  seen  a  breccia  in  the  act  of  forming. 
Small  pieces  of  disintegrating  limestone  are  transported,  during  heavy 
rains,  by  a  streamlet,  to  the  foot  of  the  declivity,  where  land  shells  are 
very  abundant.  The  shells  and  pieces  of  stone  soon  become  cemented 
together  by  stalagmite  into  a  compact  mass,  and  the  talus  thus  formed 
is  in  one  place  fifty  feet  deep,  and  five  hundred  yards  wide.  So  firmly 
is  the  lowest  portion  consolidated,  that  it  is  quarried  for  mill-stones. 

Recent  stalagmitic  limestone  of  Cuba. — One  of  the  most  singular 
examples  of  the  recent  growth  of  stalagmitic  limestone  in  caves  and 
fissures  is  that  described  by  Mr.  R.  C.  Taylor,  as  observable  on  the 
north-east  part  of  the  island  of  Cuba.*  The  country  there  is  composed 
of  a  white  marble,  in  which  are  numerous  cavities,  partially  filled  with 
a  calcareous  deposit  of  a  brick-red  color.  In  this  red  deposit  are 
shells,  or  often  the  hollow  casts  of  shells,  chiefly  referable  to  eight  or 
nine  species  of  land  snails,  a  few  scattered  bones  of  quadrupeds,  and, 
what  is  still  more  singular,  marine  univalve  shells,  often  at  the  height 
of  many  hundred,  or  even  one  thousand  feet  above  the  sea.  The  follow- 
ing explanation  is  given  of  the  gradual  increase  of  this  deposit.  Land 
snails  of  the  genera  Helix,  Cyclostoma,  Pupa,  and  Clausilia,  retire  into 
the  caves,  the  floors  of  which  are  strewed  with  myriads  of  their  dead 
and  unoccupied  shells,  at  the  same  time  that  water  infiltered  through 
the  mountain  throws  down  carbonate  of  lime,  enveloping  the  shells, 
together  with  fragments  of  the  white  limestone  which  occasionally  falls 
from  the  roof.  Multitudes  of  bats  resort  to  the  caves ;  and  their  dung, 
which  is  of  a  bright  red  color,  (probably  derived  from  the  berries  on 
which  they  feed,)  imparts  its  red  hue  to  the  mass.  Sometimes  also  the 
Hutia,  or  great  Indian  rat  of  the  island,  dies  and  leaves  its  bones  in  the 
caves.  "  At  certain  seasons  the  soldier-crabs  resort  to  the  sea-shore,  and 
then  return  from  their  pilgrimage,  each  carrying  with  them,  or  rather 
dragging,  the  shell  of  some  marine  univalve  for  many  a  weary  mile. 
They  may  be  traced  even  at  the  distance  of  eight  or  ten  miles  from  the 
shore,  on  the  summit  of  mountains  1200  feet  high,  like  the  pilgrims  of 
the  olden  times,  each  bearing  his  shell  to  denote  the  character  and 
extent  of  his  wanderings."  By  this  means  several  species  of  marine 
testacea  of  the  genera  Trochus,  Turbo,  Littorina,  and  Monodonta,  are 
conveyed  into  inland  caverns,  and  enter  into  the  composition  of  the 
newly  formed  rock. 

*  Notes  on  Geol.  of  Cuba,  1836,  PhiL  Mag.,  July,  1837. 


CHAPTER  XLVII. 

IMBEDDING    OF    ORGANIC    REMAINS    IN    SUBAQUEOUS    DEPOSITS. 

Division  of  the  subject — Imbedding  of  terrestrial  animals  and  plants — Increased 
specific  gravity  of  wood  sunk  to  great  depths  in  the  sea — Drift-timber  of  the 
Mackenzie  in  Slave  Lake  and  Polar  Sea — Floating  trees  in  the  Mississippi — in 
the  Gulf  Stream — on  the  coast  of  Iceland,  Spitzbergen,  and  Labrador — Sub- 
marine forests — Example  on  coast  of  Hampshire — Mineralization  of  plants — 
Imbedding  of  marine  plants — of  insects — of  reptiles — Bones  of  birds  why  rare 
— Imbedding  of  terrestrial  quadrupeds  by  river  floods — Skeletons  in  recent 
shell  marl — Imbedding  of  mammiferous  remains  in  marine  strata. 

Division  of  the  subject. — HAVING  treated  of  the  imbedding  of  organic 
remains  in  deposits  formed  upon  the  land,  I  shall  next  consider  the 
including  of  the  same  in  deposits  formed  under  water. 

It  will  be  convenient  to  divide  this  branch  of  our  subject  into  three 
parts ;  considering,  first,  the  various  modes  whereby  the  relics  of  terres- 
trial species  may  be  buried  in  subaqueous  formations ;  secondly,  the 
modes  whereby  animals  and  plants  inhabiting  fresh  water  may  be  so 
entombed  ;  thirdly,  how  marine  species  may  become  preserved  in  new 
strata. 

The  phenomena  above  enumerated  demand  a  fuller  share  of  attention 
than  those  previously  examined,  since  the  deposits  which  originate  upon 
dry  land  are  insignificant  in  thickness,  superficial  extent,  and  durability, 
when  contrasted  with  those  of  subaqueous  origin.  At  the  same  time, 
the  study  of  the  latter  is  beset  with  greater  difficulties ;  for  we  are  here 
concerned  with  the  results  of  processes  much  farther  removed  from  the 
sphere  of  ordinary  observation.  There  is,  indeed,  no  circumstance 
which  so  seriously  impedes  the  acquisition  of  just  views  in  our  science 
as  an  habitual  disregard  of  the  important  fact,  that  the  reproductive 
effects  of  the  principal  agents  of  change  are  confined  to  another 
element — to  that  larger  portion  of  the  globe,  from  which  by  our  very 
organization  we  are  almost  entirely  excluded.* 

Imbedding  of  Terrestrial  Plants. 

When  a  tree  falls  into  a. river  from  the  undermining  of  the  banks  or 
from  being  washed  in  by  a  torrent  or  flood,  it  floats  on  the  surface,  not 
because  the  woody  portion  is  specifically  lighter  than  water,  but  because 
it  is  full  of  pores  containing  air.  When  soaked  for  a  considerable  time, 
the  water  makes  its  way  into  these  pores,  and  the  wood  becomes  water- 
logged and  sinks.  The  time  required  for  this  process  varies  in  different 
woods ;  but  several  kinds  may  be  drifted  to  great  distances,  sometimes 
across  the  ocean,  before  they  lose  their  buoyancy. 

*  See  above,  p.  6Y. 


CH.  XLVIL]         IMBEDDING   OF   TERRESTRIAL   PLANTS.  743 

Wood  sunk  to  a  great  depth  in  the  sea. — If  wood  be  sunk  to  vast 
depths  in  the  sea,  it  may  be  impregnated  with  water  suddenly.  Captain 
Scoresby  informs  us,  in  his  Account  of  the  Arctic  Regions,  that  on  one 
occasion  a  whale,  on  being  harpooned,  ran  out  all  the  lines  in  the  boat, 
which  it  then  dragged  under  water,  to  the  depth  of  several  thousand  feet, 
the  men  having  just  time  to  escape  to  a  piece  of  ice.  When  the  fish 
returned  to  the  surface  "to  blow,"  it  was  struck  a  second  time,  and  soon 
afterwards  killed.  The  moment  it  expired  it  began  to  sink, — an  unusual 
circumstance,  which  was  found  to  be  caused  by  the  weight  of  the  sunken 
boat,  which  still  remained  attached  to  it.  By  means  of  harpoons  and  ropes 
the  fish  was  prevented  from  sinking,  until  it  was  released  from  the  weight 
by  connecting  a  rope  to  the  lines  of  the  attached  boat,  which  was  no 
sooner  done  than  the  fish  rose  again  to  the  surface.  The  sunken  boat 
was  then  hauled  up  with  great  labor ;  for  so  heavy  was  it,  that  although 
before  the  accident  it  would  have  been  buoyant  when  full  of  water,  yet 
it  now  required  a  boat  at  each  end  to  keep  it  from  sinking.  "  When  it 
was  hoisted  into  the  ship,  the  paint  came  off  the  wood  in  large  sheets ; 
and  the  planks,  which  were  of  wainscot,  were  as  completely  soaked  in 
every  pore  as  if  they  had  lain  at  the  bottom  of  the  sea  since  the  flood ! 
A  wooden  apparatus  that  accompanied  the  boat  in  its  progress  through 
the  deep,  consisting  chiefly  of  a  piece  of  thick  deal,  about  fifteen  inches 
square,  happened  to  fall  overboard,  and,  though  it  originally  consisted  of 
the  lightest  fir,  sank  in  the  water  like  a  stone.  The  boat  was  rendered 
useless ;  even  the  wood  of  which  it  was  built,  on  being  offered  to  the 
cook  for  fuel,  was  tried  and  rejected  as  incombustible."  * 

Captain  Scoresby  found  that,  by  sinking  pieces  of  fir,  elm,  ash,  &c.,  to 
the  depth  of  four  thousand  and  sometimes  six  thousand  feet,  they  became 
impregnated  with  sea-water,  and  when  drawn  up  again,  after  immersion 
for  an  hour,  would  .no  longer  float.  The  effect  of  this  impregnation  was 
to  increase  the  dimensions  as  well  as  the  specific  gravity  of  the  wood, 
every  solid  inch  having  increased  one-twentieth  in  size  and  twenty-one 
twenty-fifths  in  weight. f 

Drift-wood  of  the  Mackenzie  River. — When  timber  is  drifted  down 
by  a  river,  it  is  often  arrested  by  lakes  ;  and,  becoming  water-logged,  it 
may  sink  and  be  imbedded  in  lacustrine  strata,  if  any  be  there  forming ; 
sometimes  a  portion  floats  on  till  it  reaches  the  sea.  In  the  course  of 
the  Mackenzie  River  we  have  an  example  of  vast  accumulations  of  vege- 
table matter  now  in  progress  under  both  these  circumstances. 

In  Slave  Lake  in  particular,  which  vies  in  dimensions  with  some  of  the 
great  fresh-water  seas  of  Canada,  the  quantity  of  drift-timber  brought 
down  annually  is  enormous.  "  As  the  trees,"  says  Dr.  Richardson, 
"retain  their  roots,  which  are  often  loaded  with  earth  and  stones,  they 
readily  sink,  especially  when  water-soaked ;  and,  accumulating  in  the 
eddies,  form  shoals,  which  ultimately  augment  into  islands.  A  thicket 
of  small  willows  covers  the  new-formed  island  as  soon  as  it  appears 

*  Account  of  the  Arctic  Regions,  vol.  ii.  p.  193.  f  Ibid.  p.  202. 


744  DRIFT-WOOD   OF   THE  MACKENZIE.          [Cn.  XLVIL 

above  water,  and  their  fibrous  roots  serve  to  bind  the  whole  firmly 
together.  Sections  of  these  islands  are  annually  made  by  the  river, 
assisted  by  the  frost ;  and  it  is  interesting  to  study  the  diversity  of  appear- 
ances they  present,  according  to  their  different  ages.  The  trunks  of  the 
trees  gradually  decay  until  they  are  converted  into  a  blackish  brown 
substance  resembling  peat,  but  which  still  retains  more  or  less  of  the 
fibrous  structure  of  the  wood ;  and  layers  of  this  often  alternate  with  lay- 
ers of  clay  and  sand,  the  whole  being  penetrated,  to  the  depth  of  four  or 
five  yards  or  more,  by  the  long  fibrous  roots  of  the  willows.  A  deposition 
of  this  kind,  with  the  aid  of  a  little  infiltration  of  bituminous  matter, 
would  produce  an  excellent  imitation  of  coal,  with  vegetable  impressions 
of  the  willow-roots.  What  appeared  most  remarkable  was  the  horizontal 
slaty  structure  that  the  old  alluvial  banks  presented,  or  the  regular  curve 
that  the  strata  assumed  from  unequal  subsidence. 

"  It  was  in  the  rivers  only  that  we  could  observe  sections  of  these 
deposits  ;  but  the  same  operation  goes  on,  on  a  much  more  magnificent 
scale,  in  the  lakes.  A  shoal  of  many  miles  in  extent  is  formed  on  the 
south  side  of  Athabasca  Lake,  by  the  drift-timber  and  vegetable  debris 
brought  down  by  the  Elk  Eiver ;  and  the  Slave  Lake  itself  must  in 
process  of  time  be  filled  up  by  matters  daily  conveyed  into  it  from  Slave 
River.  Vast  quantities  of  drift-timber  are  buried  under  the  sand  at  the 
mouth  of  the  river,  and  enormous  piles  of  it  are  accumulated  on  the 
shores  of  every  part  of  the  lake."  * 

The  banks  of  the  Mackenzie  display  almost  everywhere  horizontal 
beds  of  wood  coal,  alternating  with  bituminous  clay,  gravel,  sand,  and 
friable  sandstone ;  sections,  in  short,  of  such  deposits  as  are  now  evi- 
dently forming  at  the  bottom  of  the  lakes  which  it  traverses. 

Notwithstanding  the  vast  forests  intercepted  by  the  lakes,  a  still 
greater  mass  of  drift-wood  is  found  where  the  Mackenzie  reaches  the 
sea,  in  a  latitude  where  no  wood  grows  at  present  except  a  few  stunted 
willows.  At  the  mouths  of  the  river  the  alluvial  matter  has  formed  a 
barrier  of  islands  and  shoals,  where  we  may  expect  a  great  formation 
of  coal  at  some  distant  period. 

The  abundance  of  floating  timber  on  the  Mackenzie  is  owing,  as  Dr. 
Richardson  informs  me,  to  the  direction  and  to  the  length  of  the  course 
of  this  river,  which  runs  from  south  to  north,  so  that  the  sources  of  the 
stream  lie  in  much  warmer  latitudes  than  its  mouths.  In  the  country, 
therefore,  where  the  sources  are  situated,  the  frost  breaks  up  at  an 
earlier  season,  while  yet  the,  waters  in  the  lower  part  of  its  course  are 
ice-bound.  Hence  the  current  of  water,  rushing  down  northward, 
reaches  a  point  where  the  thaw  has  not  begun,  and,  finding  the  chan- 
nel of  the  river  blocked  up  with  ice,  it  overflows  the  banks,  sweeping 
through  forests  of  pines,  and  carrying  away  thousands  of  uprooted  trees. 

Drift-timber  on  coasts  of  Iceland,  Spitzbergen,  &c. — The  ancient 
forests  of  Iceland,  observes  Malte-Brun,  have  been  improvidently  exhausted ; 

*  Dr.  Richardson's  Geognost.  Obs.  on  Capt.  Franklin's  Polar  Expedition. 


CH.  XL VII]  DRIFT-WOOD    OF   THE   NORTH   SEA.  745 

but,  although  the  Icelander  can  obtain  no  timber  from  the  land,  he  is  sup- 
plied with  it  abundantly  by  the  ocean.  An  immense  quantity  of  thick 
trunks  of  pines,  firs,  and  other  trees,  are  thrown  upon  the  northern  coast 
of  the  island,  especially  upon  the  North  Cape  and  Cape  Langaness,  and 
are  then  carried  by  the  waves  along  these  two  promontories  to  other  parts 
of  the  coast,  so  as  to  afford  sufficiency  of  wood  for  fuel  and  for  construct- 
ing boats.  Timber  is  also  carried  to  the  shores  of  Labrador  and  Green- 
land 5  and  Crantz  assures  us  that  the  masses  of  floating  wood  thrown  by  the 
waves  upon  the  island  of  John  de  Mayen  often  equal  the  whole  of  that 
island  in  extent.* 

In  a  similar  manner  the  bays  of  Spitzbergen  are  filled  with  drift-wood, 
which  accumulates  also  upon  those  parts  of  the  coast  of  Siberia  that  are 
exposed  to  the  east,  consisting  of  larch  trees,  pines,  Siberian  cedars,  firs, 
and  Pernambuco  and  Campeachy  woods.  These  trunks  appear  to  have 
been  swept  away  by  the  great  rivers  of  Asia  and  America.  Some  of  them 
are  brought  from  the  Gulf  of  Mexico  by  the  Bahama  stream ;  while 
others  are  hurried  forward  by  the  current  which,  to  the  north  of  Siberia, 
constantly  sets  in  from  east  to  west.  Some  of  these  trees  have  been  de- 
prived of  their  bark  by  friction,  but  are  in  such  a  state  of  preservation  as 
to  form  excellent  building  timber.f  Parts  of  the  branches  and  almost  all 
the  roots  remain  fixed  to  the  pines  which  have  been  drifted  into  the  North 
Sea,  into  latitudes  too  cold  for  the  growth  of  such  timber,  but  the  trunks 
are  usually  barked. 

The  leaves  and  lighter  parts  of  plants  are  seldom  carried  out  to  sea,  in 
any  part  of  the  globe,  except  during  tropical  hurricanes  among  islands, 
and  during  the  agitations  of  the  atmosphere  which  sometimes  accompany 
earthquakes  and  volcanic  eruptions. 

Comparative  number  of  living  and  fossilized  species  of  plants. — It  will 
appear  from  these  observations  that,  although  the  remains  of  terrestrial 
vegetation,  borne  down  by  aqueous  causes  from  the  land,  are  chiefly  depo- 
sited at  the  bottom  of  lakes  or  at  the  mouths  of  rivers,  yet  a  considera- 
ble quantity  is  drifted  about  in  all  directions  by  currents,  and  may  become 
imbedded  in  any  marine  formation,  or  may  sink  down,  when  water-logged, 
to  the  bottom  of  unfathomable  abysses,  and  there  accumulate  without  inter- 
mixture with  other  substances. 

It  may  be  asked  whether  we  have  any  data  for  inferring  that  the 
remains  of  a  considerable  proportion  of  the  existing  species  of  plants  will 
be  permanently  preserved,  so  as  to  be  hereafter  recognizable,  supposing 
the  strata  now  in  progress  to  be  at  some  future  period  upraised  ?  To  this 
inquiry  it  may  be  answered,  that  there  are  no  reasons  for  expecting  that 
more  than  a  small  number  of  the  plants  now  flourishing  in  the  globe  will 
become  fossilized ;  since  the  entire  habitations  of  a  great  number  of  them 
are  remote  from  lakes  and  seas,  and  even  where  they  grow  near  to  large 
bodies  of  water,  the  circumstances  are  quite  accidental  and  partial  which 

*  Malte-Brun,  Geog.,  vol.  v.  part  1.  p.  112. — Brantz,  Hist,  of  Greenland,  torn. 
i.  pp.  53,  54. 

f  Olafsen,  Voyage  to  Iceland,  torn.  i. — Malte-Brun's  Geog.,  vol.  v.  part  i.  p.  112. 


746  IMBEDDING  OF   PLANTS.  [Ca  XLVII. 

favor  the  imbedding  and  conservation  of  vegetable  remains.  Suppose,  for 
example,  that  the  species  of  plants  inhabiting  the  hydrographical  basin 
of  the  Rhine,  or  that  region,  extending  from  the  Alps  to  the  sea,  which  is 
watered  by  the  Rhine  and  its  numerous  tributaries,  to  be  about  2500  in 
number,  exclusive  of  the  cryptogamic  class.  This  estimate  is  by  no  means 
exaggerated ;  yet  if  a  geologist  could  explore  the  deposits  which  have 
resulted  from  the  sediment  of  the  Rhine  in  the  Lake  of  Constance,  and 
off  the  coast  of  Holland,  he  could  scarcely  expect  to  obtain  from  the 
recent  strata  the  leaves,  wood,  and  seeds  of  fifty  species  in  such  a  state 
of  preservation  as  to  enable  a  botanist  to  determine  their  specific  charac- 
ters with  certainty. 

Those  naturalists,  therefore,  who  infer  that  the  ancient  flora  of  the  globe 
was,  at  certain  periods,  less  varied  than  now,  merely  because  they  have 
as  yet  discovered  only  a  few  hundred  fossil  species  of  a  particular  epoch, 
while  they  can  enumerate  more  than  one  hundred  thousand  living  ones, 
are  reasoning  on  a  false  basis,  and  their  standard  of  comparison  is  not  the 
same  in  the  two  cases. 

Submarine  forests  on  coast  of  Hants. — We  have  already  seen  that  the 
submarine  position  of  several  forests,  or  the  remains  of  trees  standing  in  a 
vertical  position  on  the  British  shores,  has  been  due,  in  some  instances, 
to  the  subsidence  of  land.*  There  are  some  cases  which  require  a  differ- 
ent explanation.  My  friend,  Mr.  Charles  Harris,  discovered,  in  1831,  evi- 
dent traces  of  a  fir-wood  beneath  the  mean  level  of  the  sea,  at  Bournmouth, 
in  Hampshire,  the  formation  having  been  laid  open  during  a  low  spring 
tide.  It  is  composed  of  peat  and  wood,  and  is  situated  between  the  beach 
and  a  bar  of  sand  about  200  yards  off",  and  extends  fifty  yards  along  the 
shore.  It  also  lies  in  the  direct  line  of  the  Bournmouth  Valley,  from  the 
termination  of  which  it  is  separated  by  200  yards  of  shingle  and  drift- 
sand.  Down  the  valley  flows  a  large  brook,  traversing  near  its  mouth  a 
considerable  tract  of  rough,  boggy,  and  heathy  ground,  which  produces  a 
few  birch-trees,  and  a  great  abundance  of  the  Myrica  gale.  Seventy-six 
rings  of  annual  growth  were  counted  in  a  transverse  section  of  one  of  the 
buried  fir-trees,  which  was  fourteen  inches  in  diameter.  Besides  the 
stumps  and  roots  of  fir,  pieces  of  alder  and  birch  are  found  in  the  peat ; 
and  it  is  a  curious  fact,  that  a  part  of  many  of  the  trees  have  been  con- 
verted into  iron  pyrites.  The  peat  rests  on  pebbly  strata,  precisely  similar 
to  the  sand  and  pebbles  occurring  on  the  adjoining  heaths. 

As  the  sea  is  encroaching  on  this  shore,  we  may  suppose  that  at  some 
former  period  the  Bourne  Valley  extended  farther,  and  that  its  extremity 
consisted,  as  at  present,  of  boggy  ground,  partly  clothed  with  fir-trees. 
The  bog  rested  on  that  bed  of  pebbles  which  we  now  see  below  the 
peat ;  and  the  sea,  in  its  progressive  encroachments,  eventually  laid  bare, 
at  low  water,  the  sandy  foundations ;  upon  which  a  stream  of  fresh 
water,  rushing  through  the  sand  at  the  fall  of  the  tides,  carried  out  loose 
sand  with  it.  The  super-stratum  of  vegetable  matter,  being  matted  and 

*  See  above,  pp.  306  and  323. 


CH.  XLVIL]  MINERALIZATION   OF   PLANTS.  747 

bound  together  by  the  roots  of  trees,  remained ;  but  being  undermined, 
sank  down  below  the  level  of  the  sea,  and  then  the  waves  washed  sand 
and  shingle  over  it.  In  support  of  this  hypothesis,  it  may  be  observed, 
that  small  streams  of  fresh  water  often  pass  under  the  sands  of  the  sea- 
beach,  so  that  they  may  be  crossed  dry-shod ;  and  the  water  is  seen,  at 
the  point  where  it  issues,  to  carry  out  sand  and  even  pebbles. 

Mineralization  of  plants. — Although  the  botanist  and  chemist  have 
as  yet  been  unable  to  explain  fully  the  manner  in  which  wood  becomes 
petrified,  it  is  nevertheless  ascertained  that,  under  favorable  circum- 
stances, the  lapidifying  process  is  now  continually  going  on.  A  piece 
of  wood  was  lately  procured  by  Mr.  Stokes,  from  an  ancient  Roman 
aqueduct  in  Westphalia,  in  which  some  portions  were  converted  into 
spindle-shaped  bodies,  consisting  of  carbonate  of  lime,  while  the  rest  of 
the  wood  remained  in  a  comparatively  unchanged  state.*  It  appears 
that  in  some  cases  the  most  perishable,  in  others  the  most  durable, 
portions  of  plants  are  preserved,  variations  which  doubtless  depend  on 
the  time  when  the  mineral  matter  was  supplied.  If  introduced  imme- 
diately, on  the  first  commencement  of  decomposition,  then  the  most 
destructible  parts  are  lapidified,  while  the  more  durable  do  not  waste 
away  till  afterwards,  when  the  supply  has  failed,  and  so  never  become 
petrified.  The  converse  of  these  circumstances  gives  rise  to  exactly 
opposite  results. 

Professor  Goppert,  of  Breslau,  has  instituted  a  series  of  curious 
experiments,  in  which  he  has  succeeded  in  producing  some  very  remark- 
able imitations  of  fossil  petrifactions.  He  placed  recent  ferns  between 
soft  layers  of  clay,  dried  these  in  the  shade,  and  then  slowly  and 
gradually  heated  them,  till  they  were  red-hot.  The  result  was  the 
production  of  so  perfect  a  counterpart  of  fossil  plants  as  might  have 
deceived  an  experienced  geologist.  According  to  the  different  degrees 
of  heat  applied,  the  plants  were  obtained  in  a  brown  or  perfectly  car 
bonized  condition ;  and  sometimes,  but  more  rarely,  they  were  in  a  black 
shining  state,  adhering  closely  to  the  layer  of  clay.  If  the  red  heat 
was  sustained  until  all  the  organic  matter  was  burnt  up,  only  an 
impression  of  the  plant  remained. 

The  same  chemist  steeped  plants  in  a  moderately  strong  solution  of 
sulphate  of  iron,  and  left  them  immersed  in  it  for  several  days,  until 
they  were  thoroughly  soaked  in  the  liquid.  They  were  then  dried,  and 
kept  heated  until  they  would  no  longer  shrink  in  volume,  and  until 
every  trace  of  organic  matter  had  dissappeared.  On  cooling  them  he 
found  that  the  oxide  formed  by  this  process  had  taken  the  form  of  the 
plants.  A  variety  of  other  experiments  were  made  by  steeping  animal 
and  vegetable  substances  in  siliceous,  calcareous,  and  metallic  solutions, 
and  all  tended  to  prove  that  the  mineralization  of  organic  bodies  can  be 
carried  much  farther  in  a  short  time  than  had  been  previously  supposed.f 

*  Geol.  Trans.,  second  series,  vol.  v.  p.  212. 

f  GOppert,  Poggendorff  s  Annalen  der  Physik  und  Chemie,  vol.  xxxviii.  part 
iv.,  Leipsic,  1836.  See  also  Lyell's  Manual  of  Geol.,  p.  40. 


748  IMBEDDING'  OF  INSECTS,  [Cn.  XLVIL 


Imbedding  of  the  Remains  of  Insects. 

I  have  observed  the  elytra  and  other  parts  of  beetles  in  a  band  of 
fissile  clay,  separating  two  beds  of  recent  shell-marl,  in  the  Loch  of 
Kinnordy  in  Forfarshire.  Amongst  these,  Mr.  Curtis  recognized  Elator 
Iwtatus  and  Atopa  cervina,  species  still  living  in  Scotland.  These,  as 
well  as  other  remains  which  accompanied  them,  appear  to  belong  to 
terrestrial,  not  aquatic  species,  and  must  have  been  carried  down  in 
muddy  water  during  an  inundation.  In  the  lacustrine  peat  of  the  same 
locality,  the  elytra  of  beetles  are  not  uncommon ;  but  in  the  deposits 
of  drained  lakes  generally,  and  in  the  silt  of  our  estuaries,  the  relics  of 
this  class  of  the  animal  kingdom  are  rare.  In  the  blue  clay  of  very 
modern  origin  of  Lewes  levels,  Dr.  Mantell  has  found  the  Indusia,  or 
cases  of  the  larvae  of  Phryganea,  in  abundance,  with  minute  shells 
belonging  to  the  genera  Planorbis,  Limnea,  &c.,  adhering  to  them.* 

When  speaking  of  the  migrations  of  insects,  I  pointed  out  that  an 
immense  number  are  floated  into  lakes  and  seas  by  rivers,  or  blown  by 
winds  far  from  the  land ;  but  they  are  so  buoyant  that  we  can  only  sup- 
pose them,  under  very  peculiar  circumstances,  to  sink  to  the  bottom 
before  they  are  either  devoured  by  insectivorous  animals  or  decomposed. 

Remains  of  Reptiles. 

As  the  bodies  of  several  crocodiles  were  found  in  the  mud  brought 
down  to  the  sea  by  the  river  inundation  which  attended  an  earthquake 
in  Java,  in  the  year  1699,  we  may  imagine  that  extraordinary  floods 
of  mud  may  stifle  many  individuals  of  the  shoals  of  alligators  and  other 
reptiles  which  frequent  lakes  and  the  deltas  of  rivers  in  tropical  climates. 
Thousands  of  frogs  were  found  leaping  about  among  the  wreck,  carried 
into  the  sea  by  the  inundations  in  Morayshire,  in  1829  ;f  and  it  is 
evident  that  whenever  a  sea-cliff  is  undermined,  or  land  is  swept  by 
other  violent  causes  into  the  sea,  land  reptiles  may  be  carried  in. 

Remains  of  Birds. 

We  might  have  anticipated  that  the  imbedding  of  the  remains  of  birds 
in  new  strata  would  be  of  very  rare  occurrence ;  for  their  powers  of  flight 
insure  them  against  perishing,  by  numerous  casualties  to  which  quadrupeds 
are  exposed  during  floods ;  and  if  they  chance  to  be  drowned,  or  to  die 
when  swimming  on  the  water,  it  will  scarcely  ever  happen  that  they  will 
be  submerged  so  as  to  become  preserved  in  sedimentary  deposits.  In 
consequence  of  the  hollow  tubular  structure  of  their  bones  and  the 
quantity  of  their  feathers,  they  are  extremely  light  in  proportion  to  their 
volume ;  so  that  when  first  killed  fhey  do  not  sink  to  the  bottom  like 

*  Trans.  Geol.  Soc.,  vol.  iii.  part  i.  p.  201,  second  series. 
\  Sir  T.  D.  Lauder's  Account,  2d.  ed.,  p.  312. 


Cn.  XLVIL]         REPTILES,   BIRDS,   AND   QUADRUPEDS.  749 

quadrupeds,  but  float  on  the  surface  until  the  carcass  either  rots  away  or 
is  devoured  by  predaceous  animals.  To  these  causes  we  may  ascribe  the 
absence  of  any  vestige  of  the  bones  of  birds  in  the  recent  marl  formations 
of  Scotland;  although  these  lakes,  until  the  moment  when  they  were 
artificially  drained,  were  frequented  by  a  great  abundance  of  waterfowl. 


Imbedding  of  Terrestrial  Quadrupeds. 

River  inundations  recur  in  most  climates  at  very  irregular  intervals, 
and  expend  their  fury  on  those  rich  alluvial  plains  where  herds  of  herbi- 
vorous quadrupeds  congregate  together.  These  animals  are  often  sur- 
prised ;  and,  being  unable  to  stem  the  current,  are  hurried  along  until 
they  are  drowned,  when  they  sink  at  first  immediately  to  the  bottom. 
Here  their  bodies  are  drifted  along,  together  with  sediment,  into  lakes  or 
seas,  and  may  then  be  covered  by  a  mass  of  mud,  sand,  and  pebbles, 
thrown  down  upon  them.  If  there  be  no  sediment  superimposed,  the 
gases  generated  by  putrefaction  usually  cause  the  bodies  to  rise  again  to 
the  surface  about  the  ninth,  or  at  latest  the  fourteenth  day.  The  pressure 
of  a  thin  covering  of  mud  would  not  be  sufficient  to  retain  them  at  the 
bottom ;  for  we  see  the  putrid  carcasses  of  dogs  and  cats,  even  in  rivers, 
floating  with  considerable  weights  attached  to  them,  and  in  sea-water  they 
would  be  still  more  buoyant. 

Where  the  body  is  so  buried  in  drift  sand,  or  mud  accumulated  upon 
it,  as  never  to  rise  again,  the  skeleton  may  be  preserved  entire ;  but  if  it 
comes  again  to  the  surface  while  in  the  process  of  putrefaction,  the  bones 
commonly  fall  piecemeal  from  the  floating  carcass,  and  may  in  that  case 
be  scattered  at  random  over  the  bottom  of  the  lake,  estuary,  or  sea ;  so 
that  a  jaw  may  afterwards  be  found  in  one  place,  a  rib  in  another,  a 
humerus  in  a  third — all  included,  perhaps,  in  a  matrix  of  fine  materials, 
where  there  may  be  evidence  of  slight  transporting  power  in  the  current, 
or  even  of  none,  but  simply  of  some  chemical  precipitate. 

A  large  number  of  the  bodies  of  drowned  animals,  if  they  float  into 
the  sea  or  a  lake,  especially  in  hot  climates,  are  instantly  devoured  by 
sharks,  alligators,  and  other  carnivorous  beasts,  which  may  have  power 
to  digest  even  the  bones ;  but  during  extraordinary  floods,  when  the 
greatest  number  of  land  animals  are  destroyed,  the  waters  are  commonly 
so  turbid,  especially  at  the  bottom  of  the  channel,  that  even  aquatic  spe- 
cies are  compelled  to  escape  into  some  retreat  where  there  is  clearer  water, 
lest  they  should  be  stifled.  For  this  reason,  as  well  as.  the  rapidity  of 
sedimentary  deposition  at  such  seasons,  the  probability  of  carcasses 
becoming  permanently  imbedded  is  considerable. 

Flood  in  the  Solway  Firth,  1794.— One  of  the  most  memorable 
floods  of  modern  date,  in  our  island,  is  that  which  visited  part  of  the 
southern  borders  of  Scotland,  on  the  24th  of  January,  1794,  and  which 
spread  particular  devastation  over  the  country  adjoining  the  Solway 
Firth. 


750  IMBEDDING  OP  [CH.  XLVIL 

We  learn  from  the  account  of  Captain  Napier,  that  the  heaVy  rains 
had  swollen  every  stream  which  entered  the  Firth  of  Solway ;  so  that 
the  inundation  not  only  carried  away  a  great  number  of  cattle  and  sheep, 
but  many  of  the  herdsmen  and  shepherds,  washing  down  their  bodies 
into  the  estuary.  After  the  storm,  when  the  flood  subsided,  an  extraordi- 
nary spectacle  was  seen  on  a  large  sand-bank  called  "  the  beds  of  Esk," 
where  there  is  a  meeting  of  the  tidal  waters,  and  where  heavy  bodies  are 
usually  left  stranded  after  great  floods.  On  this  single  bank  were  found 
collected  together  the  bodies  of  9  black  cattle,  3  horses,  1840  sheep, 
45  dogs,  180  hares,  besides  a  great  number  of  smaller  animals,  and, 
mingled  with  the  rest,  the  corpses  of  two  men  and  one  woman.* 

Floods  in  Scotland,  1829. — In  those  more  recent  floods  in  Scotland, 
in  August,  1829,  whereby  a  fertile  district  on  the  east  coast  became  a 
scene  of  dreadful  desolation,  a  vast  number  of  animals  and  plants 
were  washed  from  the  land,  and  found  scattered  about  after  the  storm, 
around  the  mouths  of  the  principal  rivers.  An  eye-witness  thus 
describes  the  scene  which  presented  itself  at  the  mouth  of  the  Spey, 
in  Morayshire  : — "  For  several  miles  along  the  beach  crowds  were 
employed  in  endeavoring  to  save  the  wood  and  other  wreck  with  which 
the  heavy-rolling  tide  was  loaded ;  whilst  the  margin  of  the  sea  was 
strewed  with  the  carcasses  of  domestic  animals,  and  with  millions  of 
dead  hares  and  rabbits."  \ 

Savannahs  of  South  America. — We  are  informed  by  Humboldt, 
that  during  the  periodical  swellings  of  the  large  rivers  in  South  America 
great  numbers  of  quadrupeds  are  annually  drowned.  Of  the  wild 
horses,  for  example,  which  graze  in  immense  troops  in  the  savannahs, 
thousands  are  said  to  perish  when  the  river  Apure,  a  tributary  of  the 
Orinoco,  is  swollen,  before  they  have  time  to  reach  the  rising  ground 
of  the  Llanos.  The  mares,  during  the  season  of  high  water,  may  be 
seen,  followed  by  their  colts,  swimming  about  and  feeding  on  the  grass, 
of  which  the  top  alone  waves  above  the  waters.  In  this  state  they  are 
pursued  by  crocodiles ;  and  their  thighs  frequently  bear  the  prints  of 
the  teeth  of  these  carnivorous  reptiles.  "Such  is  the  pliability," 
observes  the  celebrated  traveller,  "  of  the  organization  of  the  animals 
which  man  has  subjected  to  his  sway,  that  horses,  cows,  and  other  spe- 
cies of  European  origin,  lead,  for  a  time,  an  amphibious  life,  surrounded 
by  crocodiles,  water-serpents,  and  manatees.  When  the  rivers  return 
again  into  their  beds,  they  roam  in  the  savannah,  which  is  then  spread 
over  with  a  fine  odoriferous  grass,  and  enjoy,  as  in  their  native  climate, 
the  renewed  vegetation  of  spring."  \ 

Floods  of  the  Parana. — The  great  number  of  animals  which  are 
drowned  in  seasons  of  drought  in  the  tributaries  of  the  Plata,  was  before 
mentioned.  Sir  W.  Parish  states,  that  the  Parana,  flowing  from  the 
mountains  of  Brazil  to  the  estuary  of  the  Plata,  is  liable  to  great  floods, 

*  Treatise  on  Practical  Store  Farming,  p.  25. 

f  Sir  T.  D.  Lander's  Floods  in  Morayshire,  1829  ;  and  above,  p:  196. 

1  Humboldt's  Pers.  Nar.,  vol.  iv.  p.  394. 


CH.  XL VII.]  TERRESTRIAL  QUADRUPEDS.  751 

and  during  one  of  these,  in  the  year  1812,  vast  quantities  of  cattle  were 
carried  away,  "and  when  the  waters  began  to  subside,  and  the  islands 
which  they  had  covered  became  again  visible,  the  whole  atmosphere 
for  a  time  was  poisoned  by  the  effluvia  from  the  innumerable  carcasses 
of  skunks,  capybaras,  tigers,  and  other  wild  beasts  which  had  been 
drowned."  * 

Floods  of  the  Ganges. — We  find  it  continually  stated,  by  those  who 
describe  the  Ganges  and  Burrampooter,  that  these  rivers  carry  before 
them,  during  the  flood  season,  not  only  floats  of  reeds  and  timber,  but 
dead  bodies  of  men,  deer,  and  oxen.f 

In  Java,  1699. — I  have  already  referred  to  the  effects  of  a  flood  which 
attended  an  earthquake  in  Java  in  1699,  when  the  turbid  waters  of  the 
Batavian  river  destroyed  all  the  fish  except  the  carp ;  and  when  drowned 
buffaloes,  tigers,  rhinoceroses,  deer,  apes,  and  other  wild  beasts,  were 
brought  down  to  the  sea-coast  by  the  current,  with  several  crocodiles 
which  had  been  stifled  in  the  mud.  (See  above,  p.  503.) 

On  the  western  side  of  the  same  island,  in  the  territory  of  Galongoon, 
in  the  Regencies,  a  more  recent  volcanic  eruption  (that  of  1822,  before 
described)  (see  above,  p.  431)  was  attended  by  a  flood,  during  which  the 
river  Tandoi  bore  down  hundreds  of  carcasses  of  rhinoceroses  and  buffa- 
loes, and  swept  away  more  than  one  hundred  men  and  women  from  a 
multitude  assembled  on  its  banks  to  celebrate  a  festival.  Whether  the 
bodies  reached  the  sea,  or  were  deposited,  with  drift  matter,  in  some  large 
intervening  alluvial  plains,  we  are  not  informed.J 

Sumatra. — "  On  the  coast  of  Orissa,"  says  Heynes,  "  I  have  seen  tigers 
and  whole  herds  of  black  cattle  carried  along  by  what  are  called  freshes, 
and  trees  of  immense  size."§ 

In  Virginia,  1771. — I  might  enumerate  a  great  number  of  local  de- 
luges that  have  swept  through  the  fertile  lands  bordering  on  large  rivers, 
especially  in  tropical  countries,  but  I  should  surpass  the  limits  assigned  to 
this  work.  I  may  observe,  however,  that  the  destruction  of  the  islands, 
in  rivers,  is  often  attended  with  great  loss  of  lives.  Thus  when  the  prin- 
cipal river  in  Virginia  rose,  in  1771,  to  the  height  of  twenty-five  feet  above 
its  ordinary  level,  it  swept  entirely  away  Elk  Island,  on  which  were  seven 
hundred  head  of  quadrupeds, — horses,  oxen,  sheep,  and  hogs, — and  nearly 
one  hundred  houses.|| 

The  reader  will  gather,  from  what  was  before  said  respecting  the  depo- 
sition of  sediment  by  aqueous  causes,  that  the  greater  number  of  the 
remains  of  quadrupeds  drifted  away  by  rivers  must  be  intercepted  by 
lakes  before  they  reach  the  sea,  or  buried  in  freshwater  formations  near 
the  mouths  of  rivers.  If  they  are  carried  still  farther,  the  probabilities 
are  increased  of  their  rising  to  the  surface  in  a  state  of  putrefaction, 
and,  in  that  case,  of  being  there  devoured  by  aquatic  beasts  of  prey,  or  of 

*  Buenos  Ayres  and  La  Plata,  p.  187.     f  Malte-Brun's  fteog.,  vol.  iii.  p.  22. 
%  This  account  I  had  from  Mr.  Baumhauer,  Director-General  of  Finances  in 
Java. 

§  Tracts  on  India,  p.  397.  \  Scots  Mag.,  vol.  xxxiii. 


752  IMBEDDING   OF   MAMMALIA.  [On.  XLVII. 

subsiding  into  some  spots  whither  no  sediment  is  conveyed,  and,  conse- 
quently, where  every  vestige  of  them  will,  in  the  course  of  time,  disap- 
pear. 

Skeletons  of  animals  in  recent  shell-marl,  Scotland. — In  some  in- 
stances, the  skeletons  of  quadrupeds  are  met  with  abundantly  in  recent 
shell-marls  in  Scotland,  where  we  cannot  suppose  them  to  have  been 
imbedded  by  the  action  of  rivers  or  floods.  They  all  belong  to  species 
which  now  inhabit,  or  are-  known  to  have  been  indigenous  in  Scotland. 
The  remains  of  several  hundred  skeletons  have  been  procured  within  the 
last  century  from  five  or  six  small  lakes  in  Forfarshire,  where  shell-marl 
has  been  worked.  Those  of  the  stag  (Cervus  Elaphas)  are  most  nume- 
rous; and  if  the  others  be  arranged  in  the  order  of  their  relative  abun- 
dance, they  will  nearly  follow  thus — the  ox,  the  boar,  the  horse,  the 
sheep,  the  dog,  the  hare,  the  fox,  the  wolf,  and  the  cat.  The  beaver  seems 
extremely  rare;  but  it  has  been  found  in  the  shell-marl  of  Loch  Marlie,  in 
Perthshire,  and  in  the  parish  of  Edrom,  in  Berwickshire. 

In  the  greater  part  of  these  lake-deposits  there  are  no  signs  of  floods ; 
and  the  expanse  of  water  was  originally  so  confined,  that  the  smallest  of 
the  above-mentioned  quadrupeds  could  have  crossed,  by  swimming  from 
one  shore  to  the  other.  Deer,  and  such  species  as  take  readily  to  the 
water,  may  often  have  been  mired  in  trying  to  land,  where  the  bottom 
was  soft  and  quaggy,  and  in  their  efforts  to  escape  may  have  plunged 
deeper  into  the  marly  bottom.  Some  individuals,  I  suspect,  of  different 
species,  have  fallen  in  when  crossing  the  frozen  surface  in  winter;  for 
nothing  can  be  more  treacherous  than  the  ice  when  covered  with  snow, 
in  consequence  of  the  springs,  which  are  numerous,  and  which,  retaining 
always  an  equal  temperature,  cause  the  ice,  in  certain  spots,  to  be  extremely 
thin,  while  in  every  other  part  of  the  lake  it  is  strong  enough  to  bear  the 
heaviest  weights. 

Mammiferous  remains  in  marine  strata. — As  the  bones  of  mammalia 
are  often  so  abundantly  preserved  in  peat,  and  such  lakes  as  have  just 
been  described,  the  encroachments  of  a  sea  upon  a  coast  may  sometimes' 
throw  down  the  imbedded  skeletons,  so  that  they  may  be  carried  away 
by  tides  and  currents,  and  entombed  in  submarine  formations.  Some  of 
the  smaller  quadrupeds,  also,  which  burrow  in  the  ground,  as  well  as  rep- 
tiles and  every  species  of  plant,  are  liable  to  be  cast  down  into  the  waves 
by  this  cause,  which  must  not  be  overlooked,  although  probably  of  com- 
paratively small  importance  amongst  the  numerous  agents  whereby  ter- 
restrial organic  remains  are  included  in  submarine  strata. 

During  the  great  earthquake  of  Conception  in  1835,  some  cattle, 
which  were  standing  on  the  steep  sides  of  the  island  of  Quiriquina,  were 
rolled  by  the  shock  into  the  sea,  while  on  a  low  island  at  the  head  of  the 
Bay  of  Conception  seventy  animals  were  washed  off"  by  a  great  wave  and 
drowned.* 

*  Darwiu's  Journal,  p.  372.     2d  ed.,  1845,  p.  304. 


CHAPTER  XLVLH. 

IMBEDDING    OF    THE    REMAINS     OF    MAN    AND    HIS    WORKS    IN 
SUBAQUEOUS     STRATA. 

Drifting  of  human  bodies  to  the  sea  by  river  inundations — Destruction  of  bridges 
and  houses — Loss  of  lives  by  shipwreck — How  human  corpses  may  be  pre- 
served in  recent  deposits — Number  of  wrecked  vessels — Fossil  skeletons  of 
men — Fossil  canoes,  ships,  and  works  of  art — Chemical  changes  which  metallic 
articles  have  undergone  after  long  submergence — Imbedding  of  cities  and 
forests  in  subaqueous  strata  by  subsidence — Earthquake  of  Cutch  in  1819 — 
Buried  Temples  of  Cashmere — Berkeley's  arguments  for  the  recent  date  of  the 
creation  of  man — Concluding  remarks. 

I  SHALL  now  proceed  to  inquire  in  what  manner  the  mortal  remains  of 
man  and  the  works  of  his  hands  may  be  permanently  preserved  in  sub- 
aqueous strata.  Of  the  many  hundred  million  human  beings  which  perish 
in  the  course  of  every  century  on  the  land,  every  vestige  is  usually  de- 
stroyed in  the  course  of  a  few  thousand  years ;  but  of  the  smaller  number 
that  perish  in  the  waters,  a  certain  proportion  must  be  entombed  under 
circumstances  that  may  enable  parts  of  them  to  endure  throughout  entire 
geological  epochs. 

The  bodies  of  men,  together  with  those  of  the  inferior  animals,  are 
occasionally  washed  down  during  river  inundations  into  seas  and  lakes. 
(See  pp.  726 — 728.)  Belzoni  witnessed  a  flood  on  the  Nile  in  September, 
1818,  where,  although  the  river  rose  only  three  feet  and  a  half  above  its 
ordinary  level,  several  villages,  with  some  hundreds  of  men,  women,  and 
children,  were  swept  away.*  It  was  before  mentioned  that  a  rise  of  six 
feet  of  water  in  the  Ganges,  in  1763,  was  attended  with  a  much  greater 
loss  of  lives.  (See  above,  p.  278.) 

In  the  year  1771,  when  the  inundations  in  the  north  of  England 
appear  to  have  equalled  the  floods  of  Morayshire  in  1829,  a  great  num- 
ber of  houses  and  their  inhabitants  were  swept  away  by  the  rivers  Tyiie, 
Can,  Wear,  Tees,  and  Greta ;  and  no  less  than  twenty-one  bridges  were 
destroyed  in  the  courses  of  these  rivers.  At  the  village  of  By  well  the 
flood  tore  the  dead  bodies  and  coffins  out  of  the  churchyard,  and  bore 
them  away,  together  with  many  of  the  living  inhabitants.  During  the 
same  tempest  an  immense  number  of  cattle,  horses,  and  sheep,  were  also 
transport^  to  the  sea,  while  the  whole  coast  was  covered  with  the  wreck 
of  ships.  Four  centuries  before  (in  1338),  the  same  district  had  been 
visited  by  a  similar  continuance  of  heavy  rains,  followed  by  disastrous 
floods,  and  it  is  not  improbable  that  these  catastrophes  may  recur  periodi- 
cally, though  at  uncertain  intervals.  As  the  population  increases,  and 

*  Narrative  of  Discovery  in  Egypt,  Ac.,  London,  1820. 
48 


754  FOSSILIZAT10N   OF   HUMAN  BONES.          [Ca  XLVIII. 

buildings  and  bridges  are  multiplied,  we  must  expect  the  loss  of  lives  and 
property  to  augment.* 

Fossilization  of  human  bodies  in  the  bed  of  the  sea. — If  to  tbe  hun- 
dreds of  human  bodies  committed  to  the  deep  in  the  way  of  ordinary 
burial  we  add  those  of  individuals  lost  by  shipwrecks,  we  shall  find  that 
in  the  course  of  a  single  year,  a  great  number  of  human  remains  are  con- 
signed to  the  subaqueous  regions.  I  shall  hereafter  advert  to  a  calcula- 
,tion  by  which  it  appears  that  more  than  five  hundred  British  vessel 
alone,  averaging  each  a  burthen  of  about  120  tons,  are  wrecked,  ana 
sink  to  the  bottom,  annually.  Of  these  the  crews  for  the  most  part 
escape,  although  it  sometimes  happens  that  all  perish.  In  one  great 
naval  action  several  thousand  individuals  sometimes  share  a  watery  grave. 

Many  of  these  corpses  are  instantly  devoured  by  predaceous  fish,  some- 
times before  they  reach  the  bottom ;  still  more  frequently  when  they 
rise  again  to  the  surface,  and  float  in  a  state  of  putrefaction.  Many 
decompose  on  the  floor  of  the  ocean,  where  no  sediment  is  thrown  down 
upon  them ;  but  if  they  fall  upon  a  reef  where  corals  and  shells  are 
becoming  agglutinated  into  a  solid  rock,  or  subside  where  the  delta 
of  a  river  is  advancing,  they  may  be  preserved  for  an  incalculable  series 
of  ages. 

Often  at  the  distance  of  a  few  hundred  feet  from  a  coral  reef,  where 
wrecks  are  not  unfrequent,  there  are  no  soundings  at  the  depth  of  many 
hundred  fathoms.  Canoes,  merchant  vessels,  and  ships  of  war,  may  have 
sunk  and  have  been  enveloped,  in  such  situations,  in  calcareous  sand  and 
breccia,  detached  by  the  breakers  from  the  summit  of  a  submarine  moun- 
tain. Should  a  volcanic  eruption  happen  to  cover  such  remains  with 
ashes  and  sand,  and  a  current  of  lava  be  afterwards  poured  over  them, 
the  ships  and  human  skeletons  might  remain  uninjured  beneath  the 
superincumbent  mass,  like  the  houses  and  works  of  art  in  the  subter- 
ranean cities  of  Campania.  Already  many  human  remains  may  have 
been  thus  preserved  beneath  formations  more  than  a  thousand  feet  in 
thickness  ;  for,  in  some  volcanic  archipelagoes,  a  period  of  thirty  or  forty 
centuries  might  well  be  supposed  sufficient  for  such  an  accumulation.  It 
was  stated,  that  at  the  distance  of  about  forty  miles  from  the  base  of  the 
delta  of  the  Ganges  there  is  an  elliptical  space  about  fifteen  miles  in 
diameter,  where  soundings  of  from  100  to  300  fathoms  sometimes  fail  to 
reach  the  bottom.  (See  above,  p.  279.)  As  during  the  flood  season  the  quan- 
tity of  mud  and  sand  poured  by  the  great  rivers  into  the  Bay  of  Bengal 
is  so  great  that  the  sea  only  recovers  its  transparency  at  the  distance  of 
sixty  miles  from  the  coast,  this  depression  must  be  gradually  shoaling, 
especially  as  during  the  monsoons,  the  sea  loaded  with  mud  and  sand,  is 
beaten  back  in  that  direction  towards  the  delta.  Now,  if  a  ship  or  hu- 
man body  sink  to  the  bottom  in  such  a  spot,  it  is  by  no  means  improba- 
ble that  it  may  become  buried  under  a  depth  of  a  thousand  feet  of  sedi- 
ment in  the  same  number  of  years. 

*  Scots  Mag.,  vol.  xxxiii.,  1771. 
. 


OH.  XL VIII]  IMBEDDING   OF   WORKS   OF   ART.  755 

Even  on  that  part  of  the  floor  of  the  ocean  to  which  no  accession  of  drift 
matter  is  carried  (a  part  which  probably  constitutes,  at  any  given  period, 
by  far  the  larger  proportion  of  the  whole  submarine  area),  there  are  cir- 
cumstances accompanying  a  wreck  which  favor  the  conservation  of  skele- 
tons. For  when  the  vessel  fills  suddenly  with  water,  especially  in  the 
night,  many  persons  are  drowned  between  decks  and  in  their  cabins,  so 
that  their  bodies  are  prevented  from  rising  again  to  the  surface.  The 
vessel  often  strikes  upon  an  uneven  bottom,  and  Is  overturned ;  in  which 
case  the  ballast,  consisting  of  sand,  shingle,  and  rock,  or  the  cargo,  fre- 
quently composed  of  heavy  and  durable  materials,  may  be  thrown  down 
upon  the  carcasses.  In  the  case  of  ships  of  war,  cannon,  shit,  and 
other  warlike  stores,  may  press  down  with  their  weight  the  timbers  of  the 
vessel  as  they  decay,  and  beneath  these  and  the  metallic  substances  the 
bones  of  man  may  be  preserved. 

Number  of  wrecked  vessels. — When  we  reflect  on  the  number  of  curi- 
ous monuments  consigned  to  the  bed  of  the  ocean  in  the  course  of  every 
naval  war  from  the  earliest  times,  our  conceptions  are  greatly  raised 
respecting  the  multiplicity  of  lasting  memorials  which  man  is  leaving  of 
his  labors.  During  our  last  great  struggle  with  France,  thirty-two  of 
our  ships  of  the  line  went  to  the  bottom  in  the  space  of  twenty-two 
years,  besides  seven  50-gim  ships,  eighty-six  frigates,  and  a  multitude  of 
smaller  vessels.  The  navies  of  the  other  European  powers,  France,  Hol- 
land, Spain,  and  Denmark,  were  almost  annihilated  during  the  same 
period,  so  that  the  aggregate  of  their  losses  must  have  many  times 
exceeded  that  of  Great  Britain.  In  every  one  of  these  ships  were  bat- 
teries of  cannon  constructed  of  iron  or  brass,  whereof  a  great  number 
had  the  dates  and  places  of  their  manufacture  inscribed  upon  them  in 
letters  cast  in  metal.  In  each  there  were  coins  of  copper,  silver,  and 
often  many  of  gold,  capable  of  serving  as  valuable  historical  monuments; 
in  each  were  an  infinite  variety  of  instruments  of  the  arts  of  war  and 
peace ;  many  formed  of  materials,  such  as  glass  and  earthenware,  capa- 
ble of  lasting  for  indefinite  ages  when  once  removed  from  the  mechanical 
action  of  the  waves,  and  buried  under  a  mass  of  matter  which  may 
exclude  the  corroding  action  of  sea-water.  The  quantity,  moreover,  of 
timber  which  is  conveyed  from  the  land  to  the  bed  of  the  sea  by  the 
sinking  of  ships  of  a  large  size  is  enormous,  for  it  is  computed  that  2000 
tons  of  wood  are  required  for  the  building  of  one  74-gun  ship ;  and 
reckoning  fifty  oaks  of  100  years  growth  to  the  acre,  it  would  require 
forty  acres  of  oak  forest  to  build  one  of  these  vessels.* 

It  would  be  an  error  to  imagine  that  the  fury  of  war  is  more  conducive 
than  the  peaceful  spirit  of  commercial  enterprise  to  the  accumulation  of 
wrecked  vessels  in  the  bed  of  the  sea.  From  an  examination  of  Lloyd's 
lists,  from  the  year  1793  to  the  commencement  of  1829,  Captain  W.  H. 
Smyth  ascertained  that  the  number  of  British  vessels  alone  lost  during 
that  period  amounted  on  an  average  to  no  less  than  one  and  a  half  daily; 


*  Quart  Journ.  of  Agricult.,  No.  ix.  p.  438. 


• 


756  IMBEDDING  OP   HUMAN   REMAINS  [On.  XLVIII. 

an  extent  of  loss  which  would  hardly  have  been  anticipated,  although 
we  learn  from  Moreau's  tables  that  the  number  of  merchant  vessels 
employed  at  one  time,  in  the  navigation  of  England  and  Scotland,  amounts 
to  about  twenty  thousand,  having  one  with  another  a  mean  burthen  of 
120  tons.*  My  friend,  Mr.  J.  L.  Prevost,  also  informs  me  that  on  inspect- 
ing Lloyd's  list  for  the  years  1829,  1830,  and  1831,  he  finds  that  no  less 
than  1953  vessels  were  lost  in  those  three  years,  their  average  tonnage 
being  about  150  tons,  or  in  all  nearly  300,000  tons,  being  at  the  enor- 
mous rate  of  100,000  tons  annually  of  the  merchant  vessels  of  one  nation 
only.  This  increased  loss  arises,  I  presume,  from  increasing  activity  in 
commlrce. 

Out  of  551  ships  of  the  royal  navy  lost  to  the  country  during  the 
period  above  mentioned,  only  160  were  taken  or  destroyed  by  the  enemy, 
the  rest  having  either  stranded  or  foundered,  or  having  been  burnt  by 
accident ;  a  striking  proof  that  the  dangers  of  our  naval  warfare,  how- 
ever great,  may  be  far  exceeded  by  the  storm,  the  shoal,  the  lee-shore, 
and  all  the  other  perils  of  the  deep,  f 

Durable  nature  of  many  of  their  contents. — Millions  of  silver  dollars 
and  other  coins  have  been  sometimes  submerged  in  a  single  ship,  and  on 
these,  when  they  happen  to  be  enveloped  in  a  matrix  capable  of  protect- 
ing them  from  chemical  changes,  much  information  of  historical  interest 
will  remain  inscribed,  and  endure  for  periods  as  indefinite  as  have  the 
delicate  markings  of  zoophytes  or  lapidified  plants  in  some  of  the  ancient 
secondary  rocks.  In  almost  every  large  ship,  moreover,  there  are  some 
precious  stones  set  in  seals,  and  other  articles  of  use  and  ornament  com- 
posed of  the  hardest  substances  in  nature,  on  which  letters  and  various 
images  are  carved — engravings  which  they  may  retain  when  included  in 
subaqueous  strata,  as  long  as  a  crystal  preserves  its  natural  form. 

It  was,  therefore,  a  splendid  boast,  that  the  deeds  of  the  English  chi- 
valry at  Agincourt  made  Henry's  chronicle 

as  rich  with  praise 

As  is  the  ooze  and  bottom  of  the  deep 
"With  sunken  wreck  and  sumless  treasuries 

for  it  is  probable  that  a  greater  number  of  monuments  of  the  skill  and 
industry  of  man  will,  in  the  course  of  ages,  be  collected  together  in  the 
bed  of  the  ocean,  than  will  exist  at  any  one  time  on  the  surface  of  the 
continents. 

If  our  species  be  of  as  recent  a  date  as  is  generally  supposed,  it  will 
be  vain  to  seek  for  the  remains  of  man  and  the  works  of  his  hands  im- 
bedded in  submarine  strata,  except  in  those  regions  where  violent  earth- 
quakes are  frequent,  and  the  alterations  of  relative  level  so  great,  that 
the  bed  of  the  sea  may  have  been  converted  into  land  within  the  histori- 
cal era.  We  need  not  despair,  however,  of  the  discovery  of  such  monu- 

*  Caesar  Moreau's  Tables  of  the  Navigation  of  Great  Britain. 

f  I  give  these  results  on  the  authority  of  Captain  \V.  H.  Smyth,  R.  N. 


CH.  XLYIIL]  AND   WORKS   OP   ART.  757 

ments,  when  those  regions  which  have  been  peopled  by  man  from  the 
earliest  ages,  and  which  are  at  the  same  time  the  principal  theatres  of 
volcanic  action,  shall  be  examined  by  the  joint  skill  of  the  antiquary  and 
geologist. 

Power  of  human  remains  to  resist  decay. — There  can  be  no  doubt 
that  human  remains  are  as  capable  of  resisting  decay  as  are  the  harder 
parts  of  the  inferior  animals  ;  and  I  have  already  cited  the  remark  of . 
Cuvier,  that  "  in  ancient  fields  of  battle  the  bones  of  men  have  suffered 
as  little  decomposition  as  those  of  horses  which  were  buried  in  the  same 
grave."  (See  above,  p.  147.)  In  the  delta  of  the  Ganges  bones  of  men 
have  been  found  in  digging  a  well  at  the  depth  of  ninety  feet  ;*  but  as 
that  river  frequently  shifts  its  course  and  fills  up  its  ancient  channels,  we 
are  not  called  upon  to  suppose  that  these  bodies  are  of  extremely  high 
antiquity,  or  that  they  were  buried  when  that  part  of  the  surrounding 
delta  where  they  occur  was  first  gained  from  the  sea. 

Fossil  skeletons  of  men. — Several  skeletons  of  men,  more  or  less  mu- 
tilated, have  been  found  in  the  West  Indies,  on  the  north-west  coast  of 
the  main  land  of  Guadaloupe,  in  a  kind  of  rock  which  is  known  to  be 
forming  daily,  and  which  consists  of  minute  fragments  of  shells  and 
corals,  incrusted  with  a  calcareous  cement  resembling  travertin,  by  which 
also  the  different  grains  are  bound  together.  The  lens  shows  that  some 
of  the  fragments  of  coral  composing  this  stone  still  retain  the  same  red 
color  which  is  seen  in  the  reefs  of  living  coral  which  surround  the  island. 
The  shells  belong  to  species  of  the  neighboring  sea  intermixed  with 
some  terrestrial  kinds  which  now  live  on  the  island,  and  among  them  is 
the  Bulimus  G-audaloupensis  of  Ferussac.  The  human  skeletons  still 
retain  some  of  their  animal  matter,  and  all  their  phosphate  of  lime. 
One  of  them,  of  which  the  head  is  wanting,  may  now  be  seen  in  the 
British  Museum,  and  another  in  the  Royal  Cabinet  at  Paris.  According 
to  M.  Konig,  the  rock  in  which  the  former  is  inclosed  is  harder  under 
the  mason's  saw  and  chisel  than  statuary  marble.  It  is  described  as 
forming  a  kind  of  glacis,  probably  an  indurated  beach,  which  slants  from 
the  steep  cliffs  of  the  island  to  the  sea,  and  is  nearly  all  submerged  at 
high  tide. 

Similar  formations  are  in  progress  in  the  whole  of  the  West  Indian 
archipelago,  and  they  have  greatly  extended  the  plain  of  Cayes  in  St. 
Domingo,  where  fragments  of  vases  and  other  human  works  have  been 
found  at  a  depth  of  twenty  feet.  In  digging  wells  also  near  Catania,  in 
Sicily,  tools  have  been  discovered  in  a  rock  somewhat  similar. 

Buried  ships,  canoes,  and  works  of  art. — When  a  vessel  is  stranded 
in  shallow  water,  it  usually  becomes  the  nucleus  of  a  sand-bank,  as  has 
been  exemplified  in  several  of  our  harbors,  and  this  circumstance  tends 
greatly  to  its  preservation.  Between  the  years  1780  and  1790  a  vessel 
from  Purbeck,  laden  with  three  hundred  tons  of  stone,  struck  on  a  shoal 
off  the  entrance  of  Poole  harbor  and  foundered ;  the  crew  were  saved, 

*  Von  Hoff,  vol.  i.  p.  379.  ~^—+ 


758  IMBEDDING   OF   WORKS   OP   ART  [Cn.  XLVIII. 

but  the  vessel  and  cargo  remain  to  this  day  at  the  bottom.  Since  that 
period  the  shoal  at  the  entrance  of  the  harbor  has  so  extended  itself  in  a 
westerly  direction  towards  Peveril  Point  in  Purbeck,  that  the  navigable 
channel  is  thrown  a  mile  nearer  that  point.*  The  cause  is  obvious ;  the 
tidal  current  deposits  the  sediment  with  which  it  is  charged  around  any 
object  which  checks  its  velocity.  Matter  also  drifted  along  the  bottom  is 
arrested  by 'any  obstacle,  and  accumulates  round  it,  just  as  the  African 
sand-winds,  before  described,  raise  a  small  hillock  over  the  carcass  of 
every  dead  camel  exposed  on  the  surface  of  the  desert. 

I  before  alluded  to  an  ancient  Dutch  vessel,  discovered  in  the  deserted 
channel  of-  the  river  Rother  in  Sussex,  of  which  the  oak  wood  was  much 
blackened,  but  its  texture  unchanged.  (See  above,  p.  316.)  The  inte- 
rior was  filled  with  fluviatile  silt,  as  was  also  the  case  in  regard  to  a  ves- 
sel discovered  in  a  former  bed  of  the  Mersey,  and  another  disinterred 
where  the  St.  Katherine  Docks  are  excavated  in  the  alluvial  plain  of  the 
Thames.  In  like  manner  many  ships  have  been  found  preserved  entire 
in  modern  strata,  formed  by  the  silting  up  of  estuaries  along  the  southern 
shores  of  the  Baltic,  especially  in  Pomerania.  Between  Bromberg  and 
Nakel,  for  example,  a  vessel  and  two  anchors  in  a  very  perfect  state  were 
dug  up  far  from  the  sea.f 

Several  vessels  have  been  lately  detected  half  buried  in  the  delta  of 
the  Indus,  in  the  numerous  deserted  branches  of  that  river,  far  from 
where  the  stream  now  flows.  One  of  these  found  near  Vikkar  in  Sinde, 
was  400  tons  in  burthen,  old  fashioned,  and  pierced  for  fourteen  guns, 
and  in  a  region  where  it  had  been  matter  of  dispute  whether  the  Indus 
had  ever  been  navigable  by  large  vessels.^ 

At  the  mouth  of  a  river  in  Nova  Scotia,  a  schooner  of  thirty-two  tons, 
laden  with  live  stock,  was  lying  with  her  side  to  the  tide,  when  the  bore, 
or  tidal  wave,  which  rises  there  about  ten  feet  in  perpendicular  height, 
rushed  into  the  estuary,  and  overturned  the  vessel,  so  that  it  instantly 
disappeared.  After  the  tide  had  ebbed,  the  schooner  was  so  totally 
buried  in  the  sand,  that  the  taffrel  or  upper  rail  over  the  stern  was  alone 
visible.§  We  are  informed  by  Leigh  that,  on  draining  Martin  Meer,  a 
lake  eighteen  miles  in  circumference,  in  Lancashire,  a  bed  of  marl  was 
laid  dry,  wherein  no  fewer  than  eight  canoes  were  found  imbedded. 
In  figure  and  dimensions  they  were  not  unlike  those  now  used  in  Ame- 
rica. In  a  morass  about  nine  miles  distant  from  this  Meer  a  whetstone 
and  an  axe  of  mixed  metal  were  dug  up.||  In  Ayrshire,  also,  three  canoes 
were  found  in  Loch  Doon  some  few  years  ago;  and  during  the  year  1831 
four  others,  each  hewn  out  of  separate  oak  trees.  They  were  twenty- 
three  feet  in  length,  two  and  a  half  in  depth,  and  nearly  four  feet  in 
breadth  at  the  stern.  In  the  mud  which  filled  one  of  them  was  found  a 


*  This  account  I  received  from  the  Honorable  and  Rev.  Charles  Harris, 
f  Von  Hoff,  vol.  i.  p.  368. 

Lieut.  Carless,  Geograph.  Journ.,  vol.  viii.  p.  338. 
iiUhnan's  Geol  Lectures,  p.  78,  Who  cites  Penn. 
Lancashire,  p.  17,  A.  D.  1700. 


CH.  XLVIIL]  IN  SUBAQUEOUS  STRATA.  V59 

war-club  of  oak  and  a  stone  battle-axe.  A  canoe  of  oak  was  also  found 
in  1820,  in  peat  overlying  the  shell-marl  of  the  Loch  of  Kinnordy,  in 
Forfarshire.* 

Manner  in  which  ships  may  be  preserved  in  a  deep  sea. — It  is  extreme- 
ly possible  that  the  submerged  woodwork  of  ships  which  have  sunk  where 
the  sea  is  two  or  three  miles  deep  has  undergone  greater  chemical 
changes  in  an  equal  space  of  time,  than  in  the  cases  above  mentioned; 
for  the  experiments  of  Scoresby  show  that  wood  may  at  certain  depths 
be  impregnated  in  a  single  hour  TS  1th  salt  water,  so  that  its  specific  gra- 
vity is  entirely  altered.  It  may  often  happen  that  hot  springs,  charged 
with  carbonate  of  lime,  silex,  and  other  mineral  ingredients,  may  issue  at 
great  depths,  in  which  case  every  pore  of  the  vegetable  tissue  may  be 
injected  with  the  lapidifying  liquid,  whether  calcareous  or  siliceous, 
before  the  smallest  decay  commences.  The  conversion,  also,  of  wood 
into  lignite  is  probably  more  rapid  under  enormous  pressure.  But  the 
change  of  the  timber  into  lignite  or  coal  would  not  prevent  the  original 
form  of  a  ship  from  being  distinguished ;  for  as  we  find,  in  strata  of  the 
carboniferous  era,  the  bark  of  the  hollow  reed-like  trees  converted  into 
coal,  and  the  central  cavity  filled  with  sandstone,  so  might  we  trace  the 
outline  of  a  ship  in  coal ;  while  in  the  indurated  rnnd,  sandstone,  or  lime- 
stone, filling  the  interior,  we  might  discover  instruments  of  human  art, 
ballast  consisting  of  rocks  foreign  to  the  rest  of  the  stratum,  and  other 
contents  of  the  ship. 

Submerged  metallic  substances. — Many  of  the  metallic  substances 
which  fall  into  the  waters  probably  lose,  in  the  course  of  ages,  the  forms 
artificially  imparted  to  them ;  but  under  certain  circumstances  these  may 
be  preserved  for  indefinite  periods.  The  cannon  enclosed  in  a  calcareous 
rock,  drawn  up  from  the  delta  of  the  Rhone,  which  is  now  in  the  museum 
at  Montpellier,  might  probably  have  endured  as  long  as  the  calcareous 
matrix ;  but  even  if  the  metallic  matter  had  been  removed,  and  had  en- 
tered into  new  combinations,  still  a  mould  of  its  original  shape  would 
have  been  left,  corresponding  to  those  impressions  of  shells  which  we  see 
in  rocks,  from  which  all  the  carbonate  of  lime  has  been  subtracted. 
About  the  year  1776,  says  Mr.  King,  some  fishermen,  sweeping  for 
anchors  in  the  Gulf  stream  (a  part  of  the  sea  near  the  frowns),  drew  up 
a  very  curious  old  swivel  gun,  nearly  eight  feet  in  length.  The  barrel, 
which  was  about  five  feet  long,  was  of  brass ;  but  the  handle  by  which  it 
was  traversed  was  about  three  feet  in  length,  and  the  swivel  and  pivot  on 
which  it  turned  were  of  iron.  Around  these  latter  were  formed  incrusta- 
tions of  sand  converted  into  a  kind  of  stone,  of  exceedingly  strong  texture 
and  firmness ;  whereas  round  the  barrel  of  the  gun,  except  where  it  was 
near  adjoining  to  the  iron,  there  were  no  such  incrustations,  the  greater 
part  of  it  being  clean,  and  in  good  condition,  just  as  if  it  had  still  continued 
in  use.  In  the  incrusting  stone,  adhering  to  it  on  the  outside,  were  a 
number  of  shells  and  corallines,  "just  as  they  are  often  found  in  a  fossil 

*  Geol.  Trans.,  second  series,  vol.  ii.  p.  87. 


760  IMBEDDING  OF  WORKS  OF  ART.  [On.  XLVIIL 

state."  These  were  all  so  strongly  attached,  that  it  required  as  much 
force  to  separate  them  from  the  matrix  "  as  to  break  a  fragment  off  any 
hard  rock."* 

In  the  year  1745,  continues  the  same  writer,  the  Fox  man-of-war  was 
stranded  on  the  coast  of  East  Lothian,  and  went  to  pieces.  About  thirty- 
three  years  afterwards  a  violent  storm  laid  bare  a  part  of  the  wreck,  and 
threw  up  near  the  place  several  masses,  "  consisting  of  iron,  ropes,  and 
balls,"  covered  over  with  ochreous  sand,  concreted  and  hardened  into  a 
kind  of  stone.  The  substance  of  the  rope  was  ver}  .Ittle  altered.  The 
consolidated  sand  retained  perfect  impressions  of  parts  of  an  iron  ring, 
"just  as  impressions  of  extraneous  fossil  bodies  are  found  in  various  kinds 
of  strata."f 

After  a  storm  in  the  year  1824,  which  occasioned  a  considerable  shift- 
ing of  the  sands  near  St.  Andrew's,  in  Scotland,  a  gun-barrel  of  ancient 
construction  was  found,  which  is  conjectured  to  have  belonged  to  one  of 
the  wrecked  vessels  of  the  Spanish  Armada.  It  is  now  in  the  museum 
of  the  Antiquarian  Society  of  Scotland,  and  is  incrusted  over  by  a  thin 
coating  of  sand,  the  grains  of  which  are  cemented  by  brown  ferruginous 
matter.  Attached  to  this  coating  are  fragments  of  various  shells,  as  of 
the  common  cardium,  mya,  &c. 

Many  other  examples  are  recorded  of  iron  instruments  taken  up  from 
the  bed  of  the  sea  near  the  British  coast,  incased  by  a  thick  coating 
of  conglomerate,  consisting  of  pebbles  and  sand,  cemented  by  oxide  of 
iron. 

Dr.  Davy  describes  a  bronze  helmet,  of  the  antique  Grecian  form,  taken 
up  in  1825,  from  a  shallow  part  of  the  sea,  between  the  citadel  of  Corfu 
and  the  village  of  Castrades.  Both  the  interior  and  exterior  of  the  hel- 
met were  partially  incrusted  with  shells,  and  a  deposit  of  carbonate  of 
lime.  The  surface  generally,  both  under  the  incrustation,  and  where 
freed  from  it,  was  of  a  variegated  color,  mottled  with  spots  of  green, 
dirty  white,  and  red.  On  minute  inspection  with  a  lens,  the  green  and 
red  patches  proved  to  consist  of  crystals  of  the  red  oxide  and  carbonate 
of  copper,  and  the  dirty  white  chiefly  of  oxide  of  tin. 

The  mineralizing  process,  says  Dr.  Davy,  which  has  produced  these 
new  combinations,  has,  in  general,  penetrated  very  little  into  the  sub- 
stance of  the  helmet.  The  incrustation  and  rust  removed,  the  metal  is 
found  bright  beneath ;  in  some  places  considerably  corroded,  in  others 
very  slightly.  It  proves,  on  analysis,  to  be  copper,  alloyed  with  18*5  per 
cent,  of  tin.  Its  color  is  that  of  our  common  brass,  and  it  possesses 
a  considerable  degree  of  flexibility. 

"  It  is  a  curious  question,"  he  adds,  "  how  the  crystals  were  formed  in 
the  helmet,  and  on  the  adhering  calcareous  deposit.  There  being  no 
reason  to  suppose  deposition  from  solution,  are  we  not  under  the  neces- 
sity of  inferring,  that  the  mineralizing  process  depends  on  a  small  motion 
and  separation  of  the  particles  of  the  original  compound  ?  This  motion 

jM?hil.  Trans.,  1799.  f  Phil.  Trans.,  voL  Ixix.,  1779. 


CaXLVIIL]  SUBSIDENCE  OP  LAND.  761 

may  have  been  due  to  the  operation  of  electro-chemical  powers  which 
may  have  separated  the  different  metals  of  the  alloy.* 


Effects  of  the  Subsidence  of  Land,  in  imbedding  Cities  and  Forests 
in  subaqueous  Strata. 

We  have  hitherto  considered  the  transportation  of  plants  and  animals 
from  the  land  by  aqueous  agents,  and  their  inhumation  in  lacustrine  or 
submarine  deposits,  and  we  may  now  inquire  what  tendency  the  subsi- 
dence of  tracts  of  land  may  have  to  produce  analogous  effects.  Several 
examples  of  the  sinking  down  of  buildings,  and  portions  of  towns  near 
the  shore,  to  various  depths  beneath  the  level  of  the  sea  during  subterra- 
nean movements,  were  before  enumerated  in  treating  of  the  changes 
brought  about  by  inorganic  causes.  The  events  alluded  to  were  com- 
prised within  a  brief  portion  of  the  historical  period,  and  confined  to  a 
small  number  of  the  regions  of  active  volcanoes.  Yet  these  authentic 
facts,  relating  merely  to  the  last  century  and  a  half,  gave  indications  of 
considerable  changes  in  the  physical  geography  of  the  globe,  and  we  are 
not  to  suppose  that  these  were  the  only  spots  throughout  the  surrounding 
land  and  sea  which  suffered  similar  depressions. 

If,  during  the  short  period  since  South  America  has  been  colonized  by 
Europeans,  we  have  proof  of  alterations  of  level  at  the  three  principal 
ports  on  the  western  shores,  Callao,  Valparaiso,  and  Conception,  f  we 
cannot  for  a  moment  suspect  that  these  cities,  so  distant  from  each  other, 
have  been  selected  as  the  peculiar  points  where  the  desolating  power  of 
the  earthquake  has  expended  its  chief  fury.  On  considering  how  small 
is  the  area*  occupied  by  the  seaports  of  this  disturbed  region — points 
where  alone  each  slight  change  of  the  relative  level  of  the  sea  and  land 
can  be  recognized, — and  reflecting  on  the  proofs  in  our  possession  of  the 
local  revolutions  that  have  happened  on  the  site  of  each  port,  within  the 
last  century  and  a  half, — our  conceptions  must  be  greatly  exalted  respect- 
ing the  magnitude  of  the  alterations  which  the  country  between  the 
Andes  and  the  sea  may  have  undergone,  even  in  the  course  of  the  last 
six  thousand  years. 

Cutch  earthquake. — The  manner  in  which  a  large  extent  of  surface 
may  be  submerged,  so  that  the  terrestrial  plants  and  animals  may  be 
imbedded  in  subaqueous  strata,  cannot  be  better  illustrated  than  by  the 
earthquake  of  Cutch,  in  1819,  before  alluded  to  (p.  460).  It  is  stated, 
that,  for  some  years  after  that  earthquake,  the  withered  tamarisks  and 
other  shrubs  protruded  their  tops  above  the  waves,  in  parts  of  the  lagoon 
formed  by  subsidence,  on  the  site  of  the  village  of  Sindree  and  its  envi- 
rons;  but,  after  the  flood  of  1826,  they  were  seen  no  longer.  Every 
geologist  will  at  once  perceive,  that  forests  sunk  by  such  subterranean 
movements  may  become  imbedded  in  subaqueous  deposit,  both  fluviatile 

*  Phil.  Trans.,  1826,  part.  ii.  p.  55.          f  See  above,  pp.  453.  457 .4gg.  601. 


762  BURIED   TEMPLES  OF   CASHMERE.  [Cn.  XLVII1 

and  maiine,  and  the  trees  may  still  remain  erect,  or  sometimes  the  rooti 
and  part  of  the  trunks  may  continue  in  their  original  position,  while  the 
current  may  have  broken  off,  or  levelled  with  the  ground,  their  upper 
stems  and  branches. 

Buildings  how  preserved  under  water. — Some  of  the  buildings  which 
have  at  different  times  subsided  beneath  the  level  of  the  sea  have  been 
immediately  covered  up  to  a  certain  extent  with  strata  of  volcanic  mat- 
ter showered  down  upon  them.  Such  was  the  case  at  Tomboro  in 
Sumbawa,  in  the  present  century,  and  at  the  site  of  the  Temple  of  Sera- 
pis,  in  the  environs  of  Puzzuoli,  probably  about  the  12th  century.  The 
entrance  of  a  river  charged  with  sediment  in  the  vicinity  may  still  more 
frequently  occasion  the  rapid  envelopment  of  buildings  in  regularly  stra- 
tified formations.  But  if  no  foreign  matter  be  introduced,  the  buildings, 
when  once  removed  to  a  depth  where  the  action  of  the  waves  is  insensi- 
ble, and  where  no  great  current  happens  to  flow,  may  last  for  indefinite 
periods,  and  be  as  durable  as  the  floor  of  the  ocean  itself,  which  may 
often  be  composed  of  the  very  same  materials.  There  is  no  reason  to 
doubt  the  tradition  mentioned  by  the  classic  writers,  that  the  submerged 
Grecian  towns  of  Bura  and  Helice  were  seen  under  water ;  and  it  has 
been  already  mentioned  that  different  eye-witnesses  have  observed  the 
houses  of  Port  Royal,  at  the  bottom  of  the  sea,  at  intervals  of  88,  101, 
and  143  years  after  the  convulsion  of  1692.  (p.  505.) 

Buried  temples  of  Cashmere. — The  celebrated  valley  of  Cashmere 
(or  Kashmir)  in  India,  situated  at  the  southern  foot  of  the  Himalaya 
range,  is  about  60  miles  in  length,  and  20  in  breadth,  surrounded  by 
mountains  which  rise  abruptly  from  the  plain  to  the  height  of  about 
5000  feet.  In  the  cliffs  of  the  river  Jelam  and  its  tributaries,  which  tra- 
verse this  beautiful  valley,  strata  consisting  of  fine  clay,  sanfl,  soft  sand- 
stone, pebbles,  and  conglomerate  are  exposed  to  view.  They  contain 
freshwater  shells,  of  the  genera  Lymneus,  Paludina,  and  Cyrena,  with 
land  shells,  all  of  recent  species,  and  are  precisely  such  deposits  as 
would  be  formed  if  the  whole  valley  were  now  converted  into  a  great 
lake,  and  if  the  numerous  rivers  and  torrents  descending  from  the  sur- 
rounding mountains  were  allowed  sufficient  time  to  fill  up  the  lake-basin 
with  fine  sediment  and  gravel.  Fragments  of  pottery  met  with  at  the 
depth  of  40  and  50  feet  in  this  lacustrine  formation  show  that  the  upper 
part  of  it  at  least  has  accumulated  within  the  human  epoch. 

Dr.  Thomas  Thomson,  who  visited  Cashmere  in  1848,  observes  that 
several  of  the  lakes  which  still  exist  in  the  great  valley,  such  as  that 
near  the  town  of  Cashmere,  five  miles  in  diameter,  and  some  others,  are 
deeper  than  the  adjoining  river-channels,  and  may  have  been  formed  by 
subsidence  during  the  numerous  earthquakes  which  have  convulsed  that 
region  in  the  course  of  the  last  2000  years.  It  is  also  probable  that  the 
freshwater  strata  seen  to  extend  far  and  wide  over  the  whole  of  Cash- 
mere originated  not  in  one  continuous  sheet  of  water  once  occupying 
the  entire  valley,  but  in  many  lakes  of  limited  area,  formed  and  filled 
in  succession.  Among  other  proofs  of  such  lake-basins  of  moderate 


OH.  XLVIIL]  BURIED   TEMPLES   OF   CASHMERE.  763 

dimensions  having  once  existed  and  having  been  converted  into  land  at 
different  periods,  Dr.  Thomson  mentions  that  the  ruins  of  Avantipura, 
nol  far  from  the  modern  village  of  that  name,  stand  on  an  older  fresh- 
water deposit  at  the  base  of  the  mountains,  and  terminate  abruptly 
towards  the  plain  in  a  straight  line,  such  as  admits  of  no  other  explana- 
tion than  by  supposing  that  the  advance  of  the  town  in  that  direction 
was  arrested  by  a  lake,  now  drained  or  represented  only  by  a  marsh. 
In  that  neighborhood,  as  very  generally  throughout  Cashmere,  the 
rivers  run  in  channels  or  alluvial  flats,  bounded  by  cliffs  of  lacustrine 
strata,  horizontally  stratified,  and  these  strata  form  low  table-lands  from 
20  to  50  feet  high  between  the  different  watercourses.  On  a  table-land 
of  this  kind  near  Avantipura,  portions  of  two  buried  temples  are  seen, 
which  have  been  partially  explored  by  Major  Cunningham,  who,  in 
1847,  discovered  that  in  one  of  the  buildings  a  magnificent  colonnade 
of  seventy-four  pillars  is  preserved  underground.  He  exposed  to  view 
three  of  the  pillars  in  a  cavity  still  open.  All  the  architectural  decora- 
tions below  the  level  of  the  soil  are  as  perfect  and  fresh-looking  as  when 
first  executed.  The  spacious  quadrangle  must  have  been  silted  up 
gradually  at  first,  for  some  unsightly  alterations,  not  in  accordance  with 
the  general  plan  and  style  of  architecture,  were  detected,  evidently  of 
subsequent  date,  and  such  as  could  only  have  been  required  when  the 
water  and  sediment  had  already  gained  a  certain  height  in  the  interior 
of  the  temple. 

This  edifice  is  supposed  to  have  been  erected  about  the  year  850  of 
our  era,  and  was  certainly  submerged  before  the  year  1416,  when  the 
Mahomedan  king,  Sikandar,  called  Butshikan  or  the  idol-breaker, 
destroyed  all  the  images  of  Hindoo  temples  in  Cashmere.  Ferishta  the 
historian  particularly  alludes  to  Sikandar  having  demolished  every 
Cashmerian  temple  save  one,  dedicated  to  Mahadeva,  which  escaped 
"  in  consequence  of  its  foundations  being  below  the  neighboring 
water."  The  unharmed  condition  of  the  human-headed  birds  and  other 
images  in  the  buried  edifice  near  Avantipura  leaves  no  doubt  that  they 
escaped  the  fury  of  the  iconoclast  by  being  under  water,  and  perhaps 
silted  up  before  the  date  of  his  conquest.* 

Berkeley's  arguments  for  the  recent  date  of  the  creation  of  man. — 
I  cannot  conclude  this  chapter  without  recalling  to  the  reader's  mind  a 
memorable  passage  written  by  Bishop  Berkeley  a  century  ago,  in  which 
he  inferred,  on  grounds  which  may  be  termed  strictly  geological,  the 
recent  date  of  the  creation  of  man.  "  To  any  one,"  says  he,  "  who 
considers  that  on  digging  into  the  earth,  such  quantities  of  shells,  and 
in  some  places,  bones  and  horns  of  animals,  are  found  sound  and  entire, 
after  having  lain  there  in  all  probability  some  thousands  of  years ;  it 
should  seem  probable  that  guns,  medals,  and  implements  in  metal  or 
stone,  might  have  lasted  entire,  buried  under  ground  forty  or  fifty 

*  Thomson's  Western  Himalaya  and  Thibet,  p.  292.  London,  1852.  Cunning- 
ham, vol.  xvii.  Jouiui.  Asiat.  Soc.  Bengal,  pp.  241.  277. 


T64  EECENT  ORIGIN  OF  MAN.  [On.  XLVIII. 

thousand  years,  if  the  world  had  been  so  old.  How  comes  it  then  to 
pass  that  no  remains  are  found,  no  antiquities  of  those  numerous  ages 
preceding  the  Scripture  accounts  of  time ;  that  no  fragments  of  build- 
ings, no  public  monuments,  no  intaglios,  cameos,  statues,  basso-relievos, 
medals,  inscriptions,  utensils,  or  artificial  works  of  any  kind,  are  ever 
discovered,  which  may  bear  testimony  to  the  existence  of  those  mighty 
empires,  those  successions  of  monarchs,  heroes,  and  demi-gods,  for  so 
many  thousand  years  ?  Let  us  look  forward  and  suppose  ten  or  twenty 
thousand  years  to  come,  during  which  time  we  will  suppose  that  plagues, 
famine,  wars,  and  earthquakes  shall  have  made  great  havoc  in  the  world, 
is  it  not  highly  probable  that  at  the  end  of  such  a  period,  pillars,  vases, 
and  statues  now  in  being,  of  granite,  or  porphyry,  or  jasper  (stones  of 
such  hardness  as  we  know  them  to  have  lasted  two  thousand  years 
above  ground,  without  any  considerable  alteration),  would  bear  record 
of  these  and  past  ages  ?  Or  that  some  of  our  current  coins  might  then 
be  dug  up,  or  old  walls  and  the  foundations  of  buildings  show  them- 
selves, as  well  as  the  shells  and  stones  of  the  primeval  world,  which  are 
preserved  down  to  our  times."* 

That  many  signs  of  the  agency  of  man  would  have  lasted  at  least  as 
long  as  "  the  shells  of  the  primeval  world,"  had  our  race  been  so  ancient, 
we  may  feel  as  fully  persuaded  as  Berkeley ;  and  we  may  anticipate  with 
confidence  that  many  edifices  and  implements  of  human  workmanship 
and  the  skeletons  of  men,  and  casts  of  the  human  form,  will  continue  to 
exist  when  a  great  part  of  the  present  mountains,  continents,  and  seas 
have  disappeared.  Assuming  the  future  duration  of  the  planet  to  be 
indefinitely  protracted,  we  can  foresee  no  limit  to  the  perpetuation  of 
some  of  the  memorials  of  man,  which  are  continually  entombed  in  the 
bowels  of  the  earth  or  in  the  bed  of  the  ocean,  unless  we  carry  forward 
our  views  to  a  period  sufficient  to  allow  the  various  causes  of  change, 
both  igneous  and  aqueous,  to  remodel  more  than  once  the  entire  crust 
of  the  earth.  One  complete  revolution  will  be  inadequate  to  efface 
every  monument  of  our  existence  ;  for  many  works  of  art  might  enter 
again  and  again  into  the  formations  of  successive  eras,  and  escape 
obliteration  even  though  the  very  rocks  in  which  they  had  been  for 
ages  imbedded  were  destroyed,  just  as  pebbles  included  in  the  conglo- 
merates of  one  epoch  often  contain  the  organized  remains  of  beings 
which  flourished  during  a  prior  era. 

Yet  it  is  no  less  true,  as  a  late  distinguished  philosopher  has  declared, 
"that  none  of  the  works  of  a" mortal  being  can  be  eternal."f  They  are 
in  the  first  place  wrested  from  the  hands  of  man,  and  lost  as  far  as  re- 
gards their  subserviency  to  his  use,  by  the  instrumentality  of  those  very 
causes  which  place  them  in  situations  where  they  are  enabled  to  endure 
for  indefinite  periods.  And  even  when  they  have  been  included  in  rocky 
strata,  when  they  have  been  made  to  enter  as  it  were  into  the  solid  frame- 

*  Alciphron,  or  the  Minute  Philosopher,  vol.  ii.  pp.  84,  85.,  1732. 
f  Davy^Consolations  in  Travel,  p.  276. 


CH.  XLIX.]          IMBEDDING   OF   FRESHWATER   PLANTS.  765 

work  of  the  globe  itself,  they  must  nevertheless  eventually  perish ;  for 
every  year  some  portion  of  the  earth's  crust  is  shattered  by  earthquakes, 
or  melted  by  volcanic  fire,  or  ground  to  dust  by  the  moving  waters  on  the 
surface.  "  The  river  of  Lethe,"  as  Bacon  eloquently  remarks,  "  runneth 
as  well  above  ground  as  below."* 


CHAPTER  XLIX. 

IMBEDDING    OF    AQUATIC    SPECIES    IN    SUBAQUEOUS   STRATA. 

Inhumation  of  fresh  water  plants  and  animals — Shell  marl — Fossilized  seed-ves- 
sels and  stems  of  chara — Recent  deposits  in  American  lakes — Freshwater 
species  drifted  into  seas  and  estuaries — Lewes  levels — Alternations  of  marine 
and  freshwater  strata,  how  caused — Imbedding  of  marine  plants  and  animals — 
Cetacea  stranded  on  our  shores — Littoral  and  estuary  Testacea  swept  into  the 
deep  sea — Burrowing  shells — Living  Testacea  found  at  considerable  depths — 
Blending  of  organic  remains  of  different  ages. 

HAVING  treated  of  the  imbedding  of  terrestrial  plants  and  animals, 
and  of  human  remains,  in  deposits  now  forming  beneath  the  waters,  I 
come  next  to  consider  in  what  manner  aquatic  species  may  be  entombed 
in  strata  formed  in  their  own  element. 

Freshwater  plants  and  animals. — The  remains  of  species  belonging 
to  those  genera  of  the  animal  and  vegetable  kingdoms  which  are  more 
or  less  exclusively  confined  to  fresh  water  are  for  the  most  part  preserved 
in  the  beds  of  lakes  or  estuaries,  but  they  are  oftentimes  swept  down  by 
rivers  into  the  sea,  and  there  intermingled  with  the  exuvise  of  marine 
races.  The  phenomena  attending  their  inhumation  in  lacustrine  deposits 
are  sometimes  revealed  to  our  observation  by  the  drainage  of  small  lakes, 
such  as  are  those  in  Scotland,  which  have  been  laid  dry  for  the  sake  of 
obtaining  shell  marl  for  agricultural  uses. 

In  these  recent  formations,  as  seen  in  Forfarshire,  two  or  three  beds 
of  calcareous  marl  are  sometimes  observed  separated  from  each  other  by 
layers  of  drift  peat,  sand,  or  fissile  clay.  The  marl  often  consists  almost 
entirely  of  an  aggregate  of  shells  of  the  genera  Limnea,  Planorbis,  Val- 
vata,  and  Cyclas,  of  species  now  existing  in  Scotland.  A  considerable 
proportion  of  the  Testacea  appear  to  have  died  very  young,  and  few 
of  the  shells  are  of  a  size  which  indicates  their  having  attained  a  state 
of  maturity.  The  shells  are  sometimes  entirely  decomposed,  forming  a 
pulverulent  marl ;  sometimes  in  a  state  of  good  preservation.  They  are 
frequently  intermixed  with  stems  of  Charae  and  other  aquatic  vegetables, 
the  whole  being  matted  together  and  compressed,  forming  laminae  often 
as  thin  as  paper. 

*  Easay  on  the  Vicissitude  of  Things. 


766 


IMBEDDING  OP  FRESHWATER  PLANTS          [On.  XLIX. 


Fossilized  seed-vessels  and  stems  of  Chara. — As  the  Ohara  is  an 
aquatic  plant  which  occurs  frequently  fossil  in  formations  of  different 
eras,  and  is  often  of  much  importance  to  the  geologist  in  characterizing 
entire  groups  of  strata,  I  shall  describe  the  manner  in  which  I  have 
found  the  recent  species  in  a  petrified  state.  They  occur  in  a  marl-lake 
in  Forfarshire,  inclosed  in  nodules,  and  sometimes  in  a  continuous  stra- 
tum of  a  kind  of  travertin. 


Fig.  102. 


Seed-vessel  of  Chara  hispida. 

a,  Part  of  the  stem  with  the  seed-vessel  attached.    Magnified. 
•    J,  Natural  size  of  the  seed  vessel. 

c,  Integument  of  the  Gyrogonite,  or  petrified  seed-vessel  of  Chara  hispida,  found  in  the 

Scotch  marl-lakes.     Magnified. 
dy  Section  showing  the  nut  within  the  integument, 
c,  Lower  end  of  the  integument  to  which  the  stem  was  attached. 
/,  Upper  end  of  the  integument  to  which  the  stigmata  were  attached. 
g,  One  of  the  spiral  valves  of  c. 

The  seed-vessel  of  these  plants  is  remarkably  tough  and  hard,  and 
consists  of  a  membranous  nut  covered  by  an  integument  (d,  fig.  102.) 
both  of  which  are  spirally  striated  or  ribbed.  The  integument  is  com- 
posed of  five  spiral  valves,  of  a  quadrangular  form  (g).  In  Chara  his- 
pida, which  abounds  in  the  lakes  of  Forfarshire,  and  which  has  become 
fossil  in  the  Bakie  Loch,  each  of  the  spiral  valves  of  the  seed-vessel  turns 
rather  more  than  twice  round  the  circumference,  the  whole  together 
making  between  ten  and  eleven  rings.  The  number  of  these  rings  differs 
greatly  in  different  species,  but  in  the  same  appears  to  be  very  constant. 

The  stems  of  Charse  occur  fossil  in  the  Scotch  marl  in  great  abun- 
dance. In  some  species,  as  in  Chara  hispida,  the  plant  when  living 
contains  so  much  carbonate  of  lime  in  its  vegetable  organization,  inde- 
pendently of  calcareous  incrustation,  that  it  effervesces  strongly  with 
acids  when  dry.  The  stems  of  Chara  hispida  are  longitudinally  striated, 
with  a  tendency  to  be  spiral.  These  striae,  as  appears  to  be  the  case 
with  all  Charae,  turn  always  like  the  worm  of  a  screw  from  right  to  left, 
while  those  of  the  seed-vessel  wind  round  in  a  contrary  direction.  A 
cross  section  of  the  stem  exhibits  a  curious  structure,  for  it  is  composed 


CH.  XLIX.] 


IN  SUBAQUEOUS  STRATA, 


767 


of  a  large  tube  surrounded  by  smaller  tubes  (fig.  103.,  6,  c)  as  is  seen  in 
some  extinct  as  well  as  recent  species.  In  the  stems  of  several  species, 
however,  there  is  only  a  single  tube.* 


Fig.  103. 


Stem  and  branches  of  Chara  hispida. 

a,  Stem  and  branches  of  the  natural  size. 

b,  Section  of  the  stem  magnified. 

c,  Showing  the  central  tube  surrounded  by  two  rings  of  smaller  tubes. 

The  valves  of  a  small  animal  called  cypris  (0.  ornata?  Lam.)  occur 
completely  fossilized,  like  the  stems  of  Charae,  in  the  Scotch  travertin 
above  mentioned.  The  same  cypris  inhabits  the  lakes  and  ponds  of 
England,  where,  together  with  many  other  species,  it  is  not  uncommon. 
Although  extremely  minute,  they  are  visible  to  the  naked  eye,  and  may 
be  observed  in  great  numbers,  swimming  swiftly  through  the  waters  of 
our  stagnant  pools  and  ditches.  The  antennae,  at  the  end  of  which  are 
fine  pencils  of  hair,  are  the  principal  organs  for  swimming,  and  are 
moved  with  great  rapidity.  The  animal  resides  within  two  small  valves, 
not  unlike  those  of  a  bivalve  shell,  and  moults  its  integuments  annually, 
which  the  conchiferous  mollusks  do  not.  The  cast-off  shells,  resembling 
thin  scales,  and  occurring  in  countless  myriads  in  many  ancient  fresh- 
water marls,  impart  to  them  a  divisional  structure,  like  that  so  frequently 
derived  from  plates  of  mica. 

The  recent  strata  of  lacustrine  origin  above  alluded  to  are  of  very 
small  extent,  but  analogous  deposits  on  the  grandest  scale  are  forming 
in  the  great  Canadian  lakes,  as  in  Lakes  Superior  and  Huron,  where  beds 


*  On  Freshwater  Marl,  <fec. 
p.  78. 


By  C.  Lyell.     Geol.  Trans.,  vol.  ii.,  second  series, 


768  IMBEDDING  OP   FRESHWATER  SPECIES.         [Cn.  XLIX. 

Fig.  104.  Fig.  105 


Cypris  unifasciata,  a  living  species,  greatly  Cypris  vidua,  a  living  species, 

magnified  greatly  magnified.* 

a,  Upper  part.  b,  Side  view  of  the  same. 

of  sand  and  clay  are  seen  inclosing  shells  of  existing  species.f  The 
Chara  also  plays  the  same  part  in  the  subaqueous  vegetation  of  North 
America  as  in  Europe.  I  observed  along  the  borders  of  several  fresh- 
water lakes  in  the  state  of  New  York  a  luxuriant  crop  of  this  plant  in 
clear  water  of  moderate  depth,  rendering  the  bottom  as  verdant  as  a 
grassy  meadow.  Here,  therefore,  we  may  expect  some  of  the  tough 
seed  vessels  to  be  preserved  in  mud,  just  as  we  detect  them  fossil  in  the 
Eocene  strata  of  Hampshire,  or  in  the  neighborhood  of  Paris,  and  many 
other  countries. 

Imbedding  of  freshwater  Species  in  Estuary  and  Marine  Deposits. 

In  Lewes  levels. — We  have  sometimes  an  opportunity  of  examining 
the  deposits  which  within  the  historical  period  have  silted  up  some  of 
our  estuaries ;  and  excavations  made  for  wells  and  other  purposes, 
where  the  sea  has  been  finally  excluded,  enable  us  to  observe  the  state 
of  the  organic  remains  in  these  tracts.  The  valley  of  the  Ouze  between 
Newhaven  and  Lewes  is  one  of  several  estuaries  from  which  the  sea  has 
retired  within  the  last  seven  or  eight  centuries ;  and  here,  as  appears 
from  the  researches  of  Dr.  Man  tell,  strata  thirty  feet  and  upwards  in 
thickness  have  accumulated.  At  the  top,  beneath  the  vegetable  soil,  is 
a  bed  of  peat  about  five  feet  thick,  inclosing  many  trunks  of  trees. 
Next  below  is  a  stratum  of  blue  clay  containing  freshwater  shells  of 
about  nine  species,  such  as  now  inhabit  the  district.  Intermixed  with 
these  was  observed  the  skeleton  of  a  deer.  Lower  down,  the  layers  of 
blue  clay  contain,  with  the  above-mentioned  freshwater  shells,  several 
marine  species  well  known  on  our  coast.  In  the  lowest  beds,  often  at 
the  depth  of  thirty-six  feet;  these  marine  Testacea  occur  without  the 
slightest  intermixture  of  fluviatile  species,  and  amongst  them  the  skull 
of  the  narwal,  or  sea  unicorn  (Monodon  monoceros),  has  been  detected. 
Underneath  all  these  deposits  is  a  bed  of  pipe-clay,  derived  from  the 
subjacent  chalk.J 

*  See  Desmarest's  Crustacea,  pi.  55. 

f  Dr.  Bigsby,  Journ.  of  Science,  &c.  No.  xxxvii.  pp.  262,  263. 
j  Mantel!,  Geol.  of  Sussex,  p.  285  ;  also  Catalogue  of  Org.  Hem.,  Geol.    Trans., 
vol.  iii.  part  i.  p.  201.,  2nd  series. 


L 


CH.  XLIX.]          IN  SUBAQUEOUS  STRATA.  769 

If  we  had  no  historical  information  respecting  the  former  existence  of 
an  inlet  of  the  sea  in  this  valley  and  of  its  gradual  obliteration,  the 
inspection  of  the  section  above  described  would  show,  as  clearly  as  a 
written  chronicle,  the  following  sequence  of  events.  First,  there  was  a 
salt-water  estuary  peopled  for  many  years  by  species  of  marine  Testacea 
identical  with  those  now  living,  and  into  which  some  of  the  larger  Ceta- 
cea  occasionally  entered.  Secondly,  the  inlet  grew  shallower,  and  the 
water  became  brackish,  or  alternately  salt  and  fresh,  so  that  the  remains 
of  freshwater  and  marine  shells  were  mingled  in  the  blue  argillaceous 
sediment  of  its  bottom.  Thirdly,  the  shoaling  continued  until  the  river- 
water  prevailed,  so  that  it  was  no  longer  habitable  by  marine  Testacea, 
but  fitted  only  for  the  abode  of  fluviatile  species  and  aquatic  insects. 
Fourthly,  a  peaty  swamp  or  morass  was  formed,  where  some  trees  grew, 
or  perhaps  were  drifted  during  floods,  and  where  terrestrial  quadrupeds 
were  mired.  Finally,  the  soil  being  flooded  by  the  river  only  at  distant 
intervals,  became  a  verdant  meadow. 

In  delta,  of  Ganges  and  Indus. — It  was  before  stated,  that  on  the 
sea-coast,  in  the  delta  of  the  Ganges,  there  are  eight  great  openings, 
each  of  which  has  evidently,  at  some  ancient  period,  served  in  its  turn 
as  the  principal  channel  of  discharge.*  As  the  base  of  the  delta  is  200 
miles  in  length,  it  must  happen  that,  as  often  as  the  great  volume  of 
river- water  is  thrown  into  the  sea  by  a  new  mouth,  the  sea  will  at  one 
point  be  converted  from  salt  to  fresh,  and  at  another  from  fresh  to  salt ; 
for,  with  the  exception  of  those  parts  where  the  principal  discharge  takes 
place,  the  salt  water  not  only  washes  the  base  of  the  delta,  but  enters  far 
into  every  creek  and  lagoon.  It  is  evident,  then,  that  repeated  alterna- 
tions of  beds  containing  freshwater  shells,  with  others  filled  with  marine 
exuviae,  may  here  be  formed.  It  has  also  been  shown  by  artesian  borings 
at  Calcutta  (see  above,  p.  267),  that  the  delta  once  extended  much  far- 
ther than  now  into  the  gulf,  and  that  the  river  is  only  recovering 
from  the  sea  the  ground  which  had  been  lost  by  subsidence  at  some 
former  period.  Analogous  phenomena  must  sometimes  be  occasioned 
by  such  alternate  elevation  and  depression  as  has  occurred  in  modern 
times  in  the  delta  of  the  Indus,  f  But  the  subterranean  movements 
affect  but  a  small  number  of  the  deltas  formed  at  one  period  on  the 
globe ;  whereas  the  silting  up  of  some  of  the  arms  of  great  rivers 
and  the  opening  of  others,  and  the  consequent  variation  of  the  points 
where  the  chief  volume  of  their  waters  is  discharged  into  the  sea,  are 
phenomena  common  to  almost  every  delta. 

The  variety  of  species  of  Testacea  contained  in  the  recent  calcareous 
marl  of  Scotland,  before  mentioned,  is  very  small,  but  the  abundance  of 
individuals  extremely  great,  a  circumstance  very  characteristic  of  fresh- 
water formations  in  general,  as  compared  to  marine ;  for  in  the  latter,  as 
is  seen  on  sea-beaches,  coral-reefs,  or  in  the  bottom  of  the  seas  examined 
by  dredging,  wherever  the  individual  shells  are  exceedingly  numerous, 
there  rarely  fails  to  be  a  vast  variety  of  species. 

*  Page  276.   -  f  FaSe  46°- 

49 


770  IMBEDDING   OF   THE   REMAINS  [Cn.  XLIX. 


Imbedding  of  the  Remains  of  Marine  Plants  and  Animals. 

Marine  plants. — The  large  banks  of  drift  sea-weed  which  occur  on 
each  side  of  the  equator  in  the  Atlantic,  Pacific,  and. Indian  oceans,  were 
before  alluded  to.*  These,  when  they  subside,  may  often  produce  con- 
siderable beds  of  vegetable  matter.  In  Holland,  sub-marine  peat  ia 
derived  from  Fuci,  and  on  parts  of  our  own  coast  from  Zostera  marina. 
In  places  where  Algae  do  not  generate  peat,  they  may  nevertheless  leave 
traces  of  their  form  imprinted  on  argillaceous  and  calcareous  mud,  as 
they  are  usually  very  tough  in  their  texture. 

Sea-weeds  are  often  cast  up  in  such  abundance  on  our  shores  during 
heavy  gales,  that  we  cannot  doubt  that  occasionally  vast  numbers  of  them 
are  imbedded  in  littoral  deposits  now  in  progress.  We  learn  from  the 
researches  of  Dr.  Forchhammer,  that  besides  supplying  in  common  with 
land  plants  the  materials  of  coal,  the  Algae  must  give  rise  to  important 
chemical  changes  in  the  composition  of  strata  in  which  they  are  imbed- 
ded. These  plants  always  contain  sulphuric  acid,  and  sometimes  in  as 
large  a  quantity  as  8^-  per  cent.,  combined  with  potash :  magnesia  also 
and  phosphoric  acid  are  constant  ingredients.  Whenever  large  masses 
of  sea-weeds  putrefy  in  contact  with  ferruginous  clay,  sulphuret  of  iron, 
or  iron  pyrites:  is  formed  by  the  union  of  the  sulphur  of  the  plants  with 
the  iron  of  the  clay ;  while  the  potash,  released  from  its  union  with  the 
clay  (i.  e.  silicate  of  alumina),  forms  with  it  a  peculiar  compound. 
Many  of  the  mineral  characteristics  of  ancient  rocks,  especially  the  alum 
slates,  and  the  pyrites  which  occur  in  clay  slate,  and  the  fragments  of 
anthracite  in  marine  Silurian  strata,  may  be  explained  by  the  decompo- 
sition of  fucoids  or  sea- weeds,  f 

Imbedding  of  cetacea. — It  is  not  uncommon  for  the  larger  Cetacea, 
which  can  float  only  in  a  considerable  depth  of  water,  to  be  carried  dur- 
ing storms  or  high  tides  into  estuaries,  or  upon  low  shores,  where,  upon 
the  retiring  of  high  water,  they  are  stranded.  Thus  a  narwal  (Monodon 
monoceros)  was  found  on  the  beach  near  Boston  in  Lincolnshire,  in  the 
year  1800,  the  whole  of  its  body  buried  in  the  mud.  A  fisherman  going 
to  his  boat  saw  the  horn,  and  tried  to  pull  it  out,  when  the  animal  began 
to  stir  itself.  J  An  individual  of  the  common  whale  (Balccna  mysticetus), 
which  measured  seventy  feet,  came  ashore  near  Peterhead,  in  1682. 
Many  individuals  of  the  genus  Balaenoptera  have  met  the  same  fate.  It 
will  be  sufficient  to  refer  to  those  cast  on  shore  near  Burnt  Island,  and 
at  Alloa,  recorded  by  Sibbald  and  Neill.  The  other  individual  mentioned 
by  Sibbald,  as  having  come  ashore  at  Boyne,  in  Banffshire,  was  probably 
a  razor-back.  Of  the  genus  Catodon  ( Cachalot],  Ray  mentions  a  large 
one  stranded  on  the  west  coast  of  Holland  in  1598,  and  the  fact  is  also 
commemorated  in  a  Dutch  engraving  of  the  time  of  much  merit.  Sib- 
bald, too,  records  that  a  herd  of  Cachalots,  upwards  of  100  in  number, 

*  Page  599.  f  Forchhammer,  Report  British  Assoc.  1844. 

\  Fleming's  Brit.  Animals,  p.  37  ;  in  which  work  other  cases  are  enumerated. 


Co.  XLIX.]  OF   MARINE   ANIMALS.  771 

were  found  stranded  at  Cairston,  in  Orkney.  The  dead  bodies  of  the 
larger  Cetacea  are  sometimes  found  floating  on  the  surface  of  the  waters, 
as  was  the  case  with  the  immense  whale  exhibited  in  London  in  183l! 
And  the  carcase  of  a  sea-cow  or  Lamantine  (Halicora)  was,  in  1785 
cast  ashore  near  Leith. 

To  some  accident  of  this  kind  we  may  refer  the  position  of  the  skeleton 
of  a  whale,  seventy-three  feet  long,  which  was  found  at  Airthrey,  on  the 
Forth,  near  Stirling,  imbedded  in  clay  twenty  feet  higher  than  the  sur- 
face of  the  highest  tide  of  the  river  Forth  at  the  present  day.  From  the 
situation  of  the  Roman  station  and  causeways  at  a  small  distance  from 
the  spot,  it  is  concluded  that  the  whale  must  have  been  stranded  there  at 
a  period  prior  to  the  Christian  era.* 

Other  fossil  remains  of  this  class  have  also  been  found  in  estuaries  known 
to  have  been  silted  up  in  recent  times,  one  example  of  which  has  been 
already  mentioned  near  Lewes,  in  Sussex. 

Marine  reptiles. — Some  singular  fossils  have  lately  been  discovered  in 
Fj(r  106  the  Island  of  Ascension,  in  a  stone  said  to  be 

continually  forming  on  the  beach,  where  the 
waves  threw  up  small  rounded  fragments  of 
shells  and  corals,  which,  in  the  course  of  time, 
become  firmly  agglutinated  together,  and  con- 
stitute a  stone  used  largely  for  building  and 
making  lime.  In  a  quarry  on  the  N.  W.  side 
of  the  island,  about  100  yards  from  the  sea, 
some  fossil  eggs  of  turtles  have  been  discover- 
ed  in  the  hard  rock  thus  formed.  The  eggs 
must  have  been  nearly  hatched  at  the  time  when  they  perished ;  for  the 
bones  of  the  young  turtle  are  seen  in  the  interior,  with  their  shape  fully  de- 
veloped, the  interstices  between  the  bones  being  entirely  filled  with  grains 
of  sand,  which  are  cemented  together,  so  that  when  the  egg-shells  are  re- 
moved perfect  casts  of  their  form  remain  in  stone.  In  the  single  specimen 
here  figured  (fig.  106),  which  is  only  five  inches  in  its  longest  diameter, 
no  less  than  seven  eggs  are  preserved  .J 

To  explain  the  state  in  which  they  occur  fossil,  it  seems  necessary  to 
suppose  that  after  the  eggs  were  almost  hatched  in  the  warm  sand,  a 
great  wave  threw  upon  them  so  much  more  sand  as  to  prevent  the  rays 
of  the  sun  from  penetrating,  so  that  the  yolk  was  chilled  and  deprived  of 

*  Quart.  Journ.  of  Lit.  Sci.,  <fec.,  No  xv.,  p.  172.     Oct.  1819. 

f  This  specimen  has  been  presented  by  Mr.  Lonsdale  to  the  Geological  Society 
of  London. 

\  The  most  conspicuous  of  the  bones  represented  within  the  shell  in  fig.  107, 
appear  to  be  the  clavicle  and  coracoid  bone.  They  are  hollow;  and  for  this 
reason  resemble,  at  first  sight,  the  bones  of  birds  rather  than  of  reptiles ;  for  the 
latter  have  no  medullary  cavity.  Prof.  Owen,  of  the  College  of  Surgeons,  in 
order  to  elucidate  this  point,  dissected  for  me  a  very  young  turtle,  and  found 
that  the  exterior  portion  only  of  the  bones  was  ossified,  the  interior  being  still 
filled  with  cartilage.  This  cartilage  soon  dried  up  and  shrank  to  a  mere  thread 
upon  the  evaporation  of  the  spirits  of  wine  in  which  the  specimen  had  been  pre- 
served, so  that  in  a  short  time  the  bones  became  as  empty  as  those  of  birds. 


772  IMBEDDING   OF   THE   REMAINS  [Cn.  XLIX. 

Fig.  107. 


One  of  the  eggs  in  fig.  106,  of  the  natural  size,  showing  the  bones  of  the  foetus  which  had 
been  nearly  hatched. 

vitality.  The  shells  were,  perhaps,  slightly  broken  at  the  same  time,  so 
that  small  grains  of  sand  might  gradually  be  introduced  into  the  interior 
by  water  as  it  percolated  through  the  beach. 

Marine  testacea. — The  aquatic  animals  and  plants  which  inhabit  an 
estuary  are  liable,  like  the  trees  and  land  animals  which  people  the  allu- 
vial plains  of  a  great  river,  to  be  swept  from  time  to  time  far  into  the 
deep ;  for  as  a  river  is  perpetually  shifting  its  course,  and  undermining  a 
portion  of  its  banks  with  the  forests  which  cover  them,  so  the  marine 
current  alters  its  direction  from  time  to  time,  and  bears  away  the  banks 
of  sand  and  mud  against  which  it  turns  its  force.  These  banks  may  con- 
sist in  oreat  measure  of  shells  peculiar  to  shallow  and  sometimes  brackish 

O  * 

water,  which  may  have  been  accumulating  for  centuries,  until  at  length 
they  are  carried  away  and  spread  out  along  the  bottom  of  the  sea,  at  a 
depth  at  which  they  could  not  have  lived  and  multiplied.  Thus  littoral 
and  estuary  shells  are  more  frequently  liable  even  than  freshwater  species, 
to  be  intermixed  with  the  exuviae  of  pelagic  tribes. 

After  the  storm  of  February  4,  1831,  when  several  vessels  were 
wrecked  in  the  estuary  of  the  Forth,  the  current  was  directed  against  a 
bed  of  oysters  with  such  force,  that  great  heaps  of  them  were  thrown 
alive  upon  the  ieach,  and  remained  above  high-water  mark.  I  collected 
many  of  these  oysters,  as  also  the  common  eatable  whelks  (Buccina), 
thrown  up  with  them,  and  observed  that,  although  still  living,  their 
shells  were  worn  by  the  long  attrition  of  sand  which  had  passed  over 
them  as  they  lay  in  their  native  bed,  and  which  had  evidently  not  re- 
sulted from  the  mere  action  of  the  tempest  by  which  they  were  cast 
ashore. 

From  these  facts  we  learn  that  the  union  of  the  two  parts  of  a  bivalve 
shell  does  not  prove  that  it  has  not  been  transported  to  a  distance  ;  and 


CH.  XLIX.J  OF   MARINE  TESTACEA.  773 

when  we  find  shells  worn,  and  with  all  their  prominent  pails  rubbed  off, 
they  may  still  have  been  imbedded  where  they  grew. 

Burrowing  shells. — It  sometimes  appears  extraordinary,  when  we  ob- 
serve the  violence  of  the  breakers  on  our  coast,  and  see  the  strength  of 
the  current  in  removing  cliffs,  and  sweeping  out  new  channels,  that  many 
tender  and  fragile  shells  should  inhabit  the  sea  in  the  immediate  vicinity 
of  this  turmoil.  But  a  great  number  of  the  bivalve  Testacea,  and  many 
also  of  the  turbinated  univalves,  burrow  in  sand  or  mud.  The  Solen 
and  the  Cardium,  for  example,  which  are  usually  found  in  shallow 
water  near  the  shore,  pierce  through  a  soft  bottom  without  injury 
to  their  shells  ;  and  the  Pholas  can  drill  a  cavity  through  mud  of  con- 
siderable hardness.  The  species  of  these  and  many  other  tribes  can  sink, 
when  alarmed,  with  considerable  rapidity,  often  to  the  depth  of  several 
feet,  and  can  also  penetrate  upwards  again  to  the  surface,  if  a  mass  of 
matter  be  heaped  upon  them.  The  hurricane,  therefore,  may  expend  its 
fury  in  vain,  and  may  sweep  away  even  the  upper  part  of  banks  of  sand 
or  mud,  or  may  roll  pebbles  over  them,  and  yet  these  Testacea  may  re- 
main below  secure  and  uninjured. 

Shells  become  fossil  at  considerable  depths. — I  have  already  stated 
that,  at  the  depth  of  950  fathoms,  between  Gibraltar  and  Ceuta,  Cap- 
tain Smith  found  a  gravelly  bottom,  with  fragments  of  broken  shells, 
carried  thither  probably  from  the  comparatively  shallow  parts  of  the 
neighboring  straits,  through  which  a  powerful  current  flows.  Beds  of 
shelly  sand  might  here,  in  the  course  of  ages,  be  accumulated  several 
thousand  feet  thick.  But,  without  the  aid  of  the  drifting  power  of  a 
current,  shells  may  accumulate  in  the  spot  where  they  live  and  die,  at 
great  depths  from  the  surface,  if  sediment  be  thrown  down  upon  them  ; 
for  even  in  our  own  colder  latitudes,  the  depths  at  which  living  marine 
animals  abound  is  very  considerable.  Captain  Vidal  ascertained,  by 
soundings  made  off  Tory  Island,  on  the  northwest  coast  of  Ireland,  that 
Crustacea,  Star-fish,  and  Testacea  occurred  at  various  depths  between 
fifty  and  one  hundred  fathoms  ;  and  he  drew  up  Dentalia  from  the  mud 
of  Galway  Bay,  in  230  and  240  fathoms  water. 

The  same  hydrcgrapher  discovered  on  the  Rockhall  Bank  large  quan- 
tities of  shells  at  depths  varying  from  45  to  190  fathoms.  The  shells 
were  for  the  most  part  pulverized,  and  evidently  recent,  as  they  retained 
their  colors.  In  the  same  region  a  bed  of  fish  bones  was  observed  extend- 
ing for  two  miles  along  the  bottom  of  the  sea  in  eighty  and  ninety 
fathoms  water.  At  the  eastern  extremity  also  of  Rockhall  Bank,  fish- 
bones were  met  with,  mingled  with  pieces  of  fresh  shell,  at  the  depth  of 
235  fathoms. 

Analogous  formations  are  in  progress  in  the  submarine  tracts  extend- 
ing from  the  Shetland  Isles  to  the  north  of  Ireland,  wherever  soundings 
can  be  procured.  A  continuous  deposit  of  sand  and  mud,  replete  with 
broken  and  entire  shells,  Echini,  &c.,  has  been  traced  for  upwards  of 
twenty  miles  to  the  eastward  of  the  Faroe  Islands,  usually  at  the  depth 
of  from  forty  to  one  hundred  fathoms.  In  one  part  of  this  tract  (lat. 


774  IMBEDDING   OF   MARINE   TESTACEA.  [Cfl.  XLIX. 

61°  50',  long.  6°  30')  fish-bones  occur  in  extraordinary  profusion,  so  that 
the  lead  cannot  be  drawn  up  without  some  vertebrae  being  attached. 
This  "  bone  bed,"  as  it  was  called  by  our  surveyors,  is  three  miles  and  a 
half  in  length,  and  forty-five  fathoms  under  water,  and  contains  a  few 
shells  intermingled  with  the  bones. 

In  the  British  seas,  the  shells  and  other  organic  remains  lie  in  soft 
mud  or  loose  sand  and  gravel ;  whereas,  in  the  bed  of  the  Adriatic, 
Donati  found  them  frequently  inclosed  in  stone  of  recent  origin.  This 
is  precisely  the  difference  in  character  which  we  might  have  expected  to 
exist  between  the  British  marine  formations  now  in  progress  and  those 
of  the  Adriatic ;  for  calcareous  and  other  mineral  springs  abound  in  the 
Mediterranean  and  lands  adjoining,  while  they  are  almost  entirely  want- 
ing in  our  own  country.  I  have  already  adverted  to  the  eight  regions  of 
different  depths  in  the  ./Egean  Sea,  each  characterized  by  a  peculiar  as- 
semblage of  shells,  which  have  been  described  by  Professor  E.  Forbes, 
who  explored  them  by  dredging.  (See  above,  p.  649.) 

During  his  survey  of  the  west  coast  of  Africa,  Captain  Sir  E.  Belcher 
found,  by  frequent  soundings  between  the  twenty-third  and  twentieth  de- 
grees of  north  latitude,  that  the  bottom  of  the  sea,  at  the  depth  of  from 
twenty  to  about  fifty  fathoms,  consists  of  sand  with  a  great  intermixture 
of  shells,  often  entire,  but  sometimes  finely  comminuted.  Between  the 
eleventh  and  ninth  degrees  of  north  latitude,  on  the  same  coast,  at  sound- 
ings varying  from  twenty  to  about  eighty  fathoms,  he  brought  up  abun- 
dance of  corals  and  shells  mixed  with  sand.  These  also  were  in  somf 
parts  entire,  and  in  others  worn  and  broken. 

In  all  these  cases,  it  is  only  necessary  that  there  should  be  some  depo- 
sition of  sedimentary  matter,  however  minute,  such  as  may  be  supplied 
by  rivers  draining  a  continent,  or  currents  preying  on  a  line  of  cliffs,  in 
order  that  stratified  formations,  hundreds  of  feet  in  thickness,  and  replete 
with  organic  remains,  should  result  in  the  course  of  ages. 

But  although  some  deposits  may  thus  extend  continuously  for  a  thou  • 
sand  miles  or  more  near  certain  coasts,  the  greater  part  of  the  bed  of  the 
ocean,  remote  from  continents  and  islands,  may  very  probably  receive,  at 
the  same  time,  no  new  accessions  of  drift  matter,  all  sediment  being  in- 
tercepted by  intervening  hollows,  in  which  a  marine  current  must  clear  its 
waters  as  thoroughly  as  a  turbid  river  in  a  lake.  Erroneous  theories  in 
geology  may  be  formed  not  only  from  overlooking  the  great  extent  of 
simultaneous  deposits  now  in  progress,  but  also  from  the  assumption 
that  such  formations  may  -be  universal  or  coextensive  with  the  bed  of 
the  ocean. 

We  frequently  observe,  on  the  sea  beach,  very  perfect  specimens  of 
fossil  shells,  quite  detached  from  their  matrix,  which  have  been  washed 
out  of  older  formations,  constituting  the  sea-cliffs.  They  may  be  all  of 
extinct  species,  like  the  Eocene  freshwater  and  marine  shells  strewed  over 
the  shores  of  Hampshire,  yet  when  they  become  mingled  with  the  shells 
of  the  present  period,  and  buried  in  the  same  deposits  of  mud  and  sand, 
they  would  appear,  if  upraised  and  examined  by  future  geologists,  to 


CH.  L.]          FORMATION  OF  CORAL  REEFS.  775 

have  been  all  of  the  same  age.  That  such  intermixture  and  blending 
of  organic  remains  of  different  ages  have  actually  taken  place  in  former 
times,  is  unquestionable,  though  the  occurrence  appears  to  be  very  local 
and  exceptional.  It  is,  however,  a  class  of  accidents  more  likely  than 
almost  any  other  to  lead  to  serious  anachronisms  in  geological  chrono- 
logy. 


CHAPTER    L. 

FORMATION    OF    CORAL    REEFS. 

Growth  of  coral  chiefly  confined  to  tropical  regions — Principal  genera  of  coral- 
building  zoophytes — Their  rate  of  growth — Seldom  flourish  at  greater  depths 
than  twenty  fathoms — Atolls  or  annular  reefs  with  lagoons — Maldive  Isles — 
Origin  of  the  circular  form — Coral  reefs  not  based  on  submerged  volcanic 
craters — Mr.  Darwin's  theory  of  subsidence  in  explanation  of  atolls,  encircling 
and  barrier  reefs — Why  the  windward  side  of  atolls  highest — Subsidence  ex- 
plains why  all  atolls  are  nearly  on  one  level — Alternate  areas  of  elevation  and 
subsidence — Origin  of  openings  into  the  lagoons — Size  of  atolls  and  barrier 
reefs — Objection  to  the  theory  of  subsidence  considered — Composition,  struc- 
ture, and  stratified  arrangement  of  rocks  now  forming  in  coral  reefs — Lime, 
whence  derived — Supposed  increase  of  calcareous  matter  in  modern  epochs 
controverted — Concluding  remarks. 

THE  powers  of  the  organic  creation  in  modifying  the  form  and  structure 
of  the  earth's  crust,  are  most  conspicuously  displayed  in  the  labors  of  the 
coral  animals.  We  may  compare  the  operation  of  these  zoophytes  in  the 
ocean,  to  the  effects  produced  on  a  smaller  scale  upon  the  land  by  the 
plants  which  generate  peat.  In  the  case  of  the  Sphagnum,  the  upper 
part  vegetates  while  the  lower  part  is  entering  into  a  mineral  mass,  in 
which  the  traces  of  organization  remain  when  life  has  entirely  ceased. 
In  corals,  in  like  manner,  the  more  durable  materials  of  the  generation 
that  has  passed  away  serve  as  the  foundation  on  which  the  living  animals 
continue  to  rear  a  similar  structure. 

The  stony  part  of  the  lamelliform  zoophyte  may  be  likened  to  an 
internal  skeleton;  for  it  is  always  more  or  less  surrounded  by  a  soft  ani- 
mal substance  capable  of  expanding  itself;  yet,  when  alarmed,  it  has  the 
power  of  contracting  and  drawing  itself  almost  entirely  into  the  cells  and 
hollows  of  the  hard  coral.  Although  oftentimes  beautifully  colored  in 
their  own  element,  the  soft  parts  become  when  taken  from  the  sea 
nothing  more  in  appearance  than  a  brown  slime  spread  over  the  stony 
nucleus.* 

The  growth  of  those  corals  which  form  reefs  of  solid  stone  is  entirely 
confined  to  the  warmer  regions  of  the  globe,  rarely  extending  beyond  the 
tropics  above  two  or  three  degrees,  except  under  peculiar  circumstances, 

*  Ehrenberg,  Nat  und  Bild.  der  Coralleninseln,  <fec.,  Berlin,  1834. 


776 


RATE  OF  THE  GROWTH  OP  CORAL. 


[Ca  L. 


Fi«r.  108. 


as  in  the  Bermuda  Islands,  in  lat.  32°  K,  where  the  Atlantic  is  warmed 
by  the  Gulf  stream.  The  Pacific  Ocean,  throughout  a  space  compre- 
hended between  the  thirtieth  parallels  of  latitude  on  each  side  of  the 
equator,  is  extremely  productive  of  coral ;  as  also  are  the  Arabian  and 
Persian  Gulfs.  Coral  is  also  abundant  in  the  sea  between  the  coast  of 
Malabar  and  the  island  of  Madagascar.  Flinders  describes  a  reef  of  coral 
on  the  east  coast  of  New  Holland  as  having  a  length  of  nearly  1000 
miles,  and  as  being  in  one  part  unbroken  for  a  distance  of  350  miles. 
Rome  groups  of  coral  islands  in  the  Pacific  are  from  1100  to  1200  miles 

in  length,  by  300  or  400  in  breadth, 
as  the  Dangerous  Archipelago,  for 
example,  and  that  called  Radack  by 
Kotzebue;  but  the  islands  within 
these  spaces  are  always  small  points, 
and  often  very  thinly  sown. 

Of  the  numerous  species  of  zoo- 
phytes which  are  engaged  in  the 
production  of  coral  banks,  some  of 
the  most  common  belong  to  the 
Lamarckian  genera  Astrea,  Porites, 
Madrepora,  Millepora,  Caryophyllia, 
and  Meandrina.  4 
Rate  of  the  growth  of  Coral. — Very  different  opinions  have  been 
entertained  in  regard  to  the  rate  at  which  coral  reefs  increase.  In 
Captain  Beechey's  late  expedition  to  the  Pacific,  no  positive  information 
could  be  obtained  of  any  channel  having  been  filled  up  within  a  given 
period;  and  it  seems  established,  that  several  reefs  had  remained  for 
more  than  half  a  century,  at  about  the  same  depth  from  the  surface. 

Ehrenberg  also  questions  the  fact  of  channels  and  harbors  having 
been  closed  up  in  the  Red  Sea  by  the  rapid  increase  of  coral  limestone. 
He  supposes  the  notion  to  have  arisen  from  the  circumstance  of  havens 
having  been  occasionally  filled  up  in  some  places  with  coral  sand,  in 
others  with  large  quantities  of  ballast  of  coral  rock  thrown  down  from 
vessels. 

The  natives  of  the  Bermuda  Islands  point  out  certain  corals  now 

Genera  of  Zoophytes  most  common  in  coral  reefs. 
Fig.  J09. 


Meandrina  labyrinthica,  Lam. 


Astrea  dipsacca,  Lam. 


CH.  L] 


FORMATION   OF   CORAL   ISLANDS. 

Fig. 111. 
r.  110. 


m 


Extremity  of  branch  of  Madrepora 
muricata,  Lin. 


Fi?.  112. 


Caryophyllia  fastigiata,  Lam. 
Fig.  113. 


Forties  clavaria,  Lam. 


Oculina  hirtella,  Lam. 


growing  in  the  sea,  which,  according  to  tradition,  have  been  living  in  the 
same  spots  for  centuries.  It  is  supposed  that  some  of  them  may  vie  in 
age  with  the  most  ancient  trees  of  Europe.  Ehrenberg  also  observed 
single  corals  of  the  genera  Meandrina  and  Favia,  having  a  globular 
form,  from  six  to  nine  feet  in  diameter,  "  which  must  (he  says)  be  of 
immense  antiquity,  probably  several  thousand  years  old,  so  that  Pharaoh 
may  have  looked  upon  these  same  individuals  in  the  Red  Sea."*  They 
certainly  imply,  as  he  remarks,  that  the  reef  on  which  they  grow  has 
increased  at  a  very  slow  rate.  After  collecting  more  than  100  species, 
he  found  none  of  them  covered  with  parasitic  zoophytes,  nor  any 
instance  of  a  living  coral  growing  on  another  living  coral.  To  this 
repulsive  power  which  they  exert  whilst  living,  against  all  others  of 
their  own  class,  we  owe  the  beautiful  symmetry  of  some  large  Meandri- 


*  See  Ehrenberg's  work  above  cited,  p.  761. 


778         BATE  OF  THE  GROWTH  OF  CORAL.         [On.  L. 

rise,  and  other  species  which  adorn  our  museums.  Yet  Balani  and 
Serpulae  can  attach  themselves  to  living  corals,  and  holes  are  excavated 
in  them  by  saxicavous  rnollusca. 

At  the  island  called  Taaopoto,  in  the  South  Pacific,  the  anchor  of  a 
ship,  wrecked  about  50  years  before,  was  observed  in  seven  fathoms 
water,  still  preserving  its  original  form,  but  entirely  incrustedby  coral.* 
This  fact  would  seem  to  imply  a  slow  rate  of  augmentation ;  but  to 
form  a  correct  estimate  of  the  average  rate  must  be  very  difficult,  since 
it  must  vary  not  only  according  to  the  species  of  coral,  but  according 
to  the  circumstances  under  which  each  species  may  be  placed  ;  such,  for 
example,  as  the  depth  from  the  surface,  the  quantity  of  light,  the  tem- 
perature of  the  water,  its  freedom  from  sand  or  mud,  or  the  absence  or 
presence  of  breakers,  which  is  favorable  to  the  growth  of  some  kinds 
and  is  fatal  to  that  of  others.  It  should  also  be  observed  that  the 
apparent  stationary  condition  of  some  coral  reefs,  which  according  to 
Beechey  have  remained  for  centuries  at  the  same  depth  under  water, 
mav  be  due  to  subsidence,  the  upward  growth  of  the  coral  having  been 
just  sufficient  to  keep  pace  with  the  sinking  of  the  solid  foundation  on 
which  the  zoophytes  have  built.  We  shall  afterwards  see  how  far  this 
hypothesis  is  borne  out  by  other  evidence  in  the  regions  of  annular 
reefs  or  atolls.  • 

In  one  of  the  Maldive  islands  a  coral  reef,  which,  within  a  few  years, 
existed  on  an  islet  bearing  cocoa-nut  trees,  was  found  by  Lieutenant 
Prentice,  " entirely  covered  with  live  coral  and  madrepore"  The  natives 
'stated  that  the  islet  had  been  washed  away  by  a  change  in  the  currents, 
and  it  is  clear  that  a  coating  of  growing  coral  had  been  formed  in  a 
short  time.f  Experiments,  also,  of  Dr.  Allan,  on  the  east  coast  of 
Madagascar,  prove  the  possibility  of  coral  growing  to  a  thickness  of 
three  feet  in  about  half  a  year,J  so  that  the  rate  of  increase  may,  under 
favorable  circumstances,  be  very  far  from  slow. 

It  must  not  be  supposed  that  the  calcareous  masses  termed  coral 
reefs  are  exclusively  the  work  of  zoophytes :  a  great  variety  of  shells, 
and,  among  them,  some  of  the  largest  and  heaviest  of  known  species, 
contribute  to  augment  the  mass.  In  the  South  Pacific,  great  beds  of 
oysters,  mussels,  Pinnce  marince,  Chamce  (or  Tridacnce],  and  other 
shells,  cover  in  profusion  almost  every  reef;  and  on  the  beach  of  coral 
islands  are  seen  the  shells  of  echini  and  broken  fragments  of  crustaceous 
animals.  Large  shoals  of  fish  are  also  discernible  through  the  clear 
blue  water,  and  their  teeth  and  hard  palates  cannot  fail  to  be  often 
preserved  although  their  soft  cartilaginous  bones  may  decay. 

It  was  the  opinion  of  the  German  naturalist  Forster,  in  1780,  after  his 
voyage  round  the  world  with  Captain  Cook,  that  coral  animals  had  the 
power  of  building  up  steep  and  almost  perpendicular  walls  from  great 
depths  in  the  sea,  a  notion  afterwards  adopted  by  Captain  Flinders  and 

*  Stutchbury,  "West  of  England  Journal,  No.  i.  p.  49. 
f  Darwin's  Coral  Reefs,  p.  77. 
±  Ibid.  78. 


CH.  L.] 


DEPTH   AT   WHICH   CORALS   GROW. 


7T9 


others ;  but  it  is  now  very  generally  believed  that  these  zoophytes  cannot 
live  in  water  of  great  depths. 

Mr.  Darwin  has  come  to  the  conclusion,  that  those  species  which  are 
most  effective  in  the  construction  of  reefs,  rarely  flourish  at  a  greater 
depth  than  20  fathoms,  or  120  feet.  In  some  lagoons,  however,  where 
the  water  is  but  little  agitated,  there  are,  according  to  Kotzebue,  beds  of 
living  coral  in  25  fathoms  of  water,  or  150  feet ;  but  these  may  perhaps 
have  begun  to  live  in  shallower  water,  and  may  have  been  carried  down- 
wards by  the  subsidence  of  the  reef.  There  are  also  various  species  of 
zoophytes,  and  among  them  some  which  are  provided  with  calcareous  as 
well  as  horny  stems,  which  live  in  much  deeper  water,  even  in  some  cases 
to  a  depth  of  180  fathoms;  but  these  do  not  appear  to  give  origin  to 
stony  reefs. 

There  is  every  variety  of  form  in  coral  reefs,  but  the  most  remarkable 
and  numerous  in  the  Pacific  consist  of  circular  or  oval  strips  of  dry  land, 
enclosing  a  shallow  lake  or  lagoon  of  still  water,  in  which  zoophytes  and 
inollusca  abound.  These  annular  reefs  just  raise  themselves  above  the 
level  of  the  sea,  and  are  surrounded  by  a  deep  and  often  unfathomable 
ocean. 

In  the  annexed  cut  (fig.  114),  one  of  these  circular  islands  is  repre- 
sented, just  rising  above  the  waves,  covered  with  the  cocoa-nut  and 
other  trees,  and  inclosing  within  a  lagoon  of  tranquil  water. 

Fig.  114. 


View  of  Whitsunday  Island.     (Capt.  Beechey.)* 

The  accompanying  section  will  enable  the  reader  to  comprehend  the 
usual  form  of  such  islands.     (Fig.  115.) 


Fig.  115. 


Section  of  a  Coral  Island. 

a,  a,  Habitable  part  of  the  island,  consisting  of  a  strip  of  coral,  inclosing  the  lagoon. 

b,  b,  The  lagoon. 

*  Voyage  to  the  Pacific,  Ac.  in  1825-28. 


780  FORMATION    OF    CORAL  ISLANDS.  [Ca  L. 

The  subjoined  cut  (fig.  116.)  exhibits  a  small  part  of  the  section  of  a 
coral  island  on  a  larger  scale. 


Section  of  part  of  a  Coral  Island. 

a,  b,  Habitable  part  of  the  island. 

b,  c,  Slope  of  the  side  of  the  island,  plunging  at  an  angle  of  forty-five   to  the  depth 

of  fifteen  hundred  feet. 

c,  c,  Part  of  the  lagoon. 

d,  d,  Knolls  of  coral  in  the  lagoon,  with  overhanging  masses  of  coral  resembling  the 

capitals  of  columns. 

Of  thirty-two  of  these  coral  islands  visited  by  Beechey  in  his  voyage 
to  the  Pacific,  twenty-nine  had  lagoons  in  their  centres.  The  largest  was 
30  miles  in  diameter,  and  the  smallest  less  than  a  mile.  All  were 
increasing  their  dimensions  by  the  active  operations  of  the  lithophytes, 
which  appeared  to  be  gradually  extending  and  bringing  the  immersed 
parts  of  their  structure  to  the  surface.  The  scene  presented  by  these 
annular  reefs  is  equally  striking  for  its  singularity  and  beauty.  A  strip 
of  land  a  few  hundred  yards  wide  is  covered  by  lofty  cocoa-nut  trees, 
above  which  is  the  blue  vault  of  heaven.  This  band  of  verdure  is 
bounded  by  a  beach  of  glittering  white  sand,  the  outer  margin  of  which 
is  encircled  with  a  ring  of  snow-white  breakers,  beyond  which  are  the  dark 
heaving  waters  of  the  ocean.  The  inner  beach  incloses  the  still  clear 
water  of  the  lagoon,  resting  in  its  greater  part  on  white  sand,  and  when 
illuminated  by  a  vertical  sun,  of  a  most  vivid  green.*  Certain  species 
of  zoophytes  abound  most  in  the  lagoon,  others  on  the  exterior  margin, 
where  there  is  a  great  surf.  "  The  ocean,"  says  Mr.  Darwin,  "  throwing 
its  breakers  on  these  outer  shores,  appears  an  invincible  enemy,  yet  we 
see  it  resisted  and  even  conquered  by  means  which  at  first  seem  most 
weak  and  inefficient.  No  periods  of  repose  are  granted,  and  the  long 
swell  caused  by  the  steady  action  of  the  trade  wind  never  ceases.  The 
breakers  exceed  in  violence  those  of  our  temperate  regions,  and  it  is 
impossible  to  behold  them  without  feeling  a  conviction  that  rocks  of  gra- 
nite or  quartz  would  ultimately  yield  and  be  demolished  by  such  irresisti- 
ble forces.  Yet  these  low  insignificant  coral  islets  stand  and  are 
victorious,  for  here  another  power,  as  antagonist  to  the  former,  takes  part 
in  the  contest.  The  organic  forces  separate  the  atoms  of  carbonate  of 
lime  one  by  one  from  the  foaming  breakers,  and  unite  them  into  a  sym- 
metrical structure;  myriads  of  architects  are  at  work  night  and  day, 
month  after  month,  and  we  see  their  soft  and  gelatinous  bodies  through 
the  agency  of  the  vital  laws  conquering  the  great  mechanical  power  of 
the  waves  of  an  ocean,  which  neither  the  art  of  man,  nor  the  inanimate 
works  of  nature  could  successfully  resist."  f 

*  Darwin's  Journal,  <fcc.,  p.  540,  and  new  edit.,  of  1845,  p.  453. 

f  Darwin's  Journal,  Ac.,  pp.  547,  548.,  and  2d  edit,  of  1845,  p.  460. 


CH.  L]  FORMATION   OF    CORAL   ISLANDS.  781 

As  the  coral  animals  require  to  be  continually  immersed  in  salt  water, 
they  cannot  raise  themselves  by  their  own  efforts,  above  the  level  of  the 
lowest  tides.  The  manner  in  which  the  reefs  are  converted  into  islands 
above  the  level  of  the  sea  is  thus  described  by  Chamisso,  a  naturalist, 
who  accompanied  Kotzebue  in  his  voyages  : — "  When  the  reef,"  says  he, 
"is  of  such  a  height  that  it  remains  almost  dry  at  low  water  the  corals 
leave  off  building.  Above  this  line  a  continuous  mass  of  solid  stone  is 
seen  composed  of  the  shells  of  mollusks  and  echini,  with  their  broken-off 
prickles  and  fragments  of  coral,  united  by  calcareous  sand,  produced  by 
the  pulverization  of  shells.  The  heat  of  the  sun  often  penetrates  the 
mass  of  stone  when  it  is  dry,  so  that  it  splits  in  many  places,  and  the 
force  of  the  waves  is  thereby  enabled  to  separate  and  lift  blocks  of  coral, 
frequently  six  feet  long  and  three  or  four  in  thickness,  and  throw  them 
upon  the  reef,  by  which  means  the  ridge  becomes  at  length  so  high  that 
it  is  covered  only  during  some  seasons  of  the  year  by  the  spring  tides. 
After  this  the  calcareous  sand  lies  undisturbed,  and  offers  to  the  seeds 
of  trees  and  plants  cast  upon  it  by  the  waves  a  soil  upon  which  they 
rapidly  grow,  to  overshadow  its  dazzling  white  surface.  Entire  trunks 
of  trees,  which  are  carried  by  the  rivers  from  other  countries  and  islands, 
find  here,  at  length,  a  resting-place  after  their  long  wanderings :  with 
these  come  some  small  animals  such  as  insects  and  lizards,  as  the  first 
inhabitants.  Even  before  the  trees  form  a  wood,  the  sea-birds  nestle  here ; 
stray  land-birds  take  refuge  in  the  bushes  ;  and,  at  a  much  later  period, 
when  the  work  has  been  long  since  completed,  man  appears  and  builds 
his  hut  on  the  fruitful  soil."* 

In  the  above  description  the  solid  stone  is  stated  to  consist  of  shell  and 
coral,  united  by  sand ;  but  masses  of  very  compact  limestone  are  also 
found  even  in  the  uppermost  and  newest  parts  of  the  reef,  such  as  could 
only  have  been  produced  by  chemical  precipitation.  Professor  Agassiz 
also  informs  me  that  his  observations  on  the  Florida  reefs  (which  confirm 
Darwin's  theory  of  atolls  to  be  mentioned  in  the  sequel)  have  convinced 
him,  that  large  blocks  are  loosened,  not  by  shrinkage  in  the  sun's  heat, 
as  Chamisso  imagined,  but  by  innumerable  perforations  of  lithodomi  and 
other  boring  testacea. 

The  carbonate  of  lime  may  have  been  principally  derived  from  the 
decomposition  of  corals  and  testacea  ;  for  when  the  animal  matter  under- 
goes putrefaction,  the  calcareous  residuum  must  be  set  free  under  circum- 
stances very  favorable  to  precipitation,  especially  when  there  are  other 
calcareous  substances,  such  as  shells  and  corals,  on  which  it  may  be  de- 
posited. Thus  organic  bodies  may  be  inclosed  in  a  solid  cement,  and 
become  portions  of  rocky  masses.f 

The  width  of  the  circular  strip  of  dead  coral  forming  the  islands  ex- 
plored by  Captain  Beechey,  exceeded  in  no  instance  half  a  mile  from  the 
usual  wash  of  the  sea  to  the  edge  of.  the  lagoon,  and,  in  general,  was 
only  about  three  or  four  hundred  yards.J  The  depth  of  the  lagoons  is 

*  Kotzebue's  Voy.,  1815-18,  vol.  iii.  pp.  331-333.' 

f  Stutchbury,  West  of  Eng.  Journ.,  No.  i.  p.  50.  \  Captain  Beechey,  part  i.  p.  188. 


782 


LINEAR   DIRECTION   OF    CORAL   ISLANDS. 


[On.  L, 


various ;  in  some,  entered  by  Captain  Beechey,  it  was  from  twenty  to 
thirty-eight  fathoms. 

The  two  other  peculiarities  which  are  most  characteristic  of  the  annu- 
lar reef  or  atoll  are  first,  that  the  strip  of  dead 
coral  is  invariably  highest  on  the  windward 
side,  and  secondly,  that  there  is  very  generally 
an  opening  at  some  point  in  the  reef  afford- 
ing a  narrow  passage,  often  of  considerable 
depth,  from  the  sea  into  the  lagoon. 

Maldive  and  Laccadive  Isles. — The  chain 
of  reefs  and  islets  called  the  Maldives  (see 
fig.  117.),  situated  in  the  Indian  Ocean,  to 
the  south-west  of  Malabar,  forms  a  chain 
470  geographical  miles  in  length,  running 
due  north  and  south,  with  an  average  breadth 
of  about  50  miles.  It  is  composed  through- 
out of  a  series  of  circular  assemblages  of 
islets,  all  formed  of  coral,  the  larger  groups 
being  from  forty  to  ninety  miles  in  their 
longest  diameter.  Captain  Horsburgh,  whose 
chart  of  these  islands  is  subjoined,  states,  that 
outside  of  each  circle  or  atoll,  as  it  is  termed, 
there  are  coral  reefs  sometimes  extending  to 
the  distance  of  two  or  three  miles,  beyond 
which  there  are  no  soundings  at  immense 
depths.  But  in  the  centre  of  each  atoll  there 
is  a  lagoon  from  fifteen  to  forty-nine  fathoms 
deep.  In  the  channels  between  the  atolls  no 
soundings  can  usually  be  obtained  at  the 
depth  of  150  or  even  250  fathoms,  but  during 
Captain  Moresby's  survey,  soundings  were 
struck  at  150  and  200  fathoms,  the  only  in- 
stances as  yet  known  of  the  bottom  having 
been  reached,  either  in  the  Indian  or  Pacific 
oceans,  in  a  space  intervening  between  two 
separate  and  well  characterized  atolls. 

The  singularity  in  the  form  of  the  atolls 
of  this  archipelago  consists  in  their  being 
made  up,  not  of  one  continuous  circular  reef 
but  of  a  ring  of  small  coral  islets  some- 
times more  than  a  hundred  in  number,  each 
of  which  is  a  miniature  atoll  in  itself;  in  other  words,  a  ring-shaped  strip 
of  coral  surrounding  a  lagoon  of  salt  water.  To  account  for  the  origin 
of  these,  Mr.  Darwin  supposes  the  larger  annular  reef  to  have  been  broken 
up  into  a  number  of  fragments,  each  of  which  acquired  its  peculiar  con- 
figurations under  the  influence  of  causes  similar  to  those  to  which  the 


One. 


Channel* 


•s 


CH.  L.]       CIRCULAR  FORM  OF  CORAL  ISLANDS.         783 

structure  of  the  parent  atoll  has  been  due.  Many  of  the  minor  rings  are 
no  less  than  three,  and  even  five  miles  in  diameter,  and  some  are  situated 
in  the  midst  of  the  principal  lagoon ;  but  this  happens  only  in  cases 
where  the  sea  can  enter  freely  through  breaches  in  the  outer  or  marginal 
reef. 

The  rocks  of  the  Maldives  are  composed  of  sandstone  formed  of  broken 
shells  and  corals,  such  as  may  be  obtained  in  a  loose  state  from  the  beach, 
and  which  is  seen  when  exposed  for  a  few  days  to  the  air  to  become  har- 
dened. The  sandstone  is  sometimes  observed  to  be  an  aggregate  of  broken 
shells,  corals,  pieces  of  wood,  and  shells  of  the  cocoa-nut.* 

The  Laccadive  islands  run  in  the  same  line  with  the  Maldives,  on  the 
north,  as  do  the  isles  of  the  Chagos  Archipelago,  on  the  south ;  so  that 
these  may  be  continuations  of  the  same  chain  of  submerged  mountains, 
crested  in  a  similar  manner  by  coral  limestones. 

Origin  of  the  circular  form — not  volcanic. — The  circular  and  oval 
shape  of  so  many  reefs,  each  having  a  lagoon  in  the  centre,  and  being 
surrounded  on  all  sides  by  a  deep  ocean,  naturally  suggested  the  idea  that 
they  were  nothing  more  than  the  crests  of  submarine  volcanic  craters 
overgrown  by  coral ;  and  this  theory  I  myself  advocated  in  the  earlier 
editions  of  this  work.  Although  I  am  now  about  to  show  that  it  must 
be  abandoned,  it  may  still  be  instructive  to  point  out  the  grounds  on 
which  it  was  formerly  embraced.  In  the  first  place,  it  had  been  remarked 
that  there  were  many  active  volcanoes  in  the  coral  region  of  the  Pacific, 
and  that  in  some  places,  as  in  Gambier's  group,  rocks  composed  of  porous 
lava  rise  up  in  a  lagoon  bordered  by  a  circular  reef,  just  as  the  two  cones 
of  eruption  called  the  Kamenis  have  made  their  appearance  in  the  times 
of  history  within  the  circular  gulf  of  Santorin.f  It  was  also  observed  that, 
as  in  S.  Shetland,  Barren  Island,  and  others  of  volcanic  origin,  there  is 
one  narrow  breach  in  the  walls  of  the  outer  cone  by  which  ships  may 
enter  a  circular  gulf,  so  in  like  manner  there  is  often  a  single  deep  passage 
leading  into  the  lagoon  of  a  coral  island,  the  lagoon  itself  seeming  to 
represent  the  hollow  or  gulf  just  as  the  ring  of  dry  coral  recals  to  our 
minds  the  rim  of  a  volcanic  crater.  More  lately,  indeed,  Mr.  Darwin  has 
shown  that  the  numerous  volcanic  craters  of  the  Galapagos  Archipelago 
in  the  Pacific  have  all  of  them  their  southern  sides  the  lowest,  or  in  many 
cases  quite  broken  down,  so  that  if  they  were  submerged  and  incrusted 
with  coral,  they  would  resemble  true  atolls  in  shape.J 

Another  argument  which  I  adduced  when  formerly  defending  this  doc- 
trine was  derived  from  Ehrenberg's  statement,  that  some  banks  of  coral 
in  the  Red  Sea  were  square,  while  many  others  were  ribbon-like  strips, 
with  flat  tops,  and  without  lagoons.  Since,  therefore,  all  the  genera  and 
many  of  the  species  of  zoophytes  in  the  Red  Sea  agreed  with  those  which 
elsewhere  construct  lagoon  islands,  it  followed  that  the  stone-making 

*  Captain  Moresby  on  the  Maldives,  Journ.  Roy.  Geograph.  Soc.,  voL  T.  part 
ii.  p.  400. 

•f  See  above,  p.  442. 

i  Darwin,  Volcanic  Islands,  p.  113. 


784  ORIGIN   OF  THE  FORM  [Cn.  L. 

zoophytes  are  not  guided  by  their  own  instinct  in  the  formation  of  annu- 
lar reefs,  but  that  this  peculiar  shape  and  the  position  of  such  reefs  in  the 
midst  of  a  deep  ocean  must  depend  on  the  outline  of  the  submarine 
bottom,  which  resembles  nothing  else  in  nature  but  the  crater  of  a 
lofty  submerged  volcanic  cone.  The  enormous  size,  it  is  true,  of  some 
atolls,  made  it  necessary  for  me  to  ascribe  to  the  craters  of  many  sub- 
marine volcanoes  a  magnitude  which  was  startling,  and  which  had  often 
been  appealed  to  as  a  serious  objection  to  the  volcanic  theory.  That  so 
many  of  them  were  of  the  same  height,  or  just  level  with  the  water,  did 
not  present  a  difficulty  so  long  as  we  remained  ignorant  of  the  fact  that 
the  reef-building  species  do  not  grow  at  greater  depths  than  twenty-five 
fathoms. 

May  be  explained  by  subsidence. — Mr.  Darwin,  after  examining  a 
variety  of  coral  formations  in  different  parts  of  the  globe,  was  induced 
to  reject  the  opinion  that  their  shape  represented  the  form  of  the  original 
bottom.  Instead  of  admitting  that  the  ring  of  dead  coral  rested  on  a 
circular  or  oval  ridge  of  rock,  or  that  the  lagoon  corresponded  to  a  pre- 
existing cavity,  he  advanced  a  new  opinion,  which  must,  at  first  sight, 
seem  paradoxical  in  the  extreme ;  namely,  that  the  lagoon  is  precisely  in 
the  place  once  occupied  by  the  highest  part  of  a  mountainous  island,  or, 
in  other  cases,  by  the  top  of  a  shoal. 

The  following  is  a  brief  sketch  of  the  facts  and  arguments  in  favor  of 
this  new  view : — Besides  those  rings  of  dry  coral  which  enclose  lagoons,  there 
are  others  having  a  similar  form  and  structure  which  encircle  lofty  islands. 
Of  the  latter  kind  is  Vanikoro,  (see  map,  fig.  39,  p.  351,)  celebrated  on 
account  of  the  shipwreck  of  La  Peyrouse,  where  the  coral  reef  runs  at 
the  distance  of  two  or  three  miles  from  the  shore,  the  channel  between  it 
and  the  land  having  a  general  depth  of  between  200  and  300  feet.  This 
channel,  therefore,  is  analogous  to  a  lagoon,  but  with  an  island  standing 
in  the  middle  like  a  picture  in  its  frame.  In  like  manner  in  Tahiti  we 
see  a  mountainous  land,  with  everywhere  round  its  margin  a  lake  or 
zone  of  smooth  salt  water,  separated  from  the  ocean  by  an  encircling 
reef  of  coral,  on  which  a  line  of  breakers  is  always  foaming.  So  also 
New  Caledonia,  a  long  narrow  island  east  of  New  Holland,  in  which  the 
rocks  are  granitic,  is  surrounded  by  a  reef  which  runs  for  a  length  of  400 
miles.  This  reef  encompasses  not  only  the  island  itself,  but  a  ridge  of 
rocks  which  are  prolonged  in  the  same  direction  beneath  the  sea.  No 
one,  therefore,  will  contend  for  a  moment  that  in  this  case  the  corals  are 
based  upon  the  rim  of  a  volcanic  crater,  in  the  middle  of  which  stands  a 
mountain  or  island  of  granite. 

The  great  barrier  reef,  already  mentioned  as  running  parallel  to  the 
north-east  coast  of  Australia  for  nearly  1000  miles,  is  another  most  re- 
markable example  of  a  long  strip  of  coral  running  parallel  to  a  coast.  Its 
distance  from  the  mainland  varies  from  twenty  to  seventy  miles,  and  the 
depth  of  the  great  arm  of  the  sea  thus  enclosed  is  usually  between  ten 
and  twenty  fathoms,  but  towards  one  end  from  forty  to  sixty.  This  great 
reef  would  extend  much  farther,  according  to  Mr.  Jukes,  if  the  growth  of 


CH.  L.] 


OF    COEAL    ISLANDS. 


785 


coral  were  not  prevented  off  the  shores  of  New  Guinea  by  a  muddy  bot- 
tom, caused  by  rivers  charged  with  sediment  which  flow  from  the 
southern  coast  of  that  great  island.* 

Two  classes  of  reefs,  therefore,  have  now  been  considered ;  first,  the 
atoll,  and,  secondly,  the  encircling  and  barrier  reef,  all  agreeing  perfectly 
in  structure,  and  the  sole  difference  lying  in  the  absence  in  the  case  of  the 
atoll  of  all  land,  and  in  the  others  the  presence  of  land  bounded  either 
by  an  encircling  or  a  barrier  reef.  But  there  is  still  a  third  class  of  reefs, 
called  by  Mr.  Darwin  "  fringing  reefs,"  which  approach  much  nearer  the 
land  than  those  of  the  encircling  and  barrier  class,  and  which  indeed  so 
nearly  touched  the  coast  as  to  leave  nothing  in  the  intervening  space 
resembling  a  lagoon.  "  That  these  reefs  are  not  attached  quite  close  to 
the  shore  appears  to  be  the  result  of  two  causes;  first,  that  the  water 
immediately  adjoining  the  beach  is  rendered  turbid  by  the  surf,  and  there- 
fore injurious  to  all  zoophytes;  and,  secondly,  that  the  larger  and  efficient 
kinds  only  flourish  on  the  outer  edge  amidst  the  breakers  of  the  open 
sea."  f 

It  will  at  once  be  conceded  that  there  is  so  much  analogy  between  the 
form  and  position  of  the  strip  of  coral  in  the  atoll,  and  in  the  encircling 
and  barrier  reef,  that  no  explanation  can  be  satisfactory  which  does  not 
include  the  whole.  If  we  turn  in  the  first  place  to  the  encircling  and 
barrier  reefs,  and  endeavor  to  explain  how  the  zoophytes  could  have 
found  a  bottom  on  which  to  begin  to  build,  we  are  met  at  once  with  a 
great  difficulty.  It  is  a  general  fact,  long  since  remarked  by  Dampier, 
that  high  land  and  deep  seas  go  together.  In  other  words,  steep 
mountains  coming  down  abruptly  to  the  sea-shore  are  generally  continued 
with  the  same  slope  beneath  the  water.  But  where  the  reef,  as  at  b  and 
c  (fig.  118),  is  distant  several  miles  from  a  steep  coast,  a  line  drawn  per- 

Fig.  118. 


Supposed  section  of  an  island  with  an  encircling  reef  of  coral. 
A,  The  island. 

b,  c,  Highest  points  of  the  encircling  reef  between  which  and  the  coast  is  seen  a  space 
occupied  by  still  water. 

pendicularly  downwards  from  its  outer  edges  b  c  to  the  fundamental  rock 
d  e,  must  descend  to  a  depth  exceeding  by  several  thousand  feet  the 
limits  at  which  the  efficient  stone-building  corals  can  exist,  for  we  have 
seen  that  they  cease  to  grow  in  water  which  is  more  than  120  feet  deep. 
That  the  original  rock  immediately  beneath  the  points  6  c  is  actually  as 
far  from  the  surface  as  d  e,  is  not  merely  inferred  from  Dampier's  rule, 

*  Quart.  Journ.  Geol.  Soc  4.  xcm. 

f  Darwin's  Journal,  p.  557.  2d  edit.  chap.  20,  and  Coral  Islands,  chapters  1,  2,  3. 

50 


T86 


ORIGIN    OF   THE   FORM 


[On.  L 


but  confirmed  by  the  fact,  that,  immediately  outside  the  reef,  soundings 
are  either  not  met  with  at  all,  or  only  at  enormous /depths.  In  short,  the 
ocean  is  as  deep  there  as  might  have  been  anticipated  in  the  neighbor- 
hood of  a  bold  coast ;  and  it  is  obviously  the  presence  of  the  coral  alone 
which  has  given  rise  to  the  anomalous  existence  of  shallow  water  on  the 
reef  and  between  it  and  the  land. 

After  studying  in  minute  detail  all  the  phenomena  above  described, 
Mr.  Darwin  has  offered  in  explanation  a  theory  now  very  generally 
adopted.  The  coral-forming  polypi,  he  states,  begin  to  build  in  water  of 
a  moderate  depth,  and  while  they  are  yet  at  work,  the  bottom  of  the 
sea  subsides  gradually,  so  that  the  foundation  of  their  edifice  is  carried 
downwards  at  the  same  time  that  they  are  raising  the  superstructure. 
If,  therefore,  the  rate  of  subsidence  be  not  too  rapid,  the  growing  coral 
will  continue  to  build  up  to  the  surface ;  the  mass  always  gaining  in 
height  above  its  original  base,  but  remaining  in  other  respects  in  the 
same  position.  Not  so  with  the  land  ;  each  inch  lost  is  irreclaimably 
gone  ;  as  it  sinks,  the  water  gains  foot  by  foot  on  the  shore,  till  in  many 
cases  the  highest  peak  of  the  original  island  disappears.  What  was 
before  land  is  then  occupied  by  the  lagoon,  the  position  of  the  encircling 
coral  remaining  unaltered,  with  the  exception  of  a  slight  contraction  of 
its  dimensions. 

In  this  manner  are  encircling  reefs  and  atolls  produced ;  and  in  con- 
firmation of  his  views  Mr.  Darwin  has  pointed  out  examples  which  illus- 
trate every  intermediate  state,  from  that  of  lofty  islands,  such  as  Otaheite, 
encircled  by  coral,  to  that  of  Gambier's  group,  where  a  few  peaks  only 
of  land  rise  out  of  a  lagoon,  and  lastly,  to  the  perfect  atoll,  having  a 
lagoon  several  hundred  feet  deep,  surrounded  by  a  reef  rising  steeply 
from  an  unfathomed  ocean. 

If  we  embrace  these  views,  it  is  clear,  that  in  regions  of  growing  coral 
a  similar  subsidence  must  give  rise  to  barrier  reefs  along  the  shores  of 
a  continent.  Thus  suppose  A  (fig.  119),  to  represent  the  north-east 
portion  of  Australia,  and  b  c  the  ancient  level  of  the  sea,  when  the  coral 
reef  d  was  formed.  If  the  land  sink  so  that  it  is  submerged  more  and 


Fig.   119. 


more,  the  sea  must  at  length  stand  at  the  level  ef,  the  reef  in  the  mean 
time  having  been  enlarged  and  raised  to  the  point  g.  The  distance 
between  the  shore  /,  and  the  barrier  reef  g,  is  now  much  greater  than 
originally  between  the  shore  c  and  the  reef  d,  and  the  longer  the  subsi- 
dence continues  the  farther  will  the  coast  of  the  mainland  recede. 

When  the  first  edition  of  this  work  appeared  in  1831,  several  years 
before  Mr.  Darwin  had  investigated  the  facts  on  which  his  theory  is 


CH.  L.]  OF    CORAL   ISLANDS.  787 

founded,  I  had  come  to  the  opinion  that  the  land  was  subsiding  at  the 
bottom  of  those  parts  of  the  Pacific  where  atolls  are  numerous,  although 
I  failed  to  perceive  that  such  a  subsidence,  if  conceded,  would  equally 
solve  the  enigma  as  to  the  form  both  of  annular  and  barrier  reefs. 

I  shall  cite  the  passage  referred  to,  as  published  by  me  in  1831 : — "It 
is  a  remarkable  circumstance  that  there  should  be  so  vast  an  area  in 
Eastern  Oceanica,  studded  with  minute  islands,  without  one  single  spot 
where  there  is  a  wider  extent  of  land  than  belongs  to  such  islands  as 
Otaheite,  Owhyhee,  and  a  few  others,  which  either  have  been  or  are  still 
the  seats  of  active  volcanoes.  If  an  equilibrium  only  were  maintained  be- 
tween the  upheaving  and  depressing  force  of  earthquakes,  large  islands 
would  very  soon  be  formed  in  the  Pacific ;  for,  in  that  case,  the  growth 
of  limestone,  the  flowing  of  lava,  and  the  ejection  of  volcanic  ashes,  would 
combine  with  the  upheaving  force  to  form  new  land. 

"  Suppose  a  shoal,  600  miles  in  length,  to  sink  fifteen  feet,  and  then  to 
remain  unmoved  for  a  thousand  years ;  during  that  interval  the  growing 
coral  may  again  approach  the  surface.  Then  let  the  mass  be  re-elevated 
fifteen  feet,  so  that  the  original  reef  is  restored  to  its  former  position :  in 
this  case,  the  new  coral  formed  since  the  first  subsidence  will  constitute 
an  island  600  miles  long.  An  analogous  result  would  have  occurred  if 
a  lava-current  fifteen  feet  thick  had  overflowed  the  submerged  reef.  The 
absence,  therefore,  of  more  extensive  tracts  of  land  in  the  Pacific, 
seems  to  show  that  the  amount  of  subsidence  by  earthquakes  exceeds, 
in  that  quarter  of  the  globe,  at  present,  the  elevation  due  to  the  same 
cause."* 

Another  proof  also  of  subsidence  derived  from  the  structure  of  atolls, 
was  pointed  out  by  me  in  the  following  passage  in  all  former  editions. 
"  The  low  coral  islands  of  the  Pacific,"  says  Captain  Beechey,  "  follow 
one  general  rule  in  having  their  windward  side  higher  and  more  perfect 
than  the  other.  At  Gambia  and  Matilda  islands  this  inequality  is  very 
conspicuous,  the  weather  side  of  both  being  wooded,  and  of  the  former 
inhabited,  while  the  other  sides  are  from  twenty  to  thirty  feet  under 
water ;  where,  however,  they  may  be  perceived  to  be  equally  narrow  and 
well  defined.  It  is  on  the  leeward  side  also  that  the  entrances  into  the 
lagoons  occur ;  and  although  they  may  sometimes  be  situated  on  a  side 
that  runs  in  the  direction  of  the  wind,  as  at  Bow  Island,  yet  there  are 
none  to  windward."  These  observations  of  Captain  Beechey  accord  with 
those  which  Captain  Horsburgh  and  other  hydrographers  have  made  in 
regard  to  the  coral  islands  of  other  seas.  From  this  fortunate  circum- 
stance ships  can  enter  and  sail  out  with  ease ;  whereas  if  the  narrow  in- 
lets were  to  windward,  vessels  which  once  entered  might  not  succeed  for 
months  in  making  their  way  out  again.  The  well-known  security  of 
many  of  these  harbors  depends  entirely  on  this  fortunate  peculiarity  in 
their  structure. 

"  In  what  manner  is  this  singular  conformation  to  be  accounted  for  ? 
The  action  of  the  waves  is  seen  to  be  the  cause  of  the  superior  elevation 
*  See  Principles  of  Geology,  1st  edit,  vol.  ii.  p.  296. 


788  ORIGIN   OF   THE   FORM  [Cn.  L. 

of  some  reefs  on  their  windward  sides,  where  sand  and  large  masses  of 
coral  rock  are  thrown  up  by  the  breakers ;  but  there  is  a  variety  of  cases 
where  this  cause  alone  is  inadequate  to  solve  the  problem ;  for  reefs  sub- 
merged at  considerable  depths,  where  the  movements  of  the  sea  cannot 
exert  much  power,  have,  nevertheless,  the  same  conformation,  the  lee- 
ward being  much  lower  than  the  windward  side.* 

"  I  am  informed  by  Captain  King,  that,  on  examining  the  reefs  called 
Rowley  Shoals,  which  lie  off  the  north-west  coast  of  Australia,  where  the 
east  and  west  monsoons  prevail  alternately,  he  found  the  open  side  of  one 
crescent-shaped  reef,  the  Imperieuse,  turned  to  the  east,  and  of  another, 
the  Mermaid,  turned  to  the  west ;  while  a  third  oval  reef,  of  the  same 
group,  was  entirely  submerged.  This  want  of  conformity  is  exactly  what 
we  should  expect,  where  the  winds  vary  periodically. 

"It  seems  impossible  to  refer  the  phenomenon  now  under  consideration 
to  any  original  uniformity  in  the  configuration  of  submarine  volcanoes,  on 
the  summits  of  which  we  may  suppose  the  coral  reefs  to  grow ;  for  al- 
though it  is  very  common  for  craters  to  be  broken  down  on  one  side 
only,  we  cannot  imagine  any  cause  that  should  breach  them  all  in  the 
same  direction.  But  the  difficulty  will,  perhaps,  be  removed,  if  we  call 
in  another  part  of  the  volcanic  agency — subsidence  by  earthquakes. 
Suppose  the  windward  barrier  to  have  been  raised  by  the  mechanical 
action  of  the  waves  to  the  height  of  two  or  three  yards  above  the  wall 
on  the  leeward  side,  and  then  the  whole  island  to  sink  down  a  few 
fathoms,  the  appearances  described  would  then  be  presented  by  the 
submerged  reef.  A  repetition  of  such  operations,  by  the  alternate  eleva- 
tion and  depression  of  the  same  mass  (an  hypothesis  strictly  conformable 
to  analogy),  might  produce  still  greater  inequality  in  the  two  sides, 
especially  as  the  violent  efflux  of  the  tide  has  probably  a  strong  ten- 
dency to  check  the  accumulation  of  the  more  tender  corals  on  the  lee- 
ward reef;  while  the  action  of  the  breakers  contributes  to  raise  the 
windward  barrier."! 

Previously  to  my  adverting  to  the  signs  above  enumerated  of  a  down- 
ward movement  in  the  bed  of  the  ocean,  Dr.  MacCulloch,  Captain 
Beechey,  and  many  other  writers,  had  shown  that  masses  of  recent  coral 
had  been  laid  dry  at  various  heights  above  the  sea-level,  both  in  the  Red 
Sea,  the  islands  of  the  Pacific,  and  in  the  East  and  West  Indies.  After 
describing  thirty-two  coral  islands  in  the  Pacific,  Captain  Beechey  men- 
tioned that  they  were  all  formed  of  living  coral  except  one,  which,  although 
of  coral  formation,  was  raised  about  seventy  or  eighty  feet  above  the 
level  of  the  sea,  and  was  encompassed  by  a  reef  of  living  coral.  It  is 
called  Elizabeth  or  Henderson's  Island,  and  is  five  miles  in  length  by  one 
in  breadth.  It  has  a  flat  surface,  and,  on  all  sides,  except  the  north,  is 
bounded  by  perpendicular  cliffs  about  fifty  feet  high,  composed  entirely 
of  dead  coral,  more  or  less  porous,  honey-combed  at  the  surface,  and  har- 


*  Voyage  to  the  Pacific,  <fcc.,  p.  189. 

f  See  Principles  of  Geology,  1st  ed.,  1832,  vol.  ii.  p.  293. 


CH.  L.]  OF    CORAL   ISLANDS.  789 

dening  into  a  compact  calcareous  mass,  which  possesses  the  fracture 
of  secondary  limestone,  and  has  a  species  of  millepore  interspersed  through 
it.  These  cliffs  are  considerably  undermined  by  the  action  of  the  waves, 
and  some  of  them  appear  on  the  eve  of  precipitating  their  superincum- 

Fig.  120. 


Elizabeth,  or  Henderson's  Island. 

bent  weight  into  the  sea.  Those  which  are  less  injured  in  this  way  pre- 
sent no  alternate  ridges  or  indication  of  the  different  levels  which  the  sea 
might  have  occupied  at  different  periods ;  but  a  smooth  surface,  as  if  the 
island,  which  has  probably  been  raised  by  volcanic  agency,  had  been 
forced  up  by  one  great  subterraneous  convulsion.*  At  the  distance  of  a 
few  hundred  yards  from  this  island,  no  bottom  could  be  gained  with 
200  fathoms  of  line. 

It  will  be  seen,  from  the  annexed  sketch,  communicated  to  me  by 
Lieutenant  Smith,  of  the  Blossom,  that  the  trees  came  down  to  the  beach 
towards  the  centre  of  the  island ;  a  break  at  first  sight  resembling  the 
openings  which  usually  lead  into  lagoons  ;  but  the  trees  stand  on  a  steep 
slope,  and  no  hollow  of  an  ancient  lagoon  was  perceived. 

Beechey  also  remarks,  that  the  surface  of  Henderson's  Island  is  flat, 
and  that  in  Queen  Charlotte's  Island,  one  of  the  same  group,  but  under 
water,  there  was  no  lagoon,  the  coral  having  grown  up  everywhere  to 
one  level.  The  probable  cause  of  this  obliteration  of  the  central  basin 
or  lagoon  will  be  considered  in  the  sequel. 

That  the  bed  of  the  Pacific  and  Indian  oceans,  where  atolls  are  frequent, 
must  have  been  sinking  for  ages,  might  be  inferred,  says  Mr.  Darwin, 
from  simply  reflecting  on  two  facts ;  first,  that  the  efficient  coral-building 
zoophytes  do  not  flourish  in  the  ocean  at  a  greater  depth  than  120  feet ; 
and,  secondly,  that  there  are  spaces  occupying  areas  of  many  hundred  thou- 
sand square  miles,  where  all  the  islands  consist  of  coral,  and  yet  none 
of  which  rise  to  a  greater  height  than  may  be  accounted  for  by  the  ac- 
tion of  the  winds  and  waves  on  broken  and  triturated  coral.  Were  we 
to  take  for  granted  that  the  floor  of  the  ocean  had  remained  stationary 
from  the  time  when  the  coral  began  to  grow,  we  should  be  compelled  to 
assume  that  an  incredible  number  of  submarine  mountains  of  vast  height 
(for  the  ocean  is  always  deep,  and  often  unfathomable  between  the  dif- 
ferent atolls)  had  all  come  to  within  120  feet  of  the  surface,  and  yet  no 
one  mountain  had  risen  above  water.  But  no  sooner  do  we  admit  the 
theory  of  subsidence,  than  this  great  difficulty  vanishes.  However 
varied  may  have  been  the  altitude  of  different  islands,  or  the  separate 
peaks  of  particular  mountain-chains,  all  may  have  been  reduced  to  one 
uniform  level  by  the  gradual  submergence  of  the  loftiest  points,  and  the 
additions  made  to  the  calcareous  cappings  of  the  less  elevated  summits 
as  they  subsided  to  great  depths. 

*  Beechey's  Voyage  to  the  Pacific,  <fec.,  p.  46. 


T90  OPENINGS   INTO   THE   LAGOONS.  [On.  L. 

Openings  into  the  lagoons. — In  the  general  description  of  atolls  and 
encircling  reefs,  it  was  mentioned  that  there  is  almost  always  a  deep  nar- 
row passage  opening  into  the  lagoon,  or  into  the  still  water  between  the 
reef  and  the  shore,  which  is  kept  open  by  the  efflux  of  the  sea  as  the 
tide  goes  down. 

The  origin  of  this  channel  must,  according  to  the  theory  of  subsidence 
before  explained,  be  traced  back  to  causes  which  were  in  action  during 
the  existence  of  the  encircling  reef,  and  when  an  island  or  mountain-top 
rose  within  it,  for  such  a  reef  precedes  the  atoll  in  the  order  of  forma- 
tion. Now  in  those  islands  in  the  Pacific,  which  are  large  enough  to 
feed  small  rivers,  there  is  generally  an  opening  or  channel  in  the  sur- 
rounding coral  reef  at  the  point  where  the  stream  of  fresh  water  enters 
the  sea.  The  depth  of  these  channels  rarely  exceeds  twenty-five  feet ; 
and  they  may  be  attributed,  says  Captain  Beechey,  to  the  aversion  of 
the  lithophytes  to  fresh  water,  and  to  the  probable  absence  of  the  mineral 
matter  of  which  they  construct  their  habitations.* 

Mr.  Darwin,  however,  has  shown,  that  mud  at  the  bottom  of  river- 
courses  is  far  more  influential  than  the  freshness  of  the  water  in  pre- 
venting the  growth  of  the  polypi,  for  the  walls  which  inclose  the  open- 
ings are  perpendicular,  and  do  not  slant  off  gradually,  as  would  be  the 
case,  if  the  nature  of  the  element  presented  the  only  obstacle  to  the 
increase  of  the  coral-building  animals. 

When  a  breach  has  thus  been  made  in  the  reef,  it  will  be  prevented 
from  closing  up  by  the  efflux  of  the  sea  at  low  tides ;  for  it  is  sufficient 
that  a  reef  should  rise  a  few  feet  above  low-water  mark  to  cause  the 
waters  to  collect  in  the  lagoon  at  high  tide,  and  when  the  sea  falls,  to 
rush  out  at  one  or  more  points  where  the  reef  happens  to  be  lowest  or 
weakest.  This  event  is  strictly  analogous  to  that  witnessed  in  our  estua- 
ries, where  a  body  of  salt  water  accumulated  during  the  flow  issues  with 
great  velocity  at  the  ebb  of  the  tide,  and  scours  out  or  keeps  open  a  deep 
passage  through  the  bar,  which  is  almost  always  formed  at  the  mouth  of 
a  river.  At  first  there  are  probably  many  openings,  but  the  growth  of 
the  coral  tends  to  obstruct  all  those  which  do  not  serve  as  the  principal 
channels  of  discharge  ;  so  that  their  number  is  gradually  reduced  to  a 
few,  and  often  finally  to  one.  The  fact  observed  universally,  that  the 
principal  opening  fronts  a  considerable  valley  in  the  encircled  island,  be- 
tween the  shores  of  which  and  the  outer  reef  there  is  often  deep  water, 
scarcely  leaves  any  doubt  as  to  the  real  origin  of  the  channel  in  all  those 
countless  atolls  where  the  nucleus  of  land  has  vanished. 

Size  of  atolls  and  barrier  reefs. — In  regard  to  the  dimensions  of 
atolls,  it  was  stated  that  some  of  the  smallest  observed  by  Beechey  in 
the  Pacific  were  only  a  mile  in  diameter.  If  their  external  slope  under 
water  equals  upon  an  average  an  angle  of  45°,  then  would  such  an  atoll 
at  the  depth  of  half  a  mile,  or  2640  feet,  have  a  diameter  of  two  miles. 
Hence  it  would  appear  that  there  must  be  a  tendency  in  every  atoll  to 


*  Voyage  to  the  Pacific,  &c.,  p.  194. 


CH.  L.]  SIZE   OF    ATOLLS    AND    BARRIER   REEFS.  791 

grow  smaller,  except  in  those  cases  where  oscillations  of  level  enlarge  the 
base  on  which  the  coral  grows  by  throwing  down  a  talus  of  detrital 
matter  all  round  the  original  cone  of  limestone. 

Bow  Island  is  described  by  Captain  Beechey  as  seventy  miles  in  cir- 
cumference, and  thirty  in  its  greatest  diameter,  but  we  have  seen  that 
some  of  the  Maldives  are  much  larger. 

As  the  shore  of  an  island  or  continent  which  is  subsiding  will  recede  from 
a  coral  reef  at  a  slow  or  rapid  rate  according  as  the  surface  of  the  land 
has  a  steep  or  gentle  slope,  we  cannot  measure  the  thickness  of  the  coral 
by  its  distance  from  the  coast ;  yet,  as  a  general  rule,  those  reefs  which 
are  farthest  from  the  land  imply  the  greatest  amount  of  subsidence.  We 
learn  from  Flinders,  that  the  barrier  reef  of  north-eastern  Australia  is  in 
some  places  seventy  miles  from  the  mainland,  and  it  should  seem  that  a 
calcareous  formation  is  there  in  progress  1000  miles  long  from  north  to 
south,  with  a  breadth  varying  from  twenty  to  seventy  miles.  It  may  not, 
indeed,  be  continuous  over  this  vast  area,  for  doubtless  innumerable  islands 
have  been  submerged  one  after  another  between  the  reef  and  mainland, 
like  some  which  still  remain,  as,  for  example,  Murray's  Islands,  lat.  9° 
54'  S.  We  are  also  told  that  some  parts  of  the  gulf  inclosed  within  a 
barrier  are  400  feet  deep,  so  that  the  efficient  rock-building  corals  cannot 
be  growing  there,  and  in  other  parts  of  it  islands  appear  encircled  by 
reefs. 

It  will  follow  as  one  of  the  consequences  of  the  theory  already  explain- 
ed that,  provided  the  bottom  of  the  sea  does  not  sink  too  fast  to  allow 
the  zoophytes  to  build  upwards  at  the  same  pace,  the  thickness  of  coral 
will  be  great  in  proportion  to  the  rapidity  of  subsidence,  so  that  if  one 
area  sinks  two  feet  while  another  sinks  one,  the  mass  of  coral  in  the  first 
area  will  be  double  that  in  the  second.  But  the  downward  movement 
must  in  general  have  been  very  slow  and  uniform,  or  where  intermittent, 
must  have  consisted  of  a  great  number  of  depressions,  each  of  slight 
amount,  otherwise  the  bottom  of  the  sea  would  have  been  carried  down 
faster  than  the  corals  could  build  upwards,  and  the  island  or  continent 
would  be  permanently  submerged,  having  reached  a  depth  of  120  or  150 
feet,  at  which  the  effective  reef-constructing  zoophytes  cease  to  live.  If, 
then,  the  subsidence  required  to  account  for  all  the  existing  atolls  must 
have  amounted  to  three  or  four  thousand  feet,  or  even  sometimes  more, 
we  are  brought  to  the  conclusion  that  there  has  been  a  slow  and  gradual 
sinking  to  this  enormous  extent.  Such  an  inference  is  perfectly  in  har- 
mony with  views  which  the  grand  scale  of  denudation,  everywhere 
observable  in  the  older  rocks,  has  led  geologists  to  adopt  in  reference  to 
upward  movements.  They  must  also  have  been  gradual  and  continuous 
throughout  indefinite  ages  to  allow  the  waves  and  currents  of  the  ocean 
to  operate  with  adequate  power. 

The  map  constructed  by  Mr.  Darwin  to  display  at  one  view  the  geo- 
graphical position  of  all  the  coral  reefs  throughout  the  globe  is  of  the 
highest  geelogical  interest  (see  above,  p.  351.),  leading  to  splendid 
generalizations,  when  we  have  once  embraced  the  theory  that  all  atolls 


792  OBJECTIONS   TO   THEORY   OP  [On.  L. 

and  barrier  reefs  indicate  recent  subsidence,  while  the  presence  of  fringing 
reefs  proves  the  land  to  be  stationary  or  rising.  These  two  classes  of 
coral  formations  are  depicted  by  different  colors;  and  one  of  the  striking 
facts  brought  to  light  by  the  same  classification  of  coral  formations  is  the 
absence  of  active  volcanoes  in  the  areas  of  subsidence,  and  their  frequent 
presence  in  the  areas  of  elevation.  The  only  supposed  exception  to  this 
remarkable  coincidence  at  the  time  when  Mr.  Darwin  wrote,  in  1842,  was 
the  volcano  of  Torres  Strait,  at  the  northern  point  of  Australia,  placed  on 
the  borders  of  an  area  of  subsidence ;  but  it  has  been  since  proved  that 
this  volcano  has  no  existence. 

We  see,  therefore,  an  evident  connection,  first,  between  the  bursting 
forth  every  now  and  then  of  volcanic  matter  through  rents  and  fissures, 
and  the  expansion  or  forcing  outwards  of  the  earth's  crust,  and,  secondly, 
between  a  dormant  and  less  energetic  development  of  subterranean  heat, 
and  an  amount  of  subsidence  sufficiently  great  to  cause  mountains  to 
disappear  over  the  broad  face  of  the  ocean,  leaving  only  small  and 
scattered  lagoon  islands,  or  groups  of  atolls,  to  indicate  the  spots  where 
those  mountains  once  stood. 

On  a  review  of  the  differently-colored  reefs  on  the  map  alluded  to,  it 
will  be  seen  that  there  are  large  spaces  in  which  upheaval,  and  others  in 
which  depression  prevails,  and  these  are  placed  alternately,  while  there 
are  a  few  smaller  areas  where  movements  of  oscillation  occur.  Thus  if 
we  commence  with  the  western  shores  of  South  America,  between  the 
summit  of  the  Andes  and  the  Pacific  (a  region  of  earthquakes  and  active 
volcanoes),  we  find  signs  of  recent  elevation,  not  attested  indeed  by  coral 
formations,  which  are  wanting  there,  but  by  upraised  banks  of  marine 
shells.  Then  proceeding  westward,  we  traverse  a  deep  ocean  without 
islands,  until  we  come  to  a  band  of  atolls  and  encircled  islands,  including 
the  Dangerous  and  Society  archipelagoes,  and  constituting  an  area  of  sub- 
sidence more  than  4000  miles  long  and  600  broad.  Still  farther,  in  the 
same  direction,  we  reach  the  chain  of  islands  to  which  the  New  Hebrides, 
Salomon,  and  New  Ireland  belong,  where  fringing  reefs  and  masses  of 
elevated  coral  indicate  another  area  of  upheaval.  Again,  to  the  westward 
of  the  New  Hebrides  we  meet  with  the  encircling  reef  of  New  Caledonia 
and  the  great  Australian  barrier,  implying  a  second  area  of  subsi- 
dence. 

The  only  objection  deserving  attention  which  has  hitherto  been 
advanced  against  the  theory  of  atolls,  as  before  explained  (p.  759.),  is 
that  proposed  by  Mr.  Maclaren.*  "  On  the  outside,"  he  observes,  "  ot 
coral  reefs  very  highly  inclined,  no  bottom  is  sometimes  found  with  a  line 
of  2000  or  3000  feet,  and  this  is  by  no  means  a  rare  case.  It  follows 
that  the  reef  ought  to  have  this  thickness ;  and  Mr.  Darwin's  diagrams 
show  that  he  understood  it  so.  Now,  if  such  masses  of  coral  exist  under 
the  sea,  they  ought  somewhere  to  be  found  on  terra  firma  ;  for  there  is 
evidence  that  all  the  lands  yet  visited  by  geologists,  have  been  at  one 

*  Scotsman,  Nov.  1842,  and  Jameson's  Edin.  Journ.  of  Science,  1843. 


CH.  L.]  CORAL   ISLANDS   CONSIDERED.  793 

time  submerged.  But  neither  in  the  great  volcanic  chain,  extending 
from  Sumatra  to  Japan,  nor  in  the  West  Indies,  nor  in  any  other  region 
yet  explored,  has  a  bed  or  formation  of  coral  even  500  feet  thick  been 
discovered,  so  far  as  we  know." 

When  considering  this  objection,  it  is  evident  that  the  first  question 
we  have  to  deal  with  is,  whether  geologists  have  not  already  discovered 
calcareous  masses  of  the  required  thickness  and  structure,  or  precisely 
such  as  the  upheaval  of  atolls  might  be  expected  to  expose  to  view  ? 
We  are  called  upon,  in  short,  to  make  up  our  minds  both  as  to  the  inter- 
nal composition  of  the  rocks  that  must  result  from  the  growth  of  corals, 
whether  in  lagoon  islands  or  barrier  reefs,  and  the  external  shape  which 
the  reefs  would  retain  when  upraised  gradually  to  a  vast  height, — a  task 
by  no  means  so  easy  as  some  may  imagine.  If  the  reader  has  pictured 
to  himself  large  masses  of  entire  corals,  piled  one  upon  another,  for  a 
thickness  of  several  thousand  feet,  he  unquestionably  mistakes  altogether 
the  nature  of  the  accumulations  now  in  progress.  In  the  first  place,  the 
strata  at  present  forming  very  extensively  over  the  bottom  of  the  ocean, 
within  such  barrier  reefs  as  those  of  Australia  and  New  Caledonia,  are 
known  to  consist  chiefly  of  horizontal  layers  of  calcareous  sediment, 
while  here  and  there  an  intermixture  must  occur  of  the  detritus  of  gra- 
nitic and  other  rocks  brought  down  by  rivers  from  the  adjoining  lands, 
or  washed  from  sea-cliffs  by  the  waves  and  currents.  Secondly,  in  regard 
to  atolls,  the  stone-making  polypifers  grow  most  luxuriantly  on  the 
outer  edge  of  the  island,  to  a  thickness  of  a  few  feet  only.  Beyond  this 
margin  broken  pieces  of  coral  and  calcareous  sand  are  strewed  by  the 
breakers  over  a  steep  seaward  slope,  and  as  the  subsidence  continues  the 
next  coating  of  live  coral  does  not  grow  vertically  over  the  first  layer, 
but  on  a  narrow  annular  space  within  it,  the  reef,  as  was  before  stated 
(p.  V61),  constantly  contracting  its  dimensions  as  it  sinks.  Thirdly, 
within  the  lagoon  the  accumulation  of  calcareous  matter  is  chiefly  sedi- 
mentary, a  kind  of  chalky  mud  derived  from  the  decay  of  the  softer 
corallines,  with  a  mixture  of  calcareous  sand  swept  by  the  winds  and 
waves  from  the  surrounding  circular  reef.  Here  and  there,  but  only  in 
partial  clumps,  are  found  living  corals,  which  grow  in  the  middle  of  the 
lagoon,  and  mixed  with  fine  mud  and  sand,  a  great  variety  of  shells,  and 
fragments  of  testacea  and  echinoderms. 

We  owe  to  Lieutenant  Nelson  the  discovery  that  in  the  Bermudas  the 
calcareous  mud  resulting  from  the  decomposition  of  the  softer  corallines 
is  absolutely  undistinguishable  when  dried  from  the  ordinary  white  chalk 
of  Europe,*  and  this  mud  is  carried  to  great  distances  by  currents,  and 
spread  far  and  wide  over  the  floor  of  the  ocean.  We  also  have  opportu- 
nities of  seeing  in  upraised  atolls,  such  as  Elizabeth  Island,  Tonga,  and 
Hapai,  which  rise  above  the  level  of  the  sea  to  heights  varying  from  ten 
to  eighty  feet,  that  the  rocks  of  which  they  consist  do  not  differ  in 
structure  or  in  the  state  of  preservation  of  their  included  zoophytes  and 

*  Trans.  Geol.  Soc.,  London,  2d  series,  vol.  v. 


794  OBJECTIONS   TO   THEORY   OF  [On.  L 

shells  from  some  of  the  oldest  limestones  known  to  the  geologist.  Cap- 
tain Beechey  remarks  that  the  dead  coral  in  Elizabeth  Island  is  more  or 
less  porous  and  honeycombed  at  the  surface,  and  hardening  into  a  com 
pact  rock  which  has  the  fracture  of  secondary  limestone.  * 

The  island  of  Pulo  Nias,  off  Sumatra  (see  Map,  fig.  39.  p.  351),  which 
is  about  3000  feet  high,  is  described  by  Dr.  Jack  as  being  overspread  by 
coral  and  large  shells  of  the  Chama  (Tridacna)  gigas,  which  rest  on 
quartzose  and  arenaceous  rocks,  at  various  levels  from  the  sea-coast  to 
the  summit  of  the  highest  hills. 

The  cliffs  of  the  island  of  Timor  in  the  Indian  Ocean  are  composed, 
says  Mr.  Jukes,  of  a  raised  coral  reef  abounding  in  Astrcea,  Meandrina, 
and  Porites,  with  shells  of  Strombus,  Conus,  Nerita,  Area,  Pecten, 
Venus,  and  Lucina.  On  a  ledge  about  150  feet  above  the  sea,  a  Tri- 
dacna (or  large  clam  shell),  two  feet  across,  was  found  bedded  in  the 
rock  with  closed  valves,  just  as  they  are  often  seen  in  barrier  reefs.  This 
formation  in  the  islands  of  Sandlewood,  Sumbawa,  Madura,  and  Java, 
where  it  is  exposed  in  sea  cliffs,  was  found  to  be  from  200  to  300  feet 
thick,  and  is  believed  to  ascend  to  much  greater  heights  in  the  interior. 
It  has  usually  the  form  of  a  "  chalk-like"  rock,  white  when  broken,  but 
in  the  weathered  surface  turning  nearly  black,  f 

It  appears,  therefore,  premature  to  assert  that  there  are  no  recent  coral 
formations  uplifted  to  great  heights,  for  we  are  only  beginning  to  be 
acquainted  with  the  geological  structure  of  the  rocks  of  equatorial 
regions.  Some  of  the  upraised  islands,  such  as  Elizabeth  and  Queen 
Charlotte,  in  the  Pacific,  although  placed  in  regions  of  atolls,  are 
described  by  Captain  Beechey  and  others  as  flat-topped,  and  exhibiting 
no  traces  of  lagoons.  In  explanation  of  the  fact,  we  may  presume  that 
after  they  had  been  sinking  for  ages,  the  descending  movement  was 
relaxed ;  and  while  it  was  in  the  course  of  being  converted  into  an 
ascending  one,  the  ground  remained  for  a  long  season  almost  stationary, 
in  which  case  the  corals  within  the  lagoon  would  build  up  to  the  surface, 
and  reach  the  level  already  attained  by  those  on  the  margin  of  the  reef. 
In  this  manner  the  lagoon  would  be  effaced,  and  the  island  acquire  a 
flat  summit. 

It  may,  however,  be  thought  strange  that  many  examples  have  not 
been  noticed  of  fringing  reefs  uplifted  above  the  level  of  the  sea.  Mr. 
Darwin,  indeed,  cites  one  instance  where  the  reef  preserved,  on  dry  land 
in  the  Mauritius,  its  peculiar  moat-like  structure;  but  they  ought,  he  says, 
to  be  of  rare  occurrence,  for  in  the  case  of  atolls  or  of  barrier  or  fringing 
reefs,  the  characteristic  outline  must  usually  be  destroyed  by  denudation 
as  soon  as  a  reef  begins  to  rise  ;  since  it  is  immediately  exposed  to  the 
action  of  the  breakers,  and  the  large  and  conspicuous  corals  on  the  outer 
rim  of  the  atoll  or  barrier  are  the  first  to  be  destroyed  and  to  fall  to  the 
bottom  of  vertical  and  undermined  cliffs.  After  slow  and  continued 

*  Beechey's  Voyage,  vol.  i.  p.  45. 

f  Paper  read  to  Brit.  Assoc.,  Southampton,  1846. 


CH.  L.]  CORAL   ISLANDS    CONSIDERED.  795 

upheaval  a  wreck  alone  can  remain  of  the  original  reef.  If,  therefore, 
says  Mr.  Darwin,  "  at  some  period  as  far  in  futurity  as  the  secondary 
rocks  are  in  the  past,  the  bed  of  the  Pacific  with  its  atolls  and  barrier 
reefs  should  be  converted  into  a  continent,  we  may  conceive  that  scarcely 
any  or  none  of  the  existing  reefs  would  be  preserved,  but  only  widely 
spread  strata  of  calcareous  matter  derived  from  their  wear  and  tear."  * 

When  it  is  urged  in  support  of  the  objection  before  stated  (p.  *767), 
that  the  theory  of  atolls  by  subsidence  implies  the  accumulation  of  cal- 
careous formations  2000  or  3000  feet  thick,  it  must  be  conceded  that 
this  estimate  of  the  minimum  density  of  the  deposits  is  by  no  means 
exaggerated.  On  the  contrary,  when  we  consider  that  the  space  over 
which  atolls  are  scattered  in  Polynesia  and  the  Indian  oceans  may  be 
compared  to  the  whole  continent  of  Asia,  we  cannot  but  infer  from 
analogy  that  the  differences  in  level  in  so  vast  an  area  have  amounted, 
antecedently  to  subsidence,  to  5000  or  even  a  greater  number  of  feet. 
Whatever  was  the  difference  in  height  between  the  loftiest  and  lowest 
of  the  original  mountains  or  mountainous  islands  on  which  the  different 
atolls  are  based,  that  difference  must  represent  the  thickness  of  coral 
which  has  now  reduced  all  of  them  to  one  level.  Flinders,  therefore,  by 
no  means  exaggerated  the  volume  of  the  limestone,  which  he  conceived 
to  have  been  the  work  of  coral  animals ;  he  was  merely  mistaken  as  to 
the  manner  in  which  they  were  enabled  to  build  reefs  in  an  unfathomed 
ocean. 

But  is  it  reasonable  to  expect,  after  the  waste  caused  by  denudation, 
that  calcareous  masses,  gradually  upheaved  in  an  open  sea,  should  retain 
such  vast  thicknesses  ?  Or  may  not  the  limestones  of  the  cretaceous  and 
oolitic  epochs,  which  attain  in  the  Alps  and  Pyrenees  a  density  of  3000 
or  4000  feet,  and  are  in  great  part  made  up  of  coralline  and  shelly  matter, 
present  us  with  a  true  geological  counterpart  of  the  recent  coral  reefs  of 
equatorial  seas  ? 

Before  we  attach  serious  importance  to  arguments  founded  on  negative 
evidence,  and  opposed  to  a  theory  which  so  admirably  explains  a  great 
variety  of  complicated  phenomena,  we  ought  to  remember  that  the  up- 
heaval to  the  height  of  4000  feet  of  atolls  in  which  the  coralline  lime- 
stone would  be  4000  feet  thick,  implies,  first,  a  slow  subsidence  of  4000 
feet,  and,  secondly,  an  elevation  of  the  same  amount.  Even  if  the  reverse 
or  ascending  movement  began  the  instant  the  downward  one  ceased,  we 
must  allow  a  great  lapse  of  ages  for  the  accomplishment  of  the  whole 
operation.  We  must  also  assume  that  at  the  commencement  of  the 
period  in  question,  the  equatorial  regions  were  as  fitted  as  now  for  the 
support  of  reef-building  zoophytes.  This  postulate  would  demand  the 
continuance  of  a  complicated  variety  of  conditions  throughout  a  much 
longer  period  than  they  are  usually  persistent  in  one  place. 

To  show  the  difficulty  of  speculating  on  the  permanence  of  the  geo- 
graphical and  climatal  circumstances  requisite  for  the  growth  of  reef- 

*  Letter  to  Mr.  Maclaren,  Scotsman,  1848. 


796  LIME,  WHENCE   DERIVED.  [Cn.  L. 

building  corals,  we  have  only  to  state  the  fact  that  there  are  no  reefs  in 
the  Atlantic,  off  the  west  coast  of  Africa,  nor  among  the  islands  of  the 
Gulf  of  Guinea,  nor  in  St.  Helena,  Ascension,  the  Cape  Verdes,  or  St. 
Paul's.  With  the  exception  of  Bermuda,  there  is  not  a  single  coral  reef 
in  the  central  expanse  of  the  Atlantic,  although  in  some  parts  the  waves, 
as  at  Ascension,  are  charged  to  excess  with  calcareous  matter.  This  capri- 
cious distribution  of  coral  reefs  is  probably  owing  to  the  absence  of  fit 
stations  for  the  reef-building  polypifers,  other  organic  beings  in  those  re- 
gions obtaining  in  the  great  struggle  for  existence  a  mastery  over  them. 
Their  absence,  in  whatever  manner  it  be  accounted  for,  should  put  us  on 
our  guard  against  expecting  upraised  reefs  at  all  former  geological  epochs, 
similar  to  those  now  in  progress. 

Lime,  whence  derived. — Dr.  Maculloch,  in  his  system  of  Geology,  vol. 
i.  p.  219,  expressed  himself  in  favor  of  the  theory  of  some  of  the  earlier 
geologists,  that  all  limestones  have  originated  in  organized  substances. 
If  we  examine,  he  says,  the  quantity  of  limestone  in  the  primary  strata, 
it  will  be  found  to  bear  a  much  smaller  proportion  to  the  siliceous  and 
argillaceous  rocks  than  in  the  secondary ;  and  this  may  have  some  con- 
nexion with  the  rarity  of  testaceous  animals  in  the  ancient  ocean.  He 
farther  infers,  that  in  consequence  of  the  operations  of  animals,  "the 
quantity  of  calcareous  earth  deposited  in  the  form  of  mud  or  stone  is 
always  increasing ;  and  that  as  the  secondary  series  far  exceeds  the  pri- 
mary in  this  respect,  so  a  third  series  may  hereafter  arise  from  the  depths  of 
the  sea,  which  may  exceed  the  last  in  the  proportion  of  its  calcareous  strata." 

If  these  propositions  went  no  farther  than  to  suggest  that  every  parti- 
cle of  lime  that  now  enters  into  the  crust  of  the  globe,  may  possibly  in 
its  turn  have  been  subservient  to  the  purposes  of  life,  by  entering  into 
the  composition  of  organized  bodies,  I  should  not  deem  the  speculation 
improbable ;  but,  when  it  is  hinted  that  lime  may  be  an  animal  product 
combined  by  the  powers  of  vitality  from  some  simple  elements,  I  can  dis- 
cover no  sufficient  grounds  for  such  an  hypothesis,  and  many  facts  mili- 
tate against  it. 

If  a  large  pond  be  made  in  almost  any  soil,  and  filled  with  rain  water, 
it  may  usually  become  tenanted  by  testacea ;  for  carbonate  of  lime  is 
almost  universally  diffused  in  small  quantities.  But  if  no  calcareous  mat- 
ter be  supplied  by  waters  flowing  from  the  surrounding  high  grounds,  or 
by  springs,  no  tufa  or  shell-marl  are  formed.  The  thin  shells  of  one 
generation  of  mollusks  decompose,  so  that  their  elements  afford  nutriment 
to  the  succeeding  races ;  and  it  is  only  where  a  stream  enters  a  lake, 
which  may  introduce  a  fresh  supply  of  calcareous  matter,  or  where  the 
lake  is  fed  by  springs,  that  shells  accumulate  and  form  marl. 

All  the  lakes  in  Forfarshire  which  have  produced  deposits  of  shell-marl 
have  been  the  sites  of  springs,  which  still  evolve  much  carbonic  acid,  and 
a  small  quantity  of  carbonate  of  lime.  But  there  is  no  marl  in  Loch 
Fithie,  near  Forfar,  where  there  are  no  springs,  although  that  lake  is  sur- 
rounded by  these  calcareous  deposits,  and  although,  in  every  other  respect, 
the  site  is  favorable  to  the  accumulation  of  aquatic  testacea. 


On.  L.]  LIME   WHENCE   DERIVED.  797 

We  find  those  Charae  which  secrete  the  largest  quantity  of  calcareous 
matter  in  their  stems  to  abound  near  springs  impregnated  with  carbonate 
of  lime.  We  know  that,  if  the  common  hen  be  deprived  altogether  of 
calcareous  nutriment,  the  shells  of  her  eggs  will  become  of  too  slight  a 
consistency  to  protect  the  contents ;  and  some  birds  eat  chalk  greedily 
during  the  breeding  season. 

If,  on  the  other  hand,  we  turn  to  the  phenomena  of  inorganic  nature, 
we  observe  that,  in  volcanic  countries,  there  is  an  enormous  evolution  of 
carbonic  acid,  either  free,  in  a  gaseous  form,  or  mixed  with  water  ;  and 
the  springs  of  such  districts  are  usually  impregnated  with  carbonate  of 
lime  in  great  abundance.  No  one  who  has  travelled  in  Tuscany,  through 
the  region  of  extinct  volcanos  and  its  confines,  or  who  has  seen  the  map 
constructed  by  Targioni  (1827),  to  show  the  principal  sites  of  mineral 
springs,  can  doubt,  for  a  moment,  that  if  this  territory  was  submerged 
beneath  the  sea,  it  might  supply  materials  for  the  most  extensive  coral 
reefs.  The  importance  of  these  springs  is  not  to  be  estimated  by  the 
magnitude  of  the  rocks  which  they  have  thrown  down  on  the  slanting 
sides  of  hills,  although  of  these  alone  large  cities  might  be  built,  nor  by 
a  coating  of  travertin  that  covers  the  soil  in  some  districts  for  miles  in 
length.  The  greater  part  of  the  calcareous  matter  passes  down  in  a  state 
of  solution  to  the  sea,  and  in  all  countries  the  rivers  which  flow  from 
chalk  and  other  marly  and  calcareous  rocks  carry  down  vast  quantities  of 
lime  into  the  ocean.  Lime  is  also  one  of  the  component  parts  of  augite 
and  other  volcanic  and  hypogene  minerals,  and  when  these  decompose  is 
set  free,  and  may  then  find  its  way  in  a  state  of  solution  to  the  sea. 

The  lime,  therefore,  contained  generally  in  sea  water,  and  secreted  so 
plentifully  by  the  testacea  and  corals  of  the  Pacific,  may  have  been 
derived  either  from  springs  rising  up  in  the  bed  of  the  ocean,  or  from  rivers 
fed  by  calcareous  springs,  or  impregnated  with  lime  derived  from  disin- 
tegrated rocks,  both  volcanic  and  hypogene.  If  this  be  admitted,  the 
greater  proportion  of  limestone  in  the  more  modern  formations  as  com- 
pared to  the  most  ancient,  will  be  explained,  for  springs  in  general  hold 
no  argillaceous,  and  but  a  small  quantity  of  siliceous  matter  in  solution, 
but  they  are  continually  subtracting  calcareous  matter  from  the  inferior 
rocks.  The  constant  transfer,  therefore,  of  carbonate  of  lime  from  the 
lower  or  older  portions  of  the  earth's  crust  to  the  surface,  must  cause  at 
all  periods  and  throughout  an  indefinite  succession  of  geological  epochs, 
a  preponderance  of  calcareous  matter  in  the  newer  as  contrasted  with  the 
older  formations. 


END. 


CONCLUDING  REMARKS. 

IN  the  concluding  chapters  of  the  first  book,  I  examined  in  detail  a 
great  variety  of  arguments  which  have  been  adduced  to  prove  the  dis- 
tinctness of  the  state  of  the  earth's  crust  at  remote  and  recent  epochs. 
Among  other  supposed  proofs  of  this  distinctness,  the  dearth  of  calca- 
reous matter,  in  the  ancient  rocks  above  adverted  to,  might  have  been 
considered.  But  it  would  have  been  endless  to  enumerate  all  the  objec- 
tions urged  against  those  geologists  who  represent  the  course  of  nature 
at  the  earliest  periods  as  resembling  in  all  essential  circumstances  the 
state  of  things  now  established.  We  have  seen  that,  in  opposition  to 
this  doctrine,  a  strong  desire  has  been  manifested  to  discover  in  the  an- 
cient rocks  the  signs  of  an  epoch  when  the  planet  was  uninhabited,  and 
when  its  surface  was  in  a  chaotic  condition  and  uninhabitable.  The 
opposite  opinion,  indeed,  that  the  oldest  of  the  rocks  now  visible  may 
be  the  last  monuments  of  an  antecedent  era  in  which  living  beings  may 
already  have  peopled  the  land  and  water,  has  been  declared  to  be 
equivalent  to  the  assumption  that  there  never  was  a  beginning  to  the 
present  order  of  things. 

With  equal  justice  might  an  astronomer  be  accused  of  asserting  that 
the  works  of  creation  extended  throughout  infinite  space,  because  he 
refuses  to  take  for  granted  that  the  remotest  stars  now  seen  in  the 
heavens  are  on  the  utmost  verge  of  the  material  universe.  Every  im- 
provement of  the  telescope  has  brought  thousands  of  new  worlds  into 
view ;  and  it  would,  therefore,  be  rash  and  unphilosophical  to  imagine 
that  we  already  survey  the  whole  extent  of  the  vast  scheme,  or  that  it 
will  ever  be  brought  within  the  sphere  of  human  observation. 

But  no  argument  can  be  drawn  from  such  premises  in  favor  of  the 
infinity  of  the  space  that  has  been  filled  with  worlds ;  and  if  the  material 
universe  has  any  limits,  it  then  follows,  that  it  must  occupy  a  minute 
and  infinitesimal  point  in  infinite  space. 

So  if,  in  tracing  back  the  earth's  history,  we  arrive  at  the  monuments 
of  events  which  may  have  happened  millions  of  ages  before  our  times, 
and  if  we  still  find  no  decided  evidence  of  a  commencement,  yet  the 
arguments  from  analogy  in.  support  of  the  probability  of  a  beginning 
remain  unshaken ;  and  if  the  past  duration  of  the  earth  be  finite,  then 
the  aggregate  of  geological  epochs,  however  numerous,  must  constitute 
a  mere  moment  of  the  past,  a  mere  infinitesimal  portion  of  eternity. 

It  has  been  argued,  that,  as  the  different  states  of  the  earth's  surface, 
and  the  different  species  by  which  it  has  been  inhabited  have  all  had 
their  origin,  and  many  of  them  their  termination,  so  the  entire  series  may 
have  commenced  at  a  certain  period.  It  has  also  been  urged,  that, 
as  we  admit  the  creation  of  man  to  have  occurred  at  a  comparatively 


CONCLUDING   KEMARKS.  799 

modern  epoch — as  we  concede  the  astonishing  fact  of  the  first  introduc- 
tion of  a  moral  and  intellectual  being — so  also  we  may  conceive  the  first 
creation  of  the  planet  itself. 

I  am  far  from  denying  the  weight  of  this  reasoning  from  analogy ; 
but,  although  it  may  strengthen  our  conviction,  that  the  present  system 
of  change  has  not  gone  on  from  eternity,  it  cannot  warrant  us  in  pre- 
suming that  we  shall  be  permitted  to  behold  the  signs  of  the  earth's 
origin,  or  the  evidences  of  the  first  introduction  into  it  of  organic  beings. 
We  aspire  in  vain  to  assign  limits  to  the  works  of  creation  in  space, 
whether  we  examine  the  starry  heavens,  or  that  world  of  minute  ani- 
malcules which  is  revealed  to  us  by  the  microscope.  We  are  prepared, 
therefore,  to  find  that  in  time  also  the  confines  of  the  universe  lie  be- 
yond the  reach  of  mortal  ken.  But  in  whatever  direction  we  pursue 
our  researches,  whether  in  time  or  space,  we  discover  everywhere  the 
clear  proofs  of  a  Creative  Intelligence,  and  of  His  foresight,  wisdom, 
and  power. 

As  geologists,  we  learn  that  it  is  not  only  the  present  condition  of 
the  globe  which  has  been  suited  to  the  accommodation  of  myriads  of 
living  creatures,  but  that  many  former  states  also  have  been  adapted  to 
the  organization  and  habits  of  prior  races  of  beings.  The  disposition 
of  the  seas,  continents,  and  islands,  and  the  climates,  have  varied ;  the 
species  likewise  have  been  changed ;  and  yet  they  have  all  been  so 
modelled,  on  types  analogous  to  those  of  existing  plants  and  animals,  as 
to  indicate,  throughout,  a  perfect  harmony  of  design  and  unity  of  pur- 
pose. To  assume  that  the  evidence  of  the  beginning  or  end  of  so  vast  a 
scheme  lies  within  the  reach  of  our  philosophical  inquiries,  or  even  of 
our  speculations,  appears  to  be  inconsistent  with  a  just  estimate  of  the 
relations  which  subsist  between  the  finite  powers  of  man  and  the  attri- 
butes of  an  Infinite  and  Eternal  Being. 


GLOSSARY 


OF    GEOLOGICAL   AND    OTHER    SCIENTIFIC    TERMS    USED    IN    THIS 
WORK. 


ACEPHALOUS.  The  Acephala  are  that  division  of  molluscous  animals  which,  like  the 
oyster  and  scallop,  are  without  heads.  The  class  Acephala  of  Cuvier  compre- 
hends many  genera  of  animals  with  bivalve  shells,  and  a  few  which  are  devoid 
of  shells.  Etym.,  a,  a,  without,  and  KeQaXrj,  cephale,  the  head. 

ACIDULOUS.    Slightly  acid. 

ACROGENS.  One  of  five  classes  into  which  all  plants  may  be  divided  ;  it  includes 
such  flowerless  ones  as  grow  from  the  top  only,  and  whose  stems  consequently 
do  not  increase  materially  in  bulk,  as  Mosses,  Ferns,  Lycopodiums,  Equisetums, 
&c.  The  trunk  of  a  tree  fern  is  a  good  example.  They  are  also  called  Acro- 
brya.  Etym.,  aicpov,  acron,  the  top,  and  ytrartj,  genesis,  increase. 

ADIPOCTRE.  A  substance  apparently  intermediate  between  fat  and  wax,  into  which 
dead  animal  matter  is  converted  when  buried  in  the  earth,  and  in  a  certain  stage 
of  decomposition.  Etym.,  adeps,  fat,  and  cera,  wax. 

ALBITE.    See  "Felspar." 

ALEMBIC.     An  apparatus  for  distilling. 

ALG.E.  An  order  or  division  of  the  cryptogamic  class  of  plants.  The  whole  of  the 
sea-weeds  are  comprehended  under  this  division,  and  the  application  of  the 
term  in  this  work  is  to  marine  plants.  Etym.,  alga,  sea-weed. 

ALLUVIAL.    The  adjective  of  alluvium,  which  see. 

ALLUVION.    Synonymous  with  alluvium,  which  see. 

ALLUVIUM.  Earth,  sand,  gravel,  stones,  and  other  transported  matter  which  has 
been  washed  away  and  thrown  down  by  rivers,  floods,  or  other  causes  upon  land 
not  permanently  submerged  beneath  the  waters  of  lakes  or  seas.  Etym,,  alluo, 
to  wash  upon,  or  alluvio,  an  inundation. 

ALUM-STONE,  ALUMEN,  ALUMINOUS.  Alum  is  the  base  of  pure  clay,  and  strata  of  clay 
are  often  met  with  containing  much  iron  pyrites.  When  the  latter  substance  de- 
composes, sulphuric  acid  is  produced,  which  unites  with  the  aluminous  earth  of 
the  clay  to  form  sulphate  of  alumine,  or  common  alum.  Where  manufactories 
are  established  for  obtaining  the  alum,  the  indurated  beds  of  clay  employed  are 
called  Alum-stone. 

AMMONITE.  An  extinct  and  very  numerous  genus  of  the  order  of  molluscous  animals 
called  Cephalopoda,  allied  to  the  modern  genus  Nautilus,  which  inhabited  a  cham- 
bered shell,  curved  like  a  coiled  snake.  Species  of  it  are  found  in  all  geological 
periods  of  the  secondary  strata ;  but  they  have  not  been  seen  in  the  tertiary 
beds.  They  are  named  from  their  resemblance  to  the  horns  on  the  statues  of 
Jupiter  Ammon. 

AMORPHOUS.  Bodies  devoid  of  regular  form.  Etym.,  a,  a,  without,  and  //op^v, 
morpJie,  form. 

AMYGDALOID.  One  of  the  forms  of  the  Trap-rocks,  in  which  agates  and  simple  min- 
erals appear  to  be  scattered  like  almonds  in  a  cake.  Etym.,  a//vy<5aAa,  amygdala, 
an  almond. 

ANALCIME.  A  simple  mineral  of  the  Zeolite  family,  also  called  Cubizite,  of  frequent 
occurrence  in  the  Trap-rocks. 

ANALOGUE.  A  body  that  resembles  or  corresponds  with  another  body.  A  recent 
shell  of  the  same  species  as  a  fossil  shell  is  the  analogue  of  the  latter. 

ANGIOSPERMS.  A  term  applied  to  all  flowering  plants  in  which  the  ovules  are  in- 
closed in  an  ovary,  and  the  seeds  in  a  pericarp  or  covering,  as  in  all  flowering 
plants  except  those  mentioned  under  gymnosperms  and  gymnogens,  which  see. 
Etym.,  ayyos,  angos,  a  vessel,  and  a-Kt^a,  a  seed. 


GLOSSARY.  801 

ANOPLOTHERIUM.  A  fossil  extinct  quadruped  belonging  to  the  order  Pachydermata, 
resembling  a  pig.  It  has  received  its  name  because  the  animal  must  have  been 
singularly  wanting  in  means  of  defence,  from  the  form  of  its  teeth  and  the  ab- 
sence of  claws,  hoofs,  and  horns.  Etym.,  avonXos,  anoplos,  unarmed,  and  fyptov. 
fherion,  a  wild  beast. 

ANTAGONIST  POWF.R.  Two  powers  in  nature,  the  action  of  the  one  counteracting  that 
of  the  other,  by  which  a  kind  of  equilibrium  or  balance  is  maintained,  and  the 
destructive  effect  prevented  that  would  be  produced  by  one  operating  without 
a  check. 

ANTENNA.  The  articulated  horns  with  which  the  heads  of  insects  are  invariably 
furnished. 

ANTHRACITE.  A  shining  substance  like  black-lead ;  a  species  of  mineral  charcoal. 
Etym.,  av0pa£,  anthrax,  coal. 

ANTHRACOTHERIUM.  A  name  given  to  an  extinct  quadruped,  supposed  to  belong  to 
the  Pachydermata,  the  bones  of  which  were  first  found  in  lignite  and  coal  of  the 
tertiary  strata.  Etym.,  avQpa$,  anthrax,  coal,  and  dtjpwv,  therion,  wild  beast. 

ANTHROPOMORPHOUS.  Having  a  form  resembling  the  human.  Etym.,  avOpuiros,  an- 
tliropos,  a  man,  and  nopQij,  morphe,  form. 

ANTISEPTIC.  Substances  which  prevent  corruption  in  animal  and  vegetable  matter, 
as  common  salt  does,  are  said  to  be  antiseptic.  Etym.,  avrt,  anti,  against,  and 
<rrnrw,  sepo,  to  putrefy. 

ARENACEOUS.    Sandy.    Etym.,  arena,  sand. 

ARGILLACEOUS.    Clayey,  composed  of  clay.    Etym.,  argilla,  clay. 

ARRAGONITE.  A  simple  mineral,  a  variety  of  carbonate  of  lime,  so  called  from  having 
been  first  found  in  Aragon  in  Spain. 

ATOLLS.  Coral  islands  of  an  annular  form,  or  consisting  of  a  circular  strip  or  ring  of 
coral  surrounding  a  central  lagoon. 

AUGITE.  A  simple  mineral  of  a  dark  green,  or  black  color,  which  forms  a  constituent 
part  of  many  varieties  of  volcanic  rocks.  Name  applied  by  Pliny  to  a  particular 
mineral,  from  the  Greek  awyn,  avge,  lustre. 

AVALANCHES.  Masses  of  snow  which,  being  detached  from  great  heights  in  the  Alps, 
acquire  enormous  bulk  by  fresh  accumulations  as  they  descend ;  and  when  they 
fall  into  the  valleys  below  often  cause  great  destruction.  They  are  also  callod 
lavanges  and  lavanches  in  the  dialects  of  Switzerland. 

BASALT.  One  of  the  most  common  varieties  of  the  Trap-rocks.  It  is  a  dark  green  or 
black  stone,  composed  of  augite  and  felspar,  very  compact  in  texture,  and  of 
considerable  hardness,  often  found  in  regular  pillars  of  three  or  more  sides 
called  basaltic  columns.  Remarkable  examples  of  this  kind  are  seen  at  the 
Giant's  Causeway,  in  Ireland,  and  at  Fingal's  Cave,  in  Staffa,  one  of  the  Heb- 
rides. The  term  is  used  by  Pliny,  and  is  said  to  come  from  basal,  an  Ethio- 
pian word  signifying  iron.  The  rock  often  contains  much  iron. 

"  BASIN"  of  Paris,  "  BASIN"  of  London.  Deposits  lying  in  a  hollow  or  trough, 
formed  of  older  rocks  ;  sometimes  used  in  geology  almost  synonymously  with 
"  formations,"  to  express  the  deposits  lying  in  a  certain  cavity  or  depression  in 
older  rocks. 

BELEMNITE.  An  extinct  genus  of  the  order  of  molluscous  animals  called  Cephalo- 
poda, having  a  long,  straight,  and  chambered  conical  shell.  Etym.,  0&tnvov,  be- 
lemnon,  a  dart. 

BITUMEN.  Mineral  pitch,  of  which  the  tar-like  substance  which  is  often  seen  to  ooze 
out  of  the  Newcastle  coal  when  on  the  fire,  and  which  makes  it  cake,  is  a  good 
example.  Etym.,  bitumen,  pitch. 

BITUMINOUS  SHALE.  An  argillaceous  shale,  much  impregnated  with  bitumen,  which 
is  very  common  in  the  Coal  Measures. 

BLENDE.  A  metallic  ore,  a  compound  of  the  metal  zinc  with  sulphur.  It  is  often 
found  in  brown  shining  crystals ;  hence  its  name  among  the  German  miners, 
from  the  word  bknden,  to  dazzle. 

BLUFFS.  High  banks  presenting  a  precipitous  front  to  the  sea  or  a  river.  A  term 
used  in  the  United  States  of  North  America. 

BOTRYOIDAL.  Resembling  a  bunch  of  Grapes.  Etym.)  iSorpv?,  botrys,  a  bunch  of 
grapes,  and  «5oy,  eidos,  form. 

51 


802  GLOSSARY. 

BOULDERS.  A  provincial  term  for  large  rounded  blocks  of  stone  lying  on  the  surface 
of  the  ground,  or  sometimes  imbedded  in  loose  soil,  different  in  composition  from 
the  rocks  in  their  vicinity,  and  which  have  been  therefore  transported  from  a 
distance. 

BRECCIA.  A  rock  composed  of  angular  fragments  connected  together  by  lime  or  other 
mineral  substance.  An  Italian  term. 

CALO  SINTER.  A  German  name  for  the  deposits  from  springs  holding  carbonate  of 
lime  in  solution — petrifying  springs.  Etym.,  Italic,  lime,  and  sintern,  to  drop. 

CALCAIRE  GROSSIER.  An  extensive  stratum,  or  rather  series  of  strata,  found  in  the 
Paris  Basin,  belonging  to  the  Eocene  tertiary  period.  Etym.,  calcaire,  limestone, 
and  grassier,  coarse. 

CALCAREOUS  KOCK.     Limestone.     Etym.,  cake,  lime. 

CALCAREOUS  SPAR.    Crystallized  carbonate  of  lime. 

CARBON.  An  undecomposed  inflammable  substance,  one  of  the  simple  elementary 
bodies.  Charcoal  is  almost  entirely  composed  of  it.  Etym.,  carbo,  coal. 

CARBONATE  OF  LIME.  Lime  combines  with  great  avidity  with  carbonic  acid,  a  gase- 
ous acid  only  obtained  fluid  when  united  with  water, — and  all  combinations  of 
it  with  other  substances  are  called  Carbonates.  All  limestones  are  carbonates  of 
lime,  and  quicklime  is  obtained  by  driving  off  the  carbonic  acid  by  heat. 

CARBONATED  SPRINGS.  Springs  of  water,  containing  carbonic  acid  gas.  They  are  very 
common,  especially  in  volcanic  countries ;  and  sometimes  contain  so  much  gas, 
that  if  a  little  sugar  be  thrown  into  the  water  it  effervesces  like  soda-water. 

CARBONIC  ACID  GAS.  A  natural  gas  which  often  issues  from  the  ground,  especially 
in  volcanic  countries.  Etym.,  carlo,  coal;  because  the  gas  is  obtained  by  the 
slow  burning  of  charcoal. 

CARBONIFEROUS.  A  term  usually  applied,  in  a  technical  sense,  to  an  ancient  group 
of  secondary  strata  ;  but  any  bed  containing  coal  may  be  said  to  be  carboniferous. 
Etym.,  carbo,  coal,  and/m>,  to  bear. 

CATACLYSM.    A  deluge.    Etym.,  KaraxXv^u),  catacluzo,  to  deluge. 

CEPHALOPODA.  A  class  of  molluscous  animals,  having  their  organs  of  motion  ar- 
ranged round  their  head.  Etym.,  Ke$aXr},  cephale,  head,  and  iroSa,  poda,  feet. 

CETACEA.  An  order  of  vertebrated  mammiferous  animals  inhabiting  the  sea.  The 
whale,  dolphin,  and  narwal  are  examples.  Etym.,  cete,  whale. 

CHALCEDONY.  A  siliceous  simple  mineral,  uncrystallized.  Agates  are  partly  com- 
posed of  chalcedony. 

CHALK.    A  white  earthy  limestone,  the  uppermost  of  the  secondary  series  of  strata. 

CHERT.  A  siliceous  mineral,  nearly  allied  to  chalcedony  and  flint,  but  less  homoge- 
neous and  simple  in  texture.  A  gradual  passage  from  chert  to  limestone  is  not 
uncommon. 

CHLORITIC  SAND.  Sand  colored  green  by  an  admixture  of  the  simple  mineral  chlorite. 
Etym.,  ^Xwpvj,  chlomis,  green. 

CLEAVAGE.  Certain  rocks,  usually  called  Slate- rocks,  may  be  cleaved  into  an  indefi- 
nite number  of  thin  laminae  which  are  parallel  to  each  other,  but  which  are  gen- 
erally not  parallel  to  the  planes  of  the  true  strata  or  layers  of  deposition.  The 
planes  of  cleavage,  therefore,  are  distinguishable  from  those  of  stratification. 

CLINKSTONE,  called  also  phonolite,  a  felspathic  rock  of  the  trap  family,  usually  fissile. 
It  is  sonorous  when  struck  with  a  hammer,  whence  its  name. 

COAL  FORMATION.  This  term  is  generally  understood  to  mean  the  same  as  the  Coal 
Measures,  or  Carboniferous  group. 

COLEOPTERA.  An  order  of  insects  (Beetles)  which  have  four  wings,  the  upper  pair 
being  crustaceous  and  forming  a  shield.  Etym.,  icoXeos,  coleos,  a  sheath,  and 
irrcpov,  pteron,  a  wing. 

CONFORMABLE.  When  the  planes  of  one  set  of  strata  are  generally  parallel  to  those 
of  another  set  which  are  in  contact,  they  are  said  to  be  conformable.  Thus  the 
Fig.  93. 


set  a,  b,  Fig.  98,  rest  conformably  on  the  inferior  set  c,  d  ;  but  c,  d  rest  uncon- 
formably  on  E. 


GLOSSARY.  803 

CONGENERS.    Species  which  belong  to  the  same  genus. 

CONGLOMERATE,  or  PUDDINGSTONE.  Rounded  water-worn  fragments  of  rock  or  peb- 
bles, cemented  together  by  another  mineral  substance,  which  may  be  of  a  sili- 
ceous, calcareous,  or  argillaceous  nature.  Etym.,  con,  together,  glomero,  to  heap. 

CONIFERS.  An  order  of  plants,  all  of  which  have  disks  in  their  wood  fibres,  by  which 
they  are  recognized  in  a  fossil  state.  Their  ovules  are  naked  (see  GYMNOGENS). 
Most  of  the  northern  kinds  bear  the  seeds  in  cones  ;  but  the  yew  does  not,  nor 
do  a  host  of  tropical  and  south  temperate  species.  Etym.,  conus,  a  cone,  and 
fero,  to  bear. 

COSMOGONY,  COSMOLOGY.  Words  synonymous  in  meaning,  applied  to  speculations 
respecting  the  first  origin  or  mode  of  creation  of  the  earth.  Etym.,  Koapos,  kos- 
mos,  the  world,  and  -yovrj,  gonee,  generation,  or  Xoyoj,  logos,  discourse. 

CRAG.  A  provincial  name  in  Norfolk  and  Suffolk  for  certain  tertiary  deposits  usu- 
ally composed  of  sand  with  shells,  belonging  to  the  Older  Pliocene  period. 

CRATER.  The  circular  cavity  at  the  summit  of  a  volcano,  from  which  the  volcanic 
matter  is  ejected.  Etym.,  crater,  a  great  cup  or  bowl. 

CRETACEOUS.    Belonging  to  chalk.    Etym.,  creta,  chalk. 

CROP  OUT.  A  miner's  or  mineral  surveyor's  term,  to  express  the  rising  up  or  expo- 
sure at  the  surface  of  a  stratum  or  series  of  strata. 

CRUST  OF  THE  EARTH.     See  "  Earth's  crust." 

CRUSTACEOUS.  Animals  having  a  shelly  coating  or  crust  which  they  cast  periodically. 
Crabs,  shrimps,  and  lobsters  are  examples. 

CRYPTOGAMIC.  Asexual,  flowerless,  or  Acotyledonous  plants;  a  term  applied  to 
half  the  vegetable  kingdom  in  contradistinction  to  Pha3nogamic,  sexual,  or  flow- 
ering plants.  It  includes  Fungi,  Sea-weeds,  Lichens,  Mosses,  Ferns,  &c.,  which 
have  no  obvious  flowers,  and  no  cotyledons  (seed-lobes)  to  their  spores  or  seeds. 
Etym.,  Kpvnros,  cruptos,  concealed,  and  yapog,  gamos,  marriage. 

CRYSTALS.  Simple  minerals  are  frequently  found  in  regular  forms,  with  facets  like 
the  drops  of  cut  glass  of  chandeliers.  Quartz  being  often  met  with  in  rocks  in 
such  forms,  and  beautifully  transparent  like  ice,  was  called  rock-crystal,  /cpuaraA- 
Aoj,  crystallos,  being  Greek  for  ice.  Hence  the  regular  forms  of  other  minerals 
are  called  crystals,  whether  they  be  clear  or  opake. 

CRYSTALLIZED.  A  mineral  which  is  found  in  regular  forms  or  crystals  is  said  to  be 
crystallized. 

CRYSTALLINE.  The  internal  texture  which  regular  crystals  exhibit  when  broken,  or 
a  confused  assemblage  of  ill- defined  crystals.  Loaf-sugar  and  statuary-marble 
have  a  crystalline  texture.  Sugar-candy  and  calcareous  spar  are  crystallized. 

CUPRIFEROUS.     Copper-bearing.     Etym.,  cuprum,  copper,  and/m?,  to  bear. 

CYCADE^;.  A  small  and  very  anomalous  order  of  flowering  plants,  chiefly  found  in 
Mexico,  the  East  Indian  Islands,  South  Africa,  and  Australia.  They  are  Gym- 
nogens  as  to  ovules,  and  neither  Exogens  nor  Endogens  in  the  wood  of  their 
short,  simple,  or  branched  trunks,  and  they  have  dicotyledonous  seeds.  The 
leaves  are  pinnated  (like  those  of  cocoa-nut  palms),  and  when  young  are  rolled 
inwards  as  in  Ferns.  The  wood  fibres  are  curiously  perforated,  and  marked, 
by  which  they  are  recognized  in  a  fossil  state  as  well  as  by  the  trunk  and  foliage, 
and  the  cones,  which  contain  the  male  flowers.  The  term  is  derived  from  KVKOS, 
cycas,  a  name  applied  by  the  ancient  Greek  naturalist  Threophrastus  to  a  palm. 

CYPERACEJE.  A  tribe  of  plants  answering  to  the  English  sedges ;  they  are  distin- 
guished from  grasses  by  their  stems  being  solid,  and  generally  triangular,  instead 
of  being  hollow  and  round.  Together  with  Graminece  they  constitute  what 
writers  on  botanical  geography  often  call  glumacea. 

DEBACLE.  A  great  rush  of  waters,  which,  breaking  down  all  opposing  barriers,  car- 
ries forward  the  broken  fragments  of  rocks,  and  spreads  them  in  its  course. 
Etym.,  debacler,  French,  to  unbar,  to  break  up  as  a  river  does  at  the  cessation  of 
a  long-continued  frost. 

DELTA.  When  a  great  river,  before  it  enters  the  sea,  divides  into  separate  streams, 
they  often  diverge  and  form  two  sides  of  a  triangle,  the  sea  being  the  base.  The 
land  included  by  the  three  lines,  and  which  is  invariably  alluvial,  was  first  called, 
in  the  case  of  the  Nile  a  delta,  from  its  resemblance  to  the  letter  of  the  Greek 


804:  GLOSSARY. 

alphabet  which  goes  by  that  name  A.  Geologists  apply  the  term  to  alluvial  land 
formed  by  a  river  at  its  mouth,  without  reference  to  its  precise  shape. 

DENUDATION.  The  carrying  away  by  the  action  of  running  water  of  a  portion  of  the 
solid  materials  of  the  land,  by  which  inferior  rocks  are  laid  bare.  Etym.,  denudo, 
to  lay  bare. 

DEOXIDIZED,  DEOXIDATED.     Deprived  of  oxygen.    Disunited  from  oxygen. 

DESICCATION.    The  art  of  drying  up.    Etym.,  desicco,  to  dry  up. 

DETRITUS.    Matter  worn  or  rubbed  off'  from  rocks.    Etym.,  de,  from,  and  tero,  to  rub. 

DICOTYLEDONOUS.  A  grand  division  of  the  vegetable  kingdom,  founded  on  the  plant 
having  two  cotyledons,  or  seed-lobes.  Etym.,  Sis,  dis,  double,  and  norvXySov, 
cotyledon. 

DIKES.  When  a  mass  of  the  unstratified  or  igneous  rocks,  such  as  granite,  trap,  and 
lava,  appears  as  if  injected  into  a  rent  in  the  stratified  rocks,  cutting  across  the 
strata,  it  forms  a  dike.  They  are  (sometimes  seen  running  along  the  ground, 
and  projecting,  like  a  wall,  from  the  softer  strata  on  both  sides  of  them  having 
wasted  away ;  whence  they  were  first  called  in  the  north  of  England  and  in  Scot- 
land dikes,  a  provincial  name  for  wall.  It  is  not  easy  to  draw  the  line  between 
dikes  and  veins.  The  former  are  generally  of  larger  dimensions,  and  have  their 
sides  parallel  for  considerable  distances  ;  while  veins  have  generally  many  rami- 
fications, and  these  often  thin  away  into  slender  threads. 

DILUVIUM.  Those  accumulations  of  gravel  and  loose  materials,  which,  by  some  geol- 
ogists, are  said  to  have  been  produced  by  the  action  of  a  diluvian  wave  or  del- 
uge sweeping  over  the  surface  of  the  earth.  Etym.,  diluvium,  deluge. 

DIP.  When  a  stratum  does  not  lie  horizontally,  but  is  inclined,  it  is  said  to  di/p 
towards  some  point  of  the  compass,  and  the  angle  it  makes  with  the  horizon  is 
Called  the  angle  of  dip  or  inclination. 

DIPTERA.  An  order  of  insects,  comprising  those  which  have  only  two  wings.  Etym., 
Sis,  dis,  double,  and  nrepov,  pteron,  wing. 

DOLEEITE.    One  of  the  varieties  of  the  Trap-rocks,  composed  of  augite  and  felspar. 

DOLOMITE.  A  crystalline  limestone,  containing  magnesia  as  a  constituent  part. 
Named  after  the  French  geologist  Dolomieu. 

DUNES.  Low  hills  of  blown  sand  that  skirt  the  shores  of  Holland,  England,  Spain, 
and  other  countries. 

EARTH'S  CRUST.  Such  superficial  parts  of  our  planet  as  are  accessible  to  human  ob- 
servation. 

ECPYROSIS.    A  Greek  term  for  a  destruction  by  fire. 

ELYTRA.  The  wing-sheaths,  or  upper  crustaceous  membranes,  which  form  the  su- 
perior wings  in  the  tribe  of  beetles.  They  cover  the  body,  and  protect  the  true 
membranous  wing.  Etym.,  eXwrpov,  elytron,  a  sheath. 

ENDOGENS.  A  class  of  flowering  plants,  whose  stems  present  no  distinction  of  wood, 
pith,  and  bark.  The  wood  is  disposed  in  bundles,  placed  nearer  the  axis  than 
those  of  the  previous  year,  as  in  palm  trunks.  This  class  answers  to  the  Mono- 
cotyledones  of  Jussieu.  Etym.,  eviov,  endon,  within,  and  yevcats,  genesis,  increase. 

ENTOMOSTKACA.  Cuvier's  second  section  of  Crustacea ;  so  called  from  their  relation- 
ship to  insects.  Etym.,  cvro/ia,  entoma,  insects. 

EOCENE.  A  name  given  to  the  lowest  division  of  the  tertiary  strata,  containing  an 
extremely  small  percentage  of  living  species  amongst  its  fossil  shells,  which  indi- 
cate the  first  commencement  or  dawn  of  the  existing  state  of  the  animate  crea- 
tion. Etym.,  rjws,  eos,  aurora  or  the  dawn,  and  KUIVOS,  Tcavtws,  recent. 

ESCARPMENT.  The  abrupt  face  of  a  ridge  of  high  land.  Etym.,  escarper,  French,  to 
cut  steep. 

ESTUARIES.  Inlets  of  the  land,  which  are  entered  both  by  rivers  and  the  tides  of  the 
sea.  Thus  we  have  the  estuaries  of  the  Thames,  Severn,  Tay,  &c.  Etym., 
cestus,  the  tide. 

EXOGENS.  A  class  of  flowering  plants  whose  stems  have  bark,  wood,  and  pith.  The 
bark  is  increased  by  layers  deposited  within  the  previously  formed  layers  and 
the  wood  of  layers  or  rings  placed  outside  of  those  of  the  previous  year.  This 
class  answers  to  the  Dicotyledones  of  Jussieu,  and  includes  all  common  English 


GLOSSARY.  805 

trees  except  pines,  &c.  (See  GYMNOGENS.)  Etym.,  c|o,  exo,  outside,  ycvcois,  gen- 
esis, increase. 

KXPERIMENTUM  CRUcis.  A  decisive  experiment,  so  called,  because,  like  a  cross  or 
direction-post,  it  directs  men  to  true  knowledge  ;  or,  as  some  explain  it,  because 
it  is  a  kind  of  torture  whereby  the  nature  of  the  thing  is  extorted,  as  it  were,  by 
violence. 

KXUVLE.  Properly  speaking,  the  transient  parts  of  certain  animals  which  they  put 
off  or  lay  down  to  assume  new  ones,  as  serpents  and  caterpillars  shift  their 
skins  ;  but  in  geology  it  refers  not  only  to  the  cast-off  coverings  of  animals,  but 
to  fossil  shells  and  other  remains  which  animals  have  left  in  the  strata  of  the 
earth.  Etym.,  exuere,  to  put  off  or  divest. 

FALUNS.  A  French  provincial  name  for  some  tertiary  strata  abounding  in  shells  in 
Touraine,  which  resemble  in  lithological  characters  the  "  Crag"  of  Norfolk  and 
Suffolk. 

FAULT,  in  the  language  of  miners,  is  the  sudden  interruption  of  the  continuity  of 
strata  in  the  same  plane,  accompanied  by  a  crack  or  fissure,  varying  in  width 

from  a  mere  line  to  several  feet, 

Fig.  99.  which  is  generally  filled  with  broken 

stone,  clay,  &c. 

The. 8trata'  a>  6>  c>  &c->  must  at 
one  time  have  been  continuous  j 
but  a  fracture  having  taken  place 
at  the  fault  F,  either  by  the  upheav- 
ing of  the  portion  A,  or  the  sinking 
of  the  portion  B,  the  strata  were  so 
displaced  that  the  bed  a  in  B  is 
many  feet  lower  than  the  same  bed 
a  in  the  portion  A. 

FAUNA.  The  various  kinds  of  animals  peculiar  to  a  country  constitute  its  FAUNA,  as 
the  various  kinds  of  plants  constitute  its  FLORA.  The  term  is  derived  from  the 
FAUNI,  or  rural  deities,  in  Roman  Mythology. 

FELSPAR.  A  simple  mineral,  which,  next  to  quartz,  constitutes  the  chief  material  of 
rocks.  The  white  angular  portions  in  granite  are  felspar.  This  mineral  always 
contains  some  alkali  in  its  composition.  In  common  felspar  the  alkali  is  potash ; 
in  another  variety,  called  Albite  or  Cleavlandite,  it  is  soda.  Glassy  felspar  is  a 
term  applied  when  the  crystals  have  a  considerable  degree  of  transparency, 
Compact  felspar  is  a  name  of  more  vague  signification.  The  substance  so  called 
appears  to  contain  both  potash  and  soda. 
FELSPATHIC.  Of  or  belonging  to  felspar. 

FFRRUGINOUS.    Any  thing  containing  iron.    Etym.,ferrum,  iron. 
FISSILE,  easily  cleft,  dividing  readily  into  an  indefinite  number  of  parallel  laminae, 

like  slates. 

FLOETZ  ROCKS.    A  German  term  applied  to  the  secondary  strata  by  the  geologists  of 
that  country,  because  these  rocks  were  supposed  to  occur  most  frequently  in 
flat  horizontal  beds.    Etym.,flotZ)  a  layer  or  stratum. 
FLORA.    The  various  kinds  of  trees  and  plants  found  in  any  country  constitute  the 

FLORA  of  that  country  in  the  language  of  botanists. 
FLUVIATILE.    Belonging  to  a  river.    Mym.,fluoius,&r'\\er. 

FORAMINEFERA.    A  name  given  by  D'Orbigny  to  a  family  of  microscopic  shells'.  Their 
different  chambers  are  united  by  a  small  perforation  or  foramen.    Recent  obser- 
vation has  shown  that  some  at  least  are  not  Cephalopoda,  as  D'Orbigny  sup- 
posed. 
FORMATION.    A  group,  whether  of  alluvial  deposits,  sedimentary  strata,  or  igneous 

rocks,  referred  to  a  common  origin  or  period. 

FOSSIL.    All  minerals  were  once  called  fossils,  but  geologists  now  use  the  word  only 
to  express  the  remains  of  animals  and  plants  found  buried  in  the  earth.     £tyni., 
fossilis,  any  thing  that  may  be  dug  out  of  the  earth. 
FOSSILIFEROUS.    Containing  organic  remains. 


806  GLOSSARY. 

GALKNA.  A  metallic  ore,  a  compound  of  lead  and  sulphur.  It  has  often  the  appear- 
ance of  highly  polished  lead.  Etym.,  ya\tu>,  galeo,  to  shine. 

GARNET.  A  simple  mineral,  generally  of  a  deep  red  color,  crystallized  ;  most  com- 
monly met  with  in  mica  slate,  but  also  in  granite  and  other  igneous  rocks. 

GASTEROPODS.  A  division  of  the  Testacea,  in  which,  as  in  the  limpet,  the  foot  is 
attached  to  the  body.  Etym.,  yaarrjp,  gaster,  belly,  and  irot>a,poda,  feet. 

GAULT.  A  provincial  name  in  the  east  of  England  for  a  series  of  beds  of  clay  and 
marl,  the  geological  position  of  which  is  between  the  Upper  and  Lower  Green- 
sand. 

GAVIAL.     A  kind  of  crocodile  found  in  India. 

GKM,  or  GEMMULE,  from  the  Latin  gemma,  a  bud.  The  term,  applied  to  zoophytes, 
means  a  young  animal  not  confined  within  an  envelope  or  egg. 

GEOLOGY,  GEOGNOSY.  Both  mean  the  same  thing ;  but  with  an  unnecessary  degree 
of  refinement  in  terms,  it  has  been  proposed  to  call  our  description  of  thu  struc- 
ture of  the  earth  geognosy  (Etym.,  yea,  gea,  earth,  and  ytvwir/cw,  ginosco,  to  know), 
and  our  theoretical  speculations  as  to  its  formation  geology  (Etym.,  yea,  and  Ajyof, 
logos,  a  discourse). 

GLACIER.  Vast  accumulations  of  ice  and  hardened  snow  in  the  Alps  and  other  lofty 
mountains.  Etym.,  glace,  French  for  ice. 

GLACIS.  A  term  borrowed  from  the  language  of  fortification,  where  it  means  an  easy 
insensible  slope  or  declivity,  less  steep  than  a  talus,  which  see. 

GNEISS.  A  stratified  primary  rock,  composed  of  the  same  materials  as  granite,  but 
having  usually  a  larger  proportion  of  mica  and  a  laminated  texture.  The  word 
is  a  German  miner's  term. 

GRAMINE^:.    The  order  of  plants  to  which  grasses  belong.    Etym.,  gramen,  grass. 

GRANITE.  An  unstratified  or  igneous  rock,  generally  found  inferior  to  or  associated 
with  the  oldest  of  the  stratified  rocks,  and  sometimes  penetrating  them  in  the 
form  of  dikes  and  veins.  It  is  usually  composed  of  three  simple  minerals,  fel- 
spar, quartz,  and  mica,  and  derives  its  name  from  having  a  coarse  granular 
structure ;  granum,  Latin  for  grain.  Waterloo  bridge,  and  the  paving-stones 
in  the  carriage-way  of  the  London  streets,  afford  good  examples  of  the  most 
common  varieties  of  granite. 

GREENSAND.  Beds  of  sand,  sandstone,  limestone,  belonging  to  the  Cretaceous  Pe- 
riod. The  name  is  given  to  these  beds  because  they  often,  but  not  always,  con- 
tain an  abundance  of  green  earth  or  chlorite  scattered  through  the  substance  of 
the  sandstone,  limestone,  &c. 

GREENSTONE.     A  variety  of  trap,  composed  of  hornblende  and  felspar. 

GREYWACK^.  G-rauwacke,  a  German  name,  generally  adopted  by  geologists  for  some 
of  the  most  ancient  fossiliferous  strata.  The  rock  is  very  often  of  a  gray  color ; 
hence  the  name,  grau,  being  German  for  gray,  and  wacke,  being  a  provincial 
miner's  term. 

GRIT.     A  provincial  name  for  a  coarse-grained  sandstone. 

GYMNOSPERMOUS.  Etym.,  yv^vos,  gymnos,  naked,  and  antppa,  sperma,  a  seed.  (See 
GYMNOGENS.) 

GYMNOGENS.  A  class  of  flowering  plants,  in  which  the  ovules  are  not  inclosed  in  an 
ovary.  They  are  also  called  gymnosperms,  the  seeds  in  like  manner  not  being 
inclosed  in  a  pericarp.  It  includes  all  Coniferce,  as  pine,  fir,  juniper,  cypress, 
yew,  cedar,  &c.,  and  Cycadece.  All  are  Dicotyledonous  (a  few  have  many 
cotyledons),  and  all  Exogenous,  except  Gycas,  the  growth  of  which  is  anomalous. 
The  term  is  applied  in  contradistinction  to  Angiosperms,  which  see.  Etym., 
yvpvos,  naked,  and  yevems,  increase. 

GYPSUM.  A  mineral  composed  of  lime  and  sulphuric  acid,  hence  called  also  sulphate 
of  lime.  Plaster  and  stucco  are  obtained  by  exposing  gypsum  to  a  strong  heat. 
It  is  found  so  abundantly  near  Paris,  that  plaster  of  Paris  is  a  common  term  in 
this  country  for  the  white  powder  of  which  casts  are  made.  The  term  is  used 
by  Pliny  for  a  stone  used  'for  the  same  purposes  by  the  ancients.  The  derivation 
is  unknown. 

GYPSEOUS,  of  or  belonging  to  gypsum. 

GYHOGONITES.  Bodies  found  in  freshwater  deposits,  originally  supposed  to  be  micro- 
scopic shells,  but  subsequently  discovered  to  be  seed-vessels  of  freshwater  plants 


GLOSSARY.  807 

of  the  genus  Ctiara.     See  above  p.  742.     Etym.,  ywpoj,  gyros,  curved,  and  yovoj, 
gonos,  seed,  on  account  of  their  external  structure. 

HEMIPTERA.  An  order  of  insects,  so  called  from  a  peculiarity  in  their  wings,  the 
superior  being  coriaceous  at  the  base  and  membranous  at  the  apex,  #/HO-U,  hemisu, 
half,  and  vrtpov,  pteron,  wing. 

HORNBLENDE.  A  simple  mineral  of  a  dark  green  or  black  color,  which  enters  largely 
into  the  composition  of  several  varieties  of  the  Trap-Rocks. 

HORNSTONE.  A  siliceous  mineral  substance,  sometimes  approaching  nearly  to  flint, 
or  common  quartz.  It  has  a  conchoidal  fracture,  and  is  infusible,  which  distin- 
guishes it  from  compact  felspar. 

HUMERUS.     The  bone  of  the  upper  arm. 

HYDROPHYTES.  Plants  which  grow  in  water.  Etym.,  iSwp,  Tiydor,  water,  and  <J>VTOV, 
phyton,  plant. 

HYPOGENE  ROCKS.  Those  rocks  which  are  nether-formed,  or  which  have  not  assumed 
their  present  form  and  structure  at  the  surface,  such  as  granite,  gneiss,  &c.  The 
term,  which  includes  both  the  plutonic  and  metarnorphic  rocks,  is  substituted 
for  primary,  because  some  members  of  both  these  classes,  such  as  granite  and 
gneiss,  are  posterior  to  many  secondary  or  fossiliferous  rocks.  Etym.,  Ixo, 
hypo,  under,  and  yivopai,  ginomai,  to  be  formed  or  produced. 

ICEBERG.  Great  masses  of  ice,  often  the  size  of  hills,  which  float  in  the  polar  and  ad- 
jacent seas.  Etym.,  ice,  and  berg,  German  for  hill. 

ICHTHYOSAURUS.  A  gigantic  fossil  marine  reptile,  allied  in  part  of  its  structure  to  a 
fish.  Etym.,  i-xflvs,  ichthus,  a  fish,  and  iravpa,  saura,  a  lizard. 

IGNEOUS  ROCKS.  All  rocks,  such  as  lava,  trap,  and  granite,  known  or  supposed  to 
have  been  melted  by  volcanic  heat. 

INCANDESCENT.    White  hot — having  a  more  intense  degree  of  heat  than  red  heat. 

INDUCTION.  A  consequence,  inference,  or  general  principle  drawn  from  a  number  of 
particular  facts  or  phenomena.  The  inductive  philosophy,  says  Mr.  Whewell, 
has  been  rightly  described  as  a  science  which  ascends  from  particular  facts  to 
general  principles,  and  then  descends  again  from  these  general  principles  to  par- 
ticular applications. 

INFUSORY  ANIMALCULES.  Minute  living  creatures  found  in  many  infusions  ;  and  the 
term  infusori  has  been  given  to  all  such  animalcules,  whether  found  in  infusions 
or  in  stagnant  water,  vinegar,  &c. 

INSPISSATED.    Thickened.    Etym.,  spissus,  thick. 

INVERTEBRATED  ANIMALS.  Animals  which  are  not  furnished  with  a  back-bone.  For 
a  further  explanation,  see  "  Vertebrated  Animals." 

ISOTHERMAL.  Such  zones  or  divisions  of  the  land,  ocean,  or  atmosphere,  which  have 
an  equal  degree  of  mean  annual  warmth,  are  said  to  be  isothermal,  from  teas,  isos, 
equal,  and  3ep/<»7,  therme,  heat. 

JOINTS.  Fissures  or  lines  of  parting  in  rocks,  often  at  right  angles  to  the  planes  of 
stratification.  The  partings  which  divide  columnar  basalt  into  prisms  are  joints. 

JURA  LIMESTONE.  The  limestones  belonging  to  the  Oolite  Group  constitute  the  chief 
part  of  the  mountains  of  Jura  between  France  and  Switzerland  ;  and  hence  the 
geologists  of  the  Continent  have  given  the  name  to  the  group. 

KEUPER.     A  German  name  for  a  member  of  the  Upper  New  Red  Sandstone. 

KIMMERIDGE  CLAY.  A  thick  bed  of  clay,  constituting  a  member  of  the  Oolite  Group. 
So  called  because  it  is  found  well  developed  at  Kimmeridge,  in  the  Isle  of  Pur- 
beck,  Dorsetshire. 

LACUSTRINE.    Belonging  to  a  lake.     Etym.,  locus,  a  lake. 

LAMANTINE.  A  living  species  of  the  herbivorous  Cetacea  or  whale  tribe  which  inhab- 
its the  mouth  of  rivers  on  the  coasts  of  Africa  and  South  America :  the  sea-cow. 

LAMELLIFEROUS.  Having  a  structure  consisting  of  thin  plates  or  leaves  like  paper. 
Etym.,  lamella,  the  diminutive  of  lamina,  plate,  wndfcro,  to  bear. 

LAMINA.  Latin  for  plates  ;  used  in  geology  for  the  smaller  layers  of  which  a  strain  in 
is  frequently  composed. 


GLOSSARY. 

LANDSLIP.  A  portion  of  land  that  has  slid  down  in  consequence  of  disturbance  by 
an  earthquake,  or  from  being  undermined  by  water  washing  away  the  lower 
beds  which  supported  it. 

LAPIDIFICATION.  Lapidifying  process.  Conversion  into  stone.  Etym.,  lapis,  stone, 
and.^0,  to  make. 

LAPILLI.     Small  volcanic  cinders.    Lapillus,  a  little  stone. 

LAVA.     The  stone  which  flows  in  a  melted  state  from  a  volcano. 

LKPIDODENDRON,  a  genus  of  fossil  plants  of  the  Coal  Measures,  intermediate  in  char- 
acter between  the  Lycopodiums  and  coniferous  plants. 

LSUCITE.  A  simple  mineral  found  in  volcanic  rocks,  crystallized,  and  of  a  white 
color.  Etym.,  A«/Kof,  leucos,  white. 

LIAS.  A  provincial  name  for  an  argillaceous  limestone,  characterized  together  with 
its  associated  beds  by  peculiar  fossils,  and  forming  a  particular  group  of  strata, 
interposed  between  the  Oolite  and  the  New  Red  Sandstone. 

LIGNIPERDOUS.  A  term  applied  to  insects  which  destroy  wood.  Etym.,  lignum,  wood, 
and  perdo,  to  destroy. 

LIGNITE.     Wood  converted  into  a  kind  of  coal.    Etym.,  lignum,  wood. 

LITHODOMI.  Molluscous  animals  which  form  holes  in  the  solid  rocks  in  which  they 
lodge  themselves.  The  holes  are  not  perforated  mechanically,  but  the  rock  ap 
pears  to  be  dissolved.  Etym.,  At0o?,  lithos,  stone,  and  <5£//w,  demo,  to  build. 

LITHOGENOUS  POLYPS.    Animals  which  form  coral. 

LITHOGRAPHIC  STONE.  A  slaty  compact  limestone,  of  a  yellowish  color  and  fine  grain, 
used  in  lithography,  which  is  the  art  of  drawing  upon  and  printing  from  stone 
Etym.,  A«0os,  lithos,  stone,  and  ypa<f>o,  grapTio,  to  write. 

LITHOIDAL.    Having  a  stony  structure. 

LITHOLOGIOAL.  A  term  expressing  the  stony  structure  or  character  of  a  mineral  mass. 
We  speak  of  the  lithological  character  of  a  stratum  as  distinguished  from  its 
zoological  character.  Etym.,  At0os,  lithosj  stone,  and  Xoyoj,  logos,  discourse. 

LITHOPHAGI.  Molluscous  animals  which  form  holes  in  solid  stones.  See  "  Lithodo 
mi."  Etym.,  A«0o$,  lithos,  stone,  and  $ay£tv,phageint  to  eat. 

LrrHOPHiTEs.    The  animals  which  form  Stone-coral. 

LITTORAL.    Belonging  to  the  shore.     Etym.,  littus,  the  shore. 

LOAM.    A  mixture  of  sand  and  clay. 

LOPHIODON.  A  genus  of  extinct  quadrupeds,  allied  to  the  tapir,  named  from  emi- 
nences on  the  teeth. 

LYCOPODIACE.*;.  Plants  of  an  inferior  degree  of  organization  to  Coniferae,  some  of 
which  they  very  much  resemble  in  foliage,  but  all  recent  species  are  infinitely 
smaller.  Many  of  the  fossil  species  are  as  gigantic  as  recent  Coniferae.  Their 
mode  of  reproduction  is  analogous  to  that  of  ferns.  In  English  they  are  called 
club-mosses,  generally  found  in  mountainous  heaths  in  the  north  of  England. 

LYDIAN  STONE.  Flinty  slate ;  a  kind  of  quartz  or  flint,  allied  to  Hornstone,  but  of  a 
grayish  black  color. 

MACIGNO.  In  Italy  this  term  has  been  applied  to  a  siliceous  sandstone  sometimes  con- 
taining calcareous  grains,  mica,  &c. 

MADREPORE.  A  genus  of  corals,  but  generally  applied  to  all  the  corals  distinguished 
by  superficial  star-shaped  cavities.  There  are  several  fossil  species. 

MAGNESIAN  LIMESTONE.  An  extensive  series  of  beds,  the  geological  position  of  which 
is  immediately  above  the  Coal  Measures ;  so  called,  because  the  limestone,  the 
principal  member  of  the  series,  contains  much  of  the  earth  magnesia  as  a  con- 
stituent part. 

MAMMIFEROUS.  Mammifers.  Animals  which  give  suck  to  their  young.  To  this  class 
all  the  warm-blooded  quadrupeds,  and  the  Cetacea,  or  whales,  belong.  Etym., 
mamma,  a  breast,  fero,  to  bear. 

MAMMILLARY.  A  surface  which  is  studded  over  with  rounded  projections.  Etym., 
mammilla,  a  little  breast  or  pap. 

MAMMOTH.  An  extinct  species  of  the  elephant  (E.  primigmius),  of  which  the  fossil 
bones  are  frequently  met  with  in  various  countries.  The  name  is  of  Tartar  ori- 
gin, and  is  used  in  Siberia  for  animals  that  burrow  under  ground. 

MANATI.     One  of  the  Cetacea,  the  sea-cow,  or  lamantine  (Trichechus  manatus,  Lin.) 


GLOSSARY.  809 

MAUL.  A  mixture  of  clay  and  lime ;  usually  soft,  but  sometimes  hard,  in  -which  case 
it  is  called  indurated  marl. 

MARSUPIAL  ANIMALS.  A  tribe  of  quadrupeds  having  a  sack  or  pouch  under  the  belly, 
in  which  they  carry  their  young.  The  kangaroo  is  a  well-known  example. 
Etym.,  marsupium,  a  purse. 

MASTODON.  A  genus  of  fossil  extinct  quadrupeds  allied  to  the  elephants  ;  so  called 
from  the  form  of  the  hind  teeth  or  grinders,  which  have  their  surface  covered 
with  conical  mammillary  crests.  Etym.,  ^aaros,  mastos,  pap,  and  o&urv,  odon, 
tooth. 

MATRIX.  If  a  simple  mineral  or  shell,  in  place  of  being  detached,  be  still  fixed  in  a 
portion  of  rock,  it  is  said  to  be  in  its  matrix.  Matrix,  womb. 

MECHANICAL  ORIGIN,  ROCKS  OF.  Rocks  composed  of  sand,  pebbles,  or  fragments,  are 
so  called  to  distinguish  them  from  those  of  a  uniform  crystalline  texture,  which 
are  of  chemical  origin. 

MEDUSAE.  A  genus  of  marine  radiated  animals,  without  shells  ;  so  called,  because 
their  organs  of  motion  spread  out  like  the  snaky  hair  of  the  fabulous  Medusa. 

MEGALOSAURUS.  A  fossil  gigantic  amphibious  animal  of  the  saurian  or  lizard  and 
crocodile  tribe.  Etym.,  [tcyaXri,  megale,  great,  and  travpa,  saura,  lizard. 

MEGATHERIUM.  A  fossil  extinct  quadruped,  resembling  a  gigantic  sloth.  Etym., 
neya,  mega,  great,  and  dqpiov,  therion,  wild  beast. 

MELASTOMA.  A  genus  of  MELASTOMACEA,  an  order  of  exotic  plants  of  the  evergreen 
tree  and  shrubby  kinds.  Etym.,  ne\as,  melas,  black,  and  orojua,  stoma,  mouth ; 
because  the  fruit  of  one  of  these  species  stains  the  lips. 

MESOTYPE.  A  simple  mineral,  white,  and  needle-shaped,  one  of  the  Zeolite  family, 
frequently  met  with  in  the  Trap-rocks. 

METAMORPHIC  ROCKS.  A  stratified  division  of  hypogene  rocks,  highly  crystalline, 
such  as  gneiss  and  mica-schist,  and  so  named  because  they  have  been  altered  by 
plutonic  action.  Etym.,  pera,  meta,  trans,  and  ^optprj,  morpJie,  form. 

MICA.  A  simple  mineral,  having  a  shining  silvery  surface,  and  capable  of  being 
split  into  very  thin  elastic  leaves  or  scales.  It  is  often  called  talc  in  common 
life  ;  but  mineralogists  apply  the  term  talc  to  a  different  mineral.  The  brilliant 
scales  in  granite  are  mica.  Etym.,  mico,  to  shine. 

MICA-SLATE,  MICA-SCHIST,  MICACEOUS  SCHISTUS.  One  of  the  metamorphic  or  crystal- 
line stratified  rocks  of  the  hypogene  class,  which  is  characterized  by  being  com- 
posed of  a  large  proportion  of  mica  united  with  quartz. 

MIOCENE.  A  division  of  tertiary  strata  intervening  between  the  Eocene  and  Pliocene 
formations  ;  so  called,  because  a  minority  of  its  fossil  shells  are  referable  to  liv- 
ing species.  Etym.,  /mwv,  melon,  less,  and  xaivos,  kairios,  recent. 

MOLASSE.  A  provincial  name  for  a  soft  green  sandstone,  associated  with  marl  and 
conglomerates,  belonging  to  the  Miocene  Tertiary  Period,  extensively  developed 
in  the  lower  country  of  Switzerland.  Etym.,  French,  molle,  soft. 

MOLLUSCA,  MOLLUSCOUS  ANIMALS.  Animals,  such  as  shell-fish,  which,  being  devoid 
of  bones,  have  soft  bodies.  Etym.,  mollis,  soft. 

MONAD.  The  smallest  of  visible  animalcules,  spoken  of  by  Buffon  and  his  followers 
as  constituting  the  elementary  molecules  of  organic  beings. 

MONITOR.  An  animal  of  the  saurian  or  lizard  tribe,  species  of  which  are  found  in 
both  the  fossil  and  recent  state. 

MONOCOTYLEDONOUS.  A  grand  division  of  the  vegetable  kingdom  (including  palms, 
grasses,  Lilaceae,  &c.),  founded  on  the  plant  having  only  one  cotyledon,  or  seed- 
lobe.  Etym.,  novos,  monos,  single. 

MORAINE,  a  Swiss  term  for  the  debris  of  rocks  brought  into  valleys  by  glaciers.  See 
p.  228. 

MOSCHUS.  A  quadruped  resembling  the  chamois  or  mountain  goat,  from  which  the 
perfume  musk  is  obtained. 

MOUNTAIN  LIMESTONE,  OR  CARBONIFEROUS  LIMESTONE.  A  series  of  limestone  strata  of 
marine  origin,  usually  forming  the  lowest  member  of  the  Coal  Measures. 

MOYA.  A  term  applied  in  South  America  to  mud  poured  out  from  volcanoes  during 
eruptions. 

MULTILOCULAR.  Many-chambered ;.  a  term  applied  to  those  shells  which,  like  the 
nautilus,  ammonite,  and  others,  are  divided  into  many  compartments.  Etym., 
multus,  many,  and  loculus,  a  partition. 


810  GLOSSARY. 

MURIATE  OF  SODA.  The  scientific  name  for  common  culinary  salt,  because  it  is  com- 
posed of  muriatic  acid  and  the  alkali  soda. 

MUSACE^E.  A  family  of  tropical  monocotyledonous  plants,  including  the  banana  and 
plantains. 

MUSCHELKALK.  A  limestone,  belonging  to  the  Upper  New  Red  Sandstone  group. 
Its  position  is  between  the  Magnesian  Limestone  and  the  Lias.  This  formation 
has  not  yet  been  found  in  England,  and  the  German  name  is  adopted  by  English 
geologists.  The  word  means  shell  limestone.  Etym.,  muschel,  shell,  and  kalk- 
stein,  limestone. 

NAPHTHA.  A  very  thin,  volatile,  inflammable,  and  fluid  mineral  substance,  of  which 
there  are  springs  in  many  countries,  particularly  in  volcanic  districts. 

NENUPHAR.    A  yellow  water-lily.    P.  618. 

NEW  RED  SANDSTONE.  A  formation  so  named,  because  it  consists  chiefly  of  sandy 
and  argillaceous  strata,  the  predominant  color  of  which  is  brick-red,  but  con- 
taining portions  which  are  of  a  greenish-gray.  These  occur  often  in  spots  and 
stripes,  so  that  the  series  has  sometimes  been  called  the  variegated  sandstone. 
This  formation  is  divided  into  the  Upper  New  Eed  in  which  the  Muschelkalk 
is  included,  and  the  Lower  New  Eed,  of  which  the  Magnesian  Limestone  is  a 
member. 

NODULE.  A  rounded  irregular-shaped  lump  or  mass.  Etym.,  diminutive  of  nodus, 
knot. 

NORMAL  GROUPS.  Groups  of  certain  rocks  taken  as  a  rule  or  standard.  Mym.,  nor- 
ma,  rule  or  pattern. 

NUCLEUS.  A  solid  central  piece,  around  which  other  matter  is  collected.  The  word 
is  Latin  for  kernel. 

NUMMULITES.  An  extinct  genus  of  the  order  of  molluscous  animals,  called  Cephalo- 
poda, of  a  thin  lenticular  shape,  internally  divided  into  small  chambers.  Etym., 
nummus,  Latin  for  money,  and  Ai0oj,  lithos,  stone,  from  its  resemblance  to  a 
coin. 

OBSIDIAN.  A  volcanic  product,  or  species  of  lava,  very  like  common  green  bottle 
glass,  which  is  almost  black  in  large  masses,  but  semi-transparent  in  thin  frag- 
ments. Pumice-stone  is  obsidian  in  a  frothy  state ;  produced,  most  probably, 
by  water  that  was  contained  in  or  had  access  to  the  melted  stone,  and  converted 
into  steam.  There  are  very  often  portions  in  masses  of  solid  obsidian,  which 
are  partially  converted  into  pumice. 

OCHRE.     A  yellow  powder,  a  combination  of  some  earth  with  oxide  of  iron. 

OGYGIAN  DELUGE.  A  great  inundation  mentioned  in  fabulous  history,  supposed  to 
have  taken  place  in  the  reign  of  Ogyges  in  Attica,  whose  death  is  fixed  in  Blair's 
Chronological  Tables  in  the  year  1764  before  Christ.  See  p.  341. 

OLD  RED  SANDSTONE.  A  formation  immediately  below  the  Carboniferous  Group. 
The  term  Devonian  has  been  recently  proposed  for  strata  of  this  age,  because 
in  Devonshire  they  are  largely  developed,  and  contain  many  organic  remains. 

OLIGOCLASE.    A  mineral  of  the  felspar  family. 

OLIVINE.  An  olive-colored,  semi-transparent,  simple  mineral,  very  often  occurring 
in  the  form  of  grains  and  of  crystals  in  basalt  and  lava. 

OOLITE,  OOLITIC.  A  limestone  ;  so  named  because  it  is  composed  of  rounded  parti- 
cles like  the  roe  or  eggs  of  a  fish.  The  name  is  also  applied  to  a  large  group  of 
strata,  characterized  by  peculiar  fossils,  in  which  limestone  of  this  texture  oc- 
curs. Etym.,  wov,  oon,  egg,  and  Ai0oy,  lithos,  stone/ 

OPALIZED  WOOD.  Wood  petrified  by  siliceous  earth,  and  acquiring  a  structure  sim- 
ilar to  the  simple  mineral  called  opal. 

OPHIDIOUS  REPTILES.  Vertebrated  animals,  such  as  snakes  and  serpents.  Etym., 
o0ts,  ophis,  a  serpent. 

ORGANIC  REMAINS.  The  remains  of  animals  and  plants  (organized  bodies)  found  in  a 
fossil  state. 

ORTHOCERATA  or  ORTHOCER^E.  An  extinct  genus  of  the  order  of  molluscous  animals, 
called  Cephalopoda,  that  inhabited  a  long-chambered  conical  shell,  like  a  straight 
horn.  Mym.,  opdos,  orthos,  straight,  and  «paf,  ceras,  horn. 


GLOSSARY.  811 

OSSEOUS  BRECCIA.  The  cemented  mass  of  fragments  of  bones  of  extinct  animals 
found  in  caverns  and  fissures.  Osseous  is  a  Latin  adjective,  signifying  bony. 

OSTEOLOGY.  That  division  of  anatomy  which  treats  of  the  bones  ;  from  oartov,  oste- 
on,  bone,  and  Xoyo?,  logos,  a  discourse. 

OUTLIERS.  When  a  portion  of  a  stratum  occurs  at  some  distance,  detached  from  the 
general  mass  of  the  formation  to  which  it  belongs,  some  practical  mineral  sur- 
veyors call  it  an  outlier,  and  the  term  is  adopted  in  geological  language. 

OVATE.     The  shape  of  an  egg.     Etym.,  ovum,  egg. 

OVIPOSITING.    The  laying  of  eggs. 

OXIDE.     The  combination  of  a  metal  with  oxygen;  rust  is  oxide  of  iron. 

OXYGEN.  One  of  the  constituent  parts  of  the  air  of  the  atmosphere ;  that  part  which 
supports  life.  For  a  farther  explanation  of  the  word,  consult  elementary  works 
on  chemistry. 

PACHYDERMATA.  An  order  of  quadrupeds,  including  the  elephant,  rhinoceros,  horse, 
pig,  &c.,  distinguished  by  having  thick  skins.  Etym.,  ira%vs,  pachus,  thick,  and 
deppa,  derma,  skin,  or  hide. 

PACHYDERMATOUS.    Belonging  to  Pachydermata. 

PAL^EOTHERIUM,  PALEOTHERE.  A  fossil  extinct  quadruped,  belonging  to  the  order 
Pachydermata,  resembling  a  pig,  or  tapir,  but  of  great  size.  Etym.,  TraAcuof, 
palaios,  ancient,  and  Qrjpiov,  therion,  wild  beast. 

PALEONTOLOGY.  The  science  which  treats  of  fossil  remains,  both  animal  and  vege- 
table. Etym.,  TraAatoy,  palaios,  ancient,  ovra,  onto,,  beings,  and  Xoyoj,  logos,  a 
discourse. 

PELAGIAN,  PELAGIC.    Belonging  to  the  deep  sea.     Etym.,  pelagus,  sea. 

PEPERINO.  An  Italian  name  for  a  particular  kind  of  volcanic  rock,  formed  like  tuff, 
by  the  cementing  together  of  volcanic  sand,  cinders,  or  scoriae,  &c. 

PETFvOLEUM.  A  liquid  mineral  pitch,  so  called  because  it  is  seen  to  ooze  like  oil  out 
of  the  rock.  Etym.,petra,  rock,  and  oleum,  oil. 

PH.ENOGAMOUS  or  PHANEROGAMIC  PLANTS.  A  name  given  by  Linnaeus  to  those  plants 
in  which  the  reproductive  organs  are  apparent.  Etym.,  Qavcpos,  pTianeros,  evi- 
dent, or  <f>aivw,phaino,  to  show,  and  yajioy,  gamos,  marriage. 

PHLEGR^EAN  FIELDS.  Campi  Phlegraei,  or  "the  Burnt  Fields."  The  country  around 
Naples,  so  named  by  the  Greeks,  from  the  traces  of  igneous  action  everywhere 
visible. 

PHONOLITE.     See  "  Clinkstone." 

PHRYGANEA.  A  genus  of  four-winged  insects,  the  larvae  of  which,  called  caddis- 
worms,  are  used  by  anglers  as  a  bait. 

PHYSICS.  The  department  of  science  which  treats  of  the  properties  of  natural  bodies, 
laws  of  motion,  &c. ;  sometimes  called  natural  philosophy  and  mechanical  phi- 
losophy. Etym.,  <j>uai s,  phi/sis,  nature. 

PHYTOLOGY,  PHYTOLOGICAL.  The  department  of  science  which  relates  to  plants — 
synonymous  with  botany  and  botanical.  Etym.,  tyvrov,  phyton,  plant,  and  Aoyof, 
logos,  discourse. 

PHYTOPHAGOUS.  Plant-eating.  Etym.,  <pvrov,  phyton,  plant,  and  fayetv,  phagein,  to 
eat. 

PISOLITE.  A  stone  possessing  a  structure  like  an  agglutination  of  peas.  Etym., 
ici<jw,pison,  pea,  and  Xt9o?,  lithos,  stone. 

PISTIA.  P.  618.  The  plant  mentioned  by  Malte-Brun  is  probably  the  Pistia  Strati- 
otes,  a  floating  plant,  related  to  English  duckweed,  but  very  much  larger. 

Prr  COAL.  Ordinary  coal ;  called  so,  because  it  is  obtained  by  sinking  pits  in  the 
ground. 

PITCHSTONE.  A  rock  of  a  uniform  texture,  belonging  to  the  unstratified  and  volcanic 
classes,  which  has  an  unctuous  appearance  like  indurated  pitch. 

PLASTIC  CLAY.  One  of  the  beds  of  the  Eocene  Tertiary  Period  ;  so  called,  because  it 
is  used  for  making  pottery.  The  formation  to  which  this  name  is  applied  is  a 
series  of  beds  chiefly  sands,  with  which  the  clay  is  associated.  Etym.,  ir\a<iau, 
plasso,  to  form  or  fashion. 

PLESIOSAURUS.  A  fossil  extinct  amphibious  animal,  resembling  the  saurian,  or  lizard 
and  crocodile  tribe.  Etym.,  ir\rjatov,  plesion,  near  to,  and  aavpa,  saura,  a  lizard. 


812  GLOSSARY. 

PLIOCENE,  OLDER  and  NEWER.  Two  divisions  of  the  Tertiary  Period  which  are  the 
most  modern,  and  of  which  the  largest  part  of  the  fossil  shells  are  of  recent  spe- 
cies. Etym.,  ir\£u*v,plei<m,  more,  and  KOIVOS,  Jcainos,  recent. 

PLUTONIC  ACTION.  The  influence  of  volcanic  heat  and  other  subterranean  causes 
under  pressure. 

PLUTONIC  ROCKS.  Granite,  porphyry,  and  other  igneous  rocks  supposed  to  have 
consolidated  from  a  melted  state  at  a  great  depth  from  the  surface. 

POLFPARIA.  CORALS.  A  numerous  class  of  invertebrated  animals,  belonging  to  the 
great  division  called  Radiata. 

PORPHYRY,  An  unstratified  or  igneous  rock.  The  term  is  as  old  as  the  time  of 
Piiny,  aid  was  applied  to  a  red  rock  with  small,  angular,  white  bodies  diffused 
through  it,  which  are  crystallized  felspar,  brought  from  Egypt.  The  term  is 
hence  applied  to  every  species  of  unstratified  rock  in  which  detached  crystals 
or  felspar  or  some  other  mineral  are  diffused  through  a  base  of  other  mineral 
composition.  Etym.,  irop<f>vpa,  porpliyra,  purple. 

PORTLAND  LIMESTONE,  PORTLAND  BEDS.  A  series  of  limestone  strata,  belonging  to 
the  upper  part  of  the  Oolite  Group,  found  chiefly  in  England  in  the  Island  of 
Portland  on  the  coast  of  Dorsetshire.  The  great  supply  of  the  building-stone 
used  in  London  is  from  these  quarries. 

POZZUOLANA.  Volcanic  ashes,  largely  used  as  mortar  for  buildings,  similar  in  nature 
to  what  is  called  in  this  country  Roman  cement.  It  gets  its  name  from  Puzzuoli, 
a  town  in  the  Bay  of  Naples,  from  which  it  is  shipped  in  large  quantities  to  all 
parts  of  the  Mediterranean. 

PRECIPITATE.  Substances  which,  having  been  dissolved  in  a  fluid,  are  separated  from 
it  by  combining  chemically  and  forming  a  solid,  which  falls  to  the  bottom  of  the 
fluid.  This  process  is  the  opposite  to  that  of  chemical  solution. 

PRODUCTA.  An  extinct  genus  of  fossil  bivalve  shells  occurring  only  in  the  older  sec- 
ondary rocks.  It  is  closely  allied  to  the  living  genus  Terebratula. 

PTERODACTYL.  A  flying  reptile  :  species  of  this  genus  have  been  found  in  the  Oolite 
and  Muschelkalk.  Some  of  the  finger-joints  are  lengthened,  so  as  to  serve  as 
the  expansors  of  a  membranous  wing.  Hence  the  name  wing-fingered.  Etyni., 
irrepov,  pteron,  a  wing,  and  (Ja/cruAof,  dactylos,  a  finger. 

PUBESCENCE.  The  soft  hairy  down  on  insects.  Etym.,  pubesco,  the  first  growth  of 
the  beard. 

PUDDINGSTONE.    See  "  Conglomerate." 

PUMICE.  A  light  spongy  lava,  chiefly  felspathic,  of  a  white  color,  produced  by  gases 
or  watery  vapor  getting  access  to  the  particular  kind  of  glassy  lava  called  obsidi- 
an, when  in  a  state  of  fusion ;  it  may  be  called  the  froth  of  melted  volcanic 
glass.  The  word  comes  from  the  Latin  name  of  the  stone,  pumex. 

PURBECK  LIMESTONE,  PURBECK  BEDS.  Limestone  strata,  belonging  to  the  Wealden 
Group,  which  intervenes  between  the  Greensand  and  the  Oolite. 

PYRITES.  (Iron.)  A  compound  of  sulphur  and  iron,  found  usually  in  yellow  shining 
crystals  like  brass,  and  in  almost  every  rock,  stratified  and  unstratified.  The 
shining  metallic  bodies  so  often  seen  in  common  roofing  slate  are  a  familiar  ex- 
ample of  the  mineral.  The  word  is  Greek,  and  comes  from  irvp,pyr,  fire;  be- 
cause under  particular  circumstances,  the  stone  produces  spontaneous  heat,  and 
even  inflammation.  " 

PYROMETER.    An  instrument  for  measuring  intense  degrees  of  heat. 

QUADRUMANA.    The  order  of  mammiferous  animals  to  which  apes  belong.    Etym., 

quadrus,  a  derivative  of  the  Latin  word  for  the  number  four,  and  manus,  hand, 

the  four  feet  of  those  animals  being  in  some  degree  usable  as  hands. 
QUA-QUA-VERSAL  DD?.     The  dip  of  beds  to  all  points  of  the  compass  around  a  centre, 

as  in  the  case  of  beds  of  lava  round  the  crater  of  a  volcano.    Etym.^  qud-qud- 

versum,  on  every  side. 
QUARTZ.    A  German  provincial  term,  universally  adopted  in  scientific  language  for 

a  simple  mineral  composed  of  pure  silex,  or  earth  of  flints :  rock-crystal  is  an 

example. 
QUARTZITE  or  QUARTZ  ROCK.     An  aggregate  of  grains  of  quartz,  sometimes  passing 

into  compact  quartz. 


GLOSSARY.  813 

RED  MAKL.    A  term  often  applied  to  the  New  Eed  Sandstone. 

RETICULATE.  A  structure  of  cross  lines,  like  a  net,  is  said  to  be  reticulated,  from  reie, 
a  net. 

ROCK  SALT.  Common  culinary  salt,  or  muriate  of  soda,  found  in  vast  solid  masses 
or  beds,  in  different  formations,  extensively  in  the  New  Red  Sandstone  forma- 
tion, as  in  Cheshire  ;  and  it  is  then  called  ra;£-salt. 

RUBBLE.  A  term  applied  by  quarry-men  to  the  upper  fragmentary  and  decomposed 
portion  of  a  mass  of  stone. 

RUMINANTIA.  Animals  which  ruminate  or  chew  the  cud,  such  as  the  ox,  deer,  &c. 
Etym.,  the  Latin  verb  rumino,  meaning  the  same  thing. 

SACCHAROID,  SACCHARINE.  When  a  stone  has  a  texture  resembling  that  of  loaf- 
sugar.  Mym.,  aaKxap,  saccJiar,  sugar,  and  etSos,  eidos,  form. 

SALIENT  ANGLE.     In  a  zigzag  line 

a  a  are  the  salient  angles,  Fig.  100. 

b  b  the  re-entering  angles.  a 

Mym.,    salire,    to    leap    or  ^\         X^N  jX'X          /\ 

bound  forward.  /  \5/        \$/         \ff       \ 

SALT  SPRINGS.    Springs  of  water  *^-  \/  \ 

containing  a  large  quantity 

of  common  salt.    They  are  very  abundant  in  Cheshire  and  Worcestershire,  and 
culinary  salt  is  obtained  from  them  by  mere  evaporation. 

SANDSTONE.  Any  stone  which  is  composed  of  an  agglutination  of  grains  of  sand, 
whether  calcareous,  siliceous,  or  of  any  other  mineral  nature. 

SAURIAN.     Any  animal  belonging  to  the  lizard  tribe.     Mym.,  aavpa,  saura,  a  lizard. 

SAXICAVOUS.    Hollowing  out  stone. 

SCHIST  is  often  used  as  synonymous  with  slate  ;  but  it  may  be  very  useful  to  distin- 
guish between  a  schistose  and  a  slaty  structure.  The  hypogene  or  primary 
schists,  as  they  are  termed,  such  as  gneiss,  mica-schist,  and  others,  cannot  be 
split  into  an  indefinite  number  of  parallel  laminae  like  rocks  which  have  a  true 
slaty  cleavage.  The  uneven  schistose  layers  of  mica-schist  and  gneiss  are 
probably  layers  of  deposition,  which  have  assumed  a  crystalline  texture.  See 
"  Cleavage."  Etym.,  schistus,  adj.  Latin,  that  which  may  be  split. 

SCHISTOSE  ROCKS.    See  "  Schist." 

SCORLE.    Volcanic  cinders.    The  word  is  Latin  for  cinders. 

SEAMS.    Thin  layers  which  separate  two  strata  of  greater  magnitude. 

SECONDARY  STRATA.  An  extensive  series  of  the  stratified  rocks  which  compose  the 
crust  of  the  globe,  with  certain  characters  in  common,  which  distinguish  them 
from  another  series  below  them  called  primary,  and  from  a  third  series  above 
them  called  tertiary. 

SECULAR  REFRIGERATION.  The  periodical  cooling  and  consolidation  of  the  globe  from 
a  supposed  original  state  of  fluidity  from  heat.  Sceculum,  age  or  period. 

SEDIMENTARY  ROCKS  are  those  which  have  been  formed  by  their  materials  having  been 
thrown  down  from  a  state  of  suspension  or  solution  in  water. 

SELENITE.    Crystallized  gypsum,  or  sulphate  of  lime — a  simple  mineral . 

SEPTARIA.  Flattened  balls  of  stone,  generally  a  kind  of  iron-stone,  which,  on  being 
split,  are  seen  to  be  separated  in  their  interior  into  irregular  masses.  Mym., 
septa,  inclosures. 

SERPENTINE.  A  rock  usually  containing  much  magnesian  earth,  for  the  most  part 
unstratified,  but  sometimes  appearing  to  be  an  altered  or  metainorphic  stratified 
rock.  Its  name  is  derived  from  frequently  presenting  contrasts  of  color,  like  the 
3kin  of  some  serpents. 

SHALE.  A  provincial  term,  adopted  by  geologists,  to  express  an  indurated  slaty  clay. 
Etym.,  German  schalen,  to  peel,  to  split. 

SHELL  MARL.  A  deposit  of  clay,  peat,  and  other  substances  mixed  with  shells,  which 
collects  at  the  bottom  of  lakes. 

SHINGLE.    The  loose  and  completely  water-worn  gravel  on  the  sea-shore. 

SILEX.  The  name  of  one  of  the  pure  earths,  being  the  Latin  word  for  flint,  which  is 
wholly  composed  of  that  earth.  French  geologists  have  applied  it  as  a  generic 


814  GLOSSARY. 

name  for  all  minerals  composed  entirely  of  that  earth,  of  which  there  are  many 
of  different  external  forms. 

SILICA.     One  of  the  pure  earths.     Mym.,  silex,  flint,  because  found  in  that  mineral. 

SILICATE.  A  chemical  compound  of  silica  and  another  substance,  such  as  silicate  of 
iron.  Consult  elementary  works  on  chemistry. 

SILICEOUS.  Of  or  belonging  to  the  earth  of  flint.*  Etym.,  silex,  which  see.  A  silice- 
ous rock  is  one  mainly  composed  of  silex. 

SILICIFIED.    Any  substance  that  is  petrified  or  mineralized  by  siliceous  earth. 

SILT.  The  more  comminuted  sand,  clay,  and  earth,  which  is  transported  by  running 
water.  It  is  often  accumulated  by  currents  in  banks.  Thus  the  mouth  of  a 
river  is  silted  up  when  its  entrance  into  the  sea  is  impeded  by  such  accumula- 
tion of  loose  materials. 

SIMPLE  MINERAL.  Individual  mineral  substances,  as  distinguished  from  rocks, 
which  last  are  usually  an  aggregation  of  simple  minerals.  They  are  not  simple 
in  regard  to  their  nature ;  for  when  subjected  to  chemical  analysis,  they  are 
found  to  consist  of  a  variety  of  different  substances.  Pyrites  is  a  simple  min- 
eral in  the  sense  we  use  the  term,  but  it  is  a  chemical  compound  of  sulphur  and 
iron. 

SINTEE,  CALCAREOUS  on  SILICEOUS.  A  German  name  for  a  rock  precipitated  from 
mineral  waters.  Mym.,  sintern,  to  drop. 

SLATE.    See  "  Cleavage"  and  "  Schist." 

SOLFATARA.  A  volcanic  vent  from  which  sulphur,  sulphureous,  watery,  and  acid 
vapors  and  gases  are  emitted. 

SPOKULES.  The  reproductory  corpuscula  (minute  bodies)  of  cryptogamic  plants. 
Etym.,  ffjropa,  spora,  a  seed. 

STALACTITE.  When  water  holding  lime  in  solution  deposits  it  as  it  drops  from  the  roof 
of  a  cavern,  long  rods  of  stone  hang  down  like  icicles,  and  these  are  called  sta- 
lactites. Etym.,  ffraXa^u,  stalazo,  to  drop. 

STALAGMITE.  When  water  holding  lime  in  solution  drops  on  the  floor  of  a  cavern, 
the  water  evaporating  leaves  a  crust  composed  of  layers  of  limestone  :  such  a 
crust  is  called  stalagmite,  from  «rraXay//a,  stalagma,  a  drop,  in  opposition  to  sta- 
lactite, which  see. 

STATICAL  FIGURE.  The  figure  which  results  from  the  equilibrium  of  forces.  From 
oraro?,  statos,  stable,  or  standing  still. 

STERNUM.    The  breast-bone,  or  the  flat  bone  occupying  the  front  of  the  chest. 

STILBITE.  A  crystallized  simple  mineral,  usually  white,  one  of  the  Zeolite  family, 
frequently  included  in  the  mass  of  the  Trap-rocks. 

STRATIFIED.    Rocks  arranged  in  the  form  of  strata,  which  see. 

STRATIFICATION.     An  arrangement  of  rocks  in  strata,  which  see. 

STRATA,  STRATUM.  The  term  stratum,  derived  from  the  Latin  verb  struo,  to  strew  or 
lay  out,  means  a  bed  or  mass  of  matter  spread  out  over  a  certain  surface  by  the 
action  of  water,  or  in  some  cases  by  wind.  The  deposition  of  successive  layers 
of  sand  and  gravel  in  the  bed  of  a  river,  or  in  a  canal,  affords  a  perfect  illus- 
tration both  of  the  form  and  origin  of  stratification.  A  large  portion  of  the 
masses  constituting  the  earth's  crust  are  thus  stratified,  the  successive  strata  of 
a  given  rock  preserving  a  general  parallelism  to  each  other ;  but  the  planes  of 
stratification  not  being  perfectly  parallel  throughout  a  great  extent  like  the 
planes  of  cleavage,  which  see. 

STRIKE.  The  direction  or  line  of  bearing  of  strata,  which  is  always  at  right  angles 
to  their  prevailing  dip. 

STUFAS.  Jets  of  steam  issuing  from  fissures  in  volcanic  regions  at  a  temperature 
often  above  the  boiling  point. 

SUBAPENNLNES.  Low  hills  which  skirt  or  lie  at  the  foot  of  the  great  chain  of  the 
Apennines  in  Italy.  The  term  Subapennine  is  applied  geologically  to  a  series  of 
strata  of  the  Older  Pliocene  Period. 

SYENITE.  A  kind  of  granite ;  so  called,  because  it  was  brought  from  Syene  in 
Egypt. 

TALUS.  When  fragments  are  broken  off  by  the  action  of  the  weather  from  the  face 
of  a  steep  rock,  as  they  accumulate  at  its  foot,  they  form  a  sloping  heap,  called  a 


GLOSSARY.  815 

talus.  The  term  is  borrowed  from  the  language  of  fortification,  where  talus 
means  the  outside  of  a  wall  of  which  the  thickness  is  diminished  by  degrees,  as 
it  rises  in  height,  to  make  it  the  firmer. 

TARSI.  The  feet  in  insects,  which  are  articulated,  and  formed  of  five  or  a  less  num- 
ber of  joints. 

TERTIARY  STRATA.  A  series  of  sedimentary  rocks,  with  characters  which  distinguish 
them  from  two  other  great  series  of  strata — the  secondary  and  primary — which 
lie  beneath  them. 

TESTACEA.  Molluscous  animals,  having  a  shelly  covering.  Mym.,  testa,  a  shell,  such 
as  snails,  whelks,  oysters,  &c. 

THALLOGENS.  A  class  of  flowerless  plants  including  all  those  that  have  no  defined 
axis,  stem,  or  leaves;  as  Lichens,  Seaweeds,  and  Fungi.  Mym.,  SaAAoj,  thallos, 
a  branch,  and  yeveffts,  genesis,  increase. 

THERMAL.     Hot.    Mym.,  Sep/^os,  thermos,  hot. 

THERMO-ELECTRICITY.    Electricity  developed  by  heat. 

THIN  OUT.  When  a  stratum,  in  the  course  of  its  prolongation  in  any  direction,  be- 
comes gradually  less  in  thickness,  the  two  surfaces  approach  nearer  and  nearer ; 
and  when  at  last  they  meet,  the  stratum  is  said  to  thin  out  or  disappear. 

TRACHYTE.  A  variety  of  lava  essentially  composed  of  glassy  felspar,  and  frequently 
having  detached  crystals  of  felspar  in  the  base  or  body  of  the  stone,  giving  it  the 
structure  of  porphyry.  It  sometimes  contains  hornblende  and  augite;  and 
when  these  last  predominate,  the  trachyte  passes  into  the  varieties  of  trap,  called 
Greenstone,  Basalt,  Dolorite,  &c.  The  term  is  derived  from  rpaxvs,  tracTius, 
rough,  because  the  rock  has  a  peculiar  rough  feel. 

TRAP  and  TRAPPEAN  ROCKS.  Volcanic  rocks  composed  of  felspar,  augite,  and  horn- 
blende. The  various  proportions  and  state  of  aggregation  of  these  simple  min- 
erals, and  differences  in  external  forms,  give  rise  to  varieties,  which  have  received 
distinct  appellations,  such  as  Basalt,  Amygdaloid,  Dolorite,  Greenstone,  and 
others.  The  term  is  derived  from  trappa,  a  Swedish  word  for  stair,  because  the 
rocks  of  this  class  sometimes  occur  in  large  tabular  masses,  rising  one  above  an- 
other like  steps. 

TRAVERTIN.  A  white  concretionary  limestone,  usually  hard  and  serai-crystalline, 
deposited  from  the  water  of  springs  holding  lime  in  solution. — Mym.  This 
stone  was  called  by  the  ancients  Lapis  Tiburtinus,  the  stone  being  formed  in 
great  quantity  by  the  river  Anio,  at  Tibur,  near  Rome.  Some  suppose  travertin 
to  be  an  abbreviation  of  trasterverino  from  transtiburtinus. 

TRIPOLI.  The  name  of  a  powder  used  for  polishing  metals  and  stones,  first  imported 
from  Tripoli,  which,  as  well  as  a  certain  kind  of  siliceous  stone  of  the  same 
name,  has  been  lately  found  to  be  composed  of  the  flinty  cases  of  Infusoria. 

TROPHI,  of  Insects.  Organs  which  form  the  mouth,  consisting  of  an  upper  and 
under  lip,  and  comprising  the  parts  called  mandibles,  maxillse,  and  palpi. 

TUFA,  CALCAREOUS.  A  porous  rock  deposited  by  calcareous  waters  on  their  exposure 
to  the  air,  and  usually  containing  portions  of  plants  and  other  organic  substances 
incrusted  with  carbonate  of  lime.  The  more  solid  form  of  the  same  deposit  is 
called  "  travertin,"  into  which  it  passes. 

TUFA,  VOLCANIC.    See  "  Tuff." 

TUFACEOUS.     A  rock  with  the  texture  of  tuff,  or  tufa,  which  see. 

TUFF,  or  TUFA  VOLCANIC.  An  Italian  name  for  a  variety  of  volcanic  rock  of  an 
earthy  texture,  seldom  very  compact,  and  composed  of  an  agglutination  of  frag- 
ments of  scoria?  and  loose  materials  ejected  from  a  volcano. 

TURBINATED.  Shells  which  have  a  spiral  or  screw-form  structure.  Etym.,  turbina- 
tus,  made  like  a  top. 

TURRILITE.  An  extinct  genus  of  chambered  shells,  allied  to  the  Ammonites,  having 
the  siphuncle  near  the  dorsal  margin. 

UNCONFORMABLE.    See  "  Conformable." 

UNOXIDIZED,  UNOXIDATED.     Not  combined  with  oxygen. 

VEINS,  MINERAL.  Cracks  in  rocks  filled  up  by  substances  different  from  the  rock, 
which  may  either  be  earthy  or  metallic.  Veins  are  sometimes  many  yards  wide ; 


816  GLOSSARY. 

and  they  ramify  or  branch  off  into  innumerable  smaller  parts,  often  as  slender 

as  threads,  like  the  veins  in  an  animal,  hence  their  name. 
VERTEBRATED  ANIMALS.    A  great  division  of  the  animal  kingdom,  including  all  those 

which  are  furnished  with  a  back-bone,  as  the  mammalia,  birds,  reptiles,  and 

fishes.    The  separate  joints  of  the  back-bone  are  called  vertebra,  from  the  Latin 

verb  verto,  to  turn. 
VESICLE.    A  small,  circular,  inclosed  space,  like  a  little  bladder.    Mym.,  diminutive 

ofvesica,  Latin  fora  bladder. 

VITRIFICATION.    The  conversion  of  a  body  into  glass  by  heat. 
VOLCANIC  BOMBS.    Volcanoes  throw  out  sometimes  detached  masses  of  melted  lava, 

which,  as  they  fall,  assume  rounded  forms  (like  bomb-shells),  and  are  often 

elongated  into  a  pear-shape. 
VOLCANIC  Foci.    The  subterranean  centres  of  action  in  volcanoes,  where  the  heat  is 

supposed  to  be  in  the  highest  degree  of  energy. 

WACKE.    A  rock  nearly  allied  to  basalt,  of  which  it  may  be  regarded  as  a  soft  and 

earthy  variety. 
WARP.    The  deposit  of  muddy  waters,  artificially  introduced  into  low  lands.    See 

p.  326. 

ZEOLITE.  A  family  of  simple  minerals,  including  stilbite,  mesotype,  analcime,  and 
some  others,  usually  found  in  the  trap  or  volcanic  rocks.  Some  of  the  most 
common  varieties  swell  or  boil  up  when  exposed  to  the  blow-pipe,  and  hence 
the  name  of  $£«>,  zeo,  to  boil,  and  Atfloj,  lithos,  stone. 

ZOOPHITES.  Corals,  sponges,  and  other  aquatic  animals  allied  to  them  ;  so  called  be- 
cause, while  they  are  the  habitation  of  animals,  they  are  fixed  to  the  ground, 
and  have  the  form  of  plants.  Etym.,  {MOV,  soon,  animal,  and  ^urov,  phyton, 
plant. 


INDEX. 


ABICH,  M.,  on  eruption  of  Vesuvius  in  1834 

878,  380,  550. 
Abo,  622,  523. 
Acosta  cited,  499,  502. 
Adams,  Mr.,  on  fossil  elephant,  80. 
Adanson  on  age  of  the  baobab  tree,  422. 
Addison  on  Burnet's  theory.  82. 
Adise.  embankment  of  the,  255. 

",  delta  of  the,  257. 

Adour,  R.,  new  passage  formed  by,  338. 
Adria,  formerly  a  seaport,  256. 
Adriatic,  deposits  in,  36,  38,  71,  257,  774. 
JEgean  Sea,  Prof.  E.  Forbes  dredging  in,  649. 
Africa,  fossil  shells  of,  mentioned  by  ancients,  15. 

,  indigenous  quadrupeds  of,  82. 

,  heat  radiated  by,  94. 

,  currents  on  coast  of,  292,  342. 

,  drift  sands  of  deserts,  726. 

,  devastations  of  locusts  in,  674. 

,  strata  forming  off  tropical  coast  of,  774. 

,  desert  of  its  area,  694. 

Agassiz,  M.,  on  fish  of  coal  formation,  136. 
,  on  abrupt  transition  from  one  fossil  fauna 

to  another,  184. 

,  on  motion,  &c.,  of  glaciers,  224,  226. 

Agricola  on  fossil  remains,  21. 

Airthrey,  fossil  whale  found  at,  771. 

Alabama,  coal  plants,  88. 

Alaska,  volcanoes  in,  352. 

Aldborough,  incursions  of  sea  at,  311. 

Alderney,  race  of,  293. 

Aleutian  Isles,  eruptions,  &c.,  in,  352,  468. 

Alexandria,  temple  of  Serapis  at,  512. 

Algae,  known  provinces  of.  617. 

Allan,  Dr.,  on  coral  in  Madagascar,  778. 

Alloa,  whale  cast  ashore  at,  771. 

Alluvium,  imbedding  of  organic  remains  in,  730. 

,  volcanic,  386. 

,  stalagmite,  alternating  with,  in  caves,  736. 

Alps,  Saussure  on  the,  45. 

,  tertiary  rocks  of  the,  119. 

,  greatly  raised  during  tertiary  epoch,  124 

,  signs  of  lateral  pressure  in  the,  171. 

Altered  rocks,  177. 

Amazon,  R.,  land  formed  by  its  deposits,  342. 

,  animals  floated  down  on  drift-wood  by,  640. 

America,  its  coast  undermined,  331. 

,  recent  strata  in  lakes  of,  254,  768. 

,  specific  distinctness  of  animals  of,  612, 629. 

,  domesticated  animals  run  wild  in,  585, 685. 

,  N.,  continuous  beds  of  coal  in,  115. 

,  N.,  deposit  "New  red"  like  English,  158. 

,  N.  and  S.,  mammiferous  fauna  of,  633. 

Ammonia  in  lavas,  550. 

Amonoosuck,  flood  in  valley  of,  209. 

Ampere,  M.,  on  electric  currents  in  the  earth, 

543. 

Amphitherium,  in  oolite  of  Stonesfleld,  188. 
Andes,  changers  of  level  in,  762. 

,  height  of  perpetual  snow  on,  112. 

,  volcanoes  of,  346 

,  sudden  upheaval  of,  170. 

,  signs  of  lateral  pressure  in,  171. 

52 


Andeeite,  rock  described,  347. 

Angiospermous  plants  wanting  in  older  rocks, 

133. 
Animals,  extinction  of,  700. 

,  quantity  of  food  required  by  large,  82. 

,  Lamarck  on  production  of  new  organs  in, 

568. 
,  imported  into  America  have  run  wild, 

585,  685. 
,  aptitude  of  some  kinds  to  domestication, 

593,  598. 

,  hereditary  instincts  of,  593. 

,  domestic  qualities  of,  592,  595. 

,  their  acquired  habits  rarely  transmissible, 

595,  600. 

,  changes  in  brain  of  fcetus  in,  609. 

,  plants  diffused  by,  623. 

,  their  geographical  distribution,  76,  77. 

,  migrations  of,  635. 

,  causes  which  determine  the  stations  ot 

669,  676. 

,  influence  of  man  on  their  distribution,  682. 

,  fossil,  in  peat  caves,  &c.,  722,  725,  730, 182, 

749,  752. 
Anio,  R.,  flood  of  the,  212. 

,  travertin  formed  by,  244. 

Anoplotherium,  fossil  of  Isle  of  Wight,  142. 
Antarctic  circle,  area  still  unexplored,  99. 
Antwerp,  sunk  region  near,  827. 
Apennines,  their  relative  age,  119, 124. 
Aphides,  account  of  a  shower  of,  656. 

,  their  multiplication,  673. 

Aqueous  causes,  supposed  former  intensity  of, 

153. 

,  their  action  described,  198. 

Aqueous  lavas,  description  of,  374,  885,  728. 
Arabian  Gulf  filling  with  coral,  776. 
Arabian  writers,  17. 
Arago,  M.,  on  influence  of  forests  on  climate, 

715. 

,  on  solar  radiation,  127. 

,  on  level  of  Mediterranean  and  Ked  Sea, 

294. 

,  on  formation  of  ground  ice,  221. 

Araucanian  tradition  of  a  flood,  499. 

Araucaria,  fir  in  coal,  88. 

Arbroath,  houses,  &c.,  swept  away  by  sea  at,  302. 

Archiac,  M.,  257. 

Arctic  fauna  extended  farther  south  than  now, 

125. 
Arduino,  memoirs  of,  41. 

,  on  submarine  volcanoes,  41,  71. 

Areas  of  elevation  and  subsidence  proved  by 

coral  islands,  792. 
Aristarchus,  212; 
Aristotle,  opinions  of,  12. 

,  on  spontaneous  generation,  22. 

,  on  deluge  of  Deucalion,  356. 

Arkansas,  R.,  264. 

,  floods  of,  270. 

Arso,  volcanic  eruption  of,  in  Ischia,  365. 
Artesian  well  at  Paris,  temperature  of  water, 

234. 

well,  at  Fort  William,  near  Calcutta,  280. 

well  in  delta  of  Po,  257. 


818 


INDEX. 


Artesian  wells  near  London,  234. 

wells,  phenomena  brought  to  light  by,  233, 

538. 

Arve,  sediment  transported  by  the,  258. 

,  section  of  debris  deposited  by,  289. 

Ascension,  Island  of,  bounded  by  lofty  shores, 
622. 

,  fossil  eggs  of  turtle  from,  7T1. 

Ashes,  volcanic,  transported  to  great  distances, 
106,349,464. 

Asia,  subject  to  earthquakes,  9. 

,  coast  of,  changed,  18. 

,  causes  of  extreme  cold  of  part  of,  94. 

Minor,  gain  of  land  on  coast  of,  260. 

,  Western,  great  cavity  in,  692. 

Ass,  wild,  638,  686. 

Astruc  on  Delta  of  Ehone,  258. 

Atchafalaya,  E.,  264. 

,  drift-wood  in,  26T. 

Atlantic,  mean  depth  of,  104. 

,  its  relative  level,  294. 

,  rise  of  the  tide  in,  295. 

,  absence  of  coral  reefs  in,  796. 

Atlantis,  submersion  of,  9. 

Atolls  described,  782,  786. 

,  theory  of,  Mr.  Maclaren's  objections  to, 

792. 

A  trio  del  Cavallo,  381. 

Aubenas,  fissures  filled  with  breccia  near,  741. 

Austen,  Mr.  E.  A.  C.,  on  shores  of  English  Chan- 
nel, 319. 

,  on  new  strata  formed  in,  341. 

Australia,  animals  of,  139. 143,  684. 

,  coral  reefs  of,  776,  784. 

,  land  quadrupeds  of,  633. 

Auvergne,  salt  springs  in,  248. 

,  carbonic  acid  gas  disengaged  in,  248. 

,  state  of  in  tertiary  period,  122. 

,  fossils  in  volcanic  ashes  of,  349. 

,  volcanic  rocks  of,  48. 

,  tertiary  red  marl  and  sandstone  of,  158. 

Ava,  fossils  of,  28. 

Avantipnra,  in  Cashmere,  763. 

Avernus  lake,  368. 

Avicenna  on  cause  of  mountains,  17. 

Axmouth,  great  landslip  near,  321. 

Azores,  icebergs  drifted  to,  99. 

,  volcanic  line  from,  to  central  Asia,  354. 

,  siliceous  springs  of,  246. 


B. 


Babbage,  Mr.,  on  the  coast  near  Puzzuoli,  507. 

,  on  Temple  of  Serapis,  517. 

,  on  expansion  of  rocks  by  heat,  562. 

Bachman,  Mr.,  on  birds,  643,  644. 

Bacon,  Lord,  cited,  765. 

Baden,  gypseous  springs  of,  245. 

Baffin's  Bay,  icebergs  in,  96. 

Bagnes,  valley  of,  bursting  of  a  lake  in  the,  210. 

Baise,  changes  on  coast  of  the  bay  of,  507. 

,  ground  plan  of  the  coast  of,  507. 

,  sections  in  bay  of,  508,  510. 

Baker,  on  Caspian,  mud  volcanoes  at,  448. 
Baker,  Lieut.,  on  fossil  quadrumana,  144. 
Bakewell,  Mr.,  on  formation  of  soils,  709. 

,  on  fall  of  Mount  Grenier,  732. 

Bakewell,  Mr.  jun.,  on  Falls  of  Niagara,  217. 
Bakie  loch,  charie  fossil  in,  767. 
Baku,  inflammable  gas  of,  11,  355. 
Balaruc,  thermal  waters  of,  259. 
Baldassari,  on  Sienese  fossils,  39. 
Balize,  mouth  of  Mississippi,  263,  272. 
Baltic  Sea,  lowering  of  level  of, -520. 

,  drifting  of  rocks  by  ice  in,  219,  231. 

,  currents  on  its  shores,  330. 

Banks  of  Mississippi  higher  than  alluvial  plain, 

266. 

Baobab  tree,  its  size,  probable  age,  &c.,  422. 
Barbadoes,  rain  diminished  by  felling  of  forests 

in,  713. 

Barren  Island  described,  447. 
Barrow,  Mr.,  on  a  bank  formed  in  sea  by  locusts, 

675. 


Barrow,  Mr.  jun.,  on  the  Geysers  of  Iceland,  247. 

Barton,  Mr.,  on  geography  of  plants,  612. 

Basalt,  opinions  of  the  early  writers  on,  48,  71. 

Batavia,  effects  of  earthquake  at,  502. 

Baton  Rouge,  in  Louisiana,  265. 

Bay  of  Bengal,  its  depth,  recent  deposits  in,  &c., 

279. 
Bay  field,  Capt,  on  geology  of  Lake  Superior, 

,  on  drifting  of  rock  by  ice,  221,  230. 

,  on  bursting  of  a  peninsula  by  Lake  Erie, 

333. 

,  on  earthquakes  in  Canada,  470. 

Beaches,  raised,  184 
Beachey  Head,  317. 
Bears,  once  numerous  in  Wales,  683. 

,  black,  migrations  of,  637. 

',  drifted  on  ice,  679. 

Beaufort,  Sir  F.,  on  gain  of  land  in  Asia  Minor, 

260. 

,  on  rise  of  tides,  291. 

Beaumont,  M.  Elie  de,  geological  map  of  France, 

122. 
,  on  pentagonal  network  of  mountain  chains, 

170. 
,  his  theory  of  contemporaneous  origin  of 

parallel  mountain  chains  considered,  163. 

,  OD  structure  and  origin  of  Etna,  400,  416. 

,  on  sand-dunes,  307. 

,  on  inroads  of  sea  in  Holland,  327. 

Beaver  once  inhabited  Scotland  and  Wales,  683. 

,  fossil  in  Perthshire,  752. 

,  lake  formed  by,  in  New  Brunswick,  716. 

Beche,  Sir  H.  de  la.    See  De  la  Beche. 

Bee,  migrations  of  the,  655. 

Beechey,  Capt.,  upheaval  of  Bay  of  Conception, 

500. 

,  on  drifting  of  canoes,  662. 

,  on  temple  of  Ipsambul,  727. 

,  on  coral  islands,  780,  782,  787. 

,  on  changes  of  level  in  Pacific,  788. 

,  on  dead  coral  in  Elizabeth  Island,  794. 

Beila,  in  India,  mud  volcanoes,  449. 

Belcher,  Sir  E.,  on  upheaval  of  Conception,  500. 

* ,  on  strata  forming  off  coast  of  Africa,  774. 

Bell,  Mr.,  on  the  Dog,  585. 

Bell  rock,  stones  thrown  up  by  storms  on,  302. 

Belzoni,  on  temple  of  Ipsambul,  726. 

,  on  a  flood  of  the  Nile,  753. 

Benin,  currents  in  Bay  of,  292. 
Berard,  M.,  on  depth  and  temperature  of  Med- 
iterranean, 296,  336. 
Berkeley,  on  recent  origin  of  man,  764. 
Bermudas,  only  coral  reef  far  out  in  Atlantic, 

796. 

,  coral  reefs  of  the,  776,  778. 

Bewick  cited,  310,  643,  683. 

Bhooj,  in  Cutch,  destroyed  by  earthquake,  459. 

,  volcanic  eruption  at,  460,  729. 

Bies  Bosch  formed,  328. 

Bigsby,  Dr.,  on  North  American  lakes,  768. 

Birds,  diffusion  of  plants  by,  624. 

geographical  distribution  of,  642,  663. 

fossils  in  secondary  rocks,  137. 

tameness  of,  in  uninhabited  islands,  597. 

rate  of  flight  of,  644. 

migrations  of,  643. 

recent  extermination  of  some  species  of, 

683. 

bones  of,  in  Gibraltar  breccia,  741. 

rarity  of  their  remains  in  new  strata,  748. 

rare  in  deposits  of  all  ages,  137. 

Bischoff,  Professor,  on  volcanoes,  551. 

,  on  carbonic  acid  in  extinct  cratera  on 

Ehine,  248. 

Biscoe,  Capt,  discoveries  in  south  Polar  Seas,  99. 

Bison,  fossil,  in  Yorkshire,  76. 

Bisons,  in  Mississippi  valley,  636. 

Bistineau  lake,  269. 

Bitumen,  oozing  from  bottom  of  sea,  near  Trin- 
idad, 250. 

Bituminous  springs,  250. 

Black  Sea,  salt  by  evaporation  in,  335. 

.    See  Euxine. 

Blue  mountains  in  Jamaica,  505. 


INDEX. 


819 


Bluffs  of  Mississippi  described,  264 

Boa  constrictor,  migration  of,  646. 

Boase,  Mr.,  on  inroads  of  sea  in  Cornwall,  323. 

,  on  drift-sand  in  Cornwall,  728. 

Boblaye,  M.,  on  ceramique,  in  Morea,  731. 

,  on  engulfed  rivers  and  caves  in  Morea,  734 

,  on  earthquakes  in  Greece,  736. 

Bog  iron-ore,  whence  derived,  722. 

Bogota,  earthquake  of,  457. 

Bonpland,  on  plants  common  to  Old  and  New 

World,  614 
Bore,  a  tidal  wave  frequent  in  Bristol  Channel 

and  Ganges,  332. 

Bory  de  St.  Vincent,  M.,  on  isle  of  Santorin,  445. 
Bosphorus,  334 

,  traditions  of  deluges  on  shores  of  the,  356. 

Botanical  evidence  bearing  on  theory  of  pro- 
gressive development,  133. 

geography,  613. 

provinces,  their  number,  616,  666,  663. 

Bothnia,  Gulf,  gradual  elevation  of  coast  of,  520. 
Bonrbon,  island,  volcanic,  546. 
Bournmouth,  submarine  forest  at,  746. 
Boussingault.  M..  on  volcanoes  in  Andes,  348. 

,  on  gases  evolved  by  volcanoes,  549. 

Bowen,  Lieut.,  on  drifting  of  rocks  by  ice,  220, 

230. 

Boyle,  on  bottom  of  the  soa,  26. 
Bracini,  on  Vesuvius  before  1631,  374. 
Brahmapootra,  delta  of,  275,  278. 
Brahmins,  their  doctrines,  4. 
Brander,  on  fossils  of  Hampshire,  46. 
Brandt,  Professor,  cited,  80. 

,  on  Wilui  rhinoceros,  80. 

Bravais,  M.,  on  upraised  sea-coast  in  Finmark, 

530. 
Breccias,  in  Val  del  Bove,  411. 

,  in  caves  now  forming  in  the  Morea,  734. 

Brenta.  delta  of  the,  256. 
Brieslak,  on  temple  of  Serapis,  517. 

,  on  Vesuvius,  381,  384. 

Briggs,  Mr.,  his  discovery  of  water  in  African 

desert,  235. 

Brighton,  waste  of  cliffs  of,  317. 
Brine  springs,  247. 
Bristol  Channel,  currents  in,  293. 
Brittany,  village,  buried  under  blown  sand,  727. 

,  marine  tertiary  strata  of,  122. 

,  waste  of  coast  of,  324. 

Brocchi,  on  fossil  conchology,  20. 

,  on  Burnett  theory,  34. 

,  on  deHa  of  Po,  257. 

,  on  extinction  of  species,  668. 

,  on  the  Subapennines.  118. 

Broderip,  Mr.,  on  opossum  of  Stonesfleld,  139. 

,  on  shells  from  Conception  Bay,  500. 

,  on  bulimi  revived,  650. 

,  on  moulting  of  crabs,  653. 

,  on  naturalization  of  a  foreign  landshell,  664. 

,  on  the  Dodo,  684. 

Brongniart,  M.  Adolphe,  87. 

,  on  fossil  plants  of  coal,  88, 117, 133. 

,  on  plants  in  islands,  112. 

Brongniart,  M.  Alex.,  on  modern  lava  streams, 

427. 

,  on  elevated  beaches  in  Sweden,  521. 

Brown,  Mr.  E.,  on  structure  of  vessels  in  myzo- 

dendron,  88. 
,  on  plants  common  to  Africa,  Guiana,  and 

Brazil,  621. 

,  on  wheat  in  Egyptian  tombs,  587. 

Buch.    See  Von  Buch. 

Buckland,  Eev.  Dr.,  on  landslip  near  Axmouth, 

821. 

,  on  fossil  elephants,  &c.,  in  India,  7. 

,  on  fossils  from  Eschscholtz's  Bay,  82. 

,  on  fossils  in  caves  and  fissures,  739,  740. 

,  on  Val  del  Bove,  402. 

Buffon,  his  theory  of  the  earth,  89. 

,  reproved  by  the  Sorbonne,  89. 

,  on  geographical  distribution  of  animals, 

590,  612,  629. 

,  on  extinction  of  species,  701. 

Buist,  Mr.,  on  submarine  forests  in  the  estuary 

of  Tay,  303. 


Buist,  on  mud  volcanoes  in  India,  448. 
Bunbury,  Mr.,  on  coal  plante  of  Alabama,  88. 

,  on  ferns  in  carboniferous  era,  87. 

Bunsen,  Chievalier,  on  Ancient  Egypt,  659. 
Bunsen,  Professor,  on  Geysers  of  Iceland,  558. 

,  on  mineral  springs  in  Iceland,  246. 

,  on  mud  volcanoes  of  Iceland,  447. 

,  pn  solfataras  of  Iceland,  551. 

Bunter  Sandstein,  fossils  of,  193. 

Bura,  submerged  Grecian  town,  15,  762. 

Buried  cones  on  Etna,  section  of,  397. 

temples  of  Cashmere,  762. 

Burnes,  Sir  A.,  on  Cutch,  earthquake  of,  461, 464. 
Burnet,  his  theory  of  the  earth,  31. 
Burntisland,  whale  cast  ashore  near.  771. 
Burrampooter,  li.,  delta  of  the,  275.'    See  Brah- 
mapootra. 

,  bodies  of  men,  deer,  &c.  floated  off  by,  751. 

Bustards  recently  extirpated  in  England,  683. 


Calabria,  geological  description  of,  474 

,  earthquake  of  1783  in,  471. 

,  tertiary  strata  of,  74. 

Calanna,  lava  of  Etna  turned  from  its  course  by 

hill  of,  409,  410. 

,  valley  of,  402,  404. 

Calcareous  springs,  239. 

Calcutta,  artesian  well  at,  280. 

Caldcleugh,  Mr.,  on  earthquake  in  Chili,  1835, 

453. 

,  on  eruption  of  Coseguina,  349. 

California,  volcanoes  in,  349. 
Callao  town  destroyed  by  sea,  502. 

-,  changes  caused  by  earthquakes  at,  501,  761. 

Camels,  carcasses  of,  imbedded  in  drift  sand,  727. 
Campagna  di  Eoma,  calcareous  deposits  of,  242. 
Campania,  aqueous  lavas  in,  728. 
Camper,  on  facial  angle,  608. 
Canada,  earthquakes  frequent  in,  470. 

,  climate  of,  582. 

,  probably  colder  in  newest  tertiary  period, 

125. 

Canary  Islands,  eruptions  in,  436. 
Cannon  in  calcareous  rock,  759. 
,  account  of  one  taken  up  near  the  Downs, 

726. 
Canoes  drifted  to  great  distances,  661. 

,  fossil,  759. 

Cape  May,  encroachment  of  sea  at,  332. 

of  Good  Hope,  icebergs  seen  off,  100. 

Capocci,  M.,  on  temple  of  Serapis,  518. 

Caraccas,  earthquakes  in,  465,  470. 

Carang  Assam  volcano,  465. 

Carbonated  springs,  248. 

Carbonic  acid,  supposed  atmosphere  of,  248. 

gas,  its  effects  on  rocks,  249. 

Carboniferous  series,  115,  137. 

era,  predominance  of  ferns  in,  87. 

era,  climate  in,  87. 

flora,  knowledge  of,  recently  acquired,  126. 

period,  vast  duration  of,  249. 

.    SeeCo&L 

Cardiganshire,  tradition  of  loss  of  land  in,  324. 
Cardium,  locomotive  powers  when  young,  652. 
Caribbean  Sea,  tides  in,  842. 
Carpenter,  Dr.,  observations  on  Mississippi  E., 

272. 

,  on  encroachment  of  sea  at  Lyme  Eegis,  321. 

Carrara  marble,  177. 

Cashmere,  temples  buried  in  freshwater  strata, 

762. 
Caspian,  Pallas  on  former  extent  of,  45. 

,  evaporation  of  the,  260. 

,  its  level,  156,  692. 

Catalonia,  devastation  of  torrents  in,  713. 
Catania,  in  part  overwhelmed  by  lava,  400,  72S. 

,  destroyed  by  earthquakes,  508. 

,  tools  discovered  in  digging  a  well  at,  758. 

Catastrophes,  theories  respecting.  7. 
Catcott,  on  deluges  in  different  countries,  42. 
Cattegat,  devastations  caused  by  current  in  the, 

331. 


820 


INDEX. 


Cautley,  Capt,  on  buried  Hindoo  town,  731. 

,  on  fossil  quadrumana,  144. 

,  on  bones  in  ancient  wells,  740. 

Caves,  organic  remains  in,  732. 

,  alternations  of,  and  stalagmite  in,  736. 

,  on  Etna,  401. 

Celestial  Mountains,  77,  355. 

Celsius,  on  diminution  of  Baltic,  83,  521. 

Central  America,  volcanoes  of,  849. 

Asia,  volcanic  line  from,  to  the  Azores,  354. 

France,  lavas  excavated  in,  213. 

France,  comparison  between  the  lavas  of 

Iceland  and,  426,  427. 
Centres,  specific  doctrine  of,  630. 
Centrifugal  force,  534,  544. 
Cephalonia,  earthquakes  in,  474. 

,  infusoria  in  submarine  caverns  in,  389. 

Ccsalpino,  on  organic  remains,  22. 
Cetacea,  geographical  range  of,  635. 

,  migrations  of  the,  642. 

,  imbedding  of,  in  recent  strata,  770. 

,  fossil,  absence  of  in  secondary  rocks,  145. 

,  fossil  in  New  Jersey  chalk,  145. 

,  rarity  of  in  secondary  rocks,  145. 

Chagos  coral  isles,  783. 

Chaluzet,  calcareous  spring  at,  239. 

,  volcanic  cone  of,  248. 

Chambers,  Robert,  cited,  530. 

Chamisso,  M.,  on  coral  islands,  781. 

Chamouni,  glaciers  of,  223. 

Chara,  growing  in  lakes  of  N.  America,  768. 

Chara,  fossilized,  767. 

Charlevoix,  chart  of  coast  of  Gulf  of  Mexico,  272. 

Charpentier,  M.,  on  glaciers,  223,  227. 

Cheirotherium,  in  old  red  sandstone  and  coal,  136. 

Chemical  theory  of  volcanoes,  542,  546. 

Chepstow,  rise  of  the  tides  at,  291. 

Cheshire,  brine  springs  of,  247. 

,  waste  of  coast  of,  324 

Chesil  bank,  320. 

Chesilton,  overwhelmed  by  sea,  820. 

Chili,  earthquakes  in,  65,  347,  357,  453,  457. 

,  numerous  volcanoes  in,  346. 

,  coast  of,  upheaved,  170, 172,  347,  455,  457. 

Chiloe,  349. 

Chimborazo,  height  of,  102. 

China,  climate  of,  95. 

,  earthquakes  in,  355. 

Chinese  deluge,  7. 

Chines,  or  narrow  ravines,  described,  319. 

Chittagong,  earthquakes  at,  476. 

Cheekier,  cave  at,  736. 

Chonos  archipelago,  rise  of  land  in,  453. 

Christchurch  Head  promontory,  819. 

Christie,  Mr.,  on  plasticity  of  ice,  226. 

Christol,  M.  de,  on  fossils  in  caves,  738,  739. 

Chronology  of  Hebrew  Scriptures,  659. 

of  Dr.  Hales,  659. 

Cimbrian  deluge,  331. 

Cisterna  on  Etna,  how  formed,  414. 

Cities  engulfed,  173. 

Civita  Vecchia,  springs  at,  243. 

Clarke,  Dr.,  on  lava  in  motion,  377. 

Cleavage,  or  slaty  Structure,  176. 

Clermont,  calcareous  springs  at,  239. 

Climate  of  Europe,  Raspe  on  former,  43. 

,  changes  of,  75,  86. 

,  change  of,  in  northern  hemisphere,  73, 123. 

,  on  causes  of  vicissitudes  in,  92. 

,  astronomical  causes  of  fluctuations  in,  126. 

,  its  influence  on  distribution  of  plants,  613. 

,  effect  of  changes  in,  on  range  of  species, 

696. 

,  influence  of  vegetation  on,  713. 

Climates,  insular  and  excessive,  94. 

Coal,  modern,  at  mouths  of  Mackenzie,  743. 

,  ancient  beds,  formed  of  plants,  90. 

,  ancient,  formed  in  deltas,  116. 

fields,  American,  115. 

.  formed  by  plants  which  grow  on  the  spot, 

115. 
period,  warmth,  moisture,  &c.  of  climate, 

126. 

formation,  fossil  plants  of  the,  88, 115,  133. 

,  climate  indicated  by,  91. 


Coal,  reptilian  fossils  in,  136. 

.    See  Carboniferous. 

Colchester,  Mr.  W.,  on  fossil  qnadrurnana,  144. 
Colebrooke,  Mr.  H.  T.,  on  age  of  Vedas,  4 

,  on  crocodiles  of  the  Ganges,  277. 

,  Major  R.  H.,  on  the  Ganges,  277. 

Colle,  travertin  of,  240. 
Colombia,  earthquakes  in,  456. 
Colonna,  on  organic  remains,  23. 
Columbia,  R.,  submerged  forest  in,  270. 
Conception,  earthquakes  at,  453,  456,  499,  761. 
Conglomerates,  now  formed  by  rivers,  &c.,  289. 

,  volcanic,  411,  438. 

Coniferae  of  coal,  133. 

,  Araucarian,  in  coal,  88. 

Consolidation  of  strata,  175. 
Conybeare,  Rev.  W.  D.,  on  Lister,  26. 

,  on  landslip  near  Axmouth,  321,  322. 

Cook,  Captain,  on  drifting  of  canoes  far,  661. 

,  on  highland  near  the  South  Pole,  98,  99. 

Copaic  lake,  735. 

Copernican  theory,  edicts  against,  repealed  at 

Rome,  56. 
Copiapo,  earthquakes  at,  347. 

,  raised  banks  of  shells  at,  458. 

Coral  islands,  775,  776,  793. 

,  origin  of  their  circular  form,  783. 

,  linear  direction  of,  782. 

,  rate  of  growth,  776: 

,  downward  movement  slow  and  uniform, 

791. 

,  absence  of,  in  Atlantic,  &c.,  796. 

Coralline  crag  fossils,  142. 

Corda,  on  palm  wood  in  Bohemian  coal,  88. 

cited,  133. 

Cordier,  M.,  on  rate  of  increase  of  heat  in  mines, 

588,  539. 

,  on  tides  in  the  internal  melted  ocean,  541. 

Cordilleras  shaken  by  earthquakes,  457,  466. 

,  parallel  ridges  successively  upheaved,  170. 

Corinth,  decomposition  of  rocks  in,  733. 

Cornwall,  waste  of  cliffs  of.  323. 

,  land  inundated  by  drift-sand  in,  727. 

,  temperature  of  mines  in,  538. 

Coromandel,  inundations  of  sea  on  coast  of,  730. 

Coseguina  volcano,  great  eruption  of,  347. 

Cosmogony  distinct  from  geology,  3. 

,  of  the  Hindoos,  4 

,  Egyptian,  8. 

,  of  the  Koran,  18. 

Cosmopolite  shells,  650. 

Coste,  Capt,  on  elevation  caused  by  earth- 
quakes, 453. 

Cotopaxi,  848,  560. 

Covelli,  M.,  on  hot  spring  in  Ischia,  456. 

,  on  Vesuvian  minerals,  385. 

Cowper,  the  poet,  on  age  of  earth,  55. 

Crag  strata,  fossils  of  the,  142. 

Craters  of  elevation,  theory  of,  871,  380,  415. 

Crawfurd,  Mr.,  his  discovery  of  fossils  in  Ava,  28. 

,  on  eruption  in  Sumbawa,  106,  464,  466. 

.  on  drifting  of  canoes,  662. 

Creation,  supposed  centres  or  foci  of,  667. 

,  epoch  of,  difference  of  opinion  on,  660. 

Cremona,  lakes  filled  up  near,  255. 

Crocodiles  imbedded  by  a  river  inundation  in 
Java,  503,  748. 

Cromer,  waste  of  cliffs  of,  306. 

Cropthorn,  fossils  found  at,  76. 

Cruickshanks,  Mr.  A.,  on  Chilian  earthquake,  457. 

Cuba,  fossils  in  caves  of,  741. 

Culver,  cliff,  318. 

Cumana,  earthquake  of,  470. 

Cunningham,  Major,  on  buried  temples  of  Cash- 
mere, 764. 

Cupressus  thyoides,  725. 

Currents  from  equatorial  regions,  96. 

,  from  the  pole  to  the  equator,  107. 

,  causes  and  velocity  of,  293. 

,  polar  and  tropical,  direction  of,  295. 

,  destroying  and  transporting  power  of,  297, 

840. 

,  in  estuaries,  their  power,  837. 

,  in  the  Straits  of  Gibraltar,  833. 


INDEX. 


821 


Currents,  reproductive  effects  of,  887. 

,  on  the  British  shores,  339. 

,  convey  species  from  Antarctic  to  Arctic 

Ocean,  622. 
Curtis,  Mr.,  on  ravages  caused  by  aphides,  674 

,  on  power  of  the  Ti  pulse  to  cross  the  sea,  667. 

,  on  number  of  British  insects,  705. 

,  on  fossil  insects,  748. 

Curves  of  the  Mississippi,  265. 

Cutch,  changes  caused  by  earthquake  of  1819 

in.  459,  761. 
Cuvier  on  durability  of  bones  of  men,  147,  757. 

on  crocodiles  of  Ganges,  277. 

on  variability  in  species,  583,  584. 

on  fish  not  crossing  the  Atlantic,  647. 

on  identity  of  Egyptian  mummies  with 

living  species,  586. 

on  number  of  fishes,  705. 

Cuvier,  M.  F.,  on  aptitude  of  some  animals  to 

domestication,  593. 

,  on  influence  of  domestication,  595. 

Cypris,  fossil  and  living,  768. 


D. 


Dana,  Mr.,  on  Sandwich  Islands,  354,  372,  383, 

548. 
,  on  fragments  of  recent  coral  thrown  up  by 

Polynesian  volcanoes,  372. 

,  on  Mount  Loa,  volcano,  552. 

,  on  "volcanoes  no  safety-valves,"  552. 

Dangerfield,  Capt  F.,  on  buried  cities  in  India, 

729. 

,  on  Oujein,  729. 

Daniell,  Professor,  on  the  trade  winds,  106. 

,  on  melting  point  of  iron,  539. 

Dante  cited,  52,  256. 

Dantzic,  waste  of  land  near,  331. 

Darby,  on  lakes  formed  by  Red  Eiver,  269. 

,  on  delta  of  Mississippi,  272. 

Darwin,  Mr.  C.,  on  distribution  of  animals  and 

plants,  77,  98,  141. 
,  on  vegetation  required  for  support  of  large 

quadrupeds,  82. 

,  Mr.  C.,  on  drifting  of  rocks  by  ice,  228. 

,  on  earthquakes,  347,  453,  456,  476,  753. 

,  on  earthquake  waves,  497. 

,  on  rise  of  land,  458,  502. 

,  on  oolitic  travertin,  439. 

,  on  great  droughts  in  S.  America,  696. 

,  on  peat  of  8.  America,  719. 

,  on  coral  islands,  779,  780,  782,  785,  789. 

,  geology  of  8.  America,  170. 

,  on  recent  shells  in  Chili,  190. 

,  on  shingle  on  coast  of  8.  America,  342. 

,  map  of  coral  reefs,  852,  791,  794. 

,  on  crateriform  hills  of  Galapagos,  872. 

,  infusoria  brought  home  by,  888. 

,  on  new  islands  forming  in  Atlantic,  436. 

,  oa  nat.  hist  of  Galapagos,  141,  597,  615, 

616,  642. 

,  on  extinction  of  animals,  700. 

Daubeny,  Dr.,  on  springs,  287. 

,  on  Mount  Vultur,  356. 

,  on  Vesuvius,  380. 

,  on  decomposition  of  trachyte,  885. 

on  flowing  of  lava  under  water,  383. 

,  on  volcanoes,  548,  549,  550,  551. 

D'Aubuisson  cited,  58,  411. 

Davis,  Mr.,  on  Chinese  deluge,  7. 

Davy,  Sir  H.,  on  lake  of  the  Solfatara,  243. 

,  on  formation  of  travertin,  243. 

.,  on  theory  of  progressive  development,  131. 

,  on  eruption  of  Vesuvius,  378. 

,  on  chemical  agency  of  electricity,  542. 

,  his  theory  of  unoxidated  metallic  nucleus, 

546. 
,  on  agency  of  air  and  water  in  volcanoes,  548, 

550. 

,  his  analysis  of  peat,  718. 

Davy,  Dr.,  on  Graham  Island,  436,  549. 

,  on  helmet  taken  from  sea  near  Corfu,  760. 

De  Beaumont    See  Beaumont,  De. 


Debey,  Dr.,  of  Aix,  on  cretaceous  dicotyledons, 

183. 
De  Candolle,  on  hybrid  plants,  605. 

,  on  distribution  of  plants,  613,  616. 

,  on  agency  of  man  in  dispersion  of  plants, 

625. 

,  on  stations  of  plants,  670. 

,  on  barriers  separating  botanical  provinces, 

703. 

,  on  number  of  land  plants,  705. 

,  on  longevity  of  trees,  422. 

Dechen,  Von,  map  of  Germany,  &c.,  128. 

Dee,  R.,  bridge  over,  swept  away  by  floods,  208, 

Deer,  their  powers  of  swimming,  636. 

,  diminished  number  in  Great  Britain,  683. 

,  remains  of,  in  marl  lakes,  752. 

De  la  Beche,  Sir  H.,  on  rocks  in  8.  Wales,  91. 

,  on  delta  of  Bhone  in  Lake  of  Geneva,  253. 

,  on  storm  of  Nov.,  1824.  321. 

,  on  submarine  forests,  323. 

,  on  earthquake  of  Jamaica,  1692,  504 

,  on  action  of  rain  in  the  tropics,  713. 

De  la  Hire,  on  fossil  wood  from  Ava,  1692,  28. 
Delhi  territory,  elephants  in,  81. 
Delta  of  the  Adige  and  Brenta,  256. 

of  the  Brahmapootra  or  Burrampooter,  275. 

of  the  Ganges,  275  to  284 

of  the  Mississippi,  263  to  275. 

of  the  Mississippi,  antiquity  of,  271. 

of  the  Nile,  261. 

of  the  Po,  256. 

of  Rhone,  in  Lake  of  Geneva,  252. 

of  Rhone,  in  Mediterranean,  258. 

Deltas,  chronological  computations  of  age  of,  253, 

285. 

,  of  Lake  Superior,  253. 

,  grouping  of  strata  in,  286. 

De  Luc,  his  treatise  on  Geology,  56. 

,  on  conversion  of  forests  into  peat  mosses, 

721. 

De  Luc,  M.  G.  A.,  his  natural  chronometers,  726. 
Deluge,  ancient  theories  on,  18,  23, 25,  31, 42, 155. 

,  fossil  shells  referred  to  the,  20. 

Deluges,  local,  how  caused,  7,  269. 

,  traditions  of  different,  7,  11,  42,  831,  356, 

500,  501. 

Demaillet,  speculative  views  of,  572. 
Denudation  can  only  keep  pace  with  deposition, 

,  effects  of,  708. 

Deposition  of  sediment,  shifting  of  the  area  of, 

188. 
and  denudation  parts  of  the  same  process, 

154 

Deshayes,  M.,  on  fossils  of  tertiary,  184. 
Desmarest,  his  definition  of  geology,  8. 

,  on  Auvergne,  49. 

Desnoyers,  M.,  on  human  remains  in  caves,  739, 
Desor,  M.,  on  glacier  motion,  224. 
Deucalion's  deluge,  12. 
Deville,  M.,  on  contraction  of  granite,  173. 

,  on  trachytes,  440. 

Devonian  strata  formed  in  deep  seas,  117. 

Diatomaceue,  888. 

Dikes,  composition  and  position  of,  879. 

,  how  caused,  379. 

Diluvial  waves,  no  signs  of  on  Etna,  423. 

theory  of  earlier  geologists,  25. 

Diodorus  Siculus  cited.  357. 
Dion  Cassius  cited,  364. 
Dodo,  recent  extinction  of  the,  684 
Dog,  varieties  of  the,  570,  584 

,  hybrids  between  wolf  and,  601. 

,  acquired  instincts  hereditary  in,  593. 

,  has  run  wild  in  America,  686. 

Doggerbank,  340. 

Dollart,  formation  of  estuary  of  the,  829. 

Dolomieu  on  Val  di  Noto,Vicentin,  and  Tyrol,  49. 

,  on  la /as  of  Etna,  49. 

,  on  decomposition  of  granite,  249. 

,  on  earthquake  of  1788  in  Calabria,  473, 475, 

478,  480. 
Domestication,  aptitude  of  some  animals  for,  593, 

599. 
,  influence  of;  595. 


S22 


INDEX. 


Don,  river,  rocks  transported  by,  208. 

Donati  on  bed  of  4driatic,  38,  71,  774. 

Donny,  Mr.,  cited,  557. 

D'Orbigny,  M.  A.,  on  abrupt  transition  from  one 
fossil  fauna  to  another,  184. 

Dorsetshire,  landslip  in,  321. 

,  waste  of  cliffs  of,  319. 

Dove,  Mr.,  map  of  isothermal  lines,  93. 

Dover,' waste  of  chalk  cliffs  of,  314. 

• ,  depth  of  sea  near,  315. 

,  formation  of  Straits  of,  315. 

,  strata  at  foot  of  cliffs  of,  314. 

Downham  buried  by  blown  sand,  727. 

Dranse,  E..  210. 

Drift,  northern,  fossil  marine  shells  in,  186. 

Drift-sand,  fossils  in,  727. 

Drift-wood  of  Mississippi,  268. 

,  abundant  in  North  Sea,  744. 

Drontheim,  529. 

Droughts  in  8.  America,  animals  destroyed  by, 
696. 

Druids,  their  doctrines,  16. 

Dufresnoy,  M.,  geological  map  of  France,  122. 

,  on  formation  of  Monte  Nuovo,  371,  372. 

,  on  tuffs  of  Somma,  382. 

,  on  lavas  of  Vesuvius,  384. 

Dujardin,  M.,  on  shells,  &c,,  brought  up  by  ar- 
tesian well  at  Tours,  236. 

Dumont,  M.,  cited,  120,  328. 

Dumoulin,  M.,  on  earthquakes  in  Chili,  453. 

Dunes,  hills  of  blown  sand,  305,  307. 

Dunwich  destroyed  by  the  sea,  310. 

Durand,  Lieut.,  on  fossil  quadrumana,  144 

Dureau  de  la  Malle,  M.,  cited,  584,  593. 

Durham,  waste  of  coast  of,  303. 

D'Urville,  Capt,  on  temperature  of  Mediterra- 
nean, 296. 


Earth,  antiquity  of  the,  21. 

,  on  changes  in  its  axis,  30. 

,  proportion  of  land  and  sea  on  surface,  125. 

,  spheroidal  form  of  the,  534. 

,  mean  density  of  the,  535. 

,  attempt  to  calculate  thickness  of  its  crust, 

Earth,  electric  currents  in  the,  543. 

,  sections  of  the  (see  figs.  70,  71),  539. 

,  effects  produced  by  powers  of  vitality  on 

surface,  708. 
Earthquakes,  chronologically  described,  453,  et 

Keq. 

,  energy  of,  probably  uniform,  53. 

,  earth's  surface  continually  remodelled  by, 

102. 
,  recurrence  of,  at  stated  periods,  accidental, 

345. 

,  felt  at  sea,  358. 

,  land  elevated  by,  453,  455,  457,  462. 

,  all  countries  liable  to  slight  shocks  of,  358. 

,  phenomena  attending,  452. 

,  in  Cutch,  1819  (see  Map),  460. 

,  in  Calabria,  1783,  471. 

,  difficulty  of  measuring  the  effects  of,  477. 

,  chasms  formed  by,  479. 

,  excavation  of  valleys  aided  by,  488. 

,  renovating  effects  of,  565. 

,  cause  of  the  wave-like  motion  of,  475,  558. 

,  cause  of  great  waves  and  retreat-  of  sea 

during,  496,  498. 

,  ravages  caused  by  sea  during,  499, 501,  730. 

,  connection  between  state  of  atmosphere 

and,  561. 

,  people  entombed  in  caverns  during,  736. 

,  causes  of  volcanoes  and,  533. 

,  recurrence  of,  in  certain  zones  of  country, 

172. 

of  Lisbon,  area  over  which  it  extended,  496. 

more  frequent  in  winter,  561. 

Eccles,  old  church  of,  buried  under  blown  sand, 

306. 

Edmonstone  Island,  279. 
Eels,  migration  of,  647. 
Egypt  nearly  exempt  from  earthquakes,  9,  358. 


Egypt,  towns  buried  under  drift-sand  in,  726. 
,  date  of  civilization  of,  according  to  Bunsen, 

Egyptian  cosmogony,  8. 

,  mummies  identical  with  living  species,  585. 

Ehrenberg,  on  Bengal  tiger  in  Siberia,  77. 

,  on  origin  of  bog-iron  ore,  722. 

— — ,  on  corals  of  Eed  Sea,  777. 

,  on  ashes  enveloping  Pompeii,  388. 

,  on  infusoria  in  volcanic  tuff;  389. 

Electricity,  a  source  of  volcanic  heat,  542. 

,  whence  derived,  543.  ^ 

Elephant,  fossil,  in  ice,  45,  80. 

,  covered  with  hair  in  Delhi,  81. 

,  sagacity  of,  not  attributable  to  intercourse 

with  man,  598. 

,  their  powers  of  swimming.  636. 

Elevation  of  land,  how  caused,  29,  443,  444,  453, 

455,  457. 

,  proofs  of,  slow  and  gradual,  170, 184, 518, 563. 

Elevation  and  subsidence,  proportion  of,  564. 

,  alternate  areas  of,  in  Pacific,  790. 

Elevation  crater  theory,  371,  380,  420. 

Elevation,  valleys  of,  420. 

Elizabeth  or  Henderson's  Island,  upraised  atoll 

of,  788,  794. 

Elsa,  travertin  formed  by  the,  239. 
Embankment,  system  of,  in  Italy,  255. 
Emu  in  Australia  will  become  exterminated,  684. 
Englehardt  on  the  Caspian  Sea,  157. 
England,  waste  of  cliffs  on  coast  of,  303. 

,  slight  earthquakes  felt  in,  358. 

,  height  of  tides  on  coast  of,  291,  308. 

,  tertiary  strata  of,  76. 

Eocene  period,  fossils  of  the,  142, 144, 183. 
Epomeo,  Mount,  in  Ischia,  362. 
Equatorial  current,  95. 
Equinoxes,  precession  of  the,  100,  537. 
Erebus,  Mount,  the  active  volcano  of,  99. 
Erie,  Lake,  peninsula  cut  through  by,  333. 

,  waste  of  cliffs  in,  333. 

Erman,  M.,  on  eruptions  in  Kamschatka,  353. 
Erratic  blocks,  122,  154,  220. 

,  icebergs  charged  with,  86. 

Erratic  blocks,  submarine,  laid  dry  by  upheaval, 

229. 
Eruptions,  volcanic,  number  of  per  year,  450. 

,  cause  of,  533. 

Erzgebirge,  mica  slate  of  the,  48. 

Escher,  M.,  on  flood  in  valley  of  Bagnes,  211. 

Eschscholtz  Bay,  fossils  of,  82. 

Essex,  tertiary  strata  of,  76. 

,  inroads  of  sea  on  coast  of,  311. 

Estuaries,  how  formed,  327,  337. 

,  imbedding  of  freshwater  species  in,  768. 

Etna,  description  of  and  its  eruptions,  396  to 

424. 

,  towns  overflowed  by  lava  of,  400,  728. 

,  subterranean  caverns  on,  401. 

,  a  glacier  under  lava  on,  412. 

,  marine  formations  at  its  base,  401. 

,  antiquity  of  cone  of,  422. 

Euganean  Hills,  lavas  of,  359. 

Euphrates,  delta  of  advancing  rapidly,  284. 

Euxine  burst  its  barrier,  according  to  Strabo,  14 

,  gradually  filling  up,  14 

.    See  Black  Sea. 

Evaporation,  water  carried  off  by,  260,  294,  334 

,  currents  caused  by,  294. 

Everest,  Kev.  K.,  on  climate  of  fossil  elephant, 

81. 

,  on  sediment  of  Ganges,  282. 

Excavation  of  valleys,  488. 
Expansion  of  rocks  by  heat,  560. 
Extinction  of  species,  697,  701. 
of  animals,  700,  702. 


Fabio  Colonna,  23. 

Facial  angle,  608. 

Fair  Island,  action  of  the  sea  on,  301. 

Falconer,  Dr.,  on  fossil  quadrnmana,  144 

,  on  crocodiles  of  Ganges,  277. 


INDEX. 


823 


Falconer,  Dr.,  on  peat  near  Calcutta,  280. 
Falconi  on  elevation  of  coast  of  Bai;p,  367. 
Falkland  Islands,  quadrupeds  of,  141,  635. 
Falloppio  on  fossils,  21. 
Falls  of  Niagara,  214. 

of  St.  Mary,  254. 

Faluns  of  Touraine,  142. 

Faraday,  Mr.,  on  water  of  the  Geysers.  246. 

,  on  slow  deposition  of  sulphate  of  baryta, 

,  on  electric  currents  in  the  earth,  543. 

,  on  metallic  reduction  by  voltaic  agency, 

548. 

,  on  liquefaction  of  gases,  560. 

Faroe  Islands,  deposits  forming  near  the,  774. 
Farquharson,  Eev.  J.,  on  floods  in  Scotland,  208. 

,  on  formation  of  ground  ice,  222. 

Faiijas,  on  Velay  and  Vivarais,  1779,  49. 

Faults,  162. 

Fauna  formerly  as  diversified  as  now,  160. 

,  arctic,  described  by  Sir  J.  Richardson,  634. 

Felspar,  decomposition  of,  247. 
Ferrara  on  lavas  of  Etna,  283. 

,  on  floods  on  Etna,  412. 

,  on  earthquake  in  Sicily,  471. 

Ferruginous  springs,  247. 
Fez,  earthquakes  in,  358. 
Fife,  trap  rocks  of,  160. 

,  coast  of,  submarine  forests  on,  303. 

,  encroachments  of  sea  on,  203. 

Findhorn  town  swept  away  by  sea,  302. 
Fish,  their  distribution,  and  migrations,  646. 

,  fossil,  745. 

,  fossil  of  coal  formation,  136. 

Fissures,  sulphur,  &c.,  ejected  by,  470. 

,  caused  by  Calabrian  earthquake,  479,  480, 

481. 
,  caused  by  earthquake  near  New  Madrid, 

468. 

,  preservation  of  organic  remains  in,  732. 

Fitton,  Dr.,  on  history  of  English  geolosy,  51. 
Fitzroy,  Capt,  on  earthquake  in  Chili,  1835, 453, 

Flamborough  Head,  waste  of,  303. 
Fleming,  Dr.,  on  uniformity  in  climate,  74 

,  on  fossil  elephant,  76. 

,  on  submarine  forests,  303. 

,  on  rapid  flight  of  birds,  646. 

,  on  turtles  taken  on  coast  of  England.  645. 

,  on  changes  in  the  animal  kingdom  caused 

by  man,  683. 

,  on  stranding  of  cetacea,  771. 

Flinders  on  coral  reefs,  776,  791. 

Flint  on  course  of  Mississippi,  &c.,  264,  265. 

,  on  earthquakes  in  Mississippi  valley,  466. 

Floods,  by  bursting  of  lakes,  269. 

,  in  North  America,  209. 

,  in  valley  of  Bagnes,  210. 

,  in  Scotland,  207,  750. 

.  traditions  of,  499,  501. 

j  causes  which  may  give  rise  to,  156. 

,  at  Tivoli,  211. 

,  caused  by  melting  of  snow  by  lava,  348, 

411. 

.    See  Deluge. 

Flysch,  of  the  Alps,  eocene,  124. 
Folkstone,  subsidence  of  land  at,  816. 
Fontenelle,  his  eulogy  on  Palissy,  23. 
Foot-marks,  fossil,  in  North  America,  136. 
Forbes,  Prof.  E.,  on  glacial  epoch,  86. 

,  on  fossils  of  tertiary,  184. 

,  on  new  island  in  Gulf  of  Santorin,  443. 

,  on  regions  of  depth  in  ^Egean  Sea,  649. 

,  on  migration  of  mollusca,  651. 

,  cited,  "703. 

Forbes,  Prof.  J.  D.,  on  glacier  motion,  224. 

,  on  rate  of  flowing  of  lava,  878,  400. 

,  on  temple  of  Serapis,  515,  517. 

Forchhaminer,  Dr.,  on  boulders  drifted  by  ice, 

231. 

,  on  peat,  719. 

Forests,  influence  of,  712,  718,  715. 

,  sites  of,  now  covered  by  peat,  720. 

,  destroyed  by  insects,  717. 

,  submarine,  803,  323,  746. 


Forests,  submerged,  in  Columbia  E.  by  land- 
slides, 215. 

Forfarshire,  waste  of  coast  of,  302. 

,  marl  lakes  of,  766,  796. 

Forshey,  Mr.,  on  Mississippi,  264,  271. 

Forster,  Mr.,  on  coral  reefs.  778. 

Forsyth  on  climate  of  Italy,  395. 

Fortis  cited,  42. 

,  views  of  Arduino  confirmed  by,  48. 

and  Testa  on  fossil  fish,  44. 

Fort  William,  near  Calcutta,  artesian  well,  280. 

Fossiliferous  formations,  breaks  in  the  series, 
180. 

Fossilization  of  organfc  remains  on  emerged 
land,  718,  775. 

,  in  peat  mosses,  722.. 

,  in  caves  and  fissures,  732. 

,  in  alluvium  and  landslips,  730. 

,  in  volcanic  formations  on  land,  349,  728. 

,  in  subaqueous  deposits,  742,  753. 

,  in  marl  lakes,  752. 

Fossils,  early  speculations  concerning  their  na- 
ture, 19,  24  to  27. 

,  distinctness  of  secondary  and  tertiary,  119. 

,  mammiferous  of  tertiary  eras,  137,  140. 

,  why  distinct  in  successive  groups,  190. 

.    See  Organic  Remains. 

Fossil  trees,  upright  position  of  some,  91. 

Fourier,  Baron,  on  temperature  of  spaces  sur- 
rounding our  atmosphere,  108. 

,  on  central  heat,  127. 

,  on  radiation  of  heat,  127. 

Fox,  Mr.,  on  heat  in  mines,  538. 

,  on  electric  currents  in  the  earth,  548. 

France,  waste  of  coast  of,  324. 

,  caves  of,  787. 

Franconia,  caves  of,  736. 

Franklin,  on  a  whirlwind  in  Maryland,  619. 

Fremont.  Capt,  on  submerged  forests  in  Colum- 
bia, 270. 

Freshwater  plants  and  animals  fossilized,  765, 
768. 

strata  in  Cashmere,  762. 

Freyberg,  school  of,  46,  52. 

Fries,  on  dispersion  of  cryptpgamic  plants,  620. 

Fringing  reef,  nature  and  origin  of,  785. 

upraised,  794 

Fuchsel,  opinions  of,  1762,  48. 

Funchal.  rise  of  sea  at,  during  earthquake,  496. 

Fundy,  Bay  of,  wave  called  the  "bore"  in,  332. 


G. 


Gaillonettaferruginea,  722. 

Galapagos,  peculiar  character  of  the  fauna  ot 
139,  635,  643. 

island,  tameness  of  birds  in,  597. 

Archipelago,  craters  form  hills  in,  372. 

Galongoon,  great  eruption  of,  353,  430. 

Gambier  coral  island,  783,  787. 

Ganges,  delta  of,  and  Brahmapootra,  275  to  284 
— ,  antiquity  of  delta  of,  281. 

,  quantity  of  sediment  in  waters  of,  278. 

,  islands  formed  by  the,  276. 

,  bones  of  men  found  in  delta  of.  757. 

,  artesian  borings  in  delta  of,  268. 

Gardner,  Mr.,  on  unexplored  Antarctic  land,  99. 

Gases,  liquefaction  of,  560. 

,  evolved  by  volcanoes,  549. 

Gefle,  upraised  shelly  deposits  near,  526,  528. 

Geuimellaro  on  Etna,  408. 
-,  on  ice  under  lava,  412. 

Generation,  spontaneous,  theory  of,  22. 

Generelli.  on  state  of  geology  in  Europe  in  mid- 
dle of  eighteenth  century ,"35,  53. 

Geneva,  lake  of,  delta  of  Rhone  in,  252. 

Geognosy  of  Werner,  46. 

Geographical  distribution  of  plants,  618. 

-  of  animals,  629. 

-  of  birds,  642. 

-  of  reptiles,  644. 

-  of  fishes,  646. 

-  of  testacea.  649. 
of  zoophytes,  (553. 


824 


INDEX. 


Geographical  distribution  of  insects,  654. 

of  man,  669. 

Geography,  proofs  of  former  changes  in  physi- 

,  effect  of  changes  in,  on  species,  690. 

Geological  society  of  London,  59. 

,  theories,  causes  of  error  in,  61. 

Geology  defined,  1. 

,  distinct  from  cosmogony,  3. 

,  causes  of  its  retardation,  24,  55,  61. 

,  state  of,  before  eighteenth  century,  86. 

,  modern  progress  of,  58. 

Georgia,  island  of,  snow  to  level  of  sea  in,  99, 
108. 

,  U.  S.,  new  ravines  formed  in,  205. 

Gerbanites,  an  Arabian  sect,  their  doctrines,  14. 
German  Ocean,  filling  up,  340. 
Gesner,  John,  on  organic  remains,  41. 
Geysers  of  Iceland,  533,  553. 

,  cause  of  their  intermittent  action,  555. 

Gibraltar,  birds'  bones  in  breccia  at,  740. 

,  Straits  of,  383. 

Gironde,  tides  in  its  estuary,  338. 

Glacial  epoch,  T5. 

Glacier  under  lava,  on  Etna,  412. 

,  moraines  of,  223. 

,  view  of,  223. 

Glaciers,  formation  of,  222  to  227. 
,  motion  of,  223." 


,  of  Spitzbergen,  96. 

,  transportation  < 


insportation  of  rocks  by,  155. 

Glen  Tilt,  granite  veins  of,  51. 

Gloucestershire,  gain  of  land  in,  824. 

Gmelin  on  distribution  of  fish,  648. 

Goats,  multiplication  of,  in  South  America,  686. 

Goeppert,  Prof.,  87. 

,  on  fossilization  of  plants,  747. 

Golden  age,  doctrine  whence  derived,  9. 

Goodwin  Sands,  814. 

Gothenburg,  rise  of  land  near,  526. 

Graah,  Capt,  on  subsidence  of  Greenland,  530. 

Graham,  Mrs.,  on  earthquake  of  Chili  in  1822, 
459. 

Graham  Island,  newly  formed  in  1831,  432. 

,  supposed  section  of,  435. 

Granite  of  the  Hartz,  Werner  on,  47. 

,  disintegration  of,  221,  346. 

,  formed  at  different  periods,  177. 

,  veins  observed  by  Hutton  in  Glen  Tilt,  51. 

Grant,  Capt.,  on  Chilian  earthquake,  462. 

Graves,  Capt,  on  diffusion  of  insects  by  winds, 
656. 

,  survey  of  Santorin  by,  441. 

Gray,  Mr.,  on  Mytilus  polymorphus,  653. 

Great  Dismal  Swamp,  Virginia,  724. 

Grecian  Archipelago,  new  isles  of  the,  43. 

,  volcanoes  of  the,  355,  442,  450. 

Greece,  earthquakes  in,  355. 

,  traditions  of  deluges  in,  356. 

Greeks,  geology  of,  13. 

Greenland,  why  colder  than  Lapland,  94. 

,  gradual  subsidence  of,  530,  562. 

,  timber  drifted  to  shores  of,  745. 

Greville,  Dr.,  on  drift  sea-weed,  623. 

Groins  described,  318. 

Grooves  in  rocks  formed  by  glaciers,  155,  227, 
228. 

Grotto  del  Cane,  248. 

Ground  ice,  221. 

transporting  rocks  in  Baltic,  231. 

Guadaloupe,  human  skeletons  of,  757. 

Guatemala,  active  volcanoes  in,  349. 

Guiana,  partly  formed  by  sediment  of  Amazon, 
342. 

Guilding,  Kev.  L.,  on  migration  of  Boa  Con- 
strictor, 646. 

Guinea  current,  296. 

Guinea,  New,  mammalia  of,  632. 

Gulf  stream,  96,  292,  294,  621. 

stream  aids  migration  of  fish,  648. 

Guyot,  M.,  on  glacier  motion,  224. 

Gyrogonite  described,  766. 


H. 


Habitations  of  plants  described,  614. 
Hales,  Dr.,  on  epoch  of  the  creation,  659. 
Hall,  Sir  J.,  his  experiments  on  rocks,  51. 

,  Captain  B.,  on  flood  in  valley  of  Bagnes, 

211. 

,  on  the  trade-winds,  295. 

,  on  temple  of  Serapis,  512. 

,  Mr.,  State  Geologist  of  New  York,  216, 

,  Mr.  J.,  on  temple  of  Serapis,  512. 

Hamilton,  Mr.  W.  J.,  on  volcanoes  near  Smyrna, 
355. 

,  Sir  W.,  on  Herculaneum,  389. 

,  on  earthquake  in  Calabria,  473,  483,  485. 

.  Sir  W.,  on  formation  of  Monte.  Nuovo, 

367. 

,  on  eruption  of  Vesuvius  in  1779,  377. 

Hamilton,  Sir  C.,  on  submerged  houses  in  Port 

Koyal,  504. 
Hampshire,  Brander  on  fossils  of,  44. 

,  submarine  forest  on  coast  of,  746. 

Harcourt,  Kev.  W.  V.  V.,  on  bones  of  mam- 
moth, &c.,  in  Yorkshire,  76. 
Harris,  Hon.  C.,  on  sunk  vessel   near  Poole, 
758. 

,  on  submarine  forest,  Hampshire,  746. 

Hartmann,  Dr.,  on  fossils  of  Hartz,  48. 

Hartz  mountains,  48. 

Harwich,  waste  of  cliffs  at,  311. 

Hatfleld  moss,  trees  found  in,  721. 

Head,  Sir  Edmund,  on  temple  of  Serapis,  512. 

Heat,  laws  which  govern  the  diffusion  of,  93. 

Heat,  whether  gradual  decline  of,  in  globe,  129. 

,  expansion  of  rocks  by,  561. 

Heber,  Bishop,  on  animals  of  Himalaya,  81. 
Hecla,  columnar  basalt  of,  48. 

,  eruptions  of,  424. 

Helena,  St.,  bounded  by  lofty  shores,  622. 

Heligoland,  inroads  of  sea  on,  329. 

Helix,  range  of  species  of.  650. 

Henderson  on  eruption  of  Skaptar  Jokul,  1788, 

425. 

Henderson's  Island  described,  788. 
Henslow,  Eev.  Prof.,  on  the  cowslip,  590. 

,  on  diffusion  of  plants,  624. 

Herbert,  Hon.  Mr.,  on  varieties  and  hybrids  in 

plants,  590,  605. 
Herculaneum,  385,  389. 
Herne  Bay,  waste  of  cliffs  in,  312. 
Herodotus  cited,  8,  261. 

Herschel,  Sir  J.  F.  W.,  on  varying  heat  received 
by  the  two  hemispheres,  100. 
— ,  on  astronomical  causes  of  changes  in  cli- 
mate, 126. 

,  on  variable  splendor  of  stars,  128. 

,  on  the  trade-winds,  297. 

,  on  height  of  Etna,  396. 

,  on  form  of  the  earth,  534. 

,  on  Geysers  of  Iceland,  555. 

,  on  the  effects  of  heat  on  seeds,  621. 

,  on  the  author's  theory  of  climate,  92. 

Herschel,  Sir  W.,  on  the  elementary  matter  of 

the  earth,  538. 

Hewett,  Capt,  on  rise  of  tides,  291. 
-,  on  currents,  293. 
-,  on  banks  in  North  Sea,  308,  340. 
Hibbert,  Dr.,  on  the  Shetland  Islands,  299,  300. 
tlilaire.  M.  Geof.  St.,  on  animal  kingdom,  567. 
Himalaya  mountains,  animals  inhabiting  the,  81. 

,  height  of  perpetual  snow  on,  112. 

ETindoo  cosmogony,  4. 

town  buried.  731. 

Hindostan,  earthquakes  in,  494. 
Hippopotamus  indicates  warmth  of  river,  75. 
Hitchcock,  Keport  on  Geol.  of  Massachusetts,  137. 
Irloff,  Von,  on  level  of  Caspian,  IS. 

,  on  encroachments  of  sea,  331,  332. 

,  on  earthquakes,  358. 

,  on  human  remains  in  delta  of  Ganges,  75T. 

.  on  a  buried  vessel,  758. 

Hoffmann,  M.,  on  lavas  of  Vesuvius,  379. 
,  on  Etna,  415,  416. 


INDEX. 


825 


Holland,  gradual  sinking  of  coast,  327. 

,  inroads  of  sea  in,  328. 

,  submarine  peat  in,  770. 

Hooke  on  duration  of  species,  27,  28. 

,  on  earthquakes,  27,  29,  503. 

Hooker,  Dr.  J.,  on  icebergs  in  antarctic  seas, 

229. 

,  on  tropical  plants,  614. 

,  floras  of  islands  in  Southern  Ocean,  615. 

,  on  flora  of  Galapagos  Islands,  616. 

,  on  wide  range  of  certain  plants,  618,  621, 

623. 

,  on  delta  of  Ganges,  280. 

,  on  rain  in  India,  200. 

Hocker,  Sir  W.,  on  eruption  of  Skaptar  Jokul, 

425. 
,  his  view  of  the  crater  of  the  great  Geyser, 

554. 

,  on  drifting  of  a  fox  on  ice,  680. 

Hopkins,  Mr.,  on  glacier  motion,  224,  225. 

,  on  thickness  of  earth's  crust,  536. 

Hopkins,  Mr.,  on  astronomical  causes  of  change 

of  climate,  128. 

,  on  changes  of  climate,  93. 

,  on  earthquakes,  453. 

,  on  M.  E.  de  Beaumont's  theory  of  moun- 
tain chains,  170. 
Hordwell,  loss  of  land  at,  318. 
Horner,  Mr.,  on  brine  springs,  247. 

,  on  submarine  forest  in  Somersetshire,  323. 

,  dissertation  on  coal,  91. 

Horsburgh,  Capt,  on  icebergs  in  low  latitudes, 

99. 

Horsburgh  on  coral  islands,  782,  787. 
Horses  drowned  in  rivers  in  South  America, 

750. 

Horsfield,  Dr.,  on  earthquakes  in  Java,  471,  494. 
.  on  distribution  of  Mydaus  meliceps  in 

Java,  639. 

Hubbard,  Prof.,  cited,  210. 
Hue,  on  Yaks  frozen  in  ice  in  Thibet,  85. 
Human  race  geologically  modern,  660. 
Human  remains  in  peat  mosses,  722. 

,  in  caves,  735,  736.  739. 

\  their  durability,  147.  757. 

in  delta  of  Ganges,  757. 

in  calcareous  rock  at  Guadaloupe,  757. 

in  breccias  in  the  Morea,  735. 

Humber,  warp  of  the,  288. 

,  encroachment  of  sea  in  its  estuary,  304. 

Humboldt  on  laws  regulating  diffusion  of  heat, 

93. 
on  preservation  of  animals  in  frozen  mud, 

on  distribution  of  land  and  sea,  109. 

on  transportation  of  sediment  by  currents, 

342. 

,  his  definition  of  volcanic  action,  345. 

on  mud  eruptions  in  the  Andes,  348. 

on  volcanic  eruptions  in  Tartary,  355. 

on  eruption  of  Jorullo,  428. 

on  earthquakes,  466,  470. 

on  distribution  of  species,  613,  614. 

on  migrations  of  animals,  644,  656,  685. 

cited,  8,  77,  84. 

on  earthquake  in  New  Madrid,  466. 

on  earthquake  of  Lisbon,  495. 

on  mud  volcanoes,  448. 

Humboldt,  W.  von,  on  dawn  of  oriental  civiliza- 
tion, 659. 

Humming-birds,  distribution,  &c.,  97,  643. 

Hunter,  John,  on  mule  animals,  601. 

Huron,  Lake,  recent  strata  of,  768. 

Hurricanes  connected  with  earthquakes,  731. 

,  plants  drifted  to  sea  bv,  745. 

Hurst  Castle  shingle  bank,  318. 

Hutchinson,  John,  his  •'  Moses's  Principia,"  33. 

Hutton,  distinguished  geology  from  cosmogo- 
ny, 3. 

on  igneous  rocks  and  granite,  51. 

represented  oldest  rock  as  derivatives,  52. 

Huttonian  theory,  51,  57. 

Hybrid  races,  Lamarck  on.  572. 

animals,  600. 

plants,  602. 


Hydrogen,  deoxida 

,  flame  of,  seen  fn"  eruption  of  YesuviuH, 

378. 
,  why  not  found  in  a  separate  form  among 

volcanic  gases,  548. 

Hydrophytes,  distribution  of,  617,  623. 
Hydrostatic  pressure  of  ascending  lava,  416,  553. 
Hypogene  rocks,  178. 
Hyracotherium,  Eocene  mammifer,  142. 
Hythe,  encroachments  of  sea  at,  316. 


I. 

lanthina  fragilis,  its  range,  &c.,  650. 

Ice,  animals  imbedded  in,  83. 

Ice  of  rivers,  transporting  power  of,  219. 

,  drift,  influence  of,  on  temperature,  95. 

,  predominance  of,  in  antarctic  circle,  98. 

,  formation  of  field,  107. 

,  transportation  of  rocks  by,  155,  219,  521. 

Icebergs,  formation  of,  96,  97. 

,  distance  to  which  they  float,  100,  227. 

,  limits  of  glaciers  and,  228. 

,  plants  and  animals  transported  by,  622, 639. 

,  action  of,  when  stranded,  228. 

,  rocks  transported  by.    See  Ice. 

,  floating  in  Northern  hemisphere,  86. 

,  not  all  formed  by  glaciers,  228. 

Iceland,  icebergs  stranded  on,  97. 

,  geysers  of,  246,  553,  555. 

Iceland,  volcanic  eruptions  in,  424 

,  comparison  between  the  lavas  of  Central 

France  and,  426. 

,  new  island  near,  425. 

,  polar  bear  drifted  to,  679. 

Igneous  action.  See  Volcanic. 
Igneous  causes.  See  Book  II. 
,  the  antagonist  power  to  action  of  running 

water,  198,  563,  711. 
Ilford,  tertiary  strata  at,  76. 
Imbedding  of  organic  remains.  See  Fossilization. 
India,  buried  cities  in,  729,  731. 

,  terrestrial  mammalia  o£  632. 

Indo-pacific  province  of  mollusca,  649. 
Indus,  delta  of.  recent  changes  in,  459,  769. 

,  buried  ships  in,  758. 

Infusoria  in  bog  iron-ore,  722. 

,  in  volcanic  rocks  in  Mexico,  Peru,  &c.,  388. 

Infusorial  tuff,  Pompeii,  388. 

Inland  cliffs,  no  proof  of  sudden  elevation,  531. 

seas,  deltas  of,  255. 

Insects,  geographical  distribution  of,  654. 

,  certain    types    of,  distinguish    particular 

countries,  655. 
,  their  agency  in  preserving  an  equilibrium 

of  species,  671. 

,  fossil,  748. 

Instincts,  migratory,  occasional  development  of, 

in  animals,  642. 

hereditary,  593,  596. 

,  modified  by  domestication,  595. 

Insular  climates,  description  of,  94. 
Inverness-shire,  inroads  of  sea  on  coast  of,  802. 
Irawadi,  K.,  silicified  wood  of,  noticed  in  1692. 28. 
Ireland,  raised  beaches  on  coast  of,  122. 

,  reptiles  of,  645. 

,  peat  of,  and  fossils  in,  719,  720,  724. 

,  deposits  in  progress  off  coast  of,  774. 

Iron,  melting  point  of,  539. 

in  wood,  peat,  &c.,  722. 

instruments  taken  up  from  sea,  760. 

Ischia,  hot  springs  of,  247,  456. 

,  eruptions  and  earthquakes  in,  360, 865,  456. 

Islands,  vegetation  of  small,  112,  615,  667. 

,  animals  in,  635. 

formed  by  the  Ganges,  276. 

migrations  of  plants  aided  by,  622. 

,  new  volcanic,  43,  425,  432,  468. 

,  coral,  775. 

of  driftwood,  640. 

Isle  of  Purbeck,  vertical  chalk  in,  318. 
Isle  of  Wight,  mammiferous  fossils  of,  142. 

,  waste  of  its  shores,  317. 

Isothermal  lines,  Humboldt  on,  95. 


826 


INDEX. 


Italian  geologists,  their  priority,  19, 

of  the  18th  century,  83. 

Italy,  tertiary  strata  of,  64,  74. 


J. 


Jack,  Dr.,  on  island  of  Pulo  Nias,  794. 
Jamaica,  earthquakes  in,  350,  504,  517. 

,  subsidence  in,  504,  517. 

,  rain  diminished  in,  by  felling  of  forests, 

713. 

,  a  town  swept  away  by  sea  in,  731. 

Java,  volcanoes  and  earthquakes  in,  354, 464, 493, 

502. 

,  valley  of  poison  in,  353. 

,  subsidence  of  volcano  of  Papandayang  in, 

493. 

,  river-floods  in,  503,  748,  751. 

Jones,  Sir  W..  on  Institutes  of  Hindoo  law,  5. 

Jorullo,  eruption  of,  349,  428. 

Juan  Fernandez.  357,  453,  499,  686. 

Jukes,  Mr.,  on  cliffs  in  Island  of  Timor,  794. 

,  on  volcanic  islands  near  Java,  354. 

,  on  coral  reef,  784 

Jura,  Saussure  on  the,  45. 
Jutland,  inroads  of  sea  in,  330. 


K. 


Kamtschatka,  volcanoes  in,  353. 

,  new  island  near,  468. 

Kangaroo,  extirpation  of,  in  Australia,  684. 

Kashmir.    See  Cashmere. 

Katavothrons  of  Greece,  breccias  formed  in, 

734. 
Kazwini  on  changes  in  position  of  land  and  sea, 

Keilhau,  Prof.,  of  Christiana,  on  changes  of  level 

in  Norway,  529,  531. 
Keith  on  dispersion  of  plants,  620. 
Kent,  loss  of  land  on  coast  of,  312. 
Kentucky,  caves  in  limestone,  733. 
Keyserling,  Count,  on  lowland  of  Siberia,  84. 
Kincardineshire,  village  in,  washed  away  by  sea, 

302. 
King,  Captain  P..  on  humming  birds  in  Tierra 

del  Fuego,  97,  643. 

,  on  currents  in  Straits  of  Magellan,  293. 

,  on  coral  reefs,  788. 

King,  Mr.,  on  cattle  lost  in  bogs  in  Ireland,  723. 

,  on  submerged  cannon,  759. 

Kinnordy,  Loch  of,  insects  in  marl  in,  748. 

,  canoe  in  peat  of,  759. 

Kirby,  Eev.  Mr.,  on  insects,  606,  655,  673,  674. 
Kirwan,  his  geological  Essays,  56. 

,  on  connection  of  geology  and  religion,  56. 

Knight,  Mr.,  on  varieties  of  fruit  trees,  589. 
Konig,  Mr.,  on  Guadaloupe  human  skeleton, 

757. 

,  on  fossils  from  Melville  Island,  88. 

Koran,  cosmogony  of  the,  17. 

Kotzebue  on  drifted  canoe,  662. 

Kunker,  concretionary  limestone  of  Ganges,  280. 

Kurile  Isles,  active  volcanoes  in,  353. 


Labrador,  drift-timber  of,  745. 

,  rocks  drifted  by  ice  on  coast  of,  230. 

Laccadive  Islands,  782. 

Lagoons,  or  salt  lakes,  in  delta  of  Ehone,  259. 

,  of  coral  islands,  780. 

Lagullas  current,  95. 

Lagunes  on  coast  of  Adriatic,  256. 

Lake  Erie.    See  Erie,  Lake. 

,  of  Geneva.    See  Geneva,  Lake  of. 

,  Maeler,  524,  528. 

,  Superior.    See  Superior,  Lake. 

Lakes,  filling  up  of,  252. 

,  formation  of,  in  basin  of  Mississippi,  466, 

269. 
,  formed  by  earthquakes,  466,  481,  505. 


:  Lakes,  crescent-shaped,  in  plain  of  Mississippi, 

I ,  Canadian,  strata  forming  in,  768. 

i  Lamarck,  his  definition  of  species,  567. 
,  on  transmutation  of  species,  567,  587,  696, 

,  on  conversion  of  orang  into  man,  575. 

,  on  numbers  of  polyps,  706. 

Lancashire,  fossil  canoes  in,  759. 

Lancerote,  eruptions  in,  436,  439. 

Land,  quantity  of,  in  northern  and  southern 
hemispheres,  102,  109,  110. 

,  upraised  at  successive  periods,  118, 119. 

,  proofs  of  existence  of,  at  all  periods,  188. 

,  proportion  of  sea  and,  124. 

,  elevation  of,  how  caused,  171,  453, 457, 459, 

562. 

Landslips,  319,  321,  485,  505. 

,  imbedding  of  organic  remains  by,  732. 

Languedoc,  deposits  on  coast  of,  260. 

Laplace  on  change  in  the  earth's  axis,  32. 

on  mean  depth  of  Atlantic  and  Pacific,  104. 

on  no  contraction  of  globe,  129. 

on  mean  density  of  the  earth,  536. 

Lapland,  why  milder  than  Greenland,  94. 

,  migrations  of  animals  in,  637. 

Lateral  pressure  caused  by  landslips,  322. 

pressure  in  Andes  and  Alps,  171. 

Latham,  Dr.  E.  G.,  on  Natural  History  of  Man,  609. 

Lauder,  Sir  T.  D.,  on  floods  in  Scotland,  208, 
636,  730,  748. 

Lava  excavated  by  rivers.  213. 

,  effects  of  decomposition  on,  385. 

,  flowing  of,  under  water,  383. 

,  hydrostatic  pressure  of  ascending,  552. 

of  Iceland  and  Central  France,  426,  427. 

,  comparative  volume  of  ancient  and  mod- 
ern, 161,  427. 

,  pretended  distinction  between  ancient  and 

modern,  438. 

,  mineral  composition  of,  449,  551. 

,  rate  of  flowing,  378,  400. 

Lazzaro  Moro.    See  Moro. 

Lehman,  treatise  of,  1759,  40. 

Leibnitz,  theory  of,  26. 

Leidy,  Dr.,  on  Priscodelphinus,  145. 

Lemings,  migrations  of,  637. 

Lena,  E./fossil  bones  on  banks  of,  78,  80. 

Leonardo  da  Vinci,  19. 

Lewes,  human  bones  in  tumulus  near,  739. 

,  estuary  recently  filled  up  near,  748,  768. 

Liege,  caves  near,  737. 

Light,  influence  of,  on  plants,  89. 

Lightning,  effect  of,  in  Shetland  Islands,  299. 

Lignite,  conversion  of  wood  into,  759. 

Lima  destroyed  by  earthquake,  501. 

,  elevated  recent  marine  strata  at,  502. 

Lime,  whence  derived,  796. 

Lincolnshire,  inroads  of  sea  on  coast  of,  304. 

Lindley,  Dr.,  on  fossil  plants  of  Melville  Islands, 

,  on  number  of  plants,  705. 

,  on  dispersion  of  plants,  620. 

,  on  fossil  plants  of  coal,  88,  133. 

,  cited,  133. 

Linnaeus  on  filling  up  of  Gulf  of  Bothnia,  521. 

on  subsidence  of  Scania,  530. 

on  constancy  of  species.  568. 

on  real  existence  of  genera,  578. 

on  diffusion  of  plants,  624,  626. 

on  introduction  of  species,  665. 

cited,  671. 

Lionnesse  tradition  in  Cornwall,  324. 

Lippi  on  Herculaneum  and  Pompeii,  387. 

Lipsius,  12. 

Lisbon,  earthquakes  at,  358,  495. 

Lister,  first  proposed  geological  maps,  26. 

on  fossil  shells,  26. 

Lloyd,  Mr.,  on  levels  of  Atlantic  and  Pacific,  294. 
Loa,  Mount,  volcano  of  Sandwich  Isles,  552. 
Locusts,  devastations  of,  674. 

,  bank  formed  in  sea  by,  675. 

Loess  of  the  Ehine,  1S5. 

of  the  Mississippi  valley,  265. 

Loire,  tertiary  strata  of  the,  142. 


INDEX. 


82T 


London,  artesian  wells  near,  234. 
London  basin,  tertiary  deposits  of,  121. 

clay,  its  fossils,  142,  144. 

Lowestoff  Ness  described,  309. 

,  cliffs  undermined  near,  309. 

Lowland  of  Siberia,  78,  80,  83,  85. 
Luckipour,  on  the  Ganges,  276,  277. 

,  new  islands  formed  near,  276. 

Luckput,  subsidence  near,  460. 
Lund.  Dr.,  on  fossil  quadrumana,  144. 
Lybian  sands,  caravans  overwhelmed  by,  727. 
Lyme  Eegis,  waste  of  cliffs  at,  321. 
Lym-Fiord,  breaches  made  by  the  sea  in,  830. 


M. 


MacClelland,  Dr.,  on  earthquakes  in  Chittagong, 

494. 

.  on  volcanic  line  in  Bay  of  Bengal,  354. 

MacCulloch,  Dr.,  on  gradation  from  peat  to  coal, 

719. 

on  origin  of  limestones,  796. 

Macacus  pliocenus  of  Owen,  fossil  in  valley  of 

Thames,  144. 

,  Suffolk  Eocene  species,  144. 

Macaluba,  in  Sicily,  mud  volcanoes,  447. 
Mackenzie,  Sir  G.,  his  section  of  geyser,  556. 

,  on  reindeer  in  Iceland,  686. 

Mackenzie  Eiver,  driftwood  of,  90,  743. 

,  floods  of,  84. 

Maclaren,  Mr.  C.,  on  Graham  Island,  435. 

,  on  quantity  of  useful  soil  in  America,  687. 

,  on  position  of  American  forests,  714. 

remarks,  theory  of  atolls,  792. 

Macmurdo,  Captain,  on  earthquake  of  Cutch, 

460. 
Madagascar,  extent  of  coral  near,  776. 

,  assemblage  of  quadrupeds  in,  632. 

Madrid,  New,  great  earthquake  at,  466. 

,  sunk  country  near  it,  270. 

Maeler,  lake,  524,  528. 
Magellan,  Straits  of,  tides  in,  291,  293. 
Magnesia  deposited  by  springs,  23S. 
Magnesian  limestone  and  travertin  compared, 

240. 
Magnetism,  terrestrial,  phenomena  of,  543. 

,  solar,  129. 

Mahomet,  his  cosmogony,  18. 

Malabar,  coral  near,  776. 

Maldive  Islands,  coral  reefs  of,  778,  782. 

Mallet,  Captain,  on  petroleum  of  Trinidad,  250. 

Mallet,  Mr.,  on  the  dynamics  of  earthquakes, 

453,475. 
,  on  whirling  motion  during  earthquakes, 

476. 

,  cited,  560. 

,  on  transit  of  the  earth-wave,  483. 

,  on  theory  of  waves,  498. 

Mammalia,  different  regions  of  indigenous,  629. 
,  fossil,  of  successive  tertiary  periods,  138, 

139. 
,  imbedding  of,  in  subaqueous  strata,  749, 

753. 

Mammifer,  fossil  of  trias,  137. 
Mammoth,  Siberian,  75. 

,  bones  of,  in  Yorkshire,  76. 

Man,  recent  origin  of,  147,  182,  687,  764. 

,  why  able  to  live  in  all  climates,  609. 

,  diffusion  of,  657. 

,  changes  caused  by,  150, 182,  630,  663,  681, 

713. 

,  durability  of  the  bones  of,  147,  757. 

,  remains  of,  in  osseous  breccias  of  Morea, 

735. 

,  his  remains  and  works  fossil,  758. 

Manetho,  63. 

Mantel),  Dr.,  on  bones  from  Saxon  tumulus,  738. 

,  on  Lewes  levels,  748,  768. 

Map  of  Siberia,  79. 

,  of  World,  showing  present  unequal  distri- 
bution of  land  and  sea,  110. 
,  showing  position  of  land  and  sea,  which 

might  produce  extremes  of  heat  and  cold,  111. 
,  of  Europe,  showing  extent  of  land  covered 


(PI.  I.),  121. 

Map  of  coast  from  Nieuport  to  month  of  Elbe, 
326. 

of  volcanoes  from  Philippine  Islands  to 

Bengal,  351. 

of  volcanic  district  of  Naples,  361. 

of  Gulf  of  Santorin,  442. 

of  Chili,  454,455. 

of  Cutch,  460. 

of  Calabria,  472. 

of  Sweden,  522. 

Maracaybo,  Lake,  466. 

Marine  dep 
in,  749,  752. 

,  of  human  remains  and  works  of  art  in,  756. 

,  of  freshwater  species  in,  768. 

,  plants  and  animals  imbedded  in,  770. 

Marine  vegetation.  617,  622. 

Marl  lakes  of  Scotland,  animals  and  plants  fossil- 
ized in,  752,  766. 

Marsili,  on  arrangement  of  shells  in  Adriatic,  86, 
38,40. 

,  on  deposits  of  coasts  of  Languedoc,  260. 

Marsupial  animals,  distribution  of,  633. 

fossil,  138. 

Martigny  destroyed  by  floods,  211. 

Martina,  on  drifting  of  animals  by  the  Amazon, 

,  on  Brazil,  682. 

Maryland,  whirlwind  in,  619. 

Mattani  on  fossils  of  Volterra,  34. 

Mattioli  on  organic  remains,  21. 

Mauritius,  reef  uplifted  above  level  of  sea,  794. 

Mediterranean,  microscopic  testacea  of,  44. 

,  deposition  of  salt  in  the,  334 

,  new  island  in,  432. 

,  its  temperature,  depth,  level,  &c.,  45,  294, 

334,  510. 

,  same  level  as  Eed  Sea,  294 

Megna,  E.,  arm  of  Brahmapootra,  279. 

Melville  Island,  fossils  of,  90. 

,  migrations  of  animals  into,  640. 

Melville,  Dr.,  on  dodo,  684. 

Memphis,  in  delta  of  Nile.  261. 

Mendip  Hills,  caves  of,  737. 

Menu's  Institutes,  4,  5. 

Mercati  on  organic  remains,  22. 

Mersey,  vessel  in  bed  of,  758. 

Messina,  tide  in  Straits  of,  290. 

,  earthquakes  at,  477,  488,  490. 

Metallic  nucleus,  theory  of  an  unoxidated,  545. 

Metallic  substances  changed  by  submersion,  759. 

Metamorphic  rocks,  how  formed,  177. 

,  of  the  Alps,  178. 

,  why  those  visible  to  us  must  be  very  an- 
cient, 178. 

Mexico,  Gulf  of,  tides  in,  295. 

,  currents  in,  96,  292. 

,  volcanoes  of,  849,  546. 

Meyen,  Dr.,  on  earthquake  in  Chili,  1822,  458, 

Michell  on  phenomena  of  earthquakes,  41. 

on  the  geology  of  Yorkshire,  42. 

on  earthquake  at  Lisbon,  358,  497. 

on  retreat  of  the  sea  during  earthquakes, 

498. 

on  wave-like  motion  of  earthquakes,  558. 

on  earthquakes  cited,  499. 

Microlestes,  triassic  mammifer,  138, 145. 

Middendorf,  Mr.,  on  Siberian  mammoth,  81. 

Migrations  of  plants,  618. 

— -  of  animals,  635,  636. 

of  cetacea,  642. 

of  birds,  642. 

offish,  646. 

of  zoophytes,  653. 

of  insects,  655. 

Migratorv  powers  indispensable  to  animals,  689. 

Milford  Haven,  rise  of  tides  at,  291. 

Millennium,  20,  82. 

Mineral  waters,  their  connection  with  volcanoes, 
237. 

,  ingredients  most  common  in.  See  Springs, 

287. 

Mineralization  of  plants,  747. 


INDEX. 


Mines,  heat  in,  augments  with  the  depth,  588. 

Miocene  strata  of  Suffolk,  fossils  of,  142. 

—      ,  proportion  of  living  species  in  fossil  shells 

of  the,  183. 
Mississippi,  its  course,  delta,  &c.,  263,  275. 

,  drift-wood  of  the,  267. 

,  earthquakes  in  valley  of,  270,  350. 

,  antiquity  of  delta  of,  272. 

,  earthquake  region  of,  467. 

,  banks  higher  than  swamps,  266. 

Missouri,  E.,  264. 

Mitchell,  Dr.,  on  waste  of  cliffs,  311. 

Moel  Tryfane,  recent  marine  shells  on,  122. 

Mollusca.    See  Testacea. 

,  provinces  of,  649. 

Molluscous  animals,  longevity  of  species  of,  76. 

Moluccas,  eruptions  in  the,  504. 

Monkeys,  fossil,  144. 

Monte  Barbaro,  description  of,  373. 

Bolca,  fossil  fish  of,  44. 

Nuovo,  formation  of,  369,  518. 

Somma,  structure  of,  382. 

Monti  Eossi.on  Etna  described,  397,  399,  422. 
Montlosier,  on  Auvergne,  49. 
Moraines  of  glaciers,  223, 226,  228. 
Morayshire,  town  in,  destroyed  by  sea,  302. 

,  effect  of  floods  in,  208,  730. 

Morea,  Ceramique  of,  731. 

,  osseous  breccias  now  forming  in  the,  734. 

,  human  remains  imbedded  in,  735. 

Morlot,  on  subsidence  in  Adriatic,  257. 
Moro,  Lazzaro,  his  geological  views,  34 

,  on  primary  rocks,  52. 

Morocco,  earthquakes  at,  358. 

Morton,  Dr.  8.  G.,  on  hybrids  and  species,  601. 

Mountain  chains,  on  the  elevation  of,  65. 

,  theory  of  sudden  rise  of,  163. 

Moya  of  the  Andes  described,  348,  470. 
Mud  eruptions  in  Quito,  1797,  348. 

volcanoes,  447. 

Mules  sometimes  prolific,  601. 

Murchison,  Sir  K.,  on  the  Hartz  mountains,  48. 

,  on  tertiary  deposits  of  the  Alps,  119. 

,  on  geography  of  Siberia,  78,  84,  124. 

,  map  of  Eussia,  123. 

,  on  depression  of  Caspian,  157. 

,  on  travertin  of  Tivoli,  245. 

,  on  tertiary  deposits  of  Alps,  124. 

Muschelkalk,  193. 
Myda.ua  meliceps,  639. 
Myrmecobius,  fasciatus,  188. 
MytUus  polymorpkus,  652. 


N. 


Nantucket,  banks  of,  293. 

Naples,  volcanic  district  round,  361. 

,  recent  tertiary  strata  near,  74. 

Narwal  stranded  near  Boston,  771. 

,  fossil  near  Lewes,  769. 

Nasmyth,  Mr.,  on  nonconductibility  of  dry  sand 

and  clay,  413. 

Needles  of  Isle  of  Wight,  818. 
Negro  physiognomy  traced  back  8000  years, 

660. 

Neill  on  whales  stranded,  771. 
Nelson,  Lieut.,  on  coral  reefs,  793. 
Neptune,  temple  of,  under  water,  516. 
Neptunists  and  Vulcanists,  rival  factions  of,  50, 

Nerbuddah,  river,  705. 
Newbold,  Lieut.,  on  mud  of  Nile,  262. 
Newfoundland  cattle  mired  in  bogs  of,  723. 
Newhaven.  its  cliffs  undermined,  317. 
New  Holland,  plants  of,  112,  614. 

,  animals  of,  630. 

,  coral  reefs  of,  776,  791. 

New  Kameni,  formation  of,  443. 

New  Madrid,  U.  S.,  earthquakes  at,  350,  466. 

New  Zealand,  animals  in,  635. 

.  tree  ferns  in,  89. 

Niagara,  Falls  of,  214. 

,  their  recession,  217,  218. 

,  height  of,  216. 


Niccolini,  M.,  on  Temple  of  Serapis,  518. 
Nicolosi  destroyed  by  earthquake,  399. 
Nile,  E.,  delta  of  the,  261. 

,  cities  buried  under  blown  sand  near  th& 

726. 

,  swept  away  by  flood  of,  753. 

Nilson,  M.,  on  subsidence  of  Scania,  530. 

,  on  migrations  of  eels,  648. 

Nitrogen  in  springs,  710. 

Nomenclature  of  geology,  remarks  on,  158. 

Norfolk,  waste  of  cliffs  of,  305. 

,  gain  of  land  on  coast  of,  308. 

North  Cape,  drift-wood  on,  745. 
Northumberland,  land  destroyed  by  sea  in,  303. 
Norway  free  from  earthquakes,  531. 

,  rise  of  land  in,  192,  527,  529. 

Norwich  once  situated  on  an  arm  of  the  sea,  307 
Norwich  Crag,  fossils  of,  142. 
Nova  Scotia,  rise  of  tides  in,  332. 
Nummulitic  limestone,  124. 
Nymphs,  temple  of,  under  water,  516. 
Nyoe,  a  new  island  formed  in  1783,  425,  432. 


O. 

Obi,  E.,  fossils  on  shores  of,  81. 

Ocean,  permanency  of  its  level,  518. 

Odoardi  on  tertiary  strata  of  Italy,  42. 

Oersted,  discoveries  of,  543. 

Ogygian  deluge,  349,  356. 

Ohio,  junction  of,  with  Mississippi,  264. 

Oldham,  Mr.,  on  raised  sea  beaches  in  Ireland. 

122. 

Old  red  sandstone  formation,  fossils  of,  135,  193. 
Old  red  sandstone,  reptile  in,  135. 
Olivi  on  fossil  remains,  22. 
Omar,  an  Arabian  writer,  17. 
Ontario,  Lake,  distance  from  Niagara,  216. 
Oolite,  fossils  of  the,  137. 

Oolitic  structure,  recent,  in  Lancerote,  &c.,  439. 
Orang-outang,  change  of,  to  man,  575. 
Orbigny,  M.  A.  de,  on  Pampean  mud,  170. 
Organic  remains,  controversy  as  to  real  nature 
of,  19. 

,  imbedding  of.    See  Fossilization. 

,  importance  of  the  study  of,  60. 

,  abrupt  transition  from  those  of  the  second- 
ary to  those  of  the  tertiary  rocks,  120. 

.    See  also  Fossils. 

Oriental  philosophers.  10. 
Oriental  cosmogony,  7. 
Orkney  Islands,  waste  of,  301. 
Orleans,  New,  ground  sinking,  268. 

,  trunks  of  trees  in  soil  of  delta,  268. 

Osseous  breccias,  735,  736,  741. 

Otaheite,  coral  reefs  of,  784,  786. 

Oujein,  buried  Indian  city,  729. 

Otise,  E.,  has  filled  up  an  arm  of  the  Sea,  744. 

Ovid  cited,  10,  345. 

Owen,  Prof.,  on  bones  of  turtles,  772. 

on  the  dog  and  wolf,  584. 

on  tertiary  mammalia,  142, 144. 

quoted,  184. 

teeth  of  mammoth,  78. 

on  British  fossil  mammalia  and  birds,  137. 
Owhyhee,  787. 

Oysters,  &c.,  thrown  ashore  alive  by  storm,  773. 
,  migrations  of,  652. 


P. 


Pacific  Ocean,  depth  of,  104. 

,  its  height  above  the  Atlantic,  294. 

,  subsidence  greater  than  elevation  in,  787. 

,  coral  and  volcanic  islands  of,  354,  776,  780 

787. 

Palseotherium  of  Isle  of  Wight,  142. 
Palestine  shaken  by  earthquakes,  355. 
Palissy  on  organic  remains,  23. 
Pallas  on  mountains  of  Siberia,  45. 

on  Caspian  Sea,  45. 

on  fossil  bones  of  Siberia,  45,  78, 80. 

cited,  333. 


INDEX. 


829 


Palmer,  Mr.,  on  shingle  beaches,  318,  320. 
Palms,  rare  in  carboniferous  group,  88. 
Pampas,  gradual  rise  of,  170. 
Panama,  tides  in  Bay  of.  295. 
Papandayang,  eruption  of,  493. 

,  its  cone  truncated,  493. 

Papyrus  rolls  in  Herculaneum,  392. 

Paradise,  Burnet  on  seat  of,  32. 

Parana,  R.,  animals  drifted  down  on  rafts  by, 

641. 

,  animals  drowned  in,  696. 

Plrts  basin,  formations  of  the,  121. 

.  fossils  of  the,  142. 

Parish,  Sir  W.,  on  inroads  of  sea  during  earth- 
quakes, 499,  502. 

,  on  drifting  of  animals  on  floating  rafts,  641. 

,  on  great  droughts  in  S.  America,  696. 

,  on  floods  of  Parana  R ,  751. 

Parma,  tertiary  strata  near,  74. 
Paroxysmal  energy  of  ancient  causes   contro- 
verted, 174. 

Parrot,  on  Caspian  Sea,  157. 
Parrots  near  Cape  Horn,  97. 
Parry,  Captain,  highest  northern  latitude  reached 

by,  98. 

,  on  migration  of  polar  bear,  640. 

,  on  animals  of  Melville  Island,  640. 

Patagonia,  tides  on  coast  of,  291. 

Paviland  cave,  737. 

Peat  in  delta  of  Ganges,  280. 

,  on  preservation  of  fossils  in,  711,  718,  722. 

,  distribution  of,  719. 

,  bogs,  bursting  of,  724. 

,  submarine,  725. 

Peat  of  Great  Dismal  Swamp,  Virginia,  724. 
Pembrokeshire,  loss  of  land  in,  324. 
Penco  destroyed  by  earthquake,  499. 

,  elevation  near,  500. 

Pennant  on  waste  of  Yorkshire  coast,  304. 

,  on  migration  of  animals.  77,  631,  637. 

Pentagonal  network  of  mountain  chains,  M.  E. 

de  Beaumont  on,  170. 
Penzance,  loss  of  land  near,  323. 
Permian  rocks,  reptiles  in,  136. 
Peron  on  distribution  of  species,  647. 
Perrey,  M.  Alexis,  on  frequency  of  earthquakes 

in  winter,  561. 
Persian  Gulf,  coral  in,  776. 
Peru,  volcanoes  in,  347. 

,  earthquakes  in,  347,  501. 

Peruvian  tradition  of  a  great  flood,  8,  502. 
Peterhead,  whale  stranded  near,  771. 
PhascolotJierium  Bucklandi,  139. 
Philippi,  Dr.  A.,  on  fossil  tertiary  shells  of  Sicily, 

183. 
Phillips,  Mr.  J.,  on  waste  of  Yorkshire  coast, 

304. 

Phlegrsean  fields,  volcanoes  of,  373. 
Physical  Geography.    See  Geography. 
Piotra  Mala,  inflammable  gas  of,  11. 
Pigs,  instincts  of,  595. 

swim  to  great  distances,  635. 

,  fossil,  723. 

Pilla,  M.,  on  Monte  Somma,  382. 

Pindar  cited,  398. 

Pingel,  Dr.,  on  subsidence  of  Greenland,  530. 

Pisolitic  limestone  of  France,  120. 

Pitch  lake  of  Trinidad,  250. 

Plants,  carboniferous,  wide  geographical  range, 

160. 

,  varieties  in,  produced  by  horticulture,  588. 

,  extent  of  variation  in,  589. 

,  their  geographical  distribution,  97,  112, 

613. 

,  dispersion  of,  618. 

,  stations  of,  614,  669. 

,  equilibrium  among,  kept  up  by  insects, 

672. 

,  number  of  terrestrial,  705. 

,  imbedding  of,   in    subaqueous    deposits, 

742,  7*35,  770. 
,  on  number  which  are  now  becoming  fossil, 

745. 

,  mineralization  of,  747. 

Plants,  fossil,  of  the  coal  strata,  87,  115,  138. 


Plastic  clay  fossils,  142. 

Plastic  force,  fossil  shell  ascribed  to,  20. 

Playfair  on  Huttonian  theory,  53,  57. 

on  instability  of  the  earth's  surface,  212. 

on  gradual  rise  of  Sweden,  523. 

on  form  of  the  earth,  534. 

Plieninger,  Professor,  on  triassic  mammifer,  137. 
Pliny  the  Elder,  16. 

on  delta  of  Rhone,  258. 

on  islands  at  the  mouth  of  the  Texel,  329. 

,  killed  by  eruption  of  Vesuvius,  A.  D.  79, 

Pliny  the  Younger,  on  Vesuvius,  864 

Pliocene  strata,  fossils  of,  143. 

Plot  on  organic  remains,  26. 

Pluche,  theory  of,  1732,  83. 

Plutonic  rocks,  how  formed,  161. 

action,  changes  produced  by,  176,  178. 

Po,  R.,  207. 

frequently  shifts  its  course,  255. 

,  embankment  of  the,  256. 

,  delta  of  the,  256,  284. 

,  subsidence  in  delta  of,  257. 

Poisson,  M.,  on  astronomical  causes  of  changes 
in  climate,  127. 

Polyps.    See  Zoophytes. 

Pomerania,  fossil  ships  in,  758. 

Pompeii,  how  destroyed,  365,  385,  387. 

,  sectiop  of  the  mass  enveloping,  336. 

,  objects  preserved  in,  390. 

,  infusorial  beds  covering  it,  388. 

Pont  Gibaud,  gneiss  decomposed  at,  248. 

,  calcareous  springs  near,  239. 

Poole  Bay  cut  into  by  sea,  319. 

Popayan,  volcanoes  and  earthquakes  in,  849. 

Portland,  fossil  ammonites  of,  28. 

,  its  peninsula  wasting.  319. 

Port  Royal,  subsidence  of,  504,  517,  691,  762. 

Porto  Praya,  Azores,  calcareous  stratum,  436. 

Portugal,  earthquakes  in,  358. 

Porzio  on  formation  of  Monte  Nuovo,  869,  371. 

Post-tertiary  formations,  184 

Precession  of  the  equinoxes,  100,  537. 

Prentice,  Lieut,  on  coral  reef  in  Maldives,  778. 

Pressure,  effects  of,  171. 

Prestwich,  Mr.,  on  artesian  wells,  234. 

Prevost,  Const.,  on  Stonefleld  fossil  mammalia, 
138. 

,  Const,  on  gypseous  springs,  245. 

,  on  rents  formed  by  upheaval,  871. 

,  on  new  island  in  Mediterranean,  433. 

,  on  geological  causes,  718. 

,  on  osseous  breccias  of  caves,  736. 

Prevost,  Pierre,  on  radiation  of  heat,  93. 

Prevost,  Mr.  J.  L.,  on  number  of  wrecked  ves- 
sels, 756. 

Primary  fossiliferous  rocks,  fossils  of,  114. 

Priscodelphinus,  cetacean,  of  chalk,  145. 

Pritchard,  Dr.,  on  Egyptian  cosmogony,  8. 

,  on  recent  origin  of  man,  147. 

,  on  hybrid  races,  602. 

,  on  facial  angle,  608. 

,  on  distribution  of  animals,  629,  631. 

Procida,  island  of,  ancient  writers  on,  360. 

Progressive  development,  theory  of,  130-153. 

,  in  animals,  Lamarck's  theory  of.  567. 

Provinces,  geographical,  of  Testacea,  649. 

Provinces,  zoological  and  land  quadrupeds,  631. 

Pterodactyles,  137. 

Pulo  Nias,  upraised  coral  in,  794. 

Purbeck,  its  peninsula  wasting,  319. 

Pursh  on  plants  of  United  States,  614. 

Puzzuoli,  Temple  of  Serapis  near,  507. 

,  inland  clifis  near,  50S,  510. 

,  date  of  re-elevation  of  coast  of,  515,  518. 

,  encroachment  of  sea  near,  515. 

,  coast  near,  now  subsiding,  516. 

Pyrenees,  their  relative  age,  height,  &c.,  120, 
166. 

Pythagoras,  system  of,  10. 

,  on  Etna,  845. 


830 


INDEX. 


Quadrumana,  fossil,  144. 

Quadrupeds,   domestic,  multiply  in  America, 

584,  685. 

,  regions  of  indigenous,  630,  686. 

,  imbedding  of  terrestrial,  749. 

Quaggas,  migrations  of,  638. 
Quebec,  climate  of,  95. 

,  earthquakes  in,  470. 

Queenstown,  Canada,  table  land  terminates  at, 

216. 

Quintero  elevated  by  earthquake  of  1822,  457. 
Quirini,  theory  of,  25. 
Quito,  earthquakes  and  volcanoes  in,  346,  348, 


Rabenstein  cave,  736. 

Race  of  Alderney,  its  velocity,  293 

"  Races,"  tidal  currents  so  called,  341. 

Raffles,  Sir  8.,  cited,  465,  599. 

Rafts,  drift-timber  in  Mississippi,  &c.,  267. 

Rain,  action  of,  713. 

,  diminished  by  felling  of  forests,  713. 

,  fall  of,  in  basin  of  Ganges,  278. 

,  Huttonian  theory  of,  199. 

,  fall  of,  varying  with  latitude,  199. 

,  fall  of,  in  Eastern  Bengal,  200. 

Rain-prints,  recent,  on  mud  in  Nova  Scotia,  202. 

Raised  beaches,  184. 

Ramree,  volcanic  island,  354. 

Raspe  on  islands  shifting  their  position  (note), 

i  his  theory,  1763,  42,  43,  48. 

Rats,  migrations  of,  637. 

introduced  by  man  into  America,  663,  686. 

Rawlinson,  Col.,  on  delta  of  Tigris,  285. 
Ray,  his  physico-theology,  &c.,  30,  31. 

,  cited,  645,  683. 

Reaumur  on  insects,  674. 

Reculver  cliff,  action  of  sea  on,  312. 

Rccupero  on  flowing  of  lava,  401. 

Red  Crag,  fossils  of,  142. 

Redman,  J.  B.,  on  changes  of  English  coast,  315, 

316,  319. 

Red  marl,  supposed  universality  of,  158. 
Red  River,  new  lakes  formed  by,  269. 

,  drift-wood  in,  267. 

and  Mississippi,  their  junction  recent,  264, 

284. 
Red  Sea,  level  of,  and  of  Mediterranean,  294. 

,  coral  reefs  of,  777,  784. 

Reefs,  coral,  outline  destroyed  by  denudation, 795. 

Refrigeration,  Leibnitz's  theory  of,  26. 

,  causes  which  might  produce  the  extreme 

of,  106. 

Reid,  Col.,  on  motion  of  shingle  beaches,  320. 
Rein-deer,  geographical  range  of,  637. 

,  migrations  of,  640. 

,  imported  into  Iceland,  686. 

Rennel,  Major,  on  delta  of  Ganges,  275. 

,  on  delta  of  Nile,  261. 

,  on  currents,  95,  97,  291,  292,  293. 

,  on  the  tide-wave  called  "  the  Bore,"  333. 

Rennel,  Mr.,  on  delta  of  Ganges,  275. 

Rennie,  Rev.  Dr.,  on  peat,  and  fossils  in  peat, 

718,  719,  720,  722. 
Reptiles,  their  geographical  distribution,  645. 

,  their  powers  of  diffusion,  645. 

,  in  carboniferous  epoch,  136. 

,  in  Ireland,  645. 

,  imbedded  in  subaqueous  strata,  748,  771. 

.  fossil,  in  old  red  sandstone,  135. 

,  in  coal,  136. 

Rhine,  R.,  description,  of  its  course,  325. 

,  its  delta,  326. 

,  tuff  made  of  siliceous  cases  of  infusoria,  388. 

Rhinoceros,  fossil,  food  of,  80. 

Rhone,  delta  of,  in  Mediterranean,  258. 

,  delta  of,  in  Lake  of  Geneva,  189,  252,  286. 

,  deposits  at  its  confluence  with  the  Arve, 


Rhone,  a  cannon  in  calcareous  rock  in  its  delta, 

759. 
Richardson,  Sir  J.,  on  rocks  near  Mackenzie  Riv 

er  115. 

on  sheep  of  Rocky  Mountains,  598. 

on  distribution  of  animals,  640,  645. 

on  drift  timber,  in  Slave  Lake,  743. 

on  arctic  fauna,  634. 

on  diffusion  of  fish,  647. 

on  isothermal  lines,  94. 

Richardson,  Mr.  W.,  on  Herne  Bay,  312. 
Riddell,  Dr.,  on  sediment  of  Mississippi,  273. 
Rive,  M.  de  la,  on  terrestrial  magnetism,  543. 
River-ice,  carrying  power  of,  219. 

Rivers,  difference  in  the  sediment  of,  189,  258. 

,  sinuosities  of,  205. 

,  submarine,  in  Thessaly,  &c.,  357. 

,  when  confluent,  do  not  occupy  bed  of  pro- 
portionally larger  surface,  207. 

Robert,  M.,  on  geysers  of  Iceland,  246. 

Robertson,  Capt,  on  mud  volcanoes,  449. 

Rockhall  bank,  recent  deposits  on,  773. 

Rocks,  specific  gravity  of,  206. 

,  difference  in  texture  of  older  and  newer, 

175. 

,  altered  by  subterranean  gases,  248. 

,  origin  of  the  primary,  176. 

,  persistency  of  mineral  character  in,  157. 

,  older,  why  most  solid  and  disturbed,  162. 

,  action  of  frost  on,  221,  231. 

,  transportation  of,  by  ice,  155,  219. 

,  grooved  by  glacial  action,  155,  227,  229. 

Rogers,  Prof.,  on  Appalachain  chain,  559. 

Roman  roads  under  water  in  Bay  of  Baiae,  517. 

Romney  Marsh,  gained  from  sea,  316. 

Rose,  M.  G.,  on  hornblende  and  augite,  449. 

Ross,  Sir  J.,  on  cold  of  antarctic  regions,  99. 

,  obtained  soundings  at  depth  of  27,600  feet, 

104. 

,  confirms  Cook  as  to  antarctic  ice,  125. 

,  on  icebergs,  98, 229. 

Rossberg,  slide  "of  the,  732. 

Rotation  of  the  earth,  currents  caused  by,  296. 

of  crops,  670,  720. 

Rother,  River,  vessel  found  in  its  old  bed,  316, 758. 

Royle,  Mr.,  81. 

Runn  of  Cutch  described,  463. 

Rye  formerly  destroyed  by  sea,  316. 


S. 


Saarbuck,  reptiles  in  coal  strata  at,  186. 

Sabine,  Capt.,  on  well  at  Chiswick,  234. 

,  on  waters  of  Amazon  discoloring  the  sea, 

342. 

Sabine,  Col.,  on  solar  magnetic  period,  129.  544. 

Sabrina,  island  of,  432. 

Saco,  R.,  flood  on,  209. 

Sahrunpore,  buried  town  near,  731. 

St.  Andrew's,  loss  of  land  at,  303. 

,  gun-barrel,  fossil,  near,  760. 

St.  Domingo,  hot  springs  caused  by  earthquake 
in,  494. 

.  fossil  human  skeleton  in,  758. 

St.  Helena,  tides  at,  291. 

St  Jago,  earthquake  at,  457. 

St.  Katherine's  Docks,  a  fossil  vessel  found  in,  758. 

St  Lawrence,  Gulf  of,  earthquakes  in,  470. 

,  rocks  drifted  by  ice  in  the,  220. 

St  Maura,  earthquakes  in,  474. 

St.  Michael,  siliceous  springs  of,  246. 

St  Michael's  Mount,  323. 

St.  Paul,  volcanic  island,  44& 

St  Vincent's,  volcanoes  of,  466. 

,  counter-currents  in  the  air  proved  by  erup- 
tion in.  106. 

,  boa  constrictor  conveyed  on  drift-wood  to. 

646. 

Salt,  on  its  deposition  in  the  Mediterranean,  334, 

Salt  springs,  18,  247. 

Saltholm,  island  of,  520. 

Samothracian  deluge,  356. 

Sand  bars  along  western  coast  of  Adriatic,  257. 

,  drift,  estuaries  blocked  up  by,  307. 


INDEX. 


831 


Sand,  imbedding  of  towns,  &c.  in,  726. 

,  cones  of  thrown  up  during  earthquake,  483. 

Sandown  Bay,  excavated  by  sea,  318. 

Sandwich  Islands  volcanoes,  854,  372,  333,  429, 
548,552. 

Sandwich  Land,  perpetual  snow  to  level  of  sea- 
beach  in,  99. 

San  Fiiippo,  travertin  of,  241. 

San  Lio,  on  Etna,  fissures  in  plain  of,  399. 

Santa  Maria,  island  of,  raised  10  feet,  455. 

Santorin,  geological  structure  of,  445. 

,  chart  and~section  of,  442. 

,  new  islands  in  Gulf  of,  441. 

Saracens,  learning  of  the,  17. 

Saussure  on  the  Alps  and  Jura,  45. 

,  on  glaciers  in  Alps,  223. 

Savanna  la  Mar,  swept  away  by  sea,  731. 

Saato&va  rugona,  cosmopolite  shell,  650. 

Scandinavia  called  an  island  by  the  ancients,  520. 

,  gradual  rise  of,  520,  563. 

.    See  Sweden. 

Scania,  gradual  subsidence  of,  530. 

Scacchi,  Sig.,  on  temple  of  Serapis,  516. 

,  on  origin  of  Monte  Nuovo,  371. 

Scheuchzer.  his  theory,  1708,  33. 

Schmerling,  Dr.,  on  fossils  in  caves,  737. 

Schwabe,  M.,  on  spots  in  the  sun,  129,  544. 

Sciacca,  island  of.     See  Graham  Island. 

Scilla  on  organic  remains,  1670,  24. 

8 cilia,  rock  of,  488. 

Scoresby,  Capt.,  on  the  Gulf  stream,  96. 

,  on  formation  of  field  ice,  108. 

,  on  weight  of  rocks  transported  by  icebergs, 

,  cited,  640,  743. 

Scotland,  floods  in,  207,  750. 

,  colder  climate  indicated  by  newest  tertiary 

strata  of,  125. 

,  waste  of  islands  and  coast  of,  298. 

,  slight  earthquakes  felt  in,  358. 

,  peat-mosses  of,  720,  723. 

,  marl  lakes  of,  752,  766,  770. 

Scrope,  Mr.  G.  P.,  on  eruption  of  Vesuvius  in 

1822,  375. 

,  on  columnar  basalts  of  Vesuvius,  385. 

,  on  pisolitic  globules  at  Pompeii,  387. 

,  on  eruptions  of  Etna,  408,  410. 

,  on  cause  of  convexity  of  plain  of  Malpais, 

429. 
,  on  connection  between  state  of  atmosphere 

and  earthquakes,  561. 
Sea  does  not  change  its  level,  but  land,  15. 

,  its  influence  on  climate,  97. 

— — ,  area  covered  by,  124. 

,  its  encroachments  on  coasts,  298,  302,  324. 

,  its  rise  and  retreat  during  earthquakes,  407. 

Sea-beaches,  raised,  in  Ireland,  122. 

^progressive  motion  of,  316. 

Seals,  migration  of,  642. 

Sea-weed,  banks  formed  by  drift,  622,  770. 

Secondary  rocks,  fossils  of  the,  86. 

,  origin  of  the,  117. 

Sedgwick,  Professor,  on  the  Hartz  mountains, 

48. 

-,  on  tertiary  deposits  of  the  Alps,  119. 

,  on  the  antagonist  power  of  vegetation,  711. 

,  on  organic  remains  in  fissures,  740. 

,  on  diluvial  waves,  423. 

Sediment  of  the  Mississippi,  272. 

,  laws  governing  deposition  of,  188,  342. 

,  in  river  water,"  270. 

,  of  Ganges  compared  to  lavas  of  Etna,  283. 

,  rate  of  subsidence  of  some  kinds  of,  342. 

,  area  over  which  it  may  be  transported  by 

currents,  343. 
Sedimentary  deposition,  causes  which  occasion  a 

shifting  of  the  areas  of,  189. 
Seeds,  vitality  of,  587. 
,  of  Leguminosae  adapted  for  water-carriage, 

622. 
Serapis,  temple  of,  507. 

,  ground-plan  of  environs  of,  50T. 

,  date  of  its  re-elevation,  512. 

,  now  again  subsiding,  516. 

,  worship  of,  in  Italy,  512. 


Serres,  E.  R.  A.,  on  changes  in  brain  of  foetus, 

609. 
Serres,  E.  Marcel  de,  on  fossil  human  remains, 

738. 
Severn,  tides  in  estuary  of,  291. 

,  gain  of  land  in  its  estuary,  324. 

Shakspeare's  cliff,  waste  of,  314 

"  Shambles,"  a  shoal  off  Portland  Bill,  32. 

Sharpe,  Mr.  D.,  on  earthquake  of  Lisbon,  496. 

Sheep,  multiplication  of,  in  South  America,  686. 

Shell  marl,  fossils  in,  752,  766,  769. 

Shells,  fossil  of  older  strata  buried  in  newer  or 

recent  beds,  775.    See  Testacea. 
Sheppey,  waste  of  cliffs,  312. 
Shetland  Islands,  action  of  the  sea  on,  298. 

,  rock  masses  drifted  by  sea  in,  298. 

,  effect  of  lightning  on  rocks  in,  299. 

,  formation  in  progress  near,  774. 

Shingle  beaches,  318,  320. 

Ships,  number  of  British,  wrecked  annually,  754, 

— ,  fossil,  316,  725,  758. 
Siberia,  rhinoceros  entire  in  frozen  soil  of,  45,  82. 

,  map  of,  79. 

,  the  Bengal  tiger  found  in,  78. 

,  lowland'of,  78,  83,  85. 

,  drift  timber  on  coast  of,  745. 

Siberian  lowlands,  climate  of,  83. 

,  mammoths,  80. 

Sicily,  earthquakes  in,  357,  470, 477, 479,  503,736. 

,  geological  structure  of,  74, 167, 183. 

,  mud  volcanoes  of,  447. 

Sienna,  fossil  shells  of,  39,  74. 

Sigillariae,  structure  of,  88. 

Silex,  deposited  by  springs,  246. 

Silliman,  Professor,  cited,  759. 

Silurian  rocks,  wide  range  of  the  fossils,  160. 

,  fauna,  no  land  or  freshwater  plants  in,  134. 

,  horizontal,  187. 

,  altered,  177. 

,  strata  formed  in  deep  seas,  117. 

Simeto,  E.,  lava  excavated  by,  213. 

Sindree,  changes  caused  by  earthquakes  of  1819, 

near,  461,  464,  761. 
,  view  of  the  fort  of,  before  the  earthquake 

(see  PI.  xi.),  461. 

,  its  appearance  in  1838,  463. 

Skaptar  Jokul,  eruption  of,  425. 

Slave  Lake,  drift  timber  in,  743. 

Sleswick,  waste  of  coast  of,  330,  694. 

Sligo,  bursting  of  a  peat-moss  in,  724. 

Sloan  e,  Sir  H.,  on  earthquake  in  Jamaica,  505. 

,  on  dispersion  of  plants,  621. 

Smith,  William,  agreement  of  his  system  with 

Werner's,  48. 
,  his  "Tabular  View  of  the  British  Strata," 

1790,  58. 

,  his  map  of  England,  58. 

,  priority  of  his  arrangement,  58. 

Smith,  Mr.,  of  Jordan  Hill,  on  the  colder  climate 

of  newest  tertiary  period,  126. 

,  on  temple  of  Serapis,  516. 

Smyrna,  volcanic  country  round,  355. 

Smyth,  Capt.  W.  H.,  on  the  Mediterranean,  45, 

259,296,511. 

,  on  height  of  Etna,  396. 

,  on  Straits  of  Gibraltar,  333,  336. 

,  on  depth  ot  sea  from  which  Graham  Island 

rose,  432. 

,  on  floating  islands  of  drift-wood,  641. 

,  on  drifting  of  birds  by  the  wind,  645. 

,  on  diffusion  of  insects.  657. 

,  on  average  number  of  British  ships  lost, 

from  1793  to!829,  755. 

,  found  shells  at  great  depths  between  Gib- 
raltar and  Centa,  773. 
Snow,  height  of  perpetual,  in  the  Andes,  112. 

,  in  Himalaya  mountains,  1 12. 

,  lowest  limits  of  perpetual,  at  equator,  222. 

,  lowest  limits  of  perpetual,  at  Swiss  Alps, 

222. 

Sodertelje,  buried  hut  in  canal  of,  524,  528. 
Soil,  its  influence  on  plants,  590. 
Soils,  on  formation  of,  709. 
,  influence  of  plants  on,  670. 


INDEX. 


Soldani,  on  microscopic  shells  of  Mediterranean, 

,  on  the  Paris  basin,  44. 

Solent,  its  channel  widening,  318. 
Solfatara,  lake  of,  243. 

,  volcano,  85S,  868,  367,  385. 

Solitaire,  recent!}'  extinct  bird,  684. 

Solway  Moss,  728. 

Solway  Firth,  animals  washed  by  river  floods 

into,  750. 
Somersetshire,  land  gained  in,  324. 

,  submarine  forest  on  coast  of,  323. 

Somerville.  Mrs.,  on  depth  of  ocean,  104. 
Somma,  escarpment  of,  381. 

,  dikes  of,  382. 

,  supposed  section  of  Vesuvius  and,  381. 

Sorbonne,  College  of  the,  39. 

Sorting  power  of  water,  287. 

South  Carolina,  earthquake  in,  466. 

South  Downs,  waste  of  plastic  clay  on,  817. 

Spain,  earthquakes  in,  358. 

Spallanzani  on  effects  of  heat  on  seeds,  621. 

,  on  flight  of  birds,  644. 

Species,  definition  of  the  term,  567. 

,  Linnaeus  on  constancy  of,  568. 

,  Lamarck's  theory  of  transmutation  of,  567, 

580,  699. 

,  reality  of,  in  nature,  5S3,  591,  592,  611. 

,  geographical  distribution  of,  612. 

,  theories  respecting  their  origin,  666,  703. 

,  Brocchi  on  extinction  of,  668. 

,  reciprocal  influence  of  aquatic  and  terres- 
trial, 676. 
,  their  successive  creation  and  extinction, 

678,  689,  707. 
,  effect  of  changes  in  geography,  climate,  &c., 

on  their  distribution,  105,  690,  697. 

,  superior  longevity  of  molluscous,  76. 

Specific  centres,  doctrine  of,  630. 

Spence,  Mr.,  on  insects,  cited,  606,  655,  673. 

Spitsbergen,  glaciers  of,  96. 

Spix,  M.,  on  animals  drifted  by  Amazon,  641. 

,  on  Brazil,  682. 

Spontaneous  generation,  theory  of,  22. 
Springs,  origin  of,  232. 

,  the  theory  of,  illustrated  by  bored  wells,  233. 

,  most  abundant  in  volcanic  regions,  237. 

,  affected  by  earthquake,  237,  453,  456,  483, 

494 

,  transporting  power  of,  238. 

,  calcareous,  239. 

,  sulphureous  and  gypseous,  245. 

-,  siliceous,  246. 

,  ferruginous,  249. 

,  brine,  247. 

,  carbonated,  248. 

,  petroleum,  250. 

Squirrels,  migrations  of,  637. 

Stabise,  buried  city  of,  394. 

Stalagmite  alternating  with  alluvium  in  caves, 

737. 

Stars,  variable  splendor  of,  128. 
Statical  figure  of  the  earth,  534,  544. 
Stations  of  plants,  description  of,  614. 

of  animals,  677. 

Stelluti  on  organic  remains,  23. 

Steno,  opinions  of,  23. 

Stephenson  on  eruption  in  Iceland,  425. 

Stephenson,  Mr.  K.,  on  level  of  Red  Sea  and 

Mediterranean,  294, 
Stevenson,  Mr.,  on  drift  stones  on  Bell-Eock, 

302. 

,  on  the  German  Ocean,  315,  340. 

,  on  waste  of  cliffs,  324. 

Stockholm,  rise  of  land  near,  526,  527. 
Stokes,  Mr.,  on  mineralization  of  plants,  747. 
Stonesfield,  fossils  of,  138, 145. 
Storm  of  November,  1824,  effect  of,  317,  318, 320. 
Strabo  cited,  14,  260,  355,  361. 

,  geology  of,  14. 

Strachey,  Capt.  K.,  on  delta  of  Ganges,  283. 
Straits  of  Dover,  formation  of,  :!!".. 

,  their  depth,  315. 

Straits  of  Gibraltar,  currents  in,  &c.,  833,  335. 
Strata,  laws  governing  deposition  of,  188. 


Strata,  slow  deposition  of,  proved  by  fossils,  154. 

,  on  consolidation  of,  175. 

Stratifications  in  deltas,  causes  of,  287. 

of  debris  deposited  by  currents,  288. 

,  unconformable,  inferences  derived  from, 

187. 

Strabo,  hypothesis  of,  14. 

Strickland,  Mr.,  on  tertiary  strata,  Crop  thorn,  76. 

,  on  dodo,  684. 

Stromboli,  its  appearance  during  Calabrian  earth- 
quakes, 488. 

,  constancy  in  eruption,  546,  561. 

Stufas,  jets  of  steam  in  volcanic  regions,  237, 546. 

Stutchbury,  Mr.,  on  coral  islands,  778.  782. 

Subapennine  strata,  74. 

,  early  Italian  geologists  on,  42,  71. 

Submarine  forests,  303,  323,  746. 
-,  peat,  724,  770. 
-,  rivers,  357. 

,  volcanoes,  431,  454. 

,  eruptions  in  mid  Atlantic,  436. 

Subsidence  of  land,  460,  465,  470,  477,  495.  503, 
504,  507,  691,  761,  762. 

,  great  areas  of,  170,  790. 

,  greater  than  elevation,  563,  787. 

,  simultaneous  in  Miocene  epoch,  192. 

,  of  land,  delta  of  Mississippi,  271. 

,  of  coral  islands,  slow  and  uniform,  791. 

Subterranean  movements,  uniformity  of,  186. 

,  movements  near  New  Madrid,  1811-12, 270 

Suffolk,  cliffs  undermined,  809. 

,  tertiary  strata  of,  142. 

Sulphuric  acid,  lake  of,  in  Java,  353. 

Sulphureous  springs,  245. 

Sumatra,  volcanoes  in,  354. 

,  animals  destroyed  by  river  floods  in,  751. 

Sumbawa,  subsidence  in  island  of,  1815,  464,  762. 

,  ashes,  transported  to  great  distances  by 

eruptions  of,  106. 

Sun,  variations  in  spots  of,  129. 

Sunda,  Isles  of,  volcanic  region  of,  350. 

Sunderbunds,  part  of  delta  of  Ganges,  276. 

"  Sunk  country,"  west  of  New  Madrid  in  U.  S., 
467. 

Superior,  Lake,  deltas  of,  254. 

,  recent  deposits  in,  254,  768. 

,  its  depth,  extent,  &c.,  254. 

,  bursting  of,  would  cause  a  flood,  156. 

Sussex,  \vaste  of  its  coast,  317. 

Sutlej,  E.,  fossils  near,  6. 

Swanage  Bay,  excavated  by  sea,  318. 

Sweden,  gradual  rise  of,  520,  563. 

,  gradual  subsidence  of  south  of,  530. 

,  earthquakes  in,  531. 

,  land  rising,  192. 

.    See  also  Scandinavia. 

Switzerland,  towns  destroyed  by  landslips  in, 
732. 

Syria,  earthquakes  in,  355,  453. 


T. 


Tacitus  cited,  364 

Tagliamento,  E.,  delta  of  the,  258. 

Targioni,  on  geology  of  Tuscany,  40. 

Tartary,  volcanoes  in,  355. 

Taxodium  distichum  in  Great  Dismal  Swamp, 

725. 
Tay,  estuary  of,  encroachment  of  sea  in,  302. 

,  submarine  forests  in,  803. 

Taylor,  Mr.  E.  C.,  on  waste  of  cliffs.  306. 

,  on  gain  of  land  on  coast  of  Norfolk,  308. 

,  on  caves  in  isle  of  Cuba,  741. 

Tchihatchoff,  M.,  map  of  Italy,  123. 

Teissier,  M.,  on  human  bones  in  caves,  &c.,  789. 

Temperature,  great  changes  in,  92. 

,  difference  of,  in  places  in  same  latitudes,  95, 

,  warmer  in  tertiary  periods,  75. 

,  oscillation  of,  125. 

.    See  Climate- 
Temples,  buried,  in  Egypt,  726. 

under  water  in  Bay  of  Baise,  518. 

buried  in  Cashmere,  762. 

Teneriflfe,  volcanic  eruptions  in,  439. 


INDEX. 


833 


Terra  del  Fuego,  fauna  of,  141. 

Terranuova,  subsidence  near,  470. 

,  fault  in  the  tower  of,  478. 

,  landslips  near,  485. 

Tertiary  formations,  general  remarks  on,  141, 182, 
183. 

,  geographical  changes  implied  by,  118. 

,  glacial  in  Scotland,  126. 

,  origin  of  successive  periods,  182. 

,  circumstances  under  which  these  and  the 

secondary  formations   may  have  originated, 
117,  118. 

,  fossils  of  the  newest,  183. 

,  fossil  mammals  of  successive,  142. 

formations  of  England,  76,  142. 

,  of  the  Paris  basin,  142. 

,  deposits,  climate  of  warmer,  86. 

Testacea,  their  geographical  distribution,  649. 

,  fossil,  importance  of,  183. 

,  marine,  imbedding  of,  768. 

,  freshwater,  770. 

,  burrowing,  773. 

,  longevity  of  species  of,  76. 

,  number  of  recent,  in  different  tertiary  pe- 
riods, 142,  183. 

Texel,  waste  of  islands  near  the,  328. 

Thames,  valley  of,  tertiary  strata  in,  76. 

gain  and  loss  of  land  in  its  estuary,  312. 

,  tide  in  its  estuary,  338. 

,  buried  vessels  in  alluvial  plain  of  the,  758. 

Thanet,  Isle  of,  loss  of  land  in,  313. 

Thermo-electricity,  543. 

Thibet,  yak  or  wild  ox  of,  in  ice,  85. 

Thomson,   Dr.  T.,  on  Western  Himalaya  and 

Thibet,  763. 
,  on  buried  temples  in  Cashmere,  763. 

Thrace  subject  to  earthquakes,  355. 

Thury,  M.  Hericart  de,  on  artesian  wells,  234, 
236. 

Tliylacothenwn  Prevostii,  138. 

Tiber,  growth  of  its  delta,  243. 

Tide  wave  of  the  Atlantic,  308. 

Tides,  height  to  which  they  rise,  279,  290. 

,  effect  of  winds  on  the,  295. 

,  effects  of,  on  wells  near  London,  233. 

,  their  destroying  and  transporting  power, 

— •-,  their  reproductive  effects,  337. 

and  currents,  drifting  remains  of  animals 

by,  753. 

Tiedemann  on  changes  in  brain  of  foetus,  609. 
Tiger  of  Bengal  found  in  Siberia,  77. 
Tigris  and   Euphrates,  their  union  a  modern 

event,  234. 

Tigris,  river,  delta  of,  advancing,  284. 
Tilesius  on  Siberian  mammoth,  81. 
Time,  prepossessions  in  regard  to  the  duration  of 

past,  62. 
Tivoli,  flood  at,  211. 

,  travertin  of,  244. 

Tomboro,  volcano,  eruption  of,  465. 

,  town  of,  submerged,  465. 

Torre  del  Greco  overflowed  by  lava,  394. 

,  columnar  lavas  of,  384. 

Torrents,  action  of,  in  widening  valleys,  204. 

Torres'  Strait,  volcano  of,  792. 

Totten,  Col.,  on  expansion  of  rocks  by  heat, 

562. 

Tournal,  M.,  on  French  caves,  738,  739. 
Towns  destroyed  by  landslips,  732. 
Trade-winds,  106,  295. 
Traditions  of  losses  of  land,  324,  827. 

,  of  floods,  500,  601. 

Transition  texture,  176. 

,  formations,  177. 

Trap  rocks  of  many  different  ages,  160. 
Travertin  of  the  Elsa,  239. 

of  San  Vignone,  240. 

of  San  Filippo,  241. 

,  spheroidal  structure  of,  242. 

,  compared  to  English  magnesian  limestone, 

,  of  Tivoli,  244 

Travertin  oolitic,  recent,  in  Lancerote,  489. 
Tree-ferns,  distribution  of,  88. 
63 


Tree-ferns,  extend  more  south  than  north  of 

equator,  86. 

Trees,  longevity  of,  422. 
Trias,  fossil  mammifer  oft  137. 
Trimmer,  Mr.,  on  recent  marine  shells  ill  Wales 

122. 
Trinidad,  subsidence  in,  250. 

,  pitch  lake  of,  250. 

Tripergola,  370,  371,  395. 

Tripolitza,  plain  of,  breccias  in,  734. 

Trollhattan,  527. 

Truncation  of  volcanic  cones,  352,  493. 

Tufa.    See  Travertin. 

Tuff,  infusorial,  388. 

Turner,  Dr.,  on  decomposition  of  felspar,  24T. 

Turtles,  migrations  of,  645. 

,  eggs  of,  fossil,  771. 

Turton  cited,  646. 
Tuscany,  geology  of,  23,  40. 

,  calcareous  springs  of,  239. 

Tyrol,  Dolomieu  on  the,  49. 


U. 

Uddevalla,  upraised  deposits  at,  184,  527 

Ullah  Bund,  formation  of  the,  462. 

Ulloa  cited,  501,  502,  685. 

Unconformable  strata,  inferences  derived  from, 

187. 

Uniformity  of  laws  of  nature,  71, 149,  373. 
,  of  system  of  past  changes  in  animate  and 

inanimate  world,  181. 
Universal  formations,  theory  of,  49,  154. 
Universal  ocean,  theory  of,  26,  34. 

disproved  by  organic  remains,  191. 

Upsala,  strata  near,  528. 


Val  d'Arno,  Upper,  effect  of  destruction  of  for- 
ests in,  712. 

Val  del  Bove  on  Etna  described,  403. 

,  form,  composition,  and  origin  of  dikes  in. 

406. 

,  lavas  and  breccias  of  the,  411 

,  origin  of  the,  413. 

,  floods  in,  411. 

Val  di  Calanna,  405,  407,  410. 

Val  di  Noto,  Dolomieu  on  the,  49. 

Valdivia,  earthquake  at,  453. 

Valenciennes,  M.,  on  fish  not  crossing  the  At- 
lantic, 647. 

Valley,  newly  formed  in  Georgia,  U.  8.,  205. 

Valleys,  Targioni  on  origin  of,  40. 

,  excavation  of,  in  Central  France,  213. 

of  elevation,  section  of,  420.    , 

on  Etna,  account  of,  404. 

,  the  excavation  of,  assisted  by  earthquakes, 

484. 

Vallisneri  on  the  origin  of  springs,  83. 

,  on  marine  deposits  of  Italy,  34. 

cited,  34,  35,  52. 

Valparaiso,  changes  caused  by  earthquakes  at, 
457,  517,  761. 

Van  Dieman's  Land,  climate  of,  97. 

Vedas.  sacred  hymns  of,  4. 

Vegetable  soil,  why  it  does  not  increase,  709. 

,  how  formed,  710. 

Vegetation,  luxuriant,  not  required  to  support 
large  animals,  82. 

,  centres  of,  703. 

,  its  conservative  influence,  710,  711. 

,  its  influence  on  climate,  718. 

Veins,  mineral,  on  their  formation,  484. 

of  lava.    See  Dikes. 

Verneuil,  M.  de,  on  lowland  of  Siberia,  84. 

Verona,  fossils  of,  20,  22,  34. 
,  Arduino  on  mountains  of,  41. 

Verstegan,  on  separation  of  England  from  France, 
315,  642. 

Vertebrated  animals  in  oldest  strata,  185. 

Vessels,  fossil.     See  Ships. 

Vesta,  temple  of,  212. 


634: 


INDEX. 


Vesuvius,  excavation  of  tuff  on,  213. 

,  history  of,  263,  374. 

,  eruptions  of,  364,  374. 

,  dikes  of,  379. 

,  lava  of,  384. 

,  structure  and  origin  of  the  cone  of,  383. 

and  Somma,  probable  section  of,  381. 

,  volcanic  alluvium  on,  728. 

Vicentin,  Dolomieu  on  the,  49. 

,  submarine  lavas  of  the,  71. 

Victoria  land,  skirted  by  ice,  99. 
Vidal,  Capt,  on  Kockhall  bank,  773. 
Villages  buried  by  landslips,  732. 
Virlet,  M.,  on  Samothracian  deluge,  356 

,  on  volcanoes  of  Greece,  355. 

,  on  Santorin,  443,  445,  446. 

,  on  corrosion  of  rocks  by  gases,  733. 

,  on  human  bones  imbedded  in  Morea,  735. 

Vivarais,  basalts  of  the,  48. 

Volcanic  action,  defined,  345. 

power  adequate  to  effect  lateral  pressure, 

172. 

lines,  169,  352. 

craters  in  Galapagos  with   southern   side 

lowest,  783. 

,  action,  uniformity  of,  162,  711. 

cones,  truncation  of,  352,  493. 

,  their  perfect  state  no  proof  of  relative  age, 

712. 

conglomerates,  438. 

dikes.    See  Dikes. 

eruptions,  causes  of,  542. 

,  average  number  of,  per  annum,  450. 

formations,  fossils  in,  349,  728. 

products,  mineral  composition  of,  449. 

• regions,  their  geographical  boundaries,  346. 

map  showing  extent  of,  351. 

rocks,  subterranean,  178,  450. 

of  all  geological  periods,  160. 

Volcanoes,  safety-valves  according  to  Strabo,  15. 

,  remarks  on  their  position,  346, 855. 

and  earthquakes,  effects  of  same  causes,  345. 

,  agency  of  water  in,  545. 

,  mode  of  computing  the  age  of,  420. 

,  sometimes  inactive  for  centuries,  346,  421. 

of  Sandwich  Islands,  354,  372,  548,  383,  429. 

,  chemical  theory  of,  546. 

,  mud,  447. 

,  "no  safety-valves,"  Dana  on,  553. 

Voltaire  on  systems  of  geology,  54. 
Volterra,  Mattani,  on  fossils  of,  34. 
Von  Baer,  Prof,  on  frozen  soil  of  Siberia,  84. 

on  ice-drifted  rocks,  231. 

Von  Buch  on  rise  of  land  in  Sweden,  523,  526. 

on  volcanic  lines,  852. 

on  volcanoes  of  Greece,  355. 

on  formation  of -Monte  Nuovo,  369. 

on  Vesuvius  and  Somma,  367,  380,  382,  384. 

on  eruption  in  Lancerote,  436. 

1 on  glaciers,  228. 

on  new  islands,  468. 

on  volcanic  regions,  346. 

VonHoff.    SeeHofi. 

Vulcanists  and  Neptunists,  factions  of,  50,  55. 

Vultur,  Mount,  356. 

Vultures,  range  of,  643. 


W. 


Wallerius,  theory  of,  45. 
Wallich,  Dr.,  on  Ava  fossils,  28. 

,  on  wood  in  peat  near  Calcutta,  280. 

Warping,  land  gained  by,  288,  339. 
Water,  action  of  running,  204. 

,  its  power  on  freezing,  204. 

,  excavating  power  of,  204. 

,  transporting  power  of,  204. 

,  sorting  power  of,  286. 

,  agency  of,  in  volcanoes,  548. 

Waterhouse,  Mr.,  of  British  Museum,  on  prov- 
inces of  indigenous  land  quadrupeds,  631. 


Wealden  strata,  fossils  of,  117, 137, 140. 
Webster,  Dr.,  of  Nova  Scotia,  on  rain-printa, 

202. 

Wells,  artesian,  233. 
Wener,  Lake,  strata  near,  527. 
Werner,  Professor  of  Mineralogy  at  Freyberg, 

,  his  lecture,  47. 

,  on  granite  of  the  Hartz,  47. 

,  principal  merit  of  his  system,  48. 

,  technical  terms  of,  58. 

,  on  transition  rocks,  176. 

West  Indian  land  quadrupeds,  634. 

West  Indies,  earthquakes  in,  29,  350,  505. 

,  active  volcanoes  in,  350. 

Whales  stranded,  771. 

Whewell,  Rev.  Dr.,  on  modern  progress  of  ge- 
ology, 59. 

,  on  the  tides,  332. 

Whirlwinds,  violent,  during  eruption  in  Sum- 
bawa,  465. 

Whirlwind,  dispersion  of  seeds  by,  619. 

Whiston,  his  theory  of  the  earth,  32. 

White  Mountains,  landslips  in  the,  209. 

Whitehurst,  theory  of,  1778,  45. 
— ,  on  subsidence  at  Lisbon,  495. 

Wildenow  on  diffusion  of  plants  by  man,  626. 

,  on  centres  of  vegetable  creation,  703. 

Wilkinson,  Sir  J.  G.,  on  deposits  of  Nile,  262. 
,  on  sand  drift  in  Egypt,  726. 

Wilson,  Prof.,  on  cosmogony  of  Vedas,  4. 

Winds,  trade,  106,  295. 

,  currents  caused  by  the,  293. 

,  sand  drifted  by  the,  307,  726. 

Wolf,  and  dog,  distinct  species,  585. 

,  hybrids  between  the,  601. 

,  drifted  to  sea  on  ice,  640. 

extirpated  in  Great  Britain,  683. 

Wollaston,  Dr.,  on  water  of  Mediterranean,  334. 

Wood,  Mr.  S.,  on  fossil  quadrumana,  144. 

Wood  impregnated  with  salt  water  when  sunk 
to  great  depths,  743. 

,  drift,  90,  268,  640,  743. 

converted  into  lignite,  759. 

Woodward,  theory  of,  31,  34,  54,  66. 

Wrecks,  number  of,  annually,  754,  755. 


Xanthus,  the  Lydian,  his  theory,  14 


T. 

Yak,  wild  ox  of  Thibet,  frozen  in  ice,  85. 

Yakutzt,  frozen  soil  of,  84 

Yaou,  flood  of,  7. 

Yarmouth,  estuary  silted  up  at,  307. 

,  rise  of  the  tide  at,  291,  307. 

Yenesei,  E.,  fossils  on  banks  of,  79. 
Yorkshire,  bones  of  mammoth  in,  76. 

,  waste  of  its  coasts,  303. 

Young,  Dr.,  on  effects  of  compression  at  earth1* 
centre,  536. 

Z. 

Zante,  earthquakes  in  island  of,  474. 
Zealand,  New,  number  of  ferns,  116. 
,  resemblance  of  plants  with  ancient  carbon- 
iferous flora,  116. 

,  length  and  breadth  of,  116. 

Zeuglodon,  eocene  cetacea,  145. 
Zoological  provinces  how  formed,  666. 

,  why  not  more  blended  together,  668. 

Zoophytes,  their  geographical  distribution,  654» 

,  their  powers  of  diffusion,  654. 

,  abundance  of,  706. 

,  which  form  coral  reefs,  776. 

Zuyder  Zee,  formation,  328. 

,  great  mosses  on  the  site  of,  327. 


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